INSTRUCTION MANUAL

4 channel Data Recorder

DA-21

3-20-41 Higashimotomachi, Kokubunji, Tokyo 185-8533, Japan

https://www.rion.co.jp/english/
 Organization of this manual
This manual describes the features, operation and other aspects of the 4 channel
Data Recorder DA-21. If the unit is used together with other equipment to configure
a measurement system, consult the documentation of all other components as well.
The section starting on page iii contains important information and precautions
about safety. Be sure to read and observe these in full.

This manual contains the following sections.

Outline
Gives basic information on the unit.

Controls and Functions

Explains the keys, indicators, connectors, and all other parts on the panels
of the unit.

Power On/Off
Explains how to turn the unit on and off.

Display Explanation
Explains the various items that are shown on the display panel.

Menu Operations and Setting Items

Lists the basic steps that are common to all menus, and explains the indi-
vidual setting items.

Preparations
Explains checks and other steps to take before starting to record. Sensor
connection and setup as well as other functions are also explained here.

Recording
Explains the recording process as well the voice memo and marker functions.

Recall/Playback of Recorded Data

Explains how to recall and delete recorded data.

i
 Messages
Explains the meaning of messages that appear on the display and
countermeasures to take in response to such messages.

Filter Characteristics
Shows the high-pass filter and low-pass filter characteristics.

Settings and Other Information

For convenient reference, this section lists all menu settings, data recording
operation types, and other relevant information.

WAVE File Format

Provides information about the WAVE file format used by the unit.

Specifications
Lists the technical specifications of the unit.

* Company names and product names mentioned in this manual are usually
trademarks or registered trademarks of their respective owners.

The product described in this manual is in conformity with the

following European standards;
Conforming Standards
CE Marking
Low Voltage Directive: 2014/35/EU EN61010-1:2010
EMC Directive: 2014/30/EU EN61326-1:2013
RoHS Directive: 2011/65/EU EN50581:2012

This product can be used in any areas including residential areas.

To conform to the EU requirement of the Directive

on Waste Electrical and Electronic Equipment,
the symbol mark on the right is shown on the
instrument.

ii
 FOR SAFETY
In this manual, important safety instructions are specially marked as shown
below. To prevent the risk of death or injury to persons and severe damage
to the unit or peripheral equipment, make sure that all instructions are fully
understood and observed.

Caution D isrega rd i ng i nst r uct ions

printed here incurs the risk of
injury to persons and/or dam-
age to peripheral equipment.

Important
D isrega rd i ng i nst r uct ions
printed here incurs the risk of
damage to the product.

Note
Additional information about
using the unit. (These notes do
not directly affect safety.)

iii
 Caution

When using earphones, beware of excessive volume levels

When connecting earphones to the Monitor Out connector of this unit, use
only earphones with a volume adjustment function, because there is a risk
of excessive volume levels.

Do not play the supplied disc in a CD player

The supplied viewer software installation disc is not a music CD. Inserting
this disc in a CD player poses the risk of excessive volume levels that can
cause hearing damage and damage to the CD player.

Be careful around rotating machinery

When using the unit near rotating machinery, take care that cables cannot
be caught in the machinery.

Avoid excessive force and abrupt operation

Applying strong force to the keys or card slot cover of the unit can lead to
damage and injury. When connecting or disconnecting cables and opening
or closing the card slot cover, take care not to pinch your fingers.

iv
 Important

Check the install CD before installation

Before inserting the supplied viewer software install CD in the CD-ROM
drive of a computer, be sure to visually check the disc. If there are any cracks
or scratches or if the disc is deformed, do not insert the disc in the CD-ROM
drive. Otherwise there is a risk of damage to the CD-ROM drive.

Handle batteries correctly

If batteries are inserted with wrong polarity or otherwise mishandled, battery
fluid may leak and overheating may occur.

Do not apply excessive voltage

Make sure that voltage applied to the power supply connector (DC IN), to the
Input connectors, and to the external trigger (Ext. Trig.) connector does not
exceed the specified values. Otherwise there is a risk of damage to the unit.

v
 Usage Precautions
Operate the unit only as described in this manual.
Observe the following conditions with regard to locations for use and
storage of the unit:
• Do not use or store the unit in locations where the specified permissible
range for temperature and humidity may be exceeded (−10ºC to +50ºC,
max. 90% RH).
• Do not use or store the unit in locations where there are rapid and
drastic changes in temperature or where there is a possibility of
condensation.
• Do not use or store the unit in locations that may be subject to splashes
of water or other liquids.
• Do not use or store the unit for an extended time in locations that may
be exposed to direct sunlight.
• Do not use or store the unit in locations that may be subject to air
with high salt or sulphur content, or subject to the influence of gases
and other chemicals.
• Do not use or store the unit in slanted or instable locations.
• Do not use or store the unit in locations that may be subject to vibrations
or shock.
If batteries are inserted with wrong polarity or otherwise mishandled,
battery fluid may leak and overheating may occur.
Make sure that voltage applied to the power supply connector (DC IN)
and to the signal Input connectors does not exceed the specified values.
Take care that cables and other parts cannot be caught in rotating machinery.
Do not apply strong force to the keys or card slot cover of the unit.
Otherwise there is a risk of damage to the unit or injury to fingers etc.
When connecting or disconnecting cables and opening or closing the card
slot cover, take care not to pinch your fingers.
Use only earphones with volume control function at the Monitor Out
connector of this unit, and beware of excessive volume levels.
Use only SD memory cards supplied by Rion. Other commercially available
cards may not operate properly with the unit.

vi
Verify before use that all cables are correctly and safely connected. Do not
bend cables sharply or subject them to pressure. When removing cables,
always grasp the plug or connector and do not pull the cable.

Do not apply strong shock to the connected cables to the unit. Otherwise
the cables may remove from the unit.
If it starts raining while using the unit outside, stop the measurement and
protect the unit from getting wet. In case the unit gets wet, wipe it with
a dry cloth and let it dry in a well-ventilated place.
Always turn the unit off after use. Remove the batteries from the unit
if it is not to be used for a long time. Otherwise battery fluid may leak,
posing a risk of corrosion and damage. Also disconnect the AC adapter
or battery pack.
Do not tap the LCD panel or other surfaces of the unit with a pointed
object such as a pencil, screwdriver, etc.
Take care that no conductive objects such as wire, metal scraps, conductive
plastics etc. can get into the unit.
Do not disassemble the unit or attempt internal alterations. In case of
malfunction, do not attempt any repairs. Note the condition of the unit
clearly and contact your supplier.

Clean the unit only by wiping it with a soft, dry cloth or, when necessary,
with a cloth lightly moistened with water. Do not use any solvents, cleaning
alcohol or chemical cleaning agents.
When returning the unit for maintenance or servicing, use the original
packing to protect it from shocks and vibration.
The life of the backup battery for the internal clock of the unit is lim-
ited. You should have the battery replaced about once every five years.
Regarding replacement of the battery, please contact your supplier.
Please note that this product is warranted up to the product purchase price
against defects in material.
Dispose of the unit and of batteries only according to national and local
regulations at the place of use.

vii
 AC adapter precautions
Use only the specified AC adapter available as an option for the DA-21
(NC-98 series). Use of any other adapter can lead to damage or unexpected
accident. Take care not to mix up the AC adapter with the AC adapter of
another product.

Open source software

This product contains the open source software of the following licenses.
(1) GPL
(2) GPL v 2
(3) GPL v 3
(4) Boost Software License

Those source codes of the open source software according to the

license agreement will be given. Those source codes are available for
download from the Rion Support Room (https://svmeas.rion.co.jp/).
Note that we assume no responsibility for the source code.
Note that we are not responsible for exact details of the source code.
For details on the license, click [Manual] - [Open Source License]
folder in the supplied CD-ROM.

viii
 Contents
FOR SAFETY............................................................................... iii
Outline ............................................................................................1
Controls and Functions....................................................................5
Front panel .................................................................................5
Top panel ................................................................................. 10
Right side panel .......................................................................12
Bottom panel ...........................................................................13
Power On/Off ................................................................................ 14
Display Explanation ...................................................................... 17
Display screen ......................................................................... 17
Menu Operations and Setting Items ..............................................30
General menu operation steps ..................................................30
Menu Items ..............................................................................39
<Input> menu .....................................................................39
<Rec.Parameters> menu .....................................................44
<Trigger> menu..................................................................46
<Bar Graph> menu .............................................................50
<System> menu .................................................................. 51
<Synchronization> menu....................................................55
Preparations ..................................................................................56
Preparations and checks before recording ................................57
Power supply ......................................................................57
SD memory card preparations ............................................ 61
External equipment (sensor etc.) connections .....................64
Input settings ......................................................................65
Recording parameter settings...................................................70
Input range setting ..............................................................70
Sampling ............................................................................73
Recording process .............................................................. 74
Auxiliary function setup ..........................................................84
Device index number (<System> menu: Index) ...................84
Voice memo/marker ...........................................................85

ix
 Preventing inadvertent operation (key lock and menu lock) ....87
Remote control operation ...................................................89
Connection to a computer .......................................................90
Inter-unit synchronization ........................................................ 91
Tachometer signal input ...........................................................93
Recording......................................................................................94
Recording steps .......................................................................94
1. Checks before recording ......................................................94
2. Input range setting / Calibration signal recording ................96
3. Recording ............................................................................98
Using the voice memo/marker function .................................. 102
Data recording example ......................................................... 105
Recall/Playback of Recorded Data .............................................. 108
Activating recall mode ........................................................... 108
Playback of recorded data ...................................................... 111
Canceling recall mode ........................................................... 115
Other information .................................................................. 115
Messages ..................................................................................... 119
Filter Characteristics ................................................................... 128
Settings and Other Information ................................................... 129
Approximate recording times ................................................ 129
Menu items ............................................................................ 130
Data recording ....................................................................... 133
Representative value of inherent noise ................................... 138
Power save settings ................................................................ 138
WAVE File Format ...................................................................... 139
Basic structure ....................................................................... 139
Basic WAVE file structure ................................................ 139
File structure and size ...................................................... 140
Invalid values......................................................................... 141
Data types .............................................................................. 142
Chunks .................................................................................. 143
Specifications .............................................................................. 152

x
 Outline
The DA-21 is a compact, lightweight data recorder designed for waveform
recording. The unit can be powered from batteries, for convenient use in the
field.
To record sound or vibration waveforms, microphones or accelerometers can
be connected easily. The capability for sensor drive power supply (CCLD) is
also provided. Unlike with conventional units having only general-purpose
connectors, the design of the DA-21 eliminates the need to set up additional
connection equipment, allowing quick and uncomplicated recording start.

Features
The unit has the following features.
Simultaneous recording of electrical signals in up to 4 channels.
Compact and lightweight body ensures easy portability. A set of four
IEC LR6 (size AA) alkaline batteries will power the unit for about
8 hours of continuous use (at 23ºC, frequency range setting 100 Hz,
4-channel input, CCLD off, backlight off).
CCLD support allows easy hookup of sensors including microphones
and accelerometers.
A wide range of sensors for converting sound pressure, vibrations,
rotation, temperature or other measurement quantities into an electrical
signal (AC or DC) is supported. Measurement quantities measured
by sensors are displayed in units “V”, “V/EU”, “mV/(m/s2)” or “dB”
with a user selectable setting range.
Frequency range from DC to 20 kHz allows recording of a wide range
of phenomena.
Recorded data are stored on SD memory card in the commonly used
WAVE format. When using an empty 32 GB card for example, the
maximum available recording time with the 20 kHz frequency range
setting and continuous recording in 4 input channels is about 23 hours.
Depending on the setting for recording data, multiple WAVE files
may be created.
Voice memo and marker information can also be recorded, to facilitate
later data management.

1
Outline

Accurate playback of data is possible, making it easy for example to

check the reliability of data in the field. The playback signal can also
be output to an analyzer or similar equipment.
The supplied viewer software may be used to import recorded data
(including voice memos and marker information) from the SD card to
check aspects such as waveform, frequency weighting characteristics,
and time weighting characteristics. This software requires a Windows
computer to run.
Synchronize two DA-21 units to record signals simultaneously up to
8 channels.

2
 Outline

System configuration

Analysis
Target
Automobile running test
(sound and vibration data)

Road traffic noise

(sound pressure waveform data)

Product inspection data

Other data

Application software
Sensor/Measuring instrument Supplied: Viewer software
Optional:
Waveform analysis software CAT-WAVE
Tachometer Sound level meter (The version corresponding to DA-21
is required. )
Temperature meter Vibration level meter Waveform analysis software AS-70
Generic waveform processing software
Microphone Accelerometer (up to 2 channels)
(NOTE) WAVE files created by the DA-21 are not
Other sensor supported by the DA-20PA1, DA-40 Viewer
or CAT-78WR application software.

SD memory card

1 2 3 4
CARD

Windows Computer
OVERLOAD

DA-21
LIGHT CLEAR Ov RECALL RANGE MENU
CARD CAPACITY

Playback signal (generic)

4ch DATA RECORDER
ENT

monitoring output
POWER STOP PLAY REC PAUSE

Waveform monitoring equipment

4 channel Data Recorder
Voltmeter
DA-21
FFT analyzer
Other equipment

3
Outline

Operation environment
The DA-21 allows various operations for recording data. The general concept
of the basic functions is as shown in the diagram below.

Power ON Recording procedure

(record data)
[REC]
Recording end
[MENU] or [STOP]
Menu screen
(for changing settings) Main screen
[MENU]
or [STOP] [RECALL]

[RECALL]

Recall mode
(for processing of recorded data)

Main screen This screen appears as the first screen, a short

while after power to the unit is turned on. The
menu screens, recording procedure, and recall
mode are all accessed from the main screen. Input
range selection is also possible from this screen.
Menu screen Pressing the [MENU] key at the main screen brings
up a menu screen. There are a number of menu screens
that give access to recording parameters, input settings,
and various other settings (see page 30).
Recording procedure Pressing the [REC] key at the main screen initiates
the recording procedure. This encompasses all
steps required to record data (see page 94).
Recall mode Pressing the [RECALL] key at the main screen
activates the recall mode. In this mode, you can
check, playback and delete recorded data (see page
108).

4
 Controls and Functions

Front panel

(9) LIGHT key CARD CAPACITY indicator

OVERLOAD (10) CLEAR Ov key (12) RANGE key

indicator
(11) RECALL key (13) MENU key Card slot cover

1 2 3 4

OVERLOAD CARD
CARD CAPACITY
LIGHT CLEAR Ov RECALL RANGE MENU

DA-21
4ch DATA RECORDER
ENT
POWER STOP PLAY REC PAUSE

(1) POWER key PLAY REC PAUSE (8) key

indicator indicator indicator

(2) STOP key (7) ENT key

(4) REC key

(3) PLAY key (6) key

(5) PAUSE key

5
Controls and Functions

Display panel
Shows input data, recorded data, menus for changing settings, etc.

Key names and functions

The DA-21 has some dedicated keys that perform only a specific function,
and some keys that perform various functions depending on the current
operating state.
(1) [POWER] key
Serves to turn the unit on and off. The key must be kept depressed for
about 2 seconds.
(2) [STOP] key
Serves to stop data recording or data playback. The key is also used for
menu operations and other functions.
(3) [PLAY] key
Serves to start data playback.
(4) [REC] key
Serves to start data recording.
(5) [PAUSE] key
Serves to pause and resume data playback.
(6) [ ]/[ ] keys
These keys serve to switch the input range, select a monitor channel, and
perform menu operations.
(7) [ENT] key
This key serves to confirm an item to be changed and accept a setting
that has been made. It is used when setting the input range, performing
menu operations, etc.
(8) [<]/[>] keys
These keys serve to change the data display format, change the file num-
ber, perform fast reverse/forward during playback, and perform menu
operations.

6
 Controls and Functions

(9) [LIGHT] key

Serves to control backlighting of the LCD screen. The backlight is turned
on or off depending on the key press timing. When the LCD backlight
has been activated, it will automatically turn itself off if there has been
no key activity for a certain period. (The duration of this period can be
changed with a menu setting.)

Note
When the remaining battery capacity is low and the
battery icon (page 23) is flashing, the backlight does
not operate.

(10) [CLEAR Ov] key

Serves to clear the overload history display. This display indicates if there
has been any overload condition between the point when the key was last
pressed and the current time (see page 24).
(11) [RECALL] key
Serves to activate the recall mode and to cancel the recall mode and return
to the main screen.
(12) [RANGE] key
Serves to activate and cancel the input range setting condition. In recall
mode, the key serves to delete the recording data selected by cursor.
(13) [MENU] key
Serves to bring up a menu screen or return to the main screen.
There are a number of menu screens which allow changing the settings of
the unit. Menu screens are organized by function category, such as input
settings, recording parameters, etc.

Key lock
Pressing and holding the [<] and [>] keys together for a few seconds ac-
tivates the key lock condition. In this condition, all keys except the [<]/
[>] keys and the [LIGHT] key are inactive. The condition is indicated by
a key lock icon that appears on the display (page 87).
To cancel the key lock condition, press and hold the [<] and [>] keys
together once more.

7
Controls and Functions

Indicator names and functions

(1) OVERLOAD indicator (5) CARD CAPACITY indicator

1 2 3 4

CARD
OVERLOAD CARD CAPACITY
LIGHT CLEAR Ov RECALL RANGE MENU

DA-21
4ch DATA RECORDER
ENT
POWER STOP PLAY REC PAUSE

(4) PAUSE indicator

(3) REC indicator
(2) PLAY indicator

(1) OVERLOAD indicator

Indicates that the input signal level in a channel is excessive. While the
indicator is lit, correct recording is not possible for that channel.
Lit in red: While the input signal is causing overload and for 1 second
after the overload condition ceases, the indicator is lit.
(2) PLAY indicator
Indicates that recorded data are being played back.
Flashing in green: Recorded data are being played back.
(3) REC indicator
Indicates the operating condition during data recording.
Flashing in red: Data are being recorded.
Flashing in green: Unit is in trigger standby condition.

8
 Controls and Functions

(4) PAUSE indicator

Indicates that data playback is being paused.
Flashing in blue: Data playback is being paused.
(5) CARD CAPACITY indicator
Indicates that the remaining data recording time on the SD memory card
is less than 10 minutes.
Flashing in red: Data recording will stop within 10 minutes.
Also while the indicator is not flashing, the currently available recording
time is shown on the display in the format “XXX:XX:XX”. Before starting
to record, you should check this indication to make sure that the intended
data can be recorded. If the remaining recording time will be about 10
seconds, recording stops.

Display example for available recording time shown on the second line
from the bottom of LCD screen (Hours : Minutes : Seconds)

9
Controls and Functions

Top panel
(8) Ext. Trig. connector

(9) Voice Input connector (7) Monitor Out connector

(10) USB port (6) Output connectors

Voice
USB Input Ext. Trig.
Monitor
Out Output

DC IN 5-20V Tacho
4 3 2 1 Input

Sync.

Remote Controller

(1) DC IN connector (5) Input connectors

(2) Unit to Unit connector (4) Rotary pulse input connector

(3) Remote Controller connector

(1) DC IN connector
An optional AC adapter NC-98 series, car battery adapter CC-82, or
battery pack BP-21A can be connected here.

Important
Do not connect any AC adapter or car battery
adapter except for the specified models. Otherwise
the unit may be damaged.
The optional car battery adapter is only for
use in cars with a 12-V electrical system. If the
adapter is used in a car with a 24-V electrical
system to supply power to the DC IN connector
of the unit, the unit will be damaged.
When connecting an external DC source to the
DC IN connector, pay close attention to voltage
rating and polarity. The allowable voltage range
is 5 V to 20 V.
Even when using the battery pack BP-21A,
please insert four usable batteries in the battery
compartment.

(2) Unit to Unit connector

Use this connector to synchronize two DA-21 units.

10
 Controls and Functions

(3) Remote Controller connector

Serves to connect the optional remote controller.
(4) Rotary pulse input connector
A rotary pulse signal (Tacho signal) of a fan, a motor etc. can be input here.
(5) Input connectors
These connectors are used to supply the input signal for recording.
(6) Output connectors
While recorded data are being played back in recall mode, the playback
signal is available at these connectors.
(7) Monitor Out connector
The input signal or playback signal of the channel selected for monitor
operation is output from this connector.
(8) Ext. Trig. connector
Accepts an external trigger signal.
(9) Voice Input connector
Serves to connect the optional microphone for the voice memo function.
(10) USB port
Serves for connection to a computer.

11
Controls and Functions

Right side panel

Card slot cover

C
A
R
D
C
A
PA
C
IT
Y

Card slot

Card slot cover

Open this cover to access the SD memory card slot.
Card slot
The SD memory card is inserted here. The card allows storing data and
exporting data to a computer. The card slot is also used for upgrading
the system firmware etc.

Note
Use only RION supplied SD memory cards certified
for operation in the DA-21. This unit supports SD
memory cards and SDHC memory cards, but not
SDXC memory cards.
When an SD memory card with a large number of
files is inserted in the DA-21, the unit may take some
time to recognize the card.

12
 Controls and Functions

Bottom panel

Battery compartment
Battery compartment
Accepts four alkaline batteries (IEC LR6 [size AA]).
Menu lock mode (see page 88):
When the [MENU] switch inside the battery compartment is set to
“LOCK”, changing settings and deleting data via the menus is not possible.
Wake-up-on-power mode (see page 60):
When the [WAKE UP ON POWER] switch inside the battery compartment
is set to “ON”, the unit is switched on and off in conjunction with the
power supplied to the DC IN connector on the DA-21. In this case, the
[POWER] key has no effect.
Important
Take care not to reverse the (+) and (−) polarity when inserting
the batteries (see page 57).
When using the wake-up-on-power mode, there should be no
batteries inserted in the unit.
Remove the batteries from the unit if it is to be stored for a long
time with the [POWER] key set to OFF to prevent possible damage
caused by battery leakage.
Even when using the battery pack BP-21A, please insert four
usable batteries in the battery compartment.

Note
Before changing the position of these switches, disconnect any external
power that is being supplied to the DC IN connector and remove all
batteries from the battery compartment. Otherwise operation of the unit
will become unstable. If this has happened (not a defect of the unit),
disconnect the external power, remove all batteries, after a few seconds,
reconnect the power and turn the unit on.

13
 Power On/Off
Turning the power on
When you keep the [POWER] key depressed, the startup screen as shown
below appears on the display. After a while, the main screen will be shown.
If there is a setting file on the SD memory card, the main screen does not
appear straight away. Instead, a message screen is shown asking whether
you want to load the settings from the card, or use the settings that were
established before power was last turned off.
DATA RECORDER
POWER
DA-21

RION CO., Ltd.

Startup screen
Setting file No setting file
found found

Message screen
PAUSE
ENT

Settings that were

Contents of
active before power
setting file are
was last turned off
loaded. are established again.

Main screen
14
 Power On/Off

Note
The input range and menu settings etc. at power-on
will be the same as the settings that were active
before the unit was last turned off.
When the contents of a setting file are loaded at
power-on, a channel selected for CCLD will be
supplied with constant current. To prevent problems
due to unsuitable connections, it is recommended
to disconnect sensors before loading a setting file.

Turning the power off

When you keep the [POWER] key depressed, the shutdown screen as shown
below appears on the display, and the unit is turned off.

Shutdown screen

Note that if a icon is shown at the bottom of the display, the operation
keys including the [POWER] key are locked. The power cannot be turned
off in this condition. (For information on the key lock feature, see page 87.)

Indicates the key lock condition

Note
After turning the unit off, do not turn the unit on
again immediately. Wait at least a few seconds.
In case key lock is activated, pressing and holding
[POWER] key for 10 seconds or more will turn the unit off.

15
Power On/Off

About the setting file

You can store all setting values and parameters of the unit on the SD memory
card as a setting file (DA21.INI).
This capability allows you for example to store the optimum settings for a
certain recording task and then quickly re-establish these settings at power-on.
This reduces the time required for startup and the risk of making setup errors.
To create a setting file, use the “Read / Save Settings” item on <System>
menu. (see page 51)

Note
When the contents of a setting file are loaded at
power-on, a channel selected for CCLD will be
supplied with constant current. To prevent problems
due to unsuitable connections, it is recommended
to disconnect sensors before loading a setting file.

16
 Display Explanation

Display screen

Recording/operation mode indication (page 20)

Recording parameter indication (page 18)

Trigger setting indication (page 21)

Status indication (page 22)

Channel data (page 24)

17
 Display Explanation

Recording parameter indication

From left, the display shows the frequency range [sampling frequency], elapsed
recording time, recording time, and synchronization information.

(2) Elapsed recording time (3) Recording time

(1) Frequency range (4) Synchronization

[Sampling frequency] information

(1) Frequency range [Sampling frequency]

Shows the setting made with <Rec.Parameters> menu, items “Frequency
Range” and “Sampling Frequency”. The relationship between frequency
range and sampling frequency is as shown in the table below.
Sampling frequency
Frequency range
[×2.56] [×2.4]
100 Hz 256 Hz 240 Hz
500 Hz 1.28 kHz 1.2 kHz
1 kHz 2.56kHz 2.4 kHz
5 kHz 12.8 kHz 12 kHz
10 kHz 25.6 kHz 24 kHz
20 kHz 51.2 kHz 48 kHz

(2) Elapsed recording time (Format: “0000:00:00”)

In recording mode, the elapsed time since the start of recording (including
pre-recording time) is displayed. The recording time indication is retained
until a new recording is started.

18
 Display Explanation

(3) Recording time (Format: “/ xx s [m, h]” or “/ Man”)

Shows the setting made with <Rec.Parameters> menu, item “Recording
Time”. When the manual setting has been selected, the indication shows
“/ Man”.
When the [STOP] key is pressed or the SD memory card runs out of
space, recording stops. In this case, the actual recorded data time will be
shorter than the recording time setting. (The recording time also includes
the pre-recording time of 1 second or 5 seconds.)

(4) Synchronization information

If you synchronize two DA-21 units, the unit used as master shows
“Link. M” and the unit used as slave shows “Link. S” (see page 90).

19
Display Explanation

Recording/operation mode indication

This field shows recording and operation status information as well as
all-channel overload information.

(2) All-channel overload indication

(1) Recording/operation
mode indication

(1) Recording/operation mode indication

An icon indicates the current recording condition.

None Normal condition

Playback in progress (recall mode only), flashing

Recording in progress, flashing
Trigger standby, permanently on
Playback paused, flashing

Rewind (recall mode only), flashing

Fast-forward (recall mode only), flashing

(2) All-channel overload indication

This indication appears if there has been an overload condition in any
channel. There are two types of indications, for instantaneous overload
and overload history. The display method is the same as explained in
the section on overload information (page 24).

20
 Display Explanation

Trigger setting indication

The trigger setting and type are shown here. When the trigger is set to OFF
(Free), nothing is shown.

(1) Trigger setting indicator

(2) Trigger type

(1) Trigger setting indicator

This indicator appears if any trigger (except Free) has been set.

(2) Trigger type

None Free trigger (no trigger setting)
“Single/Level” Single level trigger
“Repeat/Level” Repeat level trigger
“Single/Time” Single time trigger
“Repeat/Time” Repeat time trigger
“Single/Ext” Single external trigger
“Repeat/Ext” Repeat external trigger
“Single/Ext-Gate” Single external gate trigger
“Repeat/Ext-Gate” Repeat external gate trigger
“Master” Master trigger

When a level trigger has been set, information about the trigger channel
and trigger level is shown in the channel data area. For details on the
channel data area, see the section starting on page 24.

21
Display Explanation

Status indication
In the second line from the bottom, the display shows the card icon, card
capacity (size/available recording time), and in the bottom line, the icon and
clock (date/time).

(1) Card icon /

remaining capacity

(2) Icon (3) Clock

(1) Card icon/remaining capacity

The remaining card capacity is shown here in data size and the remaining
recording time as calculated from the currently selected sampling frequency
and number of active channels.
When no card is inserted, the card icon and remaining capacity indication
are not shown, and the remaining recording time indication shows “---:--:--”.

22
 Display Explanation

(2) Icon
A graphic symbol representing the power supply status, key lock status,
or menu lock status is shown here.
: Shown when unit is being powered from an external source.
: Shows the approximate remaining battery capacity when the unit
is being powered from batteries. The number of black segments
decreases as the batteries get depleted. When the indication starts
to flash, replace the batteries with a fresh set.

Maximum Low battery Flashing (replace batteries)

capacity * Backlight cannot be used.

: Indicates the key lock condition where the operation keys except
for [LIGHT], [<], and [>] are disabled. (For details on the key lock
function, see page 86.)
The condition is activated by pressing and holding the [<] and [>]
keys together for a few seconds. Repeating the procedure cancels
key lock and causes the icon to disappear.
The keys on the Remote Controller are not affected by the key
lock function.
: Indicates the menu lock condition where the menus cannot be
used. (For details on the menu lock function, see page 88.)
: Indicates the display backlight has been lit up.

(3) Clock
Shows the current date and time, using 24-hour format.

23
Display Explanation

Channel data
From left, the display shows the level trigger target channel, channel number/
overload information, bar graph, trigger level, monitor icon and range full-
scale value.
The data for four channels are shown simultaneously on the display.

(4) Trigger level (5) Monitor icon

(1) Level trigger

target channel

(6) Range
(2) Channel number/ full-scale
overload information value

(3) Bar graph

(1) Level trigger target channel

When the level trigger function is used, the indication “TRG” is shown
to the left of the channel indication.

(2) Channel number/overload information

The channel number (CH1 to CH4) is shown here. If an overload signal
is input, the channel number switches to the overload information.

There are two types of overload indications: instantaneous overload and

overload history.

OVER Shown when instantaneous overload has occurred.

Shown when overload has occurred at least once during

OVER recording (overload history).

24
 Display Explanation

The overload history indication is cleared in the following cases:

• Power-on
• [CLEAR Ov] key pressed
• Recording settings changed:
• Frequency range
• Sampling frequency
• Input range
• Channel setting (type, HPF, LPF, sensor type, scaling)
• Recording start
• When recall mode is canceled

(3) Bar graph

Shows the magnitude of the input signal, using one of the following three
methods:
• Linear value display
This is used when “Linear” has been selected in the <Bar Graph> menu
(see page 50). If the sensor type for the channel has been set to “SLM/
VM” in the <INPUT> menu (see page 39), this mode cannot be selected.

• Logarithmic value display (bar graph covers about 80 dB)

This is used when “Log” has been selected in the <Bar Graph> menu.
If the sensor type for the channel has been set to “SLM/VM”, this
mode cannot be selected.

• dB value display (bar graph covers about 80 dB)

When the sensor type for the channel has been set to “SLM/VM”, this
mode is always used, regardless of the <Bar Graph> menu setting.

• Channel OFF
This indication is shown when the respective channel is set to OFF.

25
Display Explanation

(4) Trigger level

When level trigger is used, a vertical line on the bar graph for the respective
channel shows the level trigger position.

(5) Monitor icon

The icon is shown to the right of the bar graph for the channel selected
for monitor output.
The monitor channel can be changed using the [ ]/[ ] keys.

(6) Range full-scale value

Depending on the “Sens” and “Sensitivity” settings in the <Input> menu,
the value corresponding to the bar graph full range point is shown here.
A list of the menu settings and values/units is shown in the table below.

<Input> menu
Numeric range (number of digits) Unit
“Sens” setting

V 0.01, 0.03, 0.1, 0.3, 1, 3, 10 “V”

EU 9.99E ± 99 “V/EU”

MIC −0.1 to −99.9 (5 digits, 0.1 dB step) “dB”

PICK 9.99E ± 99 (8 digits) “mV/(m/s2)

SLM 40 to 140 (3 digits, 10 dB step) “dB”

VM 40 to 140 (3 digits, 10 dB step) “dB”

For information on changing the input range setting, see page 70.

26
 Display Explanation

CH5 data
The CH5 field either shows tachometer signal information or information
about the use of the voice memo and marker function.

(1) Channel number / (2) Bar graph and

overload information setting information

(1) Channel number/overload information

The channel number (CH5) is shown here. If an overload signal is input,
the channel number switches to the overload information (see page 24).

(2) Bar graph and setting information

Depending on the setting made for “CH5” in the <Input> menu (see page
39), the display is switched as follows.

• “OFF” setting
“OFF” is shown in the bar graph area.

27
Display Explanation

• “Tacho” setting
The rpm value of the input tachometer signal is shown.

When “Tacho” is selected, the overload/underload evaluation conditions

are as follows.
Overload signal evaluation
• “Over” is shown when revolution speed reaches or exceeds 600,000
rpm.
• Above the upper limit of 630,000 rpm, the invalid indication “---”
is shown.
Underload signal evaluation
• “Under” is shown when revolution speed is 200 rpm or lower.
• Under the lower limit of 190 rpm, the invalid indication “---” is
shown.

• “Voice Memo” setting

The level of the voice memo input is shown in the bar graph area.

• “Marker” setting
“OFF” is shown in the bar graph area, and the icon flashes when the
marker function is used.

28
 Display Explanation

History display
Besides the bar graph format, the data display can also show a history graph
of waveform data absolute values. (This is not available in recall mode.) To
switch between the bar graph and history display, use the [>] or [<] key.
The data shown on the history display are the data of the monitor channel.
The horizontal axis is the time (up to 20 seconds before), and the vertical
axis is the level. Also during history display, you can switch the monitor
channel with the [ ]/[ ] keys.

(2) Time-level graph

(1) Channel information

(1) Channel information

From left, the display shows the voice memo, tacho, or marker icon (when
channel 5 is used), the channel number, and range full-scale.

(2) Time-level graph

The time-level graph shows a history graph for waveform data of the last
20 seconds in the monitor channel.
The graph is based on the approximate absolute (not the root mean
square) values of the input waveform.

29
 Menu Operations and Setting Items

General menu operation steps

Almost all settings of the DA-21 except for the input range setting are made
via menus.
To make a setting, you call up the menu from the menu list page. When a
menu has been selected, the screen with the individual settings of that menu
appears.
There are a total of six menu pages, divided by category such as input related
settings, recording settings etc. A detailed description of menu operation
steps follows.
1. Call up the menu list
Press the [MENU] key. The menu list appears.

MENU

2. Select a menu page

Use the [ ]/[ ] keys to move the cursor to the desired menu page.

ENT

30
 Menu Operations and Setting Items

3. Open the menu page

Press the [ENT] key. The items on the selected menu page appear.

ENT

4. Select an item
Use the [ ]/[ ] /[<]/[>] keys to move the cursor to the desired
setting item.

ENT

5. Initiate the change

Press the [ENT] key to start changing the selected item.
There are three ways of changing a setting, as follows.

A : Select setting item on sub menu

ENT B : Change setting value on sub menu
C : Execute (process) selected item

31
Menu Operations and Setting Items

6. Detailed explanation of methods A, B, C

A: Select setting item on sub menu

Sub menu

The sub menu appears when the [ENT] key is pressed. Select the
setting from the sub menu. The following setting items have this
type of sub menu.
<Input> (Sensor signal type, High pass filter, Low pass filter,
Sensor type)
<Rec.Parameters>
(Frequency Range, Sampling Frequency, etc.)
<Trigger> (Trigger Mode, Trigger Type, etc.)
<Bar Graph> Bar Graph Display Type
<System> (Play Signal Output, Backlight Brightness, etc.)
<Synchronization>
(Master or slave selection)

The explanation below uses the channel 3 LPF setting on the <Input>
menu as an example. The procedure is the same for other items.

A-1 Use the [ ]/[ ] keys to move the cursor in the sub menu to
the desired setting.

ENT

Select setting

32
 Menu Operations and Setting Items

A-2 Press the [ENT] key. The change is accepted and the sub menu
disappears.

LPF OFF setting

has changed to
ENT
200 Hz

Confirm change

A-2’ By pressing the [MENU] key or [STOP] key instead of the

[ENT] key, you can cancel the sub menu without changing the
setting. In this case, the indication is as shown below.

Setting remains
MENU STOP
OFF
or

Cancel the sub menu

operation

33
Menu Operations and Setting Items

B: Change setting value on sub menu

Sub menu

The sub menu appears when the [ENT] key is pressed. Change the
setting value on the sub menu. The following setting items have this
type of sub menu.
<Input> (Sensitivity)
<Rec.Parameters>
(Recording time, Pre-recording time)
<Trigger> (Trigger level, Recording start time, Recording
stop time)
<System> (Device index number, clock setting)

The explanation below uses the CH2 Sensitivity setting on the <Input>
menu as an example. The procedure is the same for other items.

B-1 Use the [ ]/[ ] keys to change the value or unit of the item
in the sub menu. Holding down a key causes a faster change.

ENT

Change setting value

34
 Menu Operations and Setting Items

B-2 Press the [ENT] key. The change is accepted and the sub menu
disappears.

Sensitivity
setting has
ENT
changed to 130
dB from 100 dB

Confirm change

B-2’ By pressing the [MENU] key or [STOP] key instead of the

[ENT] key, you can cancel the sub menu without changing the
setting. In this case, the indication is as shown below.

Setting remains
MENU STOP 100 dB
or

Cancel the sub menu

operation

35
Menu Operations and Setting Items

C: Execute (process) selected item

This type of setting procedure applies to items such as “Card Format”
and “Read / Save Settings” on the <System> menu. To execute the
process, press the key corresponding to “Yes”. To cancel the process,
press the key corresponding to “No”. When the process is completed,
the original menu page appears again.

Execution choice example

This concludes the description of the three ways of changing a menu

setting.

36
 Menu Operations and Setting Items

7. Changing an item on another menu page

Press the [MENU] key to bring up the menu list.

MENU

To change an item on
another menu page

8. Return to main screen

Press the [MENU] key or [STOP] key to return to the main screen.

MENU STOP

or

Return to main screen

37
Menu Operations and Setting Items

Menu flow diagram

The organization of all menu operations is shown in the diagram below. Note
that you always have to use the menu list to go to a menu page.

Menu screen
MENU
Menu list
n

MENU STOP
e

MENU
ENT
e

Menu pages
Only one menu page can be used
at a time. To go to another menu
r

page, return to the menu list first.

STOP
c
s
n

Confirm change

ENT
Cancel

E xe c u t e
Cancel

MENU STOP PAUSE

i

ENT ENT
a

Execute(process)item
ENT Sub menu
M

[Processing message]

Setting changed
/processing completed

38
 Menu Operations and Setting Items

Menu Items
Setting items are organized in six pages, with related items appearing together
on one page. The contents of each menu page are described below.

<Input> menu
Allows you to select the sensor (signal) type, input signal filtering, sensor
sensitivity level and units for each channel.

Inp Sensor (signal) type setting (CH1 to CH4)

Controls the input on/off setting and sensor (signal) type.
OFF Select this setting when the input is not to be used.
DC This setting is for input of an electrical signal, with the
recording to include DC components. This is suitable for
environment sensors (temperature, wind speed, pressure, etc.)
and sound level meters that output the measurement value as
a DC signal. The setting should also be used when recording
a signal (such as from a vibration level meter) that comprises
frequency components below 1 Hz.
AC This setting is for input of a normal electrical signal, with
the recording to exclude DC components. This is suitable for
sound level meters, vibration meters and similar equipment
that outputs the measurement value as an AC signal. The cutoff
frequency is about 0.3 Hz.

Note
When Input is set to AC, a high-pass filter with a cutoff
frequency of 0.3 Hz is applied. However, if the input
signal contains high-level DC components that exceed
the input range, overload may occur in the DA-21.

39
Menu Operations and Setting Items

CCLD This setting is for microphones, accelerometers and other

sensors that require a sensor drive power supply. (See the
section starting on page 63.)
(CCLD: Constant Current Line Drive)

Note
If the unit is operated on battery power, take the
following points into account when setting the Inp
to CCLD.
When quitting the menu, if battery capacity is too
low for supporting CCLD operation, the unit will
switch itself off automatically.
In such a case, replace all batteries with fresh ones,
or connect an AC adapter or other external power
supply.

VP4x Select this setting when the accelerometer is connected to the

unit via the charge converter VP-40 etc. (see page 63).

Inp Tachometer signal, voice memo, marker setting (CH5)

This setting determines which signal type information is shown in the
CH5 area during recording.
OFF Select this setting if no signal assigned to CH5 is input.
Tacho Select this setting if a rotary pulse signal (tacho signal) is
supplied to the rotary pulse input connector.
Voice Memo
Select this setting if the optional voice memo microphone is
connected to the Voice Input connector and used for recording
voice memos.
Marker Select this setting if the switch of the connected voice memo
microphone is used for the marker function.
Voice memo recording is possible at the main screen, except when the
setting is “OFF”.

40
 Menu Operations and Setting Items

HPF High-pass filter frequency setting

Enables a high-pass filter for the input signal. The HPF frequency indicates
the cutoff frequency.
Available settings are OFF and 5 Hz.
When the Inp setting is DC, only the OFF setting is available for the
high-pass filter.
OFF / 5 Hz

LPF Low-pass filter frequency setting

Enables a low-pass filter for the input signal. The LPF frequency indicates
the cutoff frequency.
Available settings are OFF, 200 Hz, 1 kHz, and 2 kHz, but only selections
that are within the frequency range setting are allowed.
OFF / 200 Hz / 1 kHz / 2 kHz

Available parameter list

Frequency range
100 Hz 500 Hz 1 kHz 5 kHz 10 kHz 20 kHz
LPF
200 Hz ×
1 kHz × ×
2 kHz × × ×
• • • Available × • • • Not available

41
Menu Operations and Setting Items

Sens Sensor type setting

Lets you select the sensor type and make other sensor related settings.
Available options depend on the Inp setting.

Inp Available Sensor settings (depending on Inp) and description

setting Sens Description
OFF No setting available
Record input voltage from sensor or measuring
V
instrument as is.
Convert input voltage from sensor or measuring
EU
instrument into EU for recording.
AC/DC
SLM Sound level meter (with AC or DC output) is connected.

Vibration level meter (with AC or DC output) is

VM
connected.
Constant Current Line Drive compatible sensor is
V
connected. Record input voltage from sensor as is.
Constant Current Line Drive compatible sensor is
EU connected. Convert input voltage from sensor into
CCLD EU for recording.
Constant Current Line Drive compatible microphone
MIC
is connected.

PICK Accelerometer with built-in preamplifier is connected.

Accelerometer via charge converter VP-40 etc. is

VP4x PICK
connected.

EU (Engineering Units) is a unit symbol for expressing various physical

quantities detected by a sensor.

42
 Menu Operations and Setting Items

Sensitivity Unit conversion value setting

Specifies the relationship between input signal voltage and measurement
value, according to the preceding Sensor type setting (Sens).

Sens setting Sensitivity setting (depending on Sens)

V No setting
Voltage per EU (V/EU)
EU (Note that the EU setting value is the inverse of that used
in the DA-20.)
Constant Current Line Drive compatible microphone
MIC
sensitivity level (dB)
Voltage sensitivity of accelerometer with built-in preamplifier
PICK (CCLD)
[mV/(m/s2)]

PICK (VP4x) Charge sensitivity of accelerometer [pC/(m/s2)]

SLM Sound level meter level range (dB)

VM Vibration level meter level range (dB)

For additional information on the Inp, Sens, and Sensitivity settings, see also
pages 65 to 69.

43
Menu Operations and Setting Items

<Rec.Parameters> menu
This menu comprises settings for recording and auxiliary functions.

Frequency Range Frequency range setting

The value selected as the frequency range setting represents the highest
effective frequency that can be included in the recorded data.
Available settings are 100 Hz, 500 Hz, 1 kHz, 5 kHz, 10 kHz, and 20 kHz.
100 Hz / 500 Hz / 1 kHz / 5 kHz / 10 kHz / 20 kHz

Sampling Frequency Sampling frequency setting

The DA-21 provides a choice of two sampling frequency settings commonly
used for frequency analyzers and voice processing: 2.4 times or 2.56 times
the frequency range. FFT analyzers generally use 2.56 times.
×2.4 / ×2.56

Bit Length Bit length setting

Select the recording data bit length. Increased accuracy of analysis and
better sound quality can be obtained as the value increases. Available
settings are 16 bit and 24 bit.
16 bit / 24 bit

Wave Splitting Interval Set splitting interval for recording data

Select the time interval at which the WAVE files recorded for channel 1
to 4 are to be split. The maximum number of WAVE files per recorded
data set is 1000. Available settings are 10 minutes and 1 hour.
10 min / 1 h

Note
Rotary speed data and voice memo data recorded in
channel 5 are not split.

44
 Menu Operations and Setting Items

Recording Time Recording time setting

The recording time can be set in hours, minutes, or seconds, and a Manual
setting is also available. When Manual is selected, the recording time
is not preset, allowing the operator to press the [STOP] key whenever
required. With the Manual setting, recording will automatically stop
after 1000 hours have elapsed. A recording time that is longer than that
available with the inserted SD memory card cannot be set.
The sub menu moves in the following order for the recording time (1 to
59 / 1 to 24 / Manual) and the unit (s, m, h).
When data for the preset recording time have been collected, recording
stops automatically. However, if the [STOP] key is pressed before that,
or if the SD memory card becomes full, recording stops at that point.
1 s to 59 s (seconds) / 1 m to 59 m (minutes) / 1 h to 24 h (hours) / Manual

Pre Recording Time Pre-recording time setting

When recording is started by pressing the [REC] key or by a trigger event,
the pre-recording function allows data from a range before the actual
start point to be included in the recording. The Pre Recording Time value
determines the duration of the range for such data. Available settings are
0 s, 1 s, and 5 s (seconds). To disable the function, select the “0 s” setting.
For more information, refer also to page 76.
0s/1s/5s

Note
After changing the frequency range or channel
setting, the [REC] key will be inactive for the Pre
Recording Time interval, and recording cannot be
started during this interval.

45
Menu Operations and Setting Items

<Trigger> menu
Comprises trigger related items (see pages 77 to 83).

Mode Trigger operation mode setting

Determines the basic operation when a trigger event occurs. If trigger
operation is not required, choose the “Free” setting.
Free Trigger is not active. Recording starts immediately when the
[REC] key is pressed.
Single The unit goes into trigger standby mode when the [REC] key
is pressed. When a trigger event occurs, recording starts. When
the amount of data corresponding to the recording time has
been recorded, recording stops.
Repeat The unit goes into trigger standby mode when the [REC] key
is pressed. When a trigger event occurs, recording starts. When
the amount of data corresponding to the recording time has
been recorded, the unit again goes into trigger standby mode.
This is repeated with every trigger event until the [STOP] key
is pressed or the SD memory card becomes full.
Master If you synchronize two DA-21 units, the unit used as slave is
selected this mode automatically.

46
 Menu Operations and Setting Items

Type Trigger signal type setting

Determines the type of trigger signal. When the “Mode” item is set to
“Free”, this item does not appear.
Level A trigger event occurs and recording is started when the level
of the input signal in the specified channel (trigger channel)
becomes a preset value (trigger level) or higher.
External
A trigger event occurs and recording is started when the Ext.
Trig. connector is shorted.
External Gate
Recording is carried out only while the Ext. Trig. connector is
shorted (gate trigger operation). When the Ext. Trig. connec-
tor goes open, recording will stop after a delay of 5 seconds
(post-recording).
Time Recording is carried out from the specified Start Time to the
specified Stop Time, at intervals as specified by the Interval
setting.

Level Trigger level setting

When the trigger signal type is “Level”, a trigger event occurs when the
absolute value of the input signal waveform exceeds the trigger level. The
trigger level is a threshold set as a relative percentage [%] correlated to
the full-scale value of the input range setting that is active at the time of
recording.
Consequently, the actual trigger level (input signal waveform value) will
change when the input range setting is changed.
The trigger level is indicated on the bar graph for the trigger channel (see
page 26).

Ch Trigger channel setting

When the trigger signal type is “Level”, a channel (1 to 4) must be specified
for monitoring. This is called the trigger channel.

47
Menu Operations and Setting Items

Start Time/Stop Time Recording start time/stop time setting

Lets you specify a start time and stop time for recording. These settings
can span two different calendar years.
When the start time setting is before the current time, the setting
automatically becomes “current time + 5 minutes”. When the stop time
setting is before the current time, the setting automatically becomes “Start
Time + 24 hours”.

Interval Recording interval setting

When the trigger signal type has been set to “Time” and the trigger mode
to “Repeat”, the recording interval can be set here. The following settings
are available.
5 m / 10 m / 15 m / 30 m / 1 h / 8 h / 24 h

Note
The interval setting must be longer than the “Recording
Time” as set in <Rec.Parameters> menu.

48
 Menu Operations and Setting Items

Sleep Sleep function setting

When the trigger signal type is set to “Time”, this setting controls the use
of sleep mode during recording.
OFF/ON

When sleep mode is ON, the unit goes into the power save state about 60
seconds after standby was activated by pressing the [REC] key. When
Mode is set to “Repeat”, the unit will enter the power save state also
between recording intervals.
In the power save state, the LCD screen is off.
About 90 seconds before recording start, the unit wakes up and goes into
standby until the actual start.
Pressing the LIGHT key in the power save state temporarily turns on
the LCD screen. If no further key is pressed, the unit will return to the
power save state.

Operation example for sleep mode

DA-21 settings
Mode: Repeat
Start Time: 2014/01/15 12:00
Stop Time: 2014/01/15 15:00
Interval: 1h (1 hour)
Recording Time: 10m (10 minutes)
Recording start After completion of recording,
the unit does not go into
REC
the power save state.
12:00 13:00 14:00 15:00

Sleep Data Sleep Data Sleep Data

(low power recording (low power recording (low power recording
consumption) 10 min. consumption) 10 min. consumption) 10 min.

60 90 60 90 60 90
sec. sec. sec. sec. sec. sec.

1 hour 1 hour

49
Menu Operations and Setting Items

<Bar Graph> menu

This menu serves for making bar graph display settings.

Graph Bar graph display method

Lets you select linear value display (Linear) or logarithmic value display
(Log) for each channel.
For details on the bar graph display method, see page 27.
Linear / Log

Note
The Graph menu will be blank for channels whose
“Sensitivity” has been set to MIC, SLM, or VM with
<Input> menu. The bar graph indication for such
channels is fixed to dB.

50
 Menu Operations and Setting Items

<System> menu
This menu comprises general items such as display backlight brightness and
SD memory card data deleting.

Read / Save Setting Read setting values from unit or SD

memory card/Save setting values in unit
or on SD memory card

Load Default Settings

Returns all unit settings to the initial (factory default) condition. In the
<Read / Save Setting> menu, select “Load Default Settings” and press
the [ENT] key. The execution choice screen appears.

51
Menu Operations and Setting Items

Internal Memory (No. 1 to No. 5)

Input range and other settings made with the menus can be saved in the
internal memory of the unit, allowing them to be easily read (reloaded)
later. Five sets of settings identified as No. 1 to No. 5 can be saved. In
the <Read / Save Setting> menu, select No. 1 to No. 5 for “Internal
Memory” and press the [ENT] key. A screen to save or read settings
appears. Use the [ ]/[ ] keys to select the desired action and press
the [ENT] key. The execution choice screen appears.
SD CARD
The input range and other settings made with the menus can be saved on
an SD memory card for later use. Only one set of settings can be saved.
The steps for saving and reading are the same as for “Internal Memory”
described above. The setting file saved on the SD memory card can also
be used as startup file for loading when the unit is turned on (see page 14).
If the message “Card Error.” appears when you press the [ENT] key to
update the setting file, the SD memory card may be defective.

Important
Changes to settings made with the menus will
be saved on the SD memory card by the “Save
Settings” function, but for the unit, the settings
will only be activated at the point where you
return to the main screen.
If you turn the power off before returning to the
main screen, the changed settings will not be
active the next time you turn the unit on.

Note
When a setting file is loaded which contains a CCLD
setting for the Inp item of <Input> menu, the channels
for which CCLD is selected will be supplied with a
constant current.
If the unit is operated on battery power and the
remaining capacity of the batteries is low, a forced
power-down will occur when a CCLD setting is
selected (see page 40).

52
 Menu Operations and Setting Items

Clock Settings Current date and time setting

Date
Select “Date” and press the [ENT] key. Set the year (to 2037), month,
and day separately on the displayed sub menu.
Time
Select “Time” and press the [ENT] key. Set the hours, minutes, and
seconds separately on the displayed sub menu.

Backlight Settings Backlight brightness and auto off time

setting
Brightness
Select the grade of backlight brightness from the number of 1 to 4.
Auto-Off
When no key is operated for the period set here, the backlight will be
automatically turned off. Available settings are 30 s (seconds), 3 m
(minutes), and Continue. To have the backlight continuously on, select
Continue.

Battery Type Used battery type setting

Displays the sub menu to select the type of battery used for the unit.
The remaining battery capacity corresponding to the selected battery is
displayed on the main screen. Available settings are Alkaline and Ni-MH
(nickel-metal hydride).
Alkaline / Ni-MH

Card Format SD card formatting

Formats the inserted SD memory card.
Select “Card Format” and press the [ENT] key. The execution choice
screen appears.

USB Storage Function setting for connection to computer

When set to “ON”, connecting the unit to a computer via USB will cause
the SD memory card inserted in the unit to be recognized as a removable
disk. Data recording and data recall operation cannot be performed when
the state of “USB Storage” is set to “ON”.

53
Menu Operations and Setting Items

Monitor Out Function setting for Monitor Out connector

When set to “ON”, a playback signal for the monitor channel is output
from the Monitor Out connector.
For details about playback, refer to the section beginning on page 111.

Index Device index number setting

Using this setting, you can assign a unique number to each DA-21 device.
The setting range is 1 to 255. Because the index number information is
recorded along with the data, it can be used to identify multiple DA-21
units or data recording conditions.
The index number setting has no influence on performance or functions
of the unit.

Version Version information

Displays the firmware version of the unit.

54
 Menu Operations and Setting Items

<Synchronization> menu
Contains settings for operating two connected DA-21 units as a synchronized
system.
For additional information on DA-21 synchronized operation, also refer to
page 91.

Master / Slave Assign unit to master or slave operation

After connecting two DA-21 units, this setting determines whether the
respective DA-21 unit operates as master or as slave.
OFF No synchronized operation.
Master Select this setting on the DA-21 to be used as master.
Slave Select this setting on the DA-21 to be used as slave.

Synchronize Synchronize connected DA-21 units

Use the dedicated cable to connect the two DA-21 units to be used as
master and slave. Select this item on both units and press the [ENT] key.
The execution choice screen appears. Then press the [ENT] key on both
unit simultaneously. Two connected DA-21 units synchronize.

Important
Establish the same settings on both DA-21 units
(<Rec.Parameters> menu items). If settings are
different, synchronized operation is not possible.
Also, when the settings are changed after the
synchronization, it is necessary to synchronize
again.
Check the synchronization information on
the display (page 18) after operation of the
synchronization.

55
 Preparations
This chapter describes the settings and steps to take before starting to record
data.

Preparations and checks before recording

1. Power supply (inserting batteries, AC adapter, wake-up-on-power mode)
2. SD memory card preparations (insertion and removal, formatting)
3. Connection of external devices (sensors etc.)
4. Sensitivity setting

Recording parameter settings

1. Input range, overload
2. Frequency range, sampling frequency
3. Recording time, trigger

Auxiliary function setup

1. Device index number
2. Voice memo/marker
3. Preventing inadvertent operation
4. Remote control operation
5. Connection to a computer
6. Inter-unit synchronization
7. Tachometer signal input

56
 Preparations

Preparations and checks before recording

Power supply
The DA-21 can be powered from four IEC LR6 (size AA) batteries or from
the optional AC adapter NC-98 series.

Important
Use only the specified AC adapter available as an option for the DA-21.

Inserting the batteries

1. Open the battery compartment cover.
2. Insert four IEC LR6 (size AA) batteries with correct polarity, as
shown inside the compartment.
3. Replace the battery compartment cover.

Important
Take care not to reverse the (+) and (−) polarity when inserting the batteries.
Always replace all four batteries together. Do not mix old and new batteries
or batteries of different type. Remove the batteries from the unit if the unit
is not to be used for an extended period.

Note
If the unit is operated on battery power, take the following points into account
when using a CCLD type sensor. When quitting the menu after setting the “Inp”
item of <Input> menu to CCLD, the unit may switch itself off automatically. In such
a case, replace all batteries with fresh ones.

57
Preparations

Connecting the power cord and AC adapter (option)

Connect the AC adapter as shown below. Turn the unit off before making
this connection.
1. Plug one end of the power cord into the small socket on the AC
adapter.
2. Insert the plug of the supply cable from the AC adapter into the
DC IN connector on the DA-21.
3. Plug the other end of the power cord into an AC outlet.

To remove the AC adapter, turn the DA-21 off and then perform the above
steps in reverse order.

Voice
USB Input Ext. Trig.
Monitor
Out Output

DC IN 5-20V Tacho
4 3 2 1 Input

DC IN connector Sync.

Remote Controller

AC adapter
NC-98 series (option)

To AC outlet, 100 V to 240 V, 50 Hz / 60 Hz

Important
Use only the specified AC adapter available as
an option for the DA-21. Using another kind of AC
adapter may lead to damage and malfunction.
When connecting a battery or purpose-built
cable to the DC-IN connector, take great care
to ensure correct polarity and voltage.

58
 Preparations

Backup battery
The unit uses a backup battery (rechargeable battery) to operate the clock.
While power to the unit is on, the backup battery will be charged. It will
also be charged while power to the unit is off if external power is connected.
The relationship between charging time and retention period is shown below.
A full charge of the backup battery is achieved after 24 hours.
Charging time Retention period
1 hour 2 days
12 hours 30 days
24 hours 45 days
Use the AC adapter when connecting external power for battery charge while
the unit is turned off. The service life of the backup battery is limited. You
should have the battery replaced about once every five years. Please contact
your supplier.
Note
The charging time, retention period and service life
of the backup battery may vary depending on the
operating condition.

When the backup battery is old, the retention period

will be shorter.

59
Preparations

Wake-up-on-power mode
When you open the battery compartment cover as shown below, the [WAKE
UP ON POWER] switch becomes accessible. By setting this switch to ON,
you can have the on/off status of the unit controlled by the power supplied
to the DC-IN connector. In such a case, the [POWER] key on the panel has
no effect.

WAKE UP
ON POWER
ON Power is controlled by
external power supply

OFF Power is controlled by

[POWER] key

Important
When setting the [WAKE UP ON POWER] switch
to ON, remove all batteries from the battery
compartment. Otherwise the wake-up-on-power
mode will not operate normally.
Remove the batteries from the unit if it is to be
stored for a long time with the [POWER] key set
to OFF to prevent possible damage caused by
battery leakage.

60
 Preparations

SD memory card preparations

Recorded data are stored on SD memory cards in WAVE file format.
To store the data in files, a dedicated folder structure and a data management
file are required on the card. These are created automatically when the SD
memory card is used for the first time. Depending on the setting for recording
data, multiple WAVE files may be created (see page 116).
An SD memory card inserted in the unit will be recognized as a removable
disk by the computer when the “USB Storage” item of <System> menu is set
to “ON”, without having to install a USB driver.
For connection to the DA-21 and the computer, use an optional (generic) A
- mini B USB cable.

Important
SD memory cards even from the same manufacturer
and of the same type exhibit certain variations in
specifications which may cause problems. For
this reason, be sure to use only the SD memory
cards provided by Rion. The performance of other
cards is not guaranteed.
This unit supports SD memory cards and SDHC
memory cards, but not SDXC memory cards.
Format the SD memory card by the DA-21 before
recording.
If folders or files on the SD memory card have
been altered by other equipment except the
DA-21, do not continue to use the card for
recording in the DA-21. Data may not be recorded
correctly.

61
Preparations

Inserting and removing an SD memory card

Important
Make sure that power is OFF before inserting
or removing a card.
Take care to insert the SD memory card with
correct orientation.
If the SD memory card is removed while data is
being read or written to the card, the data may
be destroyed.
Note that we assume no responsibility for any
damage or loss of stored measurement data.

1. Open the card slot cover of the unit.

2. Insert the SD memory card into the card slot with the label of the
card facing up. Push the card in until it is locked in place.
3. To remove the card, push the card a bit further in, the card is released
and pops out of the card slot.
C
A
R
D
C
A
PA
C
IT
Y

Slide card slot

cover out

Raise card
slot cover
C
A
R

Label side should

D
C
A
PA
C

face up
IT
Y

SD memory
card
By sliding this switch in
the arrow direction, you
can write-protect the card

62
 Preparations

Formatting an SD memory card

Note
When an SD memory card is formatted (initialized),
all data present on the card will be lost. But the setting
file will remain if the card is formatted by this unit.

In the following cases, you should format the SD memory card:

• When using the SD memory card in the unit for the first time
• When wishing to delete all data from the SD memory card

To format an SD memory card, proceed as follows.

1. Select “Card Format” on the <System> menu and press the [ENT]
key.
2. The execution choice screen appears. Press the [ENT] key.

63
Preparations

External equipment (sensor etc.) connections

As shown below, the DA-21 is designed to handle the output of various sensors
or measuring instruments. Correct input settings must be made, depending on
the sensor and signal type and whether the sensor requires a constant current
power supply. Some possible combinations are shown below.

Measuring device with AC or DC outlet

Temperature meter
Tachometer
Other device

VIBRATION METER VM-83

LEVEL RANGE

Vibration meter LIGHT

Vibration level meter

CAL
HPF LPF

ACC/VEL RHS PICKUP

/DISP PEAK
/EQ
SENS
P-P

(VM-83, VM-55 or similar)

/EQ

HPF LPF MENU

PICKUP POWER
MAX HOLD HOLD COMP ON
ON/OFF RESET ON/OFF

BNC-BNC cable

To AC OUT BNC-mini plug cable

Sound level meter CC-24S
(NL or NA series) CC-24 can also be used

Microphone
UC-59, UC-52
Preamplifier BNC-BNC cable
NH-22A
BNC adapter
VP-52C
Piezoelectric accelerometer
(with built-in preamplifier) PV-91C etc.
VP-51 series or cable
supplied with accelerometer

Piezoelectric accelerometer Charge converter BNC adapter

PV-85, PV-90B etc. VP-42 VP-52C

Accelerometer
cable
Accelerometer Charge converter
cable VP-40
VP-40 90001
RION

Piezoelectric accelerometer Tri-axial accelerometer Charge converter

PV-97 etc. cable VP-51WL VP-40
VP-40 90001
RION

VP-40 90001
RION

VP-40 90001
RION

To input connectors

1 2 3 4

DA-21

64
 Preparations

Input settings
The four signal input connectors (BNC connectors) can not only accept a
signal, they also allow output of a constant current to a CCLD (Constant
Current Line Drive) type sensor. Some CCLD sensors use a basic preamplifier
+ accelerometer or microphone configuration. The DA-21 can record up to
four input signals. The input connectors 1 to 4 are assigned to channels 1 to 4.

Input setting (<Input> menu: Inp)

The setting is made for each channel separately, with the “Inp” item on
<Input> menu.
AC For sensors that output an electrical signal without DC
components
DC components and components 0.3 Hz or below are blocked.
Example: AC output of sound level meter or vibration
meter
DC For sensors that output an electrical signal including DC
Example: Temperature meter or tachometer output, DC
output of sound level meter
CCLD For sensors requiring a constant current source
For such sensors, a constant current is supplied via the input
connectors of the DA-21.
Example 1: Combination of microphone UC-52 or UC-59
or similar with preamplifier NH-22A (CCLD:
2 mA) or similar
Example 2: Piezoelectric accelerometer with built-in
preamplifier PV-91C, PV-97I (3-axis) or similar
VP4x Sensor connected via the charge converter VP-40
Example: Accelerometer PV-85 or PV-90B etc. connected
via the charge converter VP-40

65
Preparations

Sensitivity setting (<Input> menu: Sens, Sensitivity)

Sensor setting
Depending on the input setting described on the preceding page (AC,
DC, CCLD, VP4x), set the “Sens” item for the combinations marked with
a “ ” in the table below. EU (Engineering Units) is a unit symbol for
expressing various physical quantities detected by a sensor.
Sens
V EU MIC PICK SLM VM
Inp
AC × ×
DC × ×
CCLC × ×
VP4x × × × × ×
When the “Sens” item is set, the sensor signal units are determined
automatically, as shown in the table below.

Indication
Unit as Scaled unit set
for Sensor
shown on for Sensitivity Value input for Sensitivity
item in
main screen item in menu
menu
V
Set voltage corresponding to
EU EU V/EU
1 EU
Set microphone sensitivity level
MIC dB dB
(dB re. 1 V/Pa)
PICK Set sensitivity of accelerometer
m/s2 mV/(m/s2)
(CCLD) (with built-in preamplifier)
PICK Set cha rge sensitivity of
m/s2 pC/(m/s2)
(VP4x) accelerometer
Set sound level meter level range
SLM dB dB
(full-scale value)
Set vibration level meter (VM-55
VM dB dB or similar) level range (full-scale
value)

66
 Preparations

Sensitivity setting
This setting determines the correlation between input signal voltage and
signal units. How the values are to be set for each signal unit is explained
below.
mV/(m/s2) Set the voltage sensitivity of the accelerometer.
Example: For PV-90I rated for 0.44 mV/(m/s2), the
setting should be “0.44”.
dB Set the microphone sensitivity level (dB re. 1 V/Pa), or
level range (full-scale value) of sound level meter or
vibration level meter.
Microphone
Example: For UC-53A rated for −28 dB and used
together with NH-22A, the transmission
loss is taken as −0.5 dB and the setting
should therefore be “−28.5”.
Sound level meter
Set to full-scale value of level range
Example: 80 dB
Vibration level meter
Set to full-scale value of level range
Example: 80 dB
EU Set how many volts of the sensor signal voltage
correspond to one unit of the physical quantity.
Example: For a tachometer rated for 1 V/1000 rpm,
the setting should be “1.00E-03”.

67
Preparations

The table below shows the correlation formula for the original input range
X [V] and the condition after the sensitivity setting.

Sensitivity
Unit Inp (Sens) type Input range value after conversion
value
[V] None DC/AC(---) X[V]
[EU] K[V/EU] DC/AC(EU) X/K
[dB] S[dBV/Pa] MIC(CCLD) 94−S−3+20 log10(X)
V[mV/(m/s2)] PICK(CCLD)
[m/s2] 1/(V/1000)×X
V[pC/(m/s2)]* PICK(VP4x)
[dB] R[dB] SLM/VM 20 log10(X)+R−10
* Take the charge sensitivity [pC/(m/s2)] given in the calibration certificate
of the accelerometer and enter it as voltage sensitivity [mV/(m/s2)].

Some practical examples for applying the respective formula to actual

sensitivity values are shown below. These values are shown as input range.
(When the exponent is two digits, the mantissa is shown as one digit.
The effective number of digits for dB is three. In 3-V systems, 10 is
used instead of 3 for calculation. This is because the 3-V range actually
is 3.16) V) = 10 .)

Sensor Sensitivity Unit Actually displayed input range value

General 1 V 10 V 3V 1V 0.3 V 0.1 V 0.03 V 0.01 V

Tachometer K=1.0E-03 EU 1.00E+4 3.16E+3 1.00E+3 3.16E+2 1.00E+2 3.16E+1 1.00E+1

UC-59 S=−28.5 dB 139.5 dB 129.5 dB 119.5 dB 109.5 dB 99.5 dB 89.5 dB 79.5 dB

PV-90I V=0.44 m/s2 2.27E+4 7.19E+3 2.27E+3 7.19E+2 2.27E+2 7.19E+1 2.27E+1

SLM R=80 dB dB 90 80 70 60 50 40 30

68
 Preparations

Input settings and sensitivity settings for some representative sensors are
shown below for reference. The sensitivity value differs for each sensor.
Sensor sensitivity
Sensor example Inp Sens Sensitivity unit
DC output of general measuring ----- No setting 1
device or sensor, or AC output of DC
vibration meter EU X.XXE+XX V/EU
AC output of general measuring ----- No setting 1
device, sensor, vibration meter, AC
sound level meter EU X.XXE+XX V/EU
Microphone: UC-52 Sensitivity level dB
+ CCLD MIC (−0.1 to −99.9) (0 dB=1 V/Pa)
Preamplifier: NH-22A
Piezoelectric accelerometer Voltage sensitivity
CCLD PICK mV/(m/s2)
(with built-in amplifier):PV-90I (0.01 to 99.9)
Piezoelectric accelerometer: PV-85 Charge sensitivity
+ VP4x PICK pC/(m/s2)
(0.01 to 99.9)
Charge converter: VP-40
Voltage sensitivity
Sound level meter NL series AC SLM dB
(40 to 140)
Voltage sensitivity
Vibration level meter:VM-55 AC/DC VM dB
(40 to 140)

Note
When Inp is set to AC, a high-pass filter with a cutoff
frequency of 0.3 Hz is applied. However, if the input
signal contains high-level DC components that exceed
the input range, overload may occur in the DA-21.

69
Preparations

Recording parameter settings

This section describes how to set the parameters for recording data. Input
range, frequency range, sampling frequency, and recording time are required
items. If necessary, you should also set the Pre Recording Time, trigger, and
other related items.

Input range setting

The input range can be set to seven levels in 10 dB steps (0.01 V, 0.03 V,
0.1 V, 0.3 V, 1 V, 3 V, 10 V). Select an appropriate setting according to the
input signal level and the operation method of the DA-21.
For improved S/N ratio, setting the input range as low as possible without
causing overload is generally preferred. For inspection of products and
other kinds of periodic measurements, it may be necessary to keep the input
range setting the same, in order to allow product comparisons and to detect
deterioration over time.

To set the input range, proceed as follows from the main screen.
(The setting cannot be changed in recording or recall mode.)
1. Activate cursor in input range display section
Press the [RANGE] key to cause the input range display section
to be shown in reverse (cursor active).

RANGE

2. Select the channel for which to change the input range

Use the [ ]/[ ] keys to move the cursor to the channel whose
input range setting you want to change.

ENT

70
 Preparations

3. Activate the range change mode.

Press the [ENT] key to bring up the sub menu.

ENT

4. Select the new input range setting.

Use the [ ]/[ ] keys to change the input range.

ENT

5. Confirm the new input range setting.

Press the [ENT] key to return to the condition of step 2.

ENT

6. If you want to change the input range for another channel, repeat
the procedure from step 2. Otherwise press the [RANGE] key to
complete the range setting procedure.

RANGE

71
Preparations

Input range setting and overload

When setting the input range, check whether overload occurs. When this
happens, the overload indicator on the front panel lights up in red, and the
indication OVER appears on the display.
To improve reliability and ensure that overload does not occur for an extended
period, the overload history indication is convenient. This indication comes
on when there has been an overload event at any time within a given period.
To reset the indication, hold down the [CLEAR Ov] key. When the key is
released, overload history monitoring OVER begins, allowing the operator to
determine later whether there has been overload without having to constantly
check the overload indicator.
The overload history is also cleared when you make a recording parameter
setting. For details on clearing the overload history, see page 24 (Overload
Information).

Overload indication

Overload history indication

72
 Preparations

Sampling
The sampling action of the DA-21 is controlled by the frequency range and
sampling frequency setting. The sampling frequency can be set to 2.4 times
or 2.56 times the frequency range.

Setting the frequency range

The frequency range can be set in six steps (100 Hz, 500 Hz, 1 kHz, 5 kHz,
10 kHz, 20 kHz). Make the setting using the “Frequency Range” item in
<Rec.Parameters> menu.
The frequency range value represents the highest effective frequency that
will be included in the recorded waveform. Higher components will be cut
off. When making the setting, choose a value that is higher than the highest
frequency of components that need to be included in the recorded data.

Setting the sampling frequency

Waveform sampling is carried out at a frequency that is 2.4 times or 2.56 times
the frequency range value. Make the setting using the “Sampling Frequency”
item in <Rec.Parameters> menu.
To perform FFT analysis after recording, using the ×2.56 setting is recommended.

73
Preparations

Recording process
When you press the [REC] key, the data recording operation starts. However,
if the trigger function (described later) is used, recording may not begin
right away. In such a case, actual recording will only start when the trigger
conditions are met, or in other words when a trigger event occurs.
Recording stops when the amount of data corresponding to the recording time
has been recorded. If repeat trigger is selected, the recording condition is not
terminated at this point. Rather, the unit goes into trigger standby mode and
recording begins again at the next trigger event.
Even before the amount of data corresponding to the recording time has
been recorded, recording can be stopped by pressing the [STOP] key. It will
also stop when the SD memory card becomes full. Data recorded up to that
point will be stored.

Setting the recording time

The recording time can be set to 1 s to 59 s (seconds), 1 m to 59 m (minutes),
1 h to 24 h (hours), and a “Manual” setting is also available. When “Manual”
is selected, recording continues until the [STOP] key is pressed. Regardless
of the recording time setting, when there is no more room on the SD memory
card to store data (remaining recording time is about 10 seconds), recording
stops. Recording to one file is also limited to a maximum of 1000 hours.
When this limit is reached, recording stops.

Recording stops when SD

REC STOP
memory card becomes full or
when file length has reached
1000 h (hours).
Recording time
Recording procedure (also at settings other than
1 to 24 h Manual).
1 to 59 m Data recording in progress
1 to 59 s

Recording procedure
Manual Data recording in progress

Recording procedure
Manual Data recording in progress

74
 Preparations

Make the recording time setting using the “Recording Time” item in <Rec.
Parameters> menu.
When the “Pre Recording Time” has been set to 1 second, the recording
time can be set to a value of 2 seconds or higher. When the “Pre Recording
Time” has been set to 5 seconds, the recording time can be set to a value of
6 seconds or higher.
The recording time setting cannot exceed the remaining available capacity
of the SD memory card inserted in the DA-21. If this applies, the recording
time will automatically be changed to the maximum available time when the
[ENT] key is pressed.

75
Preparations

Setting the Pre Recording Time

If you wish to include data from a point slightly before the [REC] key was
pressed or before the trigger event, use the Pre Recording Time function.
Available pre-recording settings are 0, 1, and 5 seconds.
The overall recorded data length will correspond to the recording time. The
Pre Recording Time is not added to the recording time, rather it is included
in the total.
Make the Pre Recording Time setting using the “Pre Recording Time” item
in <Rec.Parameters> menu (page 45).
REC

Recording procedure
PreRec. Time
=0s Data recording in progress

Pre Recording
Time

PreRec. Time
=5s Data recording in progress
Recording procedure

Difference in recording procedure with Pre Recording Time

(Pre Recording Time: 5 s, Recording Time: other than Manual, Trigger Mode: Free)

REC Trigger event

Recording procedure
PreRec. Time
=0s Trigger standby Data recording in progress

Pre Recording
Time

PreRec. Time
=5s Data recording in progress
Recording procedure

Difference in trigger operation depending on Pre Recording Time setting

(Pre Recording Time: 5 s, Recording Time: other than Manual, Trigger Mode: Single)

When the “Type” item of <Trigger> menu is set to “Time”, the Pre Recording
Time setting has no effect.

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 Preparations

Trigger conditions
The trigger operation is determined by the trigger mode and trigger type.
When the trigger type is set to “Level”, the trigger level and trigger channel
must be set. For the “Time” trigger the start/stop time and interval must be
set. Only trigger events that occur while the DA-21 is in the trigger standby
condition are valid. Any trigger events that occur while data recording is in
progress are disregarded.

Setting the trigger mode

This setting determines the basic trigger operation.
Make the trigger mode setting using the “Mode” item in <Trigger> menu.
If the trigger function is not required, select the “Free” setting.
Free (trigger off)
Recording starts immediately when the [REC] key is pressed and
ends when the amount of data corresponding to the recording
time has been recorded.
Single (single trigger)
The unit goes into trigger standby mode when the [REC] key
is pressed. When a trigger event occurs, recording starts. When
the amount of data corresponding to the recording time has been
recorded, recording stops.
Repeat (repeat trigger)
The unit goes into trigger standby mode when the [REC] key
is pressed. When a trigger event occurs, recording starts. When
the amount of data corresponding to the recording time has been
recorded, the unit again goes into trigger standby mode and the
operation is repeated.

Note
Repeat setting is possible also when the Recording
Time is set to Manual. But the trigger operation is
carried out only once.

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Preparations

REC

Recording procedure

Data recording in progress

Free

Recording procedure
Trigger
Single standby Data recording in progress

Recording procedure
Trigger Trigger
standby Data recording in progress standby Data recording in progress
Repeat

During data recording,

trigger event is disregarded.

Trigger events

Difference in recording procedure according to trigger mode

(Pre Recording Time: 0, Recording Time: other than Manual, Trigger Type: Level or External)

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 Preparations

Setting the trigger type

This setting determines the type of event that serves as a trigger.
Make the setting using the “Type” item in <Trigger> menu.
Level (level trigger)
A trigger event occurs when the level of the input signal in the
specified trigger channel becomes equal or higher than a preset
threshold value (trigger level).

Note
• Delay of the record start time which recognized
by the AC input signal when the trigger type is
“Level”
If the input signal reaches a trigger level, recording
will be started from the point of time. However,
with the cause of data processing of DA-21, the
recording is started later than the time which ful-
filled trigger conditions.
If you want to record all the waveforms which
fulfilled trigger conditions, set the “Pre Recording
Time” in <Rec.Parameters> menu as 1 second or
5 seconds.

External (external trigger)

A trigger event occurs when the state of the Ext. Trig. connector
changes from H (open) to L (shorted). Detection is carried out
on the falling edge.
External Gate (external gate trigger)
Data recording is carried out while the state of the Ext. Trig.
connector is L (shorted). Also after the state changes to H (open),
recording continues for five seconds (post-recording). If the state
of the Ext. Trig. connector is already L (shorted) when the [REC]
key is pressed, recording starts straight away because the trigger
conditions are met. With this trigger type, the recording time
setting has no effect.

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Preparations

Time
Recording is carried out from the specified Start Time to the
specified Stop Time, at intervals as specified by the Interval setting.

Note
The “Pre Recording Time” setting in <Rec.Parameters>
menu has no effect. When the Stop Time is reached,
recording will stop, also if the Recording Time is not
yet completed.

REC

Recording procedure

Trigger Trigger
standby Data recording in progress standby Data recording in progress
Level

Trigger Trigger
External standby Data recording in progress standby Data recording in progress

5 seconds after state 5 seconds after state

changed from L to H changed from L to H

Trigger Data recording Trigger

External standby in progress standby Data recording in progress
Gate

Start time Stop time

Trigger Trigger
Time standby Data recording in progress standby Data recording in progress

Interval

Trigger level

Trigger channel
waveform
Trigger level

Ext. Trig.
connector signal

Ext. Trig. connectors

Level trigger event External trigger event
shorted

Difference in recording procedure according to trigger type

(Pre Recording Time: 0, Recording Time: other than Manual, Trigger Mode: Repeat)

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 Preparations

Setting the trigger level

When the trigger type is set to “Level” (level of signal at input connector),
the actual level to be used as a trigger level must be set as a percentage
[%] of the full-scale value of the current input range.
Make the setting using the “Level” item in <Trigger> menu. The actual
trigger level is indicated on the bar graph for the trigger channel (see
page 26).

Setting the trigger channel

When the trigger type is set to “Level”, the channel to be used as trigger
channel must be set.
Make the setting using the “Ch” item in <Trigger> menu.
The indication “TRG” is shown at the left of the trigger channel. (For
information on level trigger target channel indication, see page 24).

Setting the start and stop time

When the trigger type is set to “Time”, set the start time and stop time
as follows.
Make the setting using the “Start Time” and “Stop Time” items in <Trigger>.

Note
When the start time setting is before the current time,
the setting automatically becomes “current time +
5 minutes”. When the stop time setting is before
the current time, the setting automatically becomes
“Start Time + 24 hours”.

81
Preparations

Setting the recording interval

When the trigger mode is set to “Repeat” and the trigger type is set to
“Time”, set the interval as follows.
The interval setting cannot be shorter than the Recording Time setting.
Make the setting using the “Interval” item in <Trigger> menu.

When Stop Time is reached before Recording Time is up

Start Time Stop Time

Data recording Data recording

in progress in progress

Recording Time Recording Time

(1 s to 24 h) (1 s to 24 h)

Interval

Recording stops (Stop Time has priority)

When Recording Time is set to Manual, recording stops at the Stop Time

Start Time Stop Time

Data recording
in progress

Recording Time: Manual

Recording begins at the specified start date/time and ends at the

specified stop date/time.

82
 Preparations

Repeat trigger precaution

If trigger conditions are met while a file is being closed, the next recording
will not start.

Trigger event occurs during file save

Disregarded
(recording does not start)

Data recording File is Data recording File is

in progress being written in progress being written
Time

Trigger event

Trigger event occurs after file save is completed

Recording starts
" " is the time required to write previous data to SD memory
card as a file.

File write time

Recorded data are also written sequentially to a file during the recording
process, but at the point where recording stops, there will be a certain
amount of data that still need to be written. In addition, file management
information to allow later retrieval of the file also needs to be created.
The “File is being written” message refers to this process of writing
remaining data and file management information. The following message
appears on the display during the process (see page 125).

83
Preparations

Auxiliary function setup

Device index number (<System> menu: Index)

The index number setting has no influence on performance or functions of
the unit. Setting an index number is optional. The setting range is 1 to 255.
Some possible uses for the index number capability are listed below.
1. Temporary management (classification) of recorded data
Example 1 In a system where several DA-21 units are used, the
index number can serve to manage data according to
the unit on which the data were recorded.
Example 2 Manage recorded data according to measurement
purpose, measurement location, or similar.
Example 3 Manage recorded data according to measurement
parameters.
2. Using the index number as input range information
When using a system where a calibration signal is recorded in order
to calibrate recorded data, sensor range information will be required.
Using an input range value as the index number will facilitate data
management.
Example Set the index number to 120 when a sound level meter
is calibrated in input range 120 dB.

84
 Preparations

Voice memo/marker
The voice memo function allows the operator to add comments before and
after the recording procedure or during recording. The marker function can
be used to mark a certain position, for example when a particular phenomenon
occurred during recording. This makes it easy to later locate the data for that
point. For example, if noise was encountered at a certain point, the marker
can serve to locate and isolate the corresponding data.

Voice memo
While voice memo is activated, the sound picked up by the voice memo
microphone connected to the Voice Input connector can be recorded. When
the “Inp” item for CH5 in the <Input> menu is set to “Voice Memo”, the
indication appears to the right of the bar graph.
The level of the voice signal is shown by the bar graph for channel 5. Pressing
the switch on the voice memo microphone activates voice memo recording.
Releasing the switch stops voice memo recording.

Marker
The marker function is only available during data recording. The maximum
number of marker points that can be set between the beginning and the end
of data recording is about 3,000.
When the “Inp” item for CH5 in the <Input> menu is set to “Marker”, the
indication appears to the right of the bar graph.
When the microphone switch is pressed, the indication flashes for one
second.
The marker precision is about 1 second.

85
Preparations

Comparison of voice memo and marker operation

The diagram below illustrates the operation principle of the voice memo
and marker function. The functions differ in the action that occurs when the
microphone switch is pressed.

REC

Recording start

Voice memo Voice memo Voice memo

Voice Memo

Voice memo Input signal

Marker
Marker is set Marker is set
for this time point for this time point
Released
Microphone
switch status
Pressed

Voice memo before recording Voice memo or marker (according to setting) after recording start

Voice memo microphone

MIC

Microphone switch

To Voice Input
connector
Voice
USB Input Ext. Trig.
Monitor
Out Output

DC IN 5-20V Tacho
4 3 2 1 Input

Sync.

Remote Controller

86
 Preparations

Preventing inadvertent operation (key lock and menu lock)

This section explains the key lock and menu lock functions that serve to
prevent operation errors when performing data recording in the field.

Key lock Makes almost all keys inactive

Pressing and holding the [<] and [>] keys together for a few seconds activates
the key lock condition. In this condition, all keys except the [LIGHT] key
and the [<]/[>] keys are locked. Remote control operation remains possible.
To cancel the key lock state, press and hold the [<] and [>] keys once more.
During key lock, a key lock icon [ ] appears in the bottom left of the display.

Key lock activated

Hold down for 2 seconds

Indicates the key lock condition

87
Preparations

Menu lock Changing menu settings and deleting data are disabled
Opening the battery compartment cover gives access to a slide [MENU]
switch in the lower left section, as shown in the illustration below. When you
set this switch to the LOCK position, menu settings cannot be changed, and
data in recall mode cannot be deleted. Only the input range setting can still
be changed. This condition is called the menu lock mode.
When menu lock is active, the indication MENU LOCKED appears if you
call up a menu and attempt to make a setting, or if you attempt to delete data
in recall mode.
During menu lock, a menu lock icon [ ] appears in the bottom left of the
display.

MENU

Menu lock mode LOCK

Normal menu
operation
UNLOCK

Note
Operate the [MENU] switch only while power to
the unit is switched off.

88
 Preparations

Remote control operation

The optional Remote Controller (DA-20RC1) allows recording start/stop
control from a remote location. The controller features simple construction
with only a start/stop switch and an operation status indicator. The cable is
to be connected to the Remote Controller connector on the DA-21.
The Remote Controller allows for example centralized control of a measurement
system including other devices, with the DA-21 used to record data under
a given set of conditions. Because the Remote Controller is designed to be
operative also when the key lock feature is enabled, the DA-21 can be protected
from inadvertent operation.

Operation status
indicator

[START/STOP]
switch Voice
USB Input Ext. Trig.
Monitor
Out Output

DC IN 5-20V Tacho
4 3 2 1 Input

Sync.

Remote Controller

Remote Controller
Remote Controller connector

The first push of the [START/STOP] switch on the Remote Controller starts
recording. When the switch is pushed while recording is in progress, recording
stops. The operation status indicator provides the information listed in the
following table.
Status indicator Operation
Flashing red Recording
Flashing green Trigger standby
Lit in red (1 second or more) Overload has occurred
Off Other condition

When an overload condition continues, no distinction is made with regard

to whether it is before or after recording start. However, recording under
permanent overload conditions is a problem. Adjust the input range setting
to prevent overload.
89
Preparations

Connection to a computer
An SD memory card inserted in the unit will be recognized as a removable
disk by the computer when connected via USB, without having to install a
USB driver.

Connecting steps
1. Connect the USB connector of the DA-21 with a USB connector of
a computer, using the optional (generic) A - mini B USB cable as
shown below.
Voice
USB Input Ext. Trig.

USB port Monitor

Out Output

DC IN 5-20V Tacho
4 3 2 1 Input

Sync.

Remote Controller

To computer

A - mini B USB cable

2. Open the <System> menu from the Menu List to select “USB Storage”
to ON.

Important
Data recording and data recall operation cannot
be performed when the state of “USB Storage”
is set to ON.

90
 Preparations

Inter-unit synchronization
Using two DA-21 units and the separately available dedicated cable, synchronized
operation with one unit functioning as master and one unit as slave is possible.

Important
Establish the same settings on both DA-21 units
(<Rec.Parameters> menu items). If settings are
different, synchronized operation is not possible.
Also, when the settings are changed after the
synchronization, it is necessary to synchronize
again.
Check the synchronization information on
the display (page 18) after operation of the
synchronization.

Note
The size of data files recorded simultaneously on two
synchronized DA-21 units will be different for the
master unit and the slave unit.

Synchronization procedure
1. Use the optional inter-unit sync cable CC-43 to link the Unit to Unit
connectors of the two DA-21 units that are to be synchronized.
Voice
USB Input Ext. Trig.
Monitor
Out Output

DC IN 5-20V Tacho
4 3 2 1 Input

Sync.

Remote Controller

Inter-unit sync cable CC-43

Unit to Unit connector

Voice
USB Input Ext. Trig.
Monitor
Out Output

DC IN 5-20V Tacho
4 3 2 1 Input

Sync.

Remote Controller

91
Preparations

2. Access the menu list and open the <Synchronization> menu.

3. In the “Master / Slave” sub menu, select “Master” on the DA-21 to

use as master unit and “Slave” on the DA-21 to use as slave unit.

4. Enable synchronized operation by selecting “Synchronize” in the

<Synchronization> menu on both units.

5. The execution choice screen appears. Press the [ENT] key on both
units simultaneously.

Recording
First, press the [REC] key of the slave unit to set the slave unit into the trigger
standby condition. Then press the [REC] key of the master unit to start the
recording.

92
 Preparations

Tachometer signal input

The rotary pulse input connector serves for input of a rotary pulse signal
(Tacho signal). The DA-21 can record the revolution speed derived from a
rotating object such as a fan or motor.
When the “Inp” item for CH5 in the <Input> menu is set to “Tacho”, the
indication appears, and the revolution speed is displayed.

Connection example
Connecting a rotary pulse generator
The BNC - BNC coaxial cable EC-90 series (option) can be used to connect
a rotary pulse generator equipped with a BNC output, as shown below.

Voice
USB Input Ext. Trig.
Monitor
Out Output

DC IN 5-20V Tacho
4 3 2 1 Input

Sync.

Remote Controller

To rotary pulse input connector

To signal output of photoelectronic pulse generator

BNC - BNC coaxial cable or other device generating a signal controlled
EC-90 series by the revolution speed of a rotating object

93
 Recording
This section explains the recording process, including pre-recording checks
and general steps for recording.

Recording steps
1. Checks before recording
Check the power supply, sensor readiness, and all settings.
2. Adjust input range. Record calibration signal as required.
Adjust the input range setting so that no overload occurs. To ensure that
the recorded data correspond to correct measurement values, record a
calibration signal before recording. When there has been no change in
sensors and recording parameters, this step may be omitted from the second
time onwards. If the sensitivity setting of the DA-21 can be considered to
provide sufficient accuracy, recording a calibration signal is not necessary.
3. Recording
Use the [REC] key to perform the recording procedure, and repeat as
necessary. If any of the items that are to be checked before recording has
changed (connection of external equipment, input settings, etc.), return
to step 1.
After data recording has started, use the voice memo/marker function
and trigger processing as necessary.

1. Checks before recording

Before starting to record, check that all sensors are connected correctly and
that all settings are made properly. Items to be checked are listed below.
1. Power supply
Are inserted batteries in good condition? Are spare batteries
available? (See pages 23, 57.) Is an AC adapter or other suitable
external power source available?
Are wake-up-on-power mode settings appropriate? (See page 60.)

94
 Recording

2. Auxiliary functions
Are voice memo and marker settings appropriate? (See pages 40,
85.)
Has key operation been restricted as required by the usage
environment? (Key lock, menu lock mode) (See page 87, 88.)
Has Remote Controller been connected (as required)? Normally,
key lock should be enabled when using Remote Controller.
Is device index number setting appropriate? (See page 84.)
3. SD memory card
Is SD memory card certified for use in DA-21? (Insert card and
check for messages.) (See pages 12, 61, 121)
Is enough remaining capacity available? Is spare SD memory card
available? (Set number of channels and recording parameters as
required, and then check remaining recording time on main screen.)
(See pages 9, 22, 129)
4. External equipment connection
Is sensor configuration appropriate? Have sensor been connected
correctly? (See pages 10, 64)
5. Input settings
Are input and sensitivity settings matched to sensor? (If calibration
signal is to be recorded for sensitivity calibration, the sensitivity
setting check can be omitted.) (See pages 65 to 69)
Are unused input channels set to OFF? (Otherwise noise from
unused inputs may be recorded as data, unnecessarily using up SD
memory card capacity.)
Are low-pass filter and high-pass filter settings appropriate? (See
page 41)
6. Recording parameters
Trigger (See pages 77 to 83)
Frequency range, sampling frequency (See page 73)
Recording time (See page 74)
Sensitivity setting (See pages 66 to 69)
Input range (See pages 70 to 72)

95
Recording

2. Input range setting / Calibration signal recording

Changing the input range setting
1. Press the [RANGE] key to cause the input range display section to
be shown in reverse (cursor active).
2. Use the [ ]/[ ] keys to move the cursor to the channel whose input
range setting you want to change.
3. Press the [ENT] key to allow changing the current input range setting.
4. Use the [ ]/[ ] keys to change the input range.
5. Press the [ENT] key.
6. If you want to change the input range for another channel, repeat
steps 2 to 5. Otherwise press the [RANGE] key to complete the range
setting procedure.

RANGE Select channel

(by moving cursor)

ENT

RANGE

ENT ENT

10 V
3V
1V
0.3V
ENT

0.1V
0.03V
0 . 01 V

Change input range

(cursor for selected channel flashes)

96
 Recording

Recording a calibration signal

Calibration for recorded data is normally performed by recording the sensor
calibration signal before or after the data recording procedure and by correlating
the result to the recorded data.
This method allows correct calibration even if the effect of the configuration
elements of the sensor (extension cable, preamplifier, etc.) is unknown.
In principle, it will be necessary to record the calibration signal again when
the configuration elements have been changed. Input range information of
measuring device will also be required (if range switching is possible).

In the representative examples listed below, recording the calibration signal

may be necessary. In actual use, the operator should decide whether calibration
is necessary, based on information given in this manual and other data.
1. Input range setting of the measuring instrument (not DA-21) was
changed.
The instrument may change output signal being supplied to DA-21
when input range setting is changed even at the same input signal.
2. Extension cable was changed (length, cable gauge, etc.)
A change in electrical impedance may result in a different output
signal being supplied to the DA-21.

97
Recording

3. Recording

Starting to record
Press the [REC] key.
The recording procedure begins.
REC
The REC indicator at the top right above the [REC] key
flashes, and the REC icon appears on the display.
While recording is in progress, the REC icon flashes,
and the elapsed time count based on the recorded data
volume is updated. When the elapsed time equals the
preset recording time, recording stops.
During trigger standby, the elapsed time count is not
updated. If the Pre Recording Time function is used, the
elapsed time count does not start from zero but from the
Pre Recording Time value.

Elapsed Recording Elapsed Recording

time time time time

REC

Elapsed Recording Elapsed Recording

time time time time

< If one of the following messages appears and recording does not start >
[NoCard]
Insert an SD memory card and press the [ENT] key to clear the
message. Any [REC] key operation is disregarded.
[Card Error. Remove card or format card.]
An SD memory card that cannot be used in the DA-21 was inserted.
Press the [ENT] key to clear the message. Any [REC] key operation
is disregarded. Format the card by the DA-21 or insert another SD
memory card.
[Disconnect the USB from PC, please off the function “USB Storage”
from the system menu.]
Select “USB Storage” to OFF in the <System> menu.

98
 Recording

[Number of data has reached maximum.]

The maximum number of data sets that can be created has been
reached. Press the [ENT] key to clear the message. Any [REC]
key operation are disregarded. Either format the card after copying
the data (files) onto a computer, or use a different card which has
enough space.

< When does the recording procedure stop? >

The recording procedure stops in the following cases.
1. The amount of data corresponding to the recording time setting has
been recorded.
2. There is no more remaining space on the SD memory card.
3. The [STOP] key was pressed.
4. The number of hours in one data file has reached 1000.
5. The number of WAVE files in a data set (separated into folders by
start time) has reached 1000.
6. The Stop Time set for the time trigger has been reached.
7. The number of data folders (see 5.) has reached 1000. (In this case,
recording cannot be started.)
* For information on recorded data, refer to page 116.

< “Recording procedure” and “recording in progress” >

The entire process between initiating the recording and the completion of
all steps is called the “recording procedure”. This also includes the trigger
standby conditions during which no actual data are being recorded. The
condition where actual data are being recorded (i.e. where the unit is not in
the trigger standby condition) is called “recording in progress”.
REC

Trigger not used Recording in progress

Operation condition Recording procedure

Trigger used Trigger standby Recording in progress

Trigger event

99
Recording

< Overload history and display >

The overload history display OVER can be turned off during recording by
pressing the [CLEAR Ov] key. However, only the display is turned off. The
information about any overload that occurred is recorded along with the data.
The capability is used to monitor any further overload occurrences after
overload has occurred and been noted. The voice memo or marker function
can also be used in addition to overload monitoring, which can be helpful
when analyzing data later.
The overload history does not comprise information about any overload that
occurred during trigger standby or during voice memo recording.

Terminating a recording partway

Press the [STOP] key.
The REC indicator and the REC icon go out and recording
STOP stops.
After a long-term recording or when there is a large number
of files on the SD memory card, data recording to the SD
memory card may take some time. Do not remove the SD
memory card during data recording.

Elapsed Recording Elapsed Recording

time time time time

STOP

Elapsed Recording Elapsed Recording

time time time time

100
 Recording

Recording procedure conditions and indicator/icon status

The various conditions of the unit during the recording procedure can be
checked using the indicators and the icon status.
The two illustrations below show the various conditions, with and without
the use of the trigger function. (Flashing of an indicator or icon is indicated
in the illustration as .)

REC

Recording procedure
Operation condition
Recording in progress

REC indicator Red

REC icon

Basic recording

REC Trigger event

Recording procedure
Operation condition
Trigger standby Recording in progress

REC indicator Green Red

REC icon

Trig indication Tr i g

Recording with trigger function

101
Recording

Using the voice memo/marker function

Voice memo
Voice memo recording on the SD memory card starts when the microphone
switch is pushed and stops when the switch is released. The audio level is
indicated by the bar graph for CH5 during voice memo is activated, and the
icon is shown on the right side of the bar graph.

Voice memo microphone

MIC

Microphone
switch

When the unit is currently not performing the recording procedure, voice
memo recording is possible at any time. When voice memo recording was
stopped but the voice memo file is still being written to the SD memory card,
the [REC] key is not accessible.
When the unit is currently performing recording, voice memo recording can
be started only while recording is in progress (not during trigger standby).
When the “Inp” item for CH5 is set to except “Voice Memo”, voice memo
recording while recording is in progress is not possible.
When the microphone switch is operated, noise (overload) may occur.

102
 Recording

Marker
When the microphone switch is pressed while data are being recorded, the
current time is recorded as a marker. The icon is shown on the right side
of the bar graph for CH5 during marker is selected.
Pressing the switch also causes the icon to flash for about one second.
The marker function can only be used while recording is in progress.

REC REC

S1 S2

Recording start

Recording in progress

Voice
write processing

Voice
Voice memo file

Voice Memo memo memo

Voice Input signal

Marker memo
This time point
Released is recorded
Microphone
switch status
Pressed
Operation (1) Operation (2)

Voice memo is always possible Voice memo is always possible

before recording. when recording in progress.

The above illustration shows the voice memo/marker operation in detail when
the trigger function is not used. During the operation (1) interval, recording is
not in progress and voice memo recording is possible at any time, regardless
of voice memo/marker setting. However, while a voice memo file is being
written to the SD memory card, [REC] S1 is not accepted, and at [REC] S2,
recording is already in progress. The marker information is recorded only
when the switch is pressed while recording is in progress, as in operation (2).

103
Recording

REC REC Trigger event Recording of data

corresponding
to recording time
is completed.
S1 S2

Recording start

Trigger
standby
Recording in progress

Voice Voice Voice

write processing
Voice memo file
Voice Memo memo memo memo

Voice Input signal

Marker memo
This time point This time point
is recorded is recorded
Released
Microphone
switch status
Pressed
Operation (1) Operation (2) Operation (3) Operation (4)
Voice memo is always possible During trigger standby, pressing microphone switch
before recording. will not start voice memo.

The above illustration shows the voice memo/marker operation in detail when
the trigger function is used.
Except for the fact that voice memo operation is disregarded during trigger
standby, operation is the same as when the trigger function is not used.
During the voice memo operation interval (4), the voice memo recording
will be interrupted at the point where data recording is complete, even if the
microphone switch is kept depressed. (The same applies for recording end
when the trigger function is not used.)

104
 Recording

Data recording example

Monitor road noise and record sound pressure waveform when a given level is exceeded
The sound level meter NL-42/NL-52/NL-62 is used to measure noise levels.
The comparator signal and AC signal of the sound level meter are used for
recording the waveform on the DA-21.
Input the comparator signal of the sound level meter to the Ext. Trig. connector
of the DA-21, using the comparator output cable CC-42C. For voice memo
recording, connect the optional voice memo microphone to the Voice Input
connector. Input the AC signal of the sound level meter to the channel 1
(CH1) connector of the DA-21.
Make the DA-21 settings as follows.

Input settings (using <Input> menu)

CH Inp HPF LPF Sens Sensitivity
1 AC OFF OFF SLM Level range value: dB
2 OFF OFF OFF
3 OFF OFF OFF
4 OFF OFF OFF
5 Voice Memo OFF OFF
(CH1 is to be used for waveform recording. CH5 is to be used for voice
memo recording.)

Auxiliary functions
• Set device index number to level range value of sound level meter (for
calibration signal recording: see page 84)
• Set comparator level of sound level meter to level of signal to record.
• Set key lock to ON.

105
Recording

Recording parameters
Recording parameters Recording parameters
Item Setting Item Setting
Trigger mode Repeat Trigger type External
Recording time 15 s Pre Recording Time 5 s
Frequency range 20 kHz Sampling frequency ×2.56
Input range Suitable value

Procedure
1. Record calibration signal of sound level meter (at this time, trigger
mode should be set to “Free”).
2. Cancel calibration mode at sound level meter. Set trigger mode back
to “Repeat” and recording time to “15 s”.
3. Press the [REC] key to enable trigger standby.
4. Record voice memo as necessary.
5. Press the [STOP] key to terminate recording.

Note
It is also possible to select “SLM” for the “Sens” item
and set the sensitivity to the level range (full-scale
value) of the sound level meter, without recording the
calibration signal. However, for optimum measurement
accuracy, recording the calibration signal of the sound
level meter is preferable.

106
 Recording

Pre. Rec 5 s Pre. Rec 5 s Pre. Rec 5 s

Sound level

Comparator level

Data recorded (15 s) Data recorded (15 s) Data recorded (15 s)

memo
Voice

Passenger car Trucks crossing Motorbike

Sound pressure
waveform

To AC OUT To I/O connector

connector

Comparator
output cable
CC-42C
Voice memo microphone
BNC-mini plug cable
BNC relay connector
CC-24S
VP-54C
(CC-24 can also be used)

BNC-mini plug cable

CC-24S
(CC-24 can also be used)

To Input 1 connector To Ext. Trig. connector To Voice Input connector

1 2 3 4

DA-21

File name corresponding to File name corresponding to File name corresponding to

Generated file name the recording start time the recording start time the recording start time
(Trigger 1) (Trigger 2) (Trigger 3)

Recorded sound
pressure waveform
(channel 1)

Voice memo
Passenger car Trucks crossing Motorbike
(channel 5)

107
 Recall/Playback of Recorded Data
You can call up a list of recorded data and select data for playback and for
checking. You can also delete unwanted data or determine whether data have
to be recorded again.
(For a flow chart of the overall operations described in this section, see page
118.)

Activating recall mode

Press the [RECALL] key. The Select File screen appears, and the unit switches
to recall mode.

Note
When there are a lot of data on the SD memory card,
entering recall mode may take some time.
The Select File screen displays up to 1000 of the
most recent recorded data sets.

RECALL

Main
screen

Select File screen

Press [RECALL] key again in the Select File screen to return to the main
screen.

When activating the recall mode, the following message may appear.
If no SD memory card is inserted
The recall mode cannot be activated. In this case, the indication
NoCard appears on the display for a few seconds, and then the
main screen appears again.

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 Recall/Playback of Recorded Data

Viewing recorded data

The Select File screen shows the recording start time and status of the data.
The Status field shows “Voice Memo” if this was recorded during a recording
procedure. The Status field also shows “TACHO” if this was the tachometer
signal.
For data recorded with the repeat trigger function, the number of the trigger
event is shown on the Status field. (For example, Trigger-1 indicates data
recorded at the first trigger event.) Use the [ ]/[ ] keys to move the cursor.

Select File screen

Deleting recorded data

The Select File screen also lets you delete the recorded data.
1. Move the cursor to the recorded data to delete and press the [RANGE]
key.
2. The execution choice screen appears. Press the [ENT] key or [PAUSE]
key.

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Recall/Playback of Recorded Data

Selecting recorded data for playback

Move the cursor to the recorded data you want to play back, and press the
[ENT] key. The recall screen appears, and the recorded data can be played
back.

Recording time

ENT

Select File
screen
Channel number /
overload information

File creation date/time

The recall screen provides information about recording time, input range,
overload history, etc. The recording time is the time corresponding to the
actual recorded data. For data where recording was stopped partway, this
will be shorter than the recording time specified via the menu.
Playback of recorded data can also be started from this screen. The [<]/[>]
keys can be used to select recorded data.

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 Recall/Playback of Recorded Data

Playback of recorded data

The recall screen gives access to various operations related to playback of
recorded data.

Playing recorded data

Press the [PLAY] key.
Playback of recorded data starts.
PLAY During playback, the PLAY indicator at the top right of
the [PLAY] key flashes, and the playback icon flashes
on the display. When all recorded data have been played,
playback stops. During playback, the bar graphs are linked
to the playback signal. The recording time indication
changes to elapsed playback time indication.
The playback signal of the monitor channel is output at the Monitor Out
connector. The playback signal of each channel is also output at the Output
connectors. The recorded data can be checked by supplying these signals
to earphones, monitoring devices, or similar.

Recording time PLAY

Elapsed playback time

Playback screen example

111
Recall/Playback of Recorded Data

Stopping playback partway

Press the [STOP] key.
STOP The PLAY indicator and playback icon go out, and the
unit returns to the recall screen.

STOP

Pausing and restarting playback

Press the [PAUSE] key.
Playback is halted temporarily. In this condition, the pause
PAUSE
icon flashes on the display.
When you press the [PAUSE] key once more, the pause
icon goes out and playback resumes.

PAUSE

112
 Recall/Playback of Recorded Data

Performing fast forward or reverse during playback

Press and hold the [>]/[<] keys.
While you press the [>] or [<] key, the playback position
is moved quickly forwards or backwards. During this
ENT time, no playback signal is output. If the playback position
was moved all the way to the end of the recorded data,
playback will stop when you release the [>] key. If the
playback position was moved all the way to the beginning
of the recorded data, playback will start when you release
the [<] key.
The speed of fast forward or reverse is about 4 times higher
than regular playback.

or

Press key

Release key

Fast forward or reverse occurs while [>] or [<] key is pressed

113
Recall/Playback of Recorded Data

Performing high-speed forward or reverse during playback

While playback is paused, press and hold the [>] or [<] key.
When you hold down the [>] or [<] key for about one second,
high-speed forward or reverse starts and the playback
ENT position is moved quickly forwards or backwards. When
you release the key, the unit returns to the playback pause
condition at that point. The speed of high-speed forward
or reverse is about 60 times higher than regular playback.
If you press the [>] or [<] key and release it within less
than one second, the unit jumps to the voice memo start
position or marker position.

or

Press key

Release key

High-speed forward or reverse occurs while [>] or [<] key is pressed

Jumping to the voice memo start position or marker position

While playback is paused, press the [>] or [<] key.
When you press the [>] or [<] key, the playback position
jumps forwards or backwards to the next (closest) voice
ENT
memo start position or marker position. If there is no voice
memo start position or marker position in that direction, the
position jumps to the end or the beginning of the recorded
data. The elapsed playback time indication changes when
the position changes, letting you check the movement.

114
 Recall/Playback of Recorded Data

Canceling recall mode

When you press the [RECALL] key at the Select File screen, the recall mode
is terminated and the unit returns to the main screen.
If a recall screen is currently shown, press the [RECALL] key once to return
to the Select File screen, and then press it again to cancel the recall mode.

When the unit returns to the main screen, a constant current may be output
from a channel for which CCLD is selected. The power supply condition is
checked, and the unit may be shut down if battery capacity is insufficient.
In such a case, replace the batteries with a fresh set, or use an AC adapter or
other suitable external power source.

Other information

When SD memory card was removed in recall mode

While the unit is in recall mode, you should not remove the SD memory card.
If the SD memory card is removed, the recall mode will be canceled and the
unit returns to the main screen.

Important
If you remove the SD memory card while the
card is being accessed, damage may occur.

115
Recall/Playback of Recorded Data

About the supplied viewer software

Using the supplied viewer software, WAVE files can be imported from the
SD card and waveforms can be displayed on the computer.
The file structure on the SD memory card is as follows.

DA21.INI Setting file

Record
YYYY-MM-DD_HHMMSS The folder is identified by start time (Recorded data)
WR_xxx_YYYYMMDD_HHMMSS_yyyy.wav Wave recording file is WR
MM_xxx_YYYYMMDD_HHMMSS.wav Voice memo file is MM
YYYY-MM-DD_HHMMSS
WR_xxx_YYYYMMDD_HHMMSS_yyyy.wav
TC_xxx_YYYYMMDD_HHMMSS.wav Rotary measurement file is TC
Other
MM_xxx_YYYYMMDD_HHMMSS.wav Voice memo file when the recording is not performed

YYYY-MM-DD: Year(YYYY)-Month(MM)-Day(DD)
YYYYMMDD: Year(YYYY)Month(MM)Day(DD)
HHMMSS: Hour(HH)Minute(MM)Second(SS)
xxx: Index number
yyyy: Split file number

To observe the waveform of recorded data with the viewer software, select
the “.wav” file in the folder. The folder name “YYYY-MM-DD_HHMMSS”
corresponds to the indication shown on the Select File screen in recall mode.

Important
Do not change the .wav file name. The file data
is not played back correctly.

116
 Recall/Playback of Recorded Data

The DA21.INI file contains information about all settings of the DA-21 (see
page 52). You can also store the file with a suitable file name on the computer,
and use different files to manage various settings.

Important
Use only RION supplied SD memory cards.
Operation with other cards is not assured.

Note
Only WAVE files that were recorded with the DA-21
can be played using the DA-21.

117
Recall/Playback of Recorded Data

Recall Mode Operation Flow Chart

R e c a l l m o d e

Select File screen

RANGE

RECALL ENT
n

Change Delete selected

file number recorded data
e

RECALL
e

ENT
r

Recall screen
c

ENT
s

Change
file number
n

STOP PLAY
End is reached
during playback
or
i

Playback screen [Playback in progress]

a

Fast forward/reverse
PAUSE
M

Pause/resume playback

[During playback pause]

High-speed forward/reverse

Jump to voice memo start

or marker position, or to
end/start of recorded data

118
 Messages
During operation of this unit, various messages giving warnings and providing
procedure information will appear. The most important messages are listed
and described in this section.
(The actual font and placement of the message on the display may differ from
the examples shown here.)
Messages are listed below. A representative display state where the message
may appear is given in parentheses. The message explanations in this section
are also in the same order.
Adjustment failed. ------------------------------------ (Power-on)
Card Error. ----------------------------------------(Power-on etc.)
Cannot Record. All …--------------------------- (Menu setting)
Cannot Record. Card … ------------- (Voice memo, recording)
Number of data … ------------------- (Voice memo, recording)
MENU LOCKED --------------- (Menu display, data deletion)
NoCard ------------------------- (Recording start, Recall mode)
Disconnect the USB … ------- (Recording start, Recall mode)
Now Closing file. --------------------- (Voice memo, recording)
Save Settings. ------------------------------------- (Menu setting)
Default settings. -------------------------------------- (Power-on)
Please check having … ----------- (Inter-unit synchronization)
Synchronization will be … ------ (Inter-unit synchronization)
Please perform the … ------------ (Inter-unit synchronization)

The message explanation uses the following pattern.

Message string

Description Explains the meaning of the message or the condition

it refers to.
Countermeasure Describes steps to take when the message is shown.
Condition Describes the operation steps or unit condition that can
lead to the message being shown. (Omitted where not
necessary.)
119
Messages

Description At power-on, the unit performs various adjustment

routines. If these cannot be completed within a certain
period, this message appears.
Countermeasure Press the [ENT] key to clear the message, and then
perform a power-down, power-on cycle.
Condition Indication “Adjustment Executing” was displayed
for about 1 minute during the power-on phase.

120
 Messages

Description The inserted SD memory card cannot be read/written

in the DA-21.
Folder/file structure as required by the DA-21 is not
present, or another folder/file structure exists.
There has been an error while managing a fi le
required by the DA-21.
The card was formatted using a file system other
than FAT16 or FAT32, or the card is defective.
Countermeasure Press the [ENT] key to clear the message.
Format the card in the DA-21. If the message is still
shown, try a different SD memory card.
Formatting a card will permanently delete all data
present on the card. Copy any data that are still
required to another location on the computer before
starting the formatting process.
Condition At power-on, or when an SD memory card is inserted/
removed.
Recording procedure or recall mode was activated.
Attempted to write unit settings via a menu item.

121
Messages

Description All channels are set to OFF.

Countermeasure Press the [ENT] key to clear the message. The unit is
functioning normally, but data cannot be recorded. To
record data, set at least one channel to a setting other
than OFF.
Condition Quitting a menu screen and returning the main
screen.
Trying to activate recording by pressing [REC].

Description There is not enough space on the SD memory card to

write data.
Countermeasure Press the [ENT] key to clear the message. (Data recorded
up to that point will be saved on the SD memory card.)
Copy the existing files on the SD memory card to a
suitable location on the computer, and then format the
SD memory card. Alternatively, provide another SD
memory card.
Condition Card became full during recording.
Attempted to start recording while no space was
available on card.

122
 Messages

Description The maximum number of data that can be recorded

with the DA-21 has been reached.
Countermeasure Press the [ENT] key to clear the message.
Copy the existing files on the SD memory card to a
suitable location on the computer, and then format the
SD memory card. Alternatively, provide another SD
memory card.
Condition Attempted to start recording procedure.
Attempted to record voice memo from main screen.

Description One of the following actions was attempted in menu

lock mode.
Tried to change a setting in a menu
Tried to delete data (recall mode)
Countermeasure Press the [ENT] key to clear the message.
If you want to proceed with the menu setting or data
deletion, cancel the menu lock mode (see page 88).

123
Messages

Description No SD memory card is inserted in the DA-21.

Countermeasure Press the [ENT] key to clear the message.
Insert an SD memory card.
Condition Attempted to start recording procedure.
Tried to enter recall mode.

Description “USB Storage” in the <System> menu is selected ON.

Countermeasure Press the [ENT] key to clear the message.
Set “USB Storage” to OFF in the <System> menu.
Condition Attempted to start recording procedure.
Tried to enter recall mode.

124
 Messages

Description Data recording was completed, and information nec-

essary for data management is currently being written
to the SD memory card.
Countermeasure Never remove the SD memory card in this condition.
Be sure to wait until the message has disappeared.
Otherwise the card may become unusable until formatted
in the DA-21 (at this time, previously recorded data
will also be destroyed).
While the message is being shown, the [REC] key is
inactive and any trigger event is disregarded.
Condition Data recording is completed.
Voice memo recording from main screen was stopped.

Description Select whether to save the current settings of the unit.

Countermeasure Press the [ENT] key to save, [PAUSE] key to cancel.
When you press the [ENT] key, the settings of the
DA-21 are saved as a setting file on the SD memory
card. (The file name is fixed to DA21.INI.)
Condition When executing “Save Settings” item of <System>
menu.

125
Messages

Description This message appears at power-on if the input range

and menu settings from the last use could not be saved
properly. All settings will return to the factory default
condition.
Countermeasure Press the [ENT] key to clear the message.
Make the required settings again before starting to
record.

Description This message asks for check after operation of inter-unit

synchronization.
Countermeasure Press the [ENT] key to clear the message.
Check the synchronization information on the display
(page 18).
Condition When executing inter-unit synchronization (page
91).

126
 Messages

Description This message warns that change of the settings of

synchronized DA-21 will cancel the synchronization.
Countermeasure Press the [ENT] key when you would like to continue
operation.
Press the [PAUSE] key when you would like to interrupt
operation.
Condition When pressing the [MENU] key of synchronized
DA-21.

Description This message asks for re-synchronization of the DA-21

units because the synchronization of DA-21 units was
canceled.
Countermeasure Press the [ENT] key to clear the message.
Repeat the synchronization procedure (page 91) when
you would like to synchronize two DA-21 units again.
Condition When the synchronization of DA-21 units was
canceled.

127
 Filter Characteristics
The characteristics of the built-in low-pass and high-pass filters are shown
below.
The available low-pass filter settings are OFF, 200 Hz, 1 kHz, and 2 kHz, but
the setting must be equal to the frequency range setting or lower. When the
OFF setting is selected, the low-pass filter is set to the cutoff frequency of the
frequency range.
The available high-pass filter settings are OFF and 5 Hz. For DC channels, the
available setting is OFF. For AC and CCLD channels, a 0.3 Hz high-pass filter
will apply even if the OFF setting is selected.

High-pass filter characteristics

HPF 0.3 Hz
−20
Gain (dB)

HPF 5 Hz
−40

−60

−80
0.1 1 10 100 1000
Frequency (Hz)

Low-pass filter characteristics

LPF 200 Hz
−20
Gain (dB)

LPF 1 kHz
−40
LPF 2 kHz

−60

−80
10 100 1k 10 k 100 k
Frequency (Hz)

128
 Settings and Other Information
This section lists all menu settings, data recording operation types, and other
relevant information.

Approximate recording times

The approximate recording times available with an SD memory card inserted
in the unit are as shown in the table below (bit length setting 16 bit). With
the 24 bit setting, times are about one third shorter.
The maximum time for a single recording operation is 1000 hours. When
this limit is reached, recording is terminated automatically. The maximum
number of files that can be recorded in a single operation is 1000 (including
voice memo files and revolution speed files). When this number is reached,
recording is terminated automatically.
The available recording time differs depending on the type of SD memory
card. Please note that these are approximate values provided for reference.

2 GB SD memory card (Sampling frequency: ×2.56)

Number of Frequency range
channels 100 Hz 500 Hz 1 kHz 5 kHz 10 kHz 20 kHz
1066 h 213 h 106 h 21 h 10 h 5h
1
40 m 20 m 40 m 20 m 40 m 20 m
533 h 106 h 53 h 10 h 5h 2h
2
20 m 40 m 20 m 40 m 20 m 40 m
355 h 71 h 35 h 7h 3h 1h
3
32 m 6m 33 m 6m 33 m 46 m
266 h 53 h 26 h 5h 2h 1h
4
40 m 20 m 40 m 20 m 40 m 20 m

32 GB SD memory card (Sampling frequency: ×2.56)

Number of Frequency range
channels 100 Hz 500 Hz 1 kHz 5 kHz 10 kHz 20 kHz
17066 h 3413 h 1706 h 341 h 170 h 85 h
1
40 m 20 m 40 m 20 m 40 m 20 m
8533 h 1706 h 853 h 170 h 85 h 42 h
2
20 m 40 m 20 m 40 m 20 m 40 m
5688 h 1137 h 568 h 113 h 56 h 28 h
3
32 m 36 m 48 m 36 m 48 m 24 m
4266 h 853 h 426 h 85 h 42 h 21 h
4
40 m 20 m 40 m 20 m 40 m 20 m

129
Settings and Other Information

Menu items
<Input> menu (page 39)
Item Description Settings
Inp [OFF] / [DC] / [AC] / [CCLD]
Sensor signal type
(CH1 to CH4) / [VP4x]
[OFF] / [Tacho] / [Voice Memo]
Inp (CH5) CH5 input signal type
/ [Marker]
HPF High-pass filter frequency [OFF] / [5 Hz]
LPF Low-pass filter frequency [OFF] / [200 Hz] / [1 kHz] / [2 kHz]
[V] / [EU] / [MIC] / [PICK] / [SLM]
Sens Sensor type
/ [VM]
Sensor sensitivity/unit con- [V/EU] / [dB] / [mV/(m/s2)]
Sensitivity
version / [pC/(m/s2)]

<Rec.Parameters> menu (page 44)

Item Description Settings
[100 Hz] / [500 Hz] / [1 kHz] / [5 kHz]
Frequency Range Frequency range
/ [10 kHz] / [20 kHz]
Sampling Frequency Sampling frequency [×2.4] / [×2.56]
Bit Length Bit Length [16 bit] / [24 bit]
Wave Splitting Recording data file
[10 min] / [1 h]
Interval interval
[1 to 59 s] / [1 to 59 m] / [1 to 24 h]
Recording Time Recording time
/ (Manual)
Pre Recording Time Pre-recording time [0 s] / [1 s] / [5 s]

130
 Settings and Other Information

<Trigger> menu (page 46)

Item Description Settings
Mode Trigger mode [Free] / [Single] / [Repeat]*3/ [Master]
[Level] / [External] / [External Gate] /
Type Trigger signal type
[Time]
Level Trigger level *1 [0.1 to 0.9%] / [1 to 99%]
Ch Trigger channel *1 [Ch1] to [Ch4]
Start Time Start time *2 [2013/01/01 00:00] to [2037/12/31 23:59]
Stop Time Stop time *2 [2013/01/01 00:00] to [2037/12/31 23:59]
[5 m] / [10 m] / [15 m] / [30 m]
Interval Recording interval *2 / [1 h] / [8 h] / [24 h]
Sleep Sleep mode [OFF] / [ON]
*1 Trigger level and trigger channel to be set when trigger signal type is "Level".
*2 Start time, stop time, and recording interval to be set when trigger signal type is
"Time". When recording time is set to "Manual", "Interval" cannot be set.
*3 When recording time is set to "Manual", trigger "Repeat" and "Single" have the
same effect.

<Bar Graph> menu (page 50)

Item Description Settings
Graph Bar graph display method [Linear] / [Log]
Note For channels where the sensor type is [MIC], [SLM], or [VM], the graph display
method cannot be set. The bar graph is always in dB.

131
Settings and Other Information

<System> menu (page 51)

Item Description/Operation Settings
Read / Save Settings Read or save the setting values
Load default settings Initialize the setting values to default
Internal Memory
Apply or save the setting values to the unit
(No. 1 to No. 5)
Apply the setting values in the SD memory card to the
SD CARD
unit, or save the setting values to the SD memory card
Clock Settings Current time setting
Date year, month, day [2013/01/01] to [2037/12/31]
Time hour, minute, second [00:00:00] to [23:59:59]
Backlight Settings Screen backlight setting
Brightness Backlight brightness [1] to [4]
Auto-Off Backlight auto-off timer [30 s] / [3 m] / [Continue]
Battery Type Type of batteries used [Alkaline] / [Ni-MH]
Card Format SD memory card format
USB Storage Connection to computer [OFF] / [ON]
Monitor Out connector func-
Monitor Out [OFF] / [ON]
tion
Index Device index number [1] to [255]
Version Version information

<Synchronization> menu (page 55)

Item Description Settings
Assign roles when synchronizing
Master / Slave [OFF] / [Master] / [Slave]
two unit
Synchronize Synchronize two units

132
 Settings and Other Information

Data recording
The unit offers 16 different (13 practical) combinations of recording time
and trigger settings. The tables below list combinations that are useful from
a practical point of view.

Data recording operation type

Recording
Type Mode Parameter
time setting
(1) – Free – – – –
(2) Single Level Ch
Level – –
(3) Repeat (Trigger level) (Trigger channel)
(4) Recording Single
External – – – –
(5) Time Repeat
(6) 1 s to 24 h Single –

Time Start Time Stop Time Interval Sleep

(7) Repeat (Recording
interval)
(8) – Free – – – –
(9) Single Level Ch
Level – –
(10) Repeat* (Trigger level) (Trigger channel)
(11) Manual Single
External – – – –
(12) Repeat*
(13) Single
Time Start Time Stop Time – –
(14) Repeat*
(15) External Single
– – – – –
(16) Gate Repeat

"–": No setting item, "Repeat*" indicates that operation is essentially the same as for "Single"

133
Settings and Other Information

Validity of pre-recording settings etc. depending on trigger conditions

Recording stop due to
Combination Pre-recording [STOP] key operation or
Trigger Post-recording
(previous table) (Pre Recording Time) insufficient SD memory
card capacity
Mode Free (1)(8) ×
Level (2)(3)(9)(10) ×
External (4)(5)(11)(12) ×
Time (6)(7)(13)(14) × ×
External
(15)(16)
Gate

: Function is valid ×: Function is not available

Post-recording (5 seconds) function only for External Gate.

134
 Settings and Other Information

Data recording: Recording time (1 s to 24 h), no trigger (1)

REC

Recording time
(1 s to 24 h)

(1) Free Recording in progress Recording completed

Data recording: Recording time (1 s to 24 h), Level trigger (2), (3)

REC

Recording time Recording time

(1 s to 24 h) (1 s to 24 h)
Trigger Recording
(2) Single standby Recording in progress completed

Trigger Trigger ...

(3) Repeat standby Recording in progress standby Recording in progress

Trigger level

Trigger channel
waveform

Trigger level
Level trigger event

Data recording: Recording time (1 s to 24 h), External trigger (4), (5)

REC

Recording time Recording time

(1 s to 24 h) (1 s to 24 h)
Trigger Recording
(4) Single standby Recording in progress completed

Trigger Trigger ...

(5) Repeat standby Recording in progress standby Recording in progress

Ext. Trig.
connector signal
External trigger event

135
Settings and Other Information

Data recording: Recording time (1 s to 24 h), Time trigger (6), (7)

REC Recording time Recording time Recording time

(1 s to 24 h) (1 s to 24 h) (1 s to 24 h)

Trigger Recording Recording ends when stop time

(6) Single Recording completed
standby in progress is reached during recording

Trigger Recording Trigger Recording ... Recording Recording Recording

standby in progress standby in progress in progress in progress completed

Interval Interval [Stop time]

(7) Repeat
Trigger Recording Trigger Recording ... Recording Recording Recording time
standby in progress standby in progress in progress completed (1 s to 24 h)

[Stop time]

Time trigger Time trigger Time trigger Time trigger

[Start time]
If next time trigger would be later than stop time setting,
recording ends at this point

Data recording: Manual (controlled with [STOP] key), no trigger (8)

REC STOP

(8) Free Recording in progress Recording completed

Data recording: Manual (controlled with [STOP] key),

Level trigger (9), (10)

REC STOP

Trigger
(9) Single standby Recording in progress Recording completed

Trigger
standby Recording in progress Recording completed
(10) Repeat

Trigger level

Trigger channel
waveform

Trigger level
Level trigger event

136
 Settings and Other Information

Data recording: Manual (controlled with [STOP] key),

External trigger (11), (12)
REC STOP

Trigger
(11) Single standby Recording in progress Recording completed

Trigger
(12) Repeat standby Recording in progress Recording completed

Ext. Trig.
connector signal

External trigger event

Data recording: Manual (controlled with [STOP] key),

Time trigger (13), (14)
REC STOP

Trigger
(13) Single standby Recording in progress Recording completed

Trigger
(14) Repeat standby Recording in progress Recording completed

Start time Stop time

Single
Repeat Recording in progress Recording completed

If stop time is reached before [STOP] key

is pressed, recording ends at this point

Data recording: Using gate signal (15), (16)

REC

Trigger Data recording

(15) Single standby in progress Recording completed
5 seconds after state
5 seconds after state changed from L to H
changed from L to H

Trigger Data recording Trigger standby Data recording ...

(16) Repeat standby in progress in progress

Ext. Trig.
connector signal

Period during which Ext. Trig. connector is shorted

137
Settings and Other Information

Representative value of inherent noise

Representative value of inherent noise of the unit which connected a sensor is
shown in the table below. Those representative values are levelized by AS-70.
(HPF setting and LPF setting of the unit are OFF.)

Representative values
Sensors Remarks
1 V range 0.01 V range
PV-85 + VP-40 0.005 (m/s2) 0.003 (m/s2)
PV-87 + VP-40 0.001 (m/s2) 0.001 (m/s2)
PV-91C 0.027 (m/s2) 0.023 (m/s2)
X 0.069 (m/s2) 0.023 (m/s2)
PV-97I Y 0.065 (m/s2) 0.021 (m/s2)
Z 0.080 (m/s2) 0.022 (m/s2)
X 0.224 (m/s2) 0.102 (m/s2)
PV-97C + VP-40 Y 0.215 (m/s2) 0.095 (m/s2)
Z 0.191 (m/s2) 0.114 (m/s2)
A 23.3 (dB) 12.3 (dB)
NH-22A + UC-59 C 23.9 (dB) 19.5 (dB)
Z 32.6 (dB) 30.8 (dB)
Sensitivity:
1000 pF dummy + VP-40 0.005 (m/s2) 0.002 (m/s2)
5 mV/(m/s2)

Power save settings

Power consumption differs according to the usage condition of the unit.
Using the unit with settings such as indicated below will help to conserve
power.

• Screen backlight off (page 7, 53)

• Input (“Inp”) for unused channels (CH1 to CH5) set to “OFF” (page 39)
• Monitor Out set to “OFF” (page 54)
• Frequency Range set as low as possible (page 44)

138
 WAVE File Format
This section provides details about the WAVE file format used by the unit.

Note
The WAVE file format of the DA-21 differs from
that of DA-20 or DA-40.

Basic structure
The WAVE file is made up of variable-length blocks called “chunks”. The
basic structure is as follows.
The chunks and file structure used by the DA-21 are shown below.

RIFF Wave Chunk

groupID = "RIFF"
RIFF header
chunkSize = size of following data

riffType = "WAVE"

Chunk 1
chunkID = xxxx

Sub chunk 1 chunkSize = Data size

Data...

Chunk 2
RIFF data
chunkID = xxxx

Sub chunk 2 chunkSize = Data size

Data...

Basic WAVE file structure

139
WAVE File Format

The chunks and file structure used by the DA-21 are shown below.

12 bytes RIFF header

24 bytes fmt sub chunk

24 bytes Type sub chunk

40960 bytes Marker chunk

40960 bytes Reserved

Common settings 82936 bytes

chunk (fixed)
196 bytes Common chunk
652 bytes
456 bytes CH by CH chunk
(114 bytes × 4 channels)

36 bytes Wave Settings chunk*

268 bytes Padding chunk

n bytes Data sub chunk n - 8 bytes

*For the tachometer signal input, the Wave Settings chunk becomes
the Tacho Settings chunk.
Because the size of the Tacho Settings chunk is 62 bytes,
the Padding chunk size becomes 242 bytes in this case.

File structure and size

140
 WAVE File Format

Invalid values
For unused items, a value defined as an invalid value is inserted.
The invalid values for the respective data types are shown in the table below.

Type Invalid values

char Blank

int16 Minimum value

uint16 Maximum value

int32 Minimum value

uint32 Maximum value

int64 Minimum value

uint64 Maximum value

float Minimum value

double Minimum value

141
WAVE File Format

Data types
The DA-21 uses the following specially defined data types.

typedef struct {
uint32 dwDataAddress; /* < Address as counted from start of data chunk */
uint32 dwDataSize;
uint32 dwFatDateTime;
} MARKERFORMAT;

typedef struct {
year :6; /* < Year (offset from 2000) */
mon :4; /* < Month (1 to 12) */
day :5; /* < Day (1 to 31) */
hour :5; /* < Hours (0 to 23) */
min :6; /* < Minutes (0 to 59) */
sec :6; /* < Seconds (0 to 59) */
} FATDATETIME;

dwFatDateTime
The date is a packed value with the following format.
Bits Values Meaning
0 to 5 0 to 59 Second
6 to 11 0 to 59 Minutes (0 to 59)
12 to 16 0 to 23 Hours (0 to 23, 24-hour format)
17 to 21 0 to 31 Day of the month (1 to 31)
22 to 25 1 to 12 Month (1 = January, 2 = February etc.)
26 to 31 0 to 63 Year offset from 2000 (add 2000 to get actual year)

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 WAVE File Format

Chunks
The following tables provide details about the structure of the RIFF header
(RIFF chunk) and the various sub chunks listed in the section “File structure
and size” (page 140).

RIFF chunk

Table 1 RIFF chunk

Variable Size
Type name (Byte) Description Value

char[4] Chunk ID 4 Indicates RIFF "RIFF"

Depends on
Total size of following data recording
uint32 Chunk Size 4
(not including this item) parameters
char[4] riffType 4 Indicates RIFF type "WAVE"

fmt sub chunk

Table 2 fmt sub chunk

Size
Type Variable name (Byte) Description Value

char[4] Chunk ID 4 Indicates chunk type "fmt_"

Total size of following data
uint32 Chunk Size 4 16
(not including this item)
uint16 wFormatTag 2 Format type 0x0001
uint16 nChannels 2 Number of channels 1 to 4
uint32 nSamplesPerSec 4 Number of samples per second See Table 3
uint32 nAvgBytesPerSec 4 Number of bytes per second See Fig. 1
uint16 nBlockAlign 2 Block size See Fig. 2
uint16 wBitsPerSample 2 Number of bits per sample 16 / 24

Table 3 nSamplesPerSec
Range
100 Hz 500 Hz 1 kHz 5 kHz 10 kHz 20 kHz
Rate
2.4 240 1200 2400 12000 24000 48000
2.56 256 1280 2560 12800 25600 51200

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WAVE File Format

wBitsPerSample
nAvgBytesPerSec = nSamplesPerSec × nChannels ×
8

Fig. 1 nAvgBytesPerSec

wBitsPerSample
nBlockAlign = nChannels ×
8

Fig. 2 nBlockAlign

Type sub chunk

Table 4 Type sub chunk

Size
Type Variable name (Byte) Description Value

char[4] Chunk ID 4 Indicates chunk type "TYPE"

Total size of following data
uint32 Chunk Size 4 16
(not including this item)
char[8] File Type 8 File type “WR______”
uint16 File Revision 2 Chunk format version number 1 or more
Reserved 6

144
 WAVE File Format

CommonShareSetting (common) chunk

Stores setting information of the unit, including trigger settings etc.

Table 5 CommonShareSetting (common) chunk
Variable Size
Type (Byte) Description Value
name
char[4] Chunk ID 4 Indicates chunk type "CSET"
Total size of following data
uint32 Chunk Size 4 (not including this item) 644
Product
char[12] Type 12 Product designation “DA-21_______”
Repeat Top number is 1,
Repeat trigger sequential
uint16 Serial 2
Number
number Nth number is N
File Serial Top number is 1,
uint16 2 Split file sequential number
Number Nth number is N
int64 Start Time 8 File start time UNIX time
Time accuracy
is 10 ms.
Actual Refer to the
Actual record time from Start
int64 Record 8
Time
Wave Data
Time chunk for the
exact number
of samples.
Unit
int16 Equipped 2 Number of total channels 4
Channels
Total
int16 Enabled 2 Number of enabled channels 1 to 4
Channels
Reserved 2
Reserved 2
Reserved 40
Reserved 8
Unit Serial
char[16] 16 Serial number
Number
AA.BB.XXYY
Unit CPU (8 digits in hex
int32 4 CPU version
Version number)
AA.BB.XXYY
Unit DSP (8 digits in hex
int32 4 DSP version
Version number)
AA.BB.XXYY
Unit CPLD (8 digits in hex
int32 4 CPLD version
Version number)

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WAVE File Format

Variable Size
Type (Byte) Description Value
name
Unit AA.BB.XXYY
int32 SubMicon 4 Sub-microcomputer version (8 digits in hex
Version number)
0: Free
Trigger 1: Single
int16 2 Trigger mode
Mode 2: Repeat
4: External
Trigger 8: External Gate
int16
Source
2 Trigger source 16: Level
512: Time
Trigger
int16
Channel
2 Trigger monitored channel 1 to 4
Digit value in
signed 16bit or
Trigger 24bit is inputted
int32
Level Wave
4 Trigger level
by Int32 of MSB
stuffing
Reserved 2
Reserved 4
Trigger
int16 Slope 2 Trigger slope Always 10
Trigger
int64 Start Date 8 Trigger start time UNIX time
Time
Trigger
int64 Stop Date 8 Trigger stop time UNIX time
Time
Trigger
int32
Interval
4 Trigger interval Second time scale
3: 100 Hz
5: 500 Hz
Measure
6: 1 kHz
int16 Frequency 2 Frequency range 8: 5 kHz
Range
9: 10 kHz
10: 20 kHz
Measure
Frequency ratio (Sampling 0: 2.40
int16 Frequency 2
Ratio frequency / Frequency range) 1: 2.56
Tacho Codec 0: OFF
int16
Mode
2 Tacho meter codec mode 2: ON
0: OFF
Synchronous Inter-unit synchronization
int16 2 1: Master
Mode mode 2: Slave
Reserved 22

146
 WAVE File Format

CommonChSetting (each CH) chunk

Stores setting information of the unit, including each channel (for four
channels) settings etc.
Table 6 CommonChSetting (each CH) chunk
Size
Type Variable name (Byte) Description Value

Reserved 40
int16 Chx Number 2 Channel number 1 to 4
0: false
int16 Chx Enabled 2 Channel input enable
1: true
Reserved 2
0: V
1: EU
Chx Sensor 2: MIC
int16 2 Sensor type
Type 3: PIC
4: SLM
5: VM
102: 0.01 V (−40 dB)
103: 0.03 V (−30 dB)
104: 0.1 V (−20 dB)
Chx Sensor Input voltage range 105: 0.3 V (−10 dB)
int16 2
Input Range (Vpeak) 106: 1 V (0 dB)
107: 3 V (10 dB)
108: 10 V (20 dB)

int16 Chx Coupling 2 Input coupling 0: AC

1: DC
0: false
int16 Chx CCLD 2 CCLD setting
1: true
0: false
int16 Chx Inversion 2 Input inversion
1: true
0: OFF
Chx HPF Cutoff High-pass digital fi lter
int16 2 1: 0.02 Hz
Frequency cutoff frequency
8: 5 Hz
0: OFF
Chx LPF Cutoff Low-pass digital filter 4: 200 Hz
int16 2
Frequency cutoff frequency 8: 1 kHz
12: 2 kHz
V
Chx Measurement EU
char[8] 8 Unit
Unit dB
m/s2
Calibration value (physical Setting value on
double Chx ValuePerBit 8 quantity per 1 bit) calibration
Calibration value (sen- Setting value on
double Chx ValuePerVolt 8 sitivity) calibration

147
WAVE File Format

Size
Type Variable name (Byte) Description Value

Reserved 8
Chx Zero dB Calibration value (notation Setting value on
double 8 of 0 dB reference index)
Reference (EU) calibration
0: No overload
has occurred
Overload information in
uint16 Chx Overload 2 1: Overload has
the file occurred at
least once
Reserved 2
Reserved 10

Wave Settings chunk

Table 7 Wave Settings chunk

Size
Type Variable name (Byte) Description Value

char[4] Chunk ID 4 Indicates chunk type "WSET"

Total size of following data
uint32 Chunk Size 4 28
(not including this item)
Reserved 2
0
int16 Pre-time 2 Pre recording time −1
−5
Reserved 24

148
 WAVE File Format

Tacho Settings chunk

Table 8 Tacho Settings chunk

Size
Type Variable name (Byte) Description Value

char[4] Chunk ID 4 Indicates chunk type "TSET"

Total size of following data
uint32 Chunk Size 4 54
(not including this item)
Pulse Per
uint16 2 Number of pulses per rotation 1
Rotation
Reserved 2
Reserved 2
Reserved 8
Reserved 8
Reserved 8
Reserved 24

Padding chunk

Table 9 Padding chunk

Size
Type Variable name (Byte) Description Value

char[4] Chunk ID 4 Indicates chunk type "padi"

Total size of following data Wave file: 260
uint32 Chunk Size 4
(not including this item) Tacho file: 234
Padding bytes to place
Reserved the header on a 512 byte
boundary

149
WAVE File Format

Marker chunk

This chunk contains information about the start position and date/time
of marker events during recording. Regardless of whether the WAVE file
comprises marker data, the Marker chunk is always added.
Size is fixed to 12 bytes × 3412 + 8 + 8 = 40960 bytes.
Upper limit is 3412 positions.
Dummy 8 bytes at the end are not used.

Table 10 Marker chunk

Size
Type Variable name (Byte) Description Value

char[4] ChunkID 4 Indicates chunk type "memo"

Total size of following
uint32 ChunkSize 4 chunk data (not including 40952
this item)
MARKERFORMAT
40944
[3412]
uint32 dwDataAddress (4) Address from data top
uint32 dwDataSize (4) Marker size (Bytes)
uint32 dwDateTimeM (4) Date/time
Reserved 8

150
 WAVE File Format

Wave Data chunk

Recorded raw waveform data are stored here.

Table 11 Wave Data chunk

Size
Type Variable name (Byte) Description Value

char[4] Chunk ID 4 Indicates chunk type "data"

Total size of following data
uint32 Chunk Size 4 See Fig. 3
(not including this item)
Depends on
Store the recorded raw
WAVEData Data recording
time waveform data

WAVEData follows the data conventions for regular WAVE files (16 bit/24
bit, little endian, 16 bit range full-scale value 25400, 24 bit range full-scale
value 6502400).

wBitsPerSample
Chunk Size = nSamplesPerSec × nChannels × ×[Recording time (sec)]
8

Fig. 3 Chunk Size

151
 Specifications
Applicable standards
CE marking, UKCA marking, WEEE Directive, Chinese RoHS
Input section
Input connectors
Signal input × 4 (BNC)
Revolution speed (rotary pulse)
× 1 (BNC)
Voice memo input × 1
(voice memo microphone: 3.5 mm dia. 4-pole mini jack)
External trigger input
× 1 (2.5 mm dia. monaural mini jack)
Remote control × 1 (8-pin MINI DIN connector for Remote Controller
(DA-20RC1))
Synchronous signal
× 1 (8-pin connector)
USB port × 1 (Mini-B connector)
Input range ±0.01 V, ±0.03 V, ±0.1 V, ±0.3 V, ±1 V, ±3 V, ±10 V
Note: The 0.03 V, 0.3 V, 3 V input range settings stand
for 0.0316 V, 0.316 V, and 3.16 V actual values.
Input impedance 100 kΩ or more
Maximum input voltage
± approx. 13.0 V
Overload point Range full-scale +2.0 dB, tolerance ±1.0 dB
Input coupling AC/DC
(AC coupling [primary]: −3.0 dB ±1.0 dB at 0.315 Hz)
Sensor drive power (CCLD)
2 mA, 24 V
Digital filters Cutoff slope: −12.0 dB/oct,
at filter frequency −3.0 dB ±1.0 dB
High-pass filter: OFF, 5 Hz
Low-pass filter: OFF, 200 Hz, 1 kHz, 2 kHz

152
 Specifications

Frequency response DC coupling DC to 1 Hz: ±1.0 dB

1 Hz to 12.5 kHz: ±0.5 dB
12.5 kHz to 20 kHz: ±1.0 dB
AC coupling 1 Hz: ±1.0 dB
1 Hz to 12.5 kHz: ±0.5 dB
12.5 kHz to 20 kHz: ±1.0 dB
Inter-channel phase lag
1 deg max.
(AC coupling, HPF OFF, 10 V to 0.03 V range, same
frequency range, 20 kHz range)
3 deg max.
(AC coupling, HPF OFF, 0.01 V range, same frequency
range, 20 kHz range)
S/N ratio: (within frequency band, including overload)
80 dB or more (Input range: 10 V, 3 V, 1 V, 0.3 V)
75 dB or more (Input range: 0.1 V)
70 dB or more (Input range: 0.03 V)
60 dB or more (Input range: 0.01 V)
Offset DC coupling (input shorted):
max. 2.0% of range full-scale (10 V, 3 V, 1 V)
max. 2.5% of range full-scale (0.3 V, 0.1 V)
max. 5.0% of range full-scale (0.03 V)
max. 10% of range full-scale (0.01 V)
AC coupling
max. 2.0% of range full-scale
Distortion ±0.1% or less (within frequency band)
Voice memo function 2 operation modes
A: Recording in idle state
B: Revolution speed channel is always used as voice
memo during recording
Revolution speed function is disabled while using
voice memo function
* Marker function becomes also active during
recording

153
Specifications

Rotary pulse
Input impedance 100 kΩ or more
Input voltage range
0 V to 10 V (Open collector supported, TTL supported)
Threshold level +2.5 V
Counting method Periodic counting
Measurable revolution speed range
200 rpm to 600,000 rpm (1 pulse / rotation)
Output section
Output connectors
Playback output × 4 (2.5 mm dia. monaural mini jack) playback recorded
signal
Monitor out × 1 (3.5 mm dia. stereo mini jack)
When recording:
Analog signal output of a selected channel
When playing back:
Playback output (including voice menu) of a selected
channel
Playback output
Playback output connector
Output impedance
600 Ω
Frequency response
DC to 1 Hz: ±1.0 dB
1 Hz to 12.5 kHz: ±0.5 dB
12.5 kHz to 20 kHz: ±1.0 dB
Output voltage ±3.16 V (corresponding voltage at range full scale)
Maximum output voltage
±4.0 V
Offset 1.5% or less of maximum output
S/N ratio 72 dB or more
(within frequency band, including overload)
Inter-channel phase lag
1 deg max. (within frequency band)

154
 Specifications

Monitor output connector

Output impedance
100 Ω
Output voltage ±3.16 V (corresponding voltage at range full scale)
Maximum output voltage
±5.5 V
Offset 2.0% or less of maximum output
(input range 1 V or higher)
Other specifications
Same as for input (frequency response, linearity,
distortion)
Playback output selection
Output both from playback output and monitor output
connectors
Recording section
Recording media SD memory card (Operation assured only with RION
supplied SD memory cards)
Maximum capacity: 32 GB
File system FAT16, FAT32
A/D converter 24 bit quantization
(quantization dynamic range 144 dB)
Bit length can be selected from 16 bit or 24 bit
File format WAVE (16 bit/24 bit linear, no compression)
Frequency range settings
100 Hz, 500 Hz, 1 kHz, 5 kHz, 10 kHz, 20 kHz
Sampling frequency settings
Frequency range ×2.4 or ×2.56
Maximum recording time
Approx. 23 hours (20 kHz range × 4 channels, using
32 GB SD memory card)
Pre-recording Data recorded 0, 1, or 5 seconds prior to start of recording
or trigger event

155
Specifications

Trigger section
Trigger source External: Open collector supported
(internal 3.3 V, 50 kΩ)
• External
• External Gate
(Compatible with comparator output of Sound Level
Meter NL-62, NL-52, NL-42)
Internal
• Level trigger (wave form):
0.1% to 0.9%, 1% to 99% of input range full-scale,
linear peak
• Time trigger:
Recording is carried out repeatedly between preset
start time and stop time, at specified intervals (sleep
function settable)
Trigger mode Free, Single, Repeat (divide into multiple files when
repeat mode)
Pre-trigger 0, 1, or 5 seconds (pre-recording time before trigger
event)
Calibration
Readings Linear (EU), Log (dB), can be set for each channel
Main screen reading is linear only
Display
LCD screen Backlit monochrome TFT, 256 (H) × 160 (V) dots
Display contents Setting screen, recording screen, level bar graph, level
history
LED indicators Overload indication, remaining card capacity warning
Status indicator for recording, playback, trigger standby, etc.
Language English

156
 Specifications

Store settings Five settings are stored in internal memory

Startup file is available in the SD memory card
USB
Mass storage class Connected to a computer as a storage device, and
recognized as a removable disk
Power supply section
Power supply Batteries or AC adapter (NC-98 series)
Car battery adapter (CC-82)
AC adapter Rated input: 100 V to 240 V AC, 50/60 Hz, 0.4 A
Rated output: 5.9 V DC, 2 A, 11.8 W
Batteries Four IEC LR6, size AA batteries (Alkaline batteries
or Nickel metal-hydride batteries [Ni-MH])
External DC 5 V to 20 V
Battery life (representative value)
Temperature 23°C, backlight off, monitor out off, 32 GB
card
Frequency Number of
CCLD ON CCLD OFF Batteries type
range channels
20 kHz 4 Approx. 4.5 hours Approx. 8 hours Alkaline
20 kHz 1 Approx. 7.5 hours Approx. 10 hours Alkaline
20 kHz 4 Approx. 7 hours Approx. 10 hours Ni-MH
20 kHz 1 Approx. 11 hours Approx. 12 hours Ni-MH

* The capacity of the used Ni-MH battery is 2450 mAh

* Battery life may differ significantly, depending on ambient temperature,
unit settings, and brand and type of batteries and SD memory card
Inter-unit synchronization
Synchronized operation of two units allows simultaneous
waveform level recording in up to 8 channels.
Other specifications
Dimensions Approx. 140 mm (H) × 175 mm (W) × 45 mm (D)
Mass 450 g (not including batteries)
Fastening holes 1/4-20UNC (inch) screw hole on bottom panel

157
Specifications

Operating environment
Temperature −10°C to +50°C
Humidity 90% RH Max. (Non-condensing)
Altitude 2000 m Max.
Pollution Degree 2
Installation Category
Ambient conditions for storage
−10°C to +50°C, max. 90% RH (no condensation)
Supplied accessories
IEC LR6 (size AA) alkaline battery 4
CD-ROM (Instruction manual, Viewer software AS-70 Viewer) 1
Inspection certificate 1
Optional accessories
AC adapter NC-98 series
Car battery adapter CC-82
Battery pack BP-21A
SD memory card
4-channel data recorder remote control unit DA-20RC1
Voice memo microphone MH-34B4B/SSM-17A (YAESU)
Monitor earphone ATH-C320
Soft carrying case (with shoulder strap) DA-20-007
BNC - BNC cable NC-39A
BNC - BNC coaxial cable EC-90 series
BNC - mini plug cable CC-24
BNC adapter VP-52C
Joint connector VP-54C
Comparator output cable CC-42C
(for connection to NL-62, NL-52, NL-42)
Comparator output cable CC-94A
(for connection to NL-21, NL-22, NL-31, NL-32)
Inter-unit sync cable CC-43
Condenser microphones (only electret type) UC series
Preamplifier NH-22A
Piezoelectric accelerometers PV series
Charge converter VP-40
Waveform analysis software AS-70
Waveform analysis software CAT-WAVE

158
 Specifications

Top view

140

175 45

Front view Right side view

Unit: mm
Dimensional Drawings

159
No. 59377 21-10