FX-4AD

SPECIAL FUNCTION BLOCK

USER'S GUIDE
JY992D52601E

This manual contains text, diagrams and explanations which will guide the reader in the correct installation
and operation of the FX-4AD special function block and should be read and understood before attempting
to install or use the unit.
Further information can be found in the FX PROGRAMMING MANUAL and FX SERIES HARDWARE
MANUAL.

INTRODUCTION

The FX-4AD analog special function block has four input channels .The input channels receive
analog signals and convert them into a digital value.This is called an A/D conversion.The FX-4AD
has a maximum resolution of 12 bits.

The selection of voltage or current based input/output is by user wiring. Analog ranges of -10 to 10V
DC (resolution: 5mV), and/or 4 to 20mA, -20 to 20mA (resolution: 20A) may be selected.

FX PC versions 2.0 or later (those with serial number 13OOOO or larger) are required as these
units have the TO/FROM applied instructions in their instruction set. Data transfer between the FX4AD and the FX base unit is by buffer memory exchange. There are 32 buffer memories (each of
16 bits) in the FX-4AD.

The FX-4AD occupies 8 points of I/O on the FX, FX2C expansion bus. The 8 points can be allocated
from either inputs or outputs. The FX-4AD draws 30mA from the 5V rail of the FX base unit or
powered extension unit.

1.1 External dimensions

+

DC24V

V+

weight : Approx 0.5kg (1.1 lbs) Dimensions:mm (inches)

I+
FG
COM

24V
A-D

CH1

+
+

DC24V

I+

V+

M3.5 (0.14")
terminal
screws

35mm
(1.38in.)
DIN rail
mounting
slot

FG
COM

CH1

POWER
CH2

CH1

READY

CH3

125 140
(4.92") (5.51")

CH4

OFFSET

Mounting
holes
5.5mm
(0.27in.)
dia.

GAIN

Extension
cable and
connector

CH2

CH2

I+
V+

V+

CH3

COM

FG

CH4

I+
V+

FG

COM

10 (0.39")

63 (2.48")

CH4

CH3

I+

FG

COM

I+
FG
FG
I+
I+
FG
V+ COM V+ COM V+ COM

73 (2.87")

TERMINAL LAYOUTS
CH4

Voltage input
0 to +/-10V

V+

*2

I+

100K
200K
100K

COM

*1 shielded

FG

AG(analog ground)

CH1

Current input
0 to +/-20mA

V+
I+

*3

250K
100K

FG

*3 If you are using current input, connect the V+ and

I+ terminals to each other.

*4
50mA
DC24V

*5

DC24V
+

+15V
DC/DC
converter

DC24V
-

Class 3
Grounding
or less)
(100

PC

*1 The analog input is received through a twisted

pair shielded cable. This cable should be wired
separately from power lines or any other lines
which may induce electrical noise.
*2 If a voltage ripple occurs during input, or there is
electrically induced noise on the external wiring,
connect a smoothing capacitor of 0.1 to 0.47F,
25V.

100K

COM

*1 shielded

95 (3.74")

AG
-15V

Extension cable
FX-4AD Analog Input Block

*4 If there is excessive electrical noise, connect the

FG frame ground terminal with the grounded
terminal on the FX-4AD.
*5 Connect the ground terminal on the FX-4AD unit
with the grounded terminal on the base unit. Use
class 3 grounding on the base unit, if available.

INSTALLATION NOTES AND USAGE

3.1 General specification

Item

Specification

General specifications(excluding withstand voltage)

Same as those for the FX base unit

3.2 Power supply specification

Item

Specification

Analog circuits

24V DC +/- 10%, 50mA(External power supply from base unit)

Digital circuits

5V DC, 30mA(Internal power supply from base unit)

3.3 Performance specifications

Analog inputs
Voltage input
Item

Current input

Either voltage or current input can be selected with your choice of input terminal.
Up to four input points can be used at one time.

Analog input range

DC -10V to +10V (input resistance:200K ).

Warning:this unit may be damaged by input
voltage in excess of +/-15V.

DC -20mA to +20mA (input resistance:250 ).

Warning:this unit may be damaged by input
currents in excess of +/-32mA.

Digital output

12-bit conversion stored in 16-bit 2's complement form.

Maximum value:+2047 Minimum value:-2048

Resolution

5mV (10V default range 1/2000)

20 A(20mA default range 1/1000)

Overall accuracy

+/-1% (for the range of -10V to +10V)

+/-1% (for the range of -20mA to +20mA)

Conversion speed

15ms/channel (Normal speed), 6ms/channel (High speed)

Analog inputs continued.....

Preset 0 (-10V to +10V)

Digital
Output

Preset 1 (+4mA to +20mA)

Digital
Output

+2047
+2000

-10.24V

Preset 2 (-20mA to +20mA)

Digital
Output
+1750

+1600

+1000

+1000
-32mA -20mA

-10V
+10V
+10.235V
-2000
-2048
Voltage Input

+4 +20 +32
mA mA mA

+20mA +32mA
-1000
-1600
Current
Input

Current
Input

NOTE: Preset ranges are selected by an appropriate setting in buffer memory of the analog block.
Current/Voltage input selection must match the correct input terminal connections.

Miscellaneous
Item

Specification

Isolation

Photo-coupler isolation between analog and digital circuits.

DC/DC converter isolation of power from FX base unit.
No isolation between analog channels.

Number of occupied I/O points

8 points taken from the FX expansion bus (can be either inputs or outputs)

3.4 Allocation of buffer memories (BFM)

BFM
*# 0
*# 1
*# 2
*# 3
*# 4
#5
#6
#7
#8
#9
#10
#11
#12
#13-#14

Contents
Channel initialization Default = H0000
Channel 1 Contains the number of samples (1 to 4096) to
Channel 2 be used for an averaged result. The default
Channel 3 setting for normal speed is 8.
Channel 4 The default setting for high speed is 1.
Channel 1 These buffer memories contain the averaged
Channel 2 input values for the number of samples entered
Channel 3 for the channel in buffer memories #1 to #4
Channel 4 respectively.
Channel 1
Channel 2 These buffer memories contain the present
value currently being read by each input
Channel 3 channel.
Channel 4
Reserved
Selection of A-D When set to 0, a normal speed is selected of
15ms/ch (default)
conversion
#15
When set to 1, a high speed is selected of
speed see note 2
6ms/ch
#16-#19 Reserved

BFM
*#20
*#21
*#22
*#23
*#24
#25-#28
#29
#30
#31

Reset to Defaults and Preset.

Offset, Gain Adjust Prohibit.
Offset, Gain Adjust
Offset Value
Gain Value
Reserved
Error status
Identification code K2010
Cannot be used

b7 b6 b5 b4 b3 b2 b1 b0
Default=0
Default=(0,1)Permit
G4 O4 G3 O3 G2 O2 G1 O1

Default=0
Default=5,000

In buffer memory locations (BFMs) marked

with an "*" data can be written from the PC
using the TO command.
For buffer memories (BFMs) without the "*"
mark, data can be read to the PC using the
FROM command.
Before reading from the analog special
function block, ensure these settings have
been sent to the analog special function
block. Otherwise, the previous values held
in the analog block will be used.

The buffer memory also gives a facility to

adjust offset and gain by software as well
as by panel switches of the FX-4AD unit.
(see note 3)
Offset (intercept): The analog input value
when the digital output becomes 0.
Gain (slope): The analog input value when
the digital output becomes +1000.

(1) Channel Selection

Channel initialization is made by a 4 character HEX number HOOOO in buffer memory BFM #0.
The least significant character controls channel 1 and the 4 character controls channel 4.
Setting of each character is as follows:
O = 0: Preset range (-10V to +10V)
O = 2: Preset range (-20mA to +20mA)
O = 1: Preset range (+ 4mA to + 20 mA)
O = 3: Channel OFF
Example: H3310
CH1: preset range (-10V to +10V)
CH2: preset range (+ 4mA to +20mA)
CH3, CH4: Channel OFF
(2) Analog to Digital Conversion Speed Change
By writing 0 or 1 into BFM #15 of the FX-4AD, the speed at which A-D conversion is performed can be
changed. However the following points should be noted:
To maintain a high speed conversion rate, use the FROM/TO commands as seldom as possible.

NOTES: When a conversion speed change is made, BFM #1-#4 are set to their default values immediately
after the change.
This is regardless of the values they held originally. Bear this in mind if a speed change will be
made as part of the normal program execution.

(3) Adjusting Gain and Offset Values

(a) When buffer memory BFM #20 is activated by setting it to K1, all settings within the analog special
function block are reset to their default settings. This is a very quick method to erase any undesired
gain and offset adjustments.
(b) If (b1, b0) of BFM #21 is set to (1,0), gain and offset adjustments are prohibited to prevent inadvertent
changes by the operator. In order to adjust the gain and offset values, bits (b1, b0) must be set to
(0,1). The default is (0,1).
(c) Gain and offset values of BFM #23 and #24 are sent to non-volatile memory gain and offset registers
of the specified input channels. Input channels to be adjusted are specified by the appropriate G-O
(gain-offset) bits of BFM #22 Example: If bits G1 and O1 are set to 1, input channel 1 will be
adjusted when BFM #22 is written to by a TO instruction.
(d) Channels can be adjusted individually or together with the same gain and offset values.
(e) Gain and offset values in BFM #23 #24 are in units of mV or A. Due to the resolution of the unit the
actual response will be in steps of 5mV or 20A.

(4) Status information BFM #29

Bit
b 0:Error
b 1:Offset/Gain error

ON

OFF

When any of b1 to b4 is ON.

If any of b2 to b4 is ON,A/D conversion
of all the channels is stopped

No error

Offset/Gain data in EEPROM is corrupted

or adjustment error.

Offset/Gain data normal

DC 24V power supply failure

Power supply normal

b 2:Power source abnormality

b 3:Hardware error

A/D converter or other hardware failure

Hardware normal

FX-4AD MODE switch is not set to READY

READY mode

Digital output value is less than -2048

or more than +2047

Digital output value is normal

b11:Averaging error

Number of averaging samples is 4097 or

more or 0 or less
(default of 8 will be used)

Averaging is normal (between 1 and 4096)

b12:

Prohibit-(b1,b0) of BFM #21 is set to (1,0)

Permit-(b1,b0) of BFM #21 is set to (0,1)

b 8:Not READY
b10:Digital range error

Offset/Gain adjust prohibit

NOTE : b4 to b7,b9 and b13 to b15 are undefined.

(5) Identification code BFM #30

The identification (or ID) code number for a Special Function Block is read using the FROM command.
The code for the FX-4AD unit is K2010.
The user's program in the PC can use this facility in the program to identify the special function block
before commencing data transfer from and to the special function block.

CAUTION

Values of BFM #0, #23 and #24 are copied to EEPROM memory of the FX-4AD. BFM #21 and
BFM #22 are only copied when data is written to the gain/offset command buffer BFM #22. Also,
BFM #20 causes writing to the EEPROM memory. The EEPROM has a life of about 10,000 cycles
(changes), so do not use programs which frequently change these BFMs.

Because of the time needed to write to the EEPROM memory, a delay of 300 ms is required
between instructions that cause a write to the EEPROM.
Therefore, a delay timer should be used before writing to the EEPROM a second time.

DEFINING GAIN AND OFFSET

(a)

Gain

(b)

(d)

Offset
(c)

Digital 1000

(e)

(f)

Digital
0
Offset value
Analog

Gain value
Analog

Gain determines the angle or slope of the calibration line,

identified at a digital value of 1000.
(a) Small gain -- Large steps in digital readings
(b) Zero gain --- default : 5V or 20mA
(c) Large gain - Small steps in digital readings

Offset is the 'Position' of the calibrated line, identified at a

digital value of 0.
(d) Negative offset
(e) Zero offset - default : 0V or 4mA
( f ) Positive offset

Offset and gain can be set independently or together. Reasonable offset ranges are -5 to +5V or -20mA to
20mA, and gain values 1V to 15V or 4mA to 32mA. Gain and offset can be adjusted by software in the FX base
unit (see program example 2) or by the switches on the FX-4AD (with the aid of a voltmeter/ammeter)

Bit device's b1, b2 of the gain/offset BFM #21 should be set to 0, 1 to allow adjustment.
Once adjustment is complete these bit devices should be set to 1, 0 to prohibit any further changes.
Channel initialization (BFM #0) should be set to the nearest range, i. e. voltage/current etc.

1. Power the system up (the FX base unit can be in either RUN or STOP mode).
2. Set the FX-4AD MODE switch to the first channel number.
3. Apply the offset analog input to the terminal of the channel.
4. Press the OFFSET button once. The digital offset value (converted from the analog input value) is
stored in the FX-4AD.
5. Apply the gain analog input to the input terminal of the channel to be adjusted.
6. Press the GAIN button once. The digital gain value is stored in the FX-4AD.
7. Repeat operations 3 to 6 for each channel you wish to use.
8. Set the FX-4AD MODE switch to READY to complete gain and offset adjustment.

NOTE:If the MODE switch is not set to a channel number, the FX-4AD is regarded as being in the READY
status and no adjustments can be made.

EXAMPLE PROGRAM

5.1 Basic program

In the following example channels CH1 and CH2 are used as voltage inputs. The FX-4AD block is connected
at the position of special function block No.0. Averaging is set at 4 and data registers D0 and D1 of the PC
receive the averaged digital data.
M8002

K0

K30

D4

K1

CMP

K2010

D4

M0

TO P

K0

K0

H3300

K1

TO

K0

K1

K4

K2

FROM

K0

K29

K4M10

K1

FROM

K0

K5

D0

K2

FROM
Initial
pulse

M1

M10 M18
NO
error READY

The ID code for the special function block at position

"0" is read from BFM #30 of that block and stored at
D4 in the base unit. This is compared to check the
block is an FX-4AD, if OK M1 is turned ON. These
two program steps are not strictly needed to perform
an analog read. They are however a useful check
and are recommended as good practise.
The analog input channels (CH1, CH2) are setup by
writing H3300 to BFM #0 of the FX-4AD.

The number of averaged samples for CH1 and CH2

is set to 4 by writing 4 to BFM #1 and #2 respectively.
Do not execute the pulse.
The operational status of the FX-4AD is read from
BFM #29 and output as bit devices at the FX base
unit.
If there are no errors in the operation of the FX-4AD,
then the averaged data BFM's are read.
In the case of this example BFM #5 and #6 are read
into the FX base unit and stored at D0 and D1. These
devices contain the averaged data for CH1 and CH2
respectively.

5.2 Using gain and offset in a program

The gain and offset of the FX-4AD can be adjusted using push-button switches on the input terminal of the PC.
It can also be adjusted using software settings sent from the PC.
Only the gain and offset values in the memory of the FX-4AD need be adjusted. A voltmeter or an ammeter
for the analog input is not needed. A program for the PC will be needed however.
The following is an example of changing the offset value on input channel CH1 to 0V and the gain value to 2.5V.
The FX-4AD block is in the position of block No.0 (i.e. closest to the FX base unit).
Example: Adjusting gain/offset via software settings
X010

SET

M0

(H0000) BFM #0 (initialize input channels)

Enter the instructions on the left and RUN the PC with
the MODE switch of the FX-4AD set to READY.
(K1) BFM #21
BFM #21 (gain/offset adjust prohibit) must be set to
permit with (b1, b0) = (0,1).

M0

TO P

K0

K0

H0000

K1

TO P

K0

K21

K1

K1

TO

K0

K22

K0

K1

Adjustment start.

(K0) BFM #22 (offset/gain adjust)

Reset adjust bits.

T0
K4
T0

TO P

K0

K23

K0

K1

(K0) BFM #23 (offset)

TO P

K0

K24

K2500

K1

(K2500) BFM #24 (gain)

TO P

K0

K22

H0003

K1

(H0003) BFM #22 (offset/gain adjust)

3 = 0011 i.e. O1 = 1, G1 = 1.
Therefore channel 1 is adjusted.

T1
K4
T1

TO P

K0

K21

RST

M0

Adjustment end.

K2

K1

(K2) BFM #21

BFM #21 gain/offset adjust prohibit.

DIAGNOSTICS

6.1 Preliminary checks

Check whether the input wiring and/or expansion cables are properly connected on FX-4AD analog
special function block.
Check that the FX system configuration rules have not been broken, i.e. the number of blocks does
not exceed 8 and the total system I/O is equal or less than 256 I/O.
Ensure that the correct operating range has been selected for the application.
Check that the MODE switch on the FX-4AD panel is set to the READY position.
Check that there is no power overload on either the 5V or 24V power source, remember the loading
on a FX base unit or a powered extension unit varies according the number of extension block or
special function blocks connected.
Put the FX base unit into RUN.

I
II
III
IV
V
VI

6.2 Error checking

If the FX-4AD special function block does not seem to operate normally, check the following items.

Check the status of the POWER LED.

Lit : The extension cable is properly connected.
Otherwise: Check the connection of the extension cable.
Check the external wiring.
Check the status of "24V" LED (top right cover of the FX-4AD).
Lit: FX-4AD is OK, 24V DC power source is OK.
Otherwise: Possible 24V DC power failure, if OK then possible FX-4AD failure.
Check the status of the "A/D" LED (top right cover of the FX-4AD)
Lit: A/D conversion is proceeding normally
Otherwise: Check buffer memory #29 (error status). If any bits (b2 and b3) are ON, then this is why
the A/D LED is OFF.

Guidelines for the safety of the user and protection of

the FX-4AD special function block

This manual has been written to be used by trained and competent personnel. This is defined
by the European directives for machinery, low voltage and EMC.

If in doubt at any stage during the installation of the FX-4AD always consult a professional
electrical engineer who is qualified and trained to the local and national standards. If in doubt
about the operation or use of the FX-4AD please consult the nearest Mitsubishi Electric distributor.

Under no circumstances will Mitsubishi Electric be liable or responsible for any consequential
damage that may arise as a result of the installation or use of this equipment.

All examples and diagrams shown in this manual are intended only as an aid to understanding
the text, not to guarantee operation. Mitsubishi Electric will accept no responsibility for actual
use of the product based on these illustrative examples.

Manual number : JY992D52601

Manual revision : E
Data
: APRIL 1998

HEAD OFFICE : MITSUBISHI DENKI BLDG MARUNOUCH TOKYO 100

HIMEJI WORKS : 840, CHIYODA CHO, HIMEJI, JAPAN

JY992D52601E

TELEX : J24532 CABLE MELCO TOKYO

Effective APR. 1998

Specifications are subject
to change without notice.