USER'S GUIDE

®
Vaisala HUMICAP Humidity and
Temperature Module
HMM211

M210718EN-B
PUBLISHED BY

Vaisala Oyj Phone (int.): +358 9 8949 1

P.O. Box 26 Fax: +358 9 8949 2227
FI-00421 Helsinki
Finland

Visit our Internet pages at http://www.vaisala.com/

© Vaisala 2009

No part of this manual may be reproduced in any form or by any means, electronic or
mechanical (including photocopying), nor may its contents be communicated to a third
party without prior written permission of the copyright holder.

The contents are subject to change without prior notice.

Please observe that this manual does not create any legally binding obligations for
Vaisala towards the customer or end user. All legally binding commitments and
agreements are included exclusively in the applicable supply contract or Conditions of
Sale.
________________________________________________________________________________

Table of Contents

CHAPTER 1
GENERAL INFORMATION............................................................................ 7
About This Manual ................................................................... 7
Contents of This Manual ....................................................... 7
Version Information ............................................................... 8
Related Manuals ................................................................... 8
General Safety Considerations ............................................. 8
Feedback............................................................................... 9
Product Related Safety Precautions ...................................... 9
ESD Protection ......................................................................... 9
Recycling ................................................................................ 10
Regulatory Compliances ....................................................... 10
Patent Notice .......................................................................... 11
Trademarks ............................................................................. 11
Warranty.................................................................................. 11

CHAPTER 2
PRODUCT OVERVIEW................................................................................ 13
Introduction to HMM211 ........................................................ 13

CHAPTER 3
TO BE NOTED WHEN MEASURING HUMIDITY........................................ 15

CHAPTER 4
INSTALLATION............................................................................................ 17
Selecting Location ................................................................. 17
Dimensions ............................................................................. 18
Electrical Connections........................................................... 18

CHAPTER 5
CALIBRATION ............................................................................................. 21
One-Point Humidity Calibration............................................ 22
With the Hand-Held Humidity and Temperature Meter
HM70 or HMI41 Indicator and Calibration Cable ................ 22
With Pushbuttons and a Jumper......................................... 23
Two-Point Humidity Calibration............................................ 23
Two-Point Humidity Calibration Procedure ......................... 24
Calibration Table .................................................................... 25
Temperature Calibration........................................................ 26
Temperature Calibration of an RH and T Module ............... 26
Temperature Calibration of a Dewpoint Module ................. 27
Temperature Calibration of an RH and T Module with
Two Sensor Heads.............................................................. 27

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CHAPTER 6
CHEMICAL PURGE .....................................................................................29

CHAPTER 7
MAINTENANCE............................................................................................31

Replacing the HUMICAP 180R Sensor and the Filter .......31
Replacing Consumables........................................................31
Parts List for Consumables .................................................31

CHAPTER 8
TROUBLESHOOTING..................................................................................33
Troubleshooting Procedure ..................................................33
Technical Support ..................................................................33
Return Instructions ................................................................34
Vaisala Service Centers .........................................................35

CHAPTER 9
TECHNICAL DATA ......................................................................................37
Specifications .........................................................................37
Options ....................................................................................39

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List of Figures
Figure 1 Measurement Error at 100 %RH when the Temperature
Difference between the Ambient Air and the Sensor is 1 °C ... 16
Figure 2 Dimensions in mm (inches) ...................................................... 18
Figure 3 Electrical Connections.............................................................. 19
Figure 4 Calibration Connector for the HM70 or HMI41......................... 22
Figure 5 Calibration Pins and Pushbuttons ............................................ 25
Figure 6 Offset and Gain Calibration Examples ..................................... 27
Figure 7 Decrease of the Sensor Gain Due to an Interfering Chemical
and the Effect of the Chemical Purge Process ........................ 29
Figure 8 Dewpoint Temperature............................................................. 38

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List of Tables
Table 1 Manual Revisions .......................................................................8
Table 2 Related Manuals.........................................................................8
Table 3 Emission Tests .........................................................................10
Table 4 Immunity Tests .........................................................................10
Table 5 Greenspan's Calibration Table with Output Values According
to the Chosen Scale .................................................................25
Table 6 Available Spare Parts ...............................................................31
Table 7 Relative Humidity Specifications ..............................................37
Table 8 Temperature Specifications......................................................37
Table 9 Analog Output Specifications ...................................................38
Table 10 General Specifications..............................................................38
Table 11 Operating Voltage Specifications .............................................39
Table 12 Modules, Sensor Heads, and Outputs .....................................39
Table 13 Cable Lengths for Sensor Heads .............................................40
Table 14 Automatic Chemical Purge .......................................................40

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Chapter 1 ________________________________________________________ General Information

CHAPTER 1
GENERAL INFORMATION

This chapter provides general notes for the manual and the product.

About This Manual

This manual provides information for installing, operating, and
maintaining Vaisala HUMICAP® Humidity and Temperature Module
HMM211.

Contents of This Manual

This manual consists of the following chapters:

- Chapter 1, General Information, provides general notes for the manual

and the product.
- Chapter 2, Product Overview, introduces the features and advantages
of the Vaisala HUMICAP® Humidity and Temperature Module
HMM211.
- Chapter 3, To Be Noted When Measuring Humidity, describes issues
that need to be noted in the measurement of humidity.
- Chapter 4, Installation, provides you with information that is intended
to help you install this product.
- Chapter 5, Calibration, provides you with information that is intended
to help you calibrate this product.
- Chapter 6, Chemical Purge, provides you with information on
chemical purge.
- Chapter 7, Maintenance, provides information that is needed in basic
maintenance of the product.
- Chapter 8, Troubleshooting, describes common problems, their
probable causes and remedies, and contact information for technical
support.

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Version Information
Table 1 Manual Revisions
Manual Code Description
U337EN-1.1 December 1998
M210718EN-A September 2005: EMC test data revised
M210718EN-B This manual, December 2009 - HUMICAP® sensor
type has been changed.

Related Manuals
Table 2 Related Manuals
Manual Code Manual Name
M210316EN-A Vaisala HUMICAP® Indicator HMI41 and Probes
HMP41/45/46 User's Guide
M210777EN-B Calibration of Digital Transmitters with Vaisala
HUMICAP® Humidity Indicator HMI41 Cables
19164ZZ and 25917ZZ User's Guide
M210185EN-C Vaisala Humidity Calibrator HMK15 User's Guide
M210297EN-E Vaisala HUMICAP® Hand-Held Humidity and
Temperature Meter HM70 User's Guide

General Safety Considerations

Throughout the manual, important safety considerations are highlighted
as follows:

WARNING Warning alerts you to a serious hazard. If you do not read and follow
instructions very carefully at this point, there is a risk of injury or even
death.

CAUTION Caution warns you of a potential hazard. If you do not read and follow
instructions carefully at this point, the product could be damaged or
important data could be lost.

NOTE Note highlights important information on using the product.

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Chapter 1 ________________________________________________________ General Information

Feedback
Vaisala Customer Documentation Team welcomes your comments and
suggestions on the quality and usefulness of this publication. If you find
errors or have other suggestions for improvement, please indicate the
chapter, section, and page number. You can send comments to us by e-
mail: manuals@vaisala.com

Product Related Safety Precautions

The Vaisala HUMICAP® Humidity and Temperature Module HMM211
delivered to you has been tested for safety and approved as shipped from
the factory. Note the following precautions:

WARNING Ground the product, and verify outdoor installation grounding

periodically to minimize shock hazard.

CAUTION Do not modify the unit. Improper modification can damage the product
or lead to malfunction.

CAUTION Do not touch the sensor element.

ESD Protection
Electrostatic Discharge (ESD) can cause immediate or latent damage to
electronic circuits. Vaisala products are adequately protected against
ESD for their intended use. However, it is possible to damage the product
by delivering electrostatic discharges when touching, removing, or
inserting any objects inside the equipment housing.

To make sure you are not delivering high static voltages yourself:

- Handle ESD sensitive components on a properly grounded and

protected ESD workbench. When this is not possible, ground yourself
to the equipment chassis before touching the boards. Ground yourself
with a wrist strap and a resistive connection cord. When neither of the
above is possible, touch a conductive part of the equipment chassis
with your other hand before touching the boards.

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- Always hold the boards by the edges and avoid touching the
component contacts.

Recycling
Recycle all applicable material.

Dispose of batteries and the unit according to statutory regulations. Do

not dispose of with regular household refuse.

Regulatory Compliances
The Vaisala HUMICAP® Humidity and Temperature Module HMM211
complies with the following performance and environmental test
standards:

The emission and immunity tests have been performed according to

standard EN61326-1.

Table 3 Emission Tests

Test Setup According to
RF field emission CISPR 22 Class B (EN55022)
Conducted emissions CISPR 22 B (EN55022)

Table 4 Immunity Tests

Test Setup According to
Electrostatic discharge IEC 1000-4-2 (EN 61000-4-2)
Fast transient burst IEC 1000-4-4 (EN 61000-4-4)
RF field immunity IEC 1000-4-3 (EN 61000-4-3)
Conducted RF immunity IEC 1000-4-6 (EN 61000-4-6)
NOTE: cable length max. 8 meters
Surge IEC 1000-4-5 (EN 61000-4-5)
Voltage dips, short interrupts IEC 1000-4-11 (EN 61000-4-11)

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Chapter 1 ________________________________________________________ General Information

Patent Notice
The Vaisala HUMICAP® Humidity and Temperature Module HMM211
is protected by the following patents and patent applications and their
corresponding national rights:

Finnish patents 98861 and 99164, French patents 6650303 and 9504397,
German patents 69418174 and 19513274, Japanese patents 3585973 and
2801156, UK patent 0665303, and US patent 5607564.

Trademarks
Vaisala Trademark is a registered trademark of Vaisala Oyj.

HUMICAP® is a registered trademark of Vaisala Oyj.

Warranty
Vaisala hereby represents and warrants all Products manufactured by
Vaisala and sold hereunder to be free from defects in workmanship or
material during a period of twelve (12) months from the date of delivery
save for products for which a special warranty is given. If any Product
proves however to be defective in workmanship or material within the
period herein provided Vaisala undertakes to the exclusion of any other
remedy to repair or at its own option replace the defective Product or part
thereof free of charge and otherwise on the same conditions as for the
original Product or part without extension to original warranty time.
Defective parts replaced in accordance with this clause shall be placed at
the disposal of Vaisala.

Vaisala also warrants the quality of all repair and service works
performed by its employees to products sold by it. In case the repair or
service works should appear inadequate or faulty and should this cause
malfunction or nonfunction of the product to which the service was
performed Vaisala shall at its free option either repair or have repaired or
replace the product in question. The working hours used by employees of
Vaisala for such repair or replacement shall be free of charge to the
client. This service warranty shall be valid for a period of six (6) months
from the date the service measures were completed.

This warranty is however subject to following conditions:

a) A substantiated written claim as to any alleged defects shall have

been received by Vaisala within thirty (30) days after the defect or
fault became known or occurred, and

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b) the allegedly defective Product or part shall, should Vaisala so

require, be sent to the works of Vaisala or to such other place as
Vaisala may indicate in writing, freight and insurance prepaid and
properly packed and labelled, unless Vaisala agrees to inspect and
repair the Product or replace it on site.

This warranty does not however apply when the defect has been caused
through

a) normal wear and tear or accident;

b) misuse or other unsuitable or unauthorized use of the Product or
negligence or error in storing, maintaining or in handling the
Product or any equipment thereof;
c) wrong installation or assembly or failure to service the Product or
otherwise follow Vaisala's service instructions including any
repairs or installation or assembly or service made by unauthorized
personnel not approved by Vaisala or replacements with parts not
manufactured or supplied by Vaisala;
d) modifications or changes of the Product as well as any adding to it
without Vaisala's prior authorization;
e) other factors depending on the Customer or a third party.

Notwithstanding the aforesaid Vaisala's liability under this clause shall

not apply to any defects arising out of materials, designs or instructions
provided by the Customer.

This warranty is expressly in lieu of and excludes all other conditions,

warranties and liabilities, express or implied, whether under law, statute
or otherwise, including without limitation ANY IMPLIED
WARRANTIES OF MERCHANTABILITY OR OF FITNESS FOR A
PARTICULAR PURPOSE and all other obligations and liabilities of
Vaisala or its representatives with respect to any defect or deficiency
applicable to or resulting directly or indirectly from the Products supplied
hereunder, which obligations and liabilities are hereby expressly
cancelled and waived. Vaisala's liability shall under no cir-cumstances
exceed the invoice price of any Product for which a warranty claim is
made, nor shall Vaisala in any circumstances be liable for lost profits or
other consequential loss whether direct or indirect or for special damages.

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Chapter 2 __________________________________________________________ Product Overview

CHAPTER 2
PRODUCT OVERVIEW

This chapter introduces the features and advantages of the Vaisala

HUMICAP® Humidity and Temperature Module HMM211.

Introduction to HMM211
The HMM211 modules are designed especially for relative humidity
measurements in environmental chamber applications with high
temperature and humidity levels. They also measure temperature and
calculate the dewpoint temperature.

The HMM211 has actually three different module options to choose

from:

- Humidity and temperature module: with a standard humidity and

temperature sensor head
- Dewpoint module: with a warmed sensor head incorporating a
composite RH and T sensor
- Humidity and temperature module with two sensor heads: with a
warmed humidity sensor head incorporating a composite sensor, and
an additional temperature sensor head for ambient temperature
measurement

The HMM211 is a three wire module with four analog output options: 0
... 1 V, 0 ... 5 V, 0 ... 10 V, and 0 ... 20 mA. The module can be ordered
with the output option already selected. Other options include the length
of the humidity probe, the sensor protection and an additional
temperature probe. Furthermore, you can also order the module with a
suitable cable length (0.65 m, 1.50 m, or 3.0 m) and a temperature
measurement range best suited for that particular application (0 ... 100
°C, -20 ... +120 °C, -20 ... +180 °C, -40 ... +180 °C or
-70 ... +180 °C).

Output parameters can also be selected from various options according to

the module type. The output parameters for the RH and T module are
relative humidity and temperature. For the RH and T module with two
sensor heads, the parameters also include relative humidity and

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temperature, and for the dewpoint module, the parameter is dewpoint

temperature. The dewpoint temperature range can be either 0 ... +100 °C
or -40 ... +100 °C.

The probes also have a selectable chemical purge option. Note that with a
warmed sensor head, the probe length is always 90 mm and the sensor is
protected with a sintered filter.

The HMM211 modules are connected to process control systems with

screw terminals. These versatile modules incorporate the
HUMICAP®180R humidity sensor which uses an operating principle
based on changes in the capacitance of a thin polymer film as it absorbs
water molecules. The HMM211 modules measure temperature with the
reliable Pt 100 sensor. If the module is ordered with chemical purge
option, it incorporates a composite sensor.

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Chapter 3 ________________________________________ To Be Noted When Measuring Humidity

CHAPTER 3
TO BE NOTED WHEN MEASURING
HUMIDITY

This chapter describes issues that need to be noted in the measurement of

humidity.

In the measurement of relative humidity and especially in calibration, it

is essential that the temperature equilibrium is reached. Even a slight
difference in the temperature between the measured object and the sensor
causes an error. For example, at +20 °C (+ 68 °F) and 50 %RH, a
temperature difference of ±1 °C between the measured object and the
sensor causes an error of ±3 %RH. If relative humidity is 90 %RH, the
error is about ±5.4 %RH. A graph of the measurement error at 100 %RH
when the temperature difference between ambient air and the sensor is
1 °C is presented in Figure 1 on page 16.

The error is at its greatest when the temperature of the sensor differs from
that of the surroundings and the humidity is high. A difference of a few
degrees in temperature may cause water to condense on the sensor
surface. Efficient ventilation accelerates the evaporation of the condensed
water whereas in an unventilated space, it may take hours. The
HUMICAP®180R sensor returns to its normal functioning as soon as
water has evaporated. Contaminated water condensing on the sensor may
shorten its life span and alter the calibration.

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10
9
8
7
dRH (%RH)
6
5
4
3
2
1
0
-40 -20 0 20 40 60 80 100
Temperature (°C)

Figure 1 Measurement Error at 100 %RH when the

Temperature Difference between the Ambient Air and
the Sensor is 1 °C

NOTE With a dewpoint module, the temperature equilibrium is not a problem as

the temperature of the sensor head changes continuously and the sensor
head has a fast humidity response.

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Chapter 4 _______________________________________________________________ Installation

CHAPTER 4
INSTALLATION

This chapter provides you with information that is intended to help you
install this product.

Selecting Location
Finding a suitable site for HMM211 is important for getting
representative ambient measurements.

Select a place that gives a true picture of the environment or process and
is as clean as possible. Air should flow freely around the sensor.

Install the sensor head to a sufficient distance from the duct or chamber
walls. Make sure to insert enough cable to the same space with the probe
in order to prevent heat conduction. If an additional temperature probe is
used, install it so that the warmed sensor head does not interfere with the
measurement.

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Dimensions

)
14
(0. )
1 .02
2 6(

~6
5(2
.56
)

Figure 2 Dimensions in mm (inches)

Electrical Connections
Connect wires according to Figure 3 on page 19 (A = voltage output, B =
with current module).

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Chapter 4 _______________________________________________________________ Installation

Figure 3 Electrical Connections

The following numbers refer to Figure 3 above:

1 = During normal use, leave the jumper as indicated here (factory
setting).
2 = Calibration connector for the HM70 or HMI41
3 = Calibration jumper when not in use

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20 __________________________________________________________________ M210718EN-B
Chapter 5 _______________________________________________________________ Calibration

CHAPTER 5
CALIBRATION

This chapter provides you with information that is intended to help you
calibrate this product.

Vaisala recommends a recalibration of the HMM211 module after six

months of use. After the first recalibration, the recommended calibration
interval is approximately 12 months. However, please note that these
intervals depend on the operating conditions and the required accuracy.
When calibrating humidity instruments, it is important that the probe, the
reference instrument, and the calibrator are in thermal equilibrium.
Therefore, always allow enough time for stabilization before starting the
actual calibration.

- Calibration in the chamber: leave the calibrator (for example, the

HMK15) in the chamber overnight with the chamber door open.
- Calibration of a humidity and temperature module: allow at least one
hour for the stabilization of the calibrator (for example, HM70 hand-
held humidity and temperature meter with a reference probe).
- Calibration of a dewpoint module or of a humidity and temperature
module with two sensor heads: allow at least three hours for
stabilization if the sensor head is in such an environment that the
warming function has been active. The warming function can be
deactivated by connecting the jumper to any calibration connector (see
Figure 5 on page 25). Note also that when humidity calibrating a Td
transmitter, the Td signal on Channel 2 is replaced by the RH signal 0
... 100 %RH with the chosen output range. For example, if the Td
output range is 0 ... 5 V, the output during RH calibration is 0 ... 100
%RH < > 0 ... 5 V.
- Calibration of a module with chemical purge option option: chemical
purge is activated when the power is connected. When calibrating a
probe, turn the power on with the sintered stainless steel filter on the
probe, wait for 3 minutes, and remove the filter. Allow to stabilize and
perform the calibration.

NOTE Do not turn the power off during calibration.

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One-Point Humidity Calibration

With the Hand-Held Humidity and

Temperature Meter HM70 or HMI41
Indicator and Calibration Cable
You can calibrate the HMM211 module with the Hand-Held Humidity
and Temperature Meter HM70 or HMI41 indicator and an appropriate
calibration cable (for HM70: 27159ZZ; for HMI41: 19164ZZ).

Connect the cable to the test connector of the HMM211 module and
insert the jumper as indicated in Figure 4 below. For detailed
instructions, see the following documents:

- Vaisala HUMICAP® Indicator HMI41 and Probes HMP41/45/46

User's Guide
- Vaisala HUMICAP® Hand-Held Humidity and Temperature Meter
HM70
- Calibration of Digital Transmitters with Vaisala HUMICAP®
Humidity Indicator HMI41 Cables 19164ZZ and 25917ZZ User's
Guide

Figure 4 Calibration Connector for the HM70 or HMI41

The following numbers refer to Figure 4 above:

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Chapter 5 _______________________________________________________________ Calibration

The following numbers refer to Figure 4 above:

1 = For calibration with the HM70 or HMI41, insert the jumper as
indicated here.
2 = Calibration connector for the HM70 or HMI41

NOTE The serial communication parameters are:

1200 bauds, no parity, 8 data bits, 1 stop bit

NOTE When the connection is being established, the message 'CON ERROR'
blinks on the HMI41 display for a couple of times after which
measurement readings appear. This is quite normal and requires no
action; however, if the message is not replaced by measurement readings,
it is an indication of an operation error.

With Pushbuttons and a Jumper

You can also perform the calibration with pushbuttons and a jumper on
the component board (see Figure 5 on page 25). In addition, you need a
digital multimeter (DMM). There are two pushbuttons (UP and DOWN)
and six pairs of pins (RH offset, RH gain, T offset, T gain, Ta offset, and
Ta gain) that are connected with the calibration jumper. Vaisala
recommends using the RH offset pins if the RH is less than 65 %RH and
the gain pins if the RH is greater than 65 %RH.

For example, to perform a one-point humidity calibration using saturated

NaCl salt solution at 75.5 %RH as a reference, do as follows:

1. Insert the probe into a NaCl salt chamber and let stabilize.
2. Connect a DMM to the RH output and wait until the reading
stabilizes.
3. Connect a jumper to the RH gain pins and adjust the DMM reading
with buttons UP and DOWN until the output corresponds to
75.5 %RH.
4. Disconnect the jumper.

Two-Point Humidity Calibration

You can also perform a two-point calibration with saturated salt
calibrators (for example HMK15), or you can send the instrument to
Vaisala or a Vaisala representative for recalibration. See contact

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information for Vaisala Service Centers on page 35. Figure 6 on page 27

illustrates the difference between offset and gain calibrations.

Two-Point Humidity Calibration

Procedure
1. Leave the calibrator and the probe in the same environment for at
least one hour so that their temperatures have time to equalize. For
information on more accurate stabilization times, see Chapter 4,
Installation, on page 17.
2. Insert the probe into the measurement hole of the LiCl salt chamber
in the humidity calibrator.
3. Wait for 20 to 40 minutes.
4. Check the temperature and read the closest corresponding RH
value in the calibration table (Table 5 on page 25).
5. Connect the jumper to the RH offset pins (see Figure 5 on page 25)
and adjust the output signal with push buttons to the value given in
the calibration table (Table 5 on page 25).
6. Insert the probe into the measurement hole of the NaCl chamber.
7. Wait for 20 to 40 minutes.
8. Check that the reading corresponds within the desired accuracy to
the reading given in the calibration table. If not, connect the jumper
to the RH gain pins and adjust the reading with push buttons.
9. Check again the reading at the first point and repeat the procedure
if necessary.

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Chapter 5 _______________________________________________________________ Calibration

Figure 5 Calibration Pins and Pushbuttons

With the jumper connected to the RH gain pins, each pressing of the UP
or DOWN button changes the value approximately 0.05 %RH at
75 %RH. With the jumper connected to the RH offset pins, each pressing
changes the value approximately 0.05 %RH.

With the jumper connected to the T offset pins, each pressing of the UP
or DOWN button changes the value 0.05 °C or 0.05 °F in all
temperatures. With the jumper connected to the T gain pins, each
pressing changes the value 0.05 °C or 0.05 °F in the temperature
currently prevailing in the process.

Calibration Table
Table 5 Greenspan's Calibration Table with Output Values
According to the Chosen Scale
Temperature °C 15 20 25 30 35
°F 59 68 77 86 95
LiCl %RH *) 11.3 11.3 11.3 11.3
4 ... 20 mA mA 5.81 5.81 5.81 5.81
0 ... 20 mA mA 2.26 2.26 2.26 2.26
0 ... 1 V V 0.113 0.113 0.113 0.113
0 ... 5 V V 0.565 0.565 0.565 0.565
0 ... 10 V V 1.13 1.13 1.13 1.13

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Temperature °C 15 20 25 30 35
°F 59 68 77 86 95
NaCl %RH 75.6 75.5 75.3 75.1 74.9
4 ... 20 mA mA 16.10 16.08 16.05 16.02 15.98
0 ... 20 mA mA 15.12 15.10 15.06 15.02 14.98
0 ... 1 V V 0.756 0.755 0.753 0.751 0.749
0 ... 5 V V 3.780 3.775 3.765 3.755 3.745
0 ... 10 V V 7.56 7.55 7.53 7.51 7.49

*) If the LiCl solution is used or stored in temperatures below +18 °C (+64 °F), the equilibrium
humidity of the salt solution may change permanently.

Temperature Calibration
NOTE The temperature channel of the HMM211 is very stable and the modules
have been calibrated at the factory. Unless there is a strong reason to
believe that the adjustments have changed, do not perform a temperature
calibration. This is a very demanding procedure and requires both
expertise and extremely accurate references. Furthermore, it is important
to allow enough time for the stabilization during calibration. If for some
reason it is necessary to perform the temperature calibration, follow
attentively the instructions given in this section.

Temperature Calibration of an RH and T

Module
1. Allow enough time for the instruments to stabilize to the
temperature in which calibration is performed.
2. Connect a jumper to the T offset or the T gain pins. The
temperature signal is now on Channel 2. Adjust the reading with
UP and DOWN switches (see Figure 5 on page 25). Note that
during gain adjustment, the offset point does not change:

26 __________________________________________________________________ M210718EN-B
Chapter 5 _______________________________________________________________ Calibration

offset correction gain correction

voltage range before correction voltage range before correction
(for example, 0 ... 5 V) (for example, 0 ... 5 V)
after offset correction after gain correction

-20 20 40 60 80 100 120 -20 20 40 60 80 100 120 °C

°C

Figure 6 Offset and Gain Calibration Examples

3. After having performed the calibration, disconnect the jumper.

Temperature Calibration of a Dewpoint

Module
1. The warming function must be deactivated by connecting a jumper
to the T offset or T gain calibration pins (see Figure 5 on page 25).
The temperature signal is now on Channel 2 (previously Td signal).
Note that the chosen output range corresponding to -70 ... +180 °C
is now scaled on this channel. For example, if the Td output range
is 0 ... 5 V, the T output during calibration is 0 ... 5 V < > -70 ...
+180 °C (-94 ... +356 °F).
2. Allow enough time for the instruments to stabilize to the same
temperature.
3. Adjust the reading with UP and DOWN switches (see Figure 5 on
page 25). Note that during gain adjustment, the offset point
(-70 °C) does not change (see Figure 6 above).
4. After having performed the calibration, disconnect the jumper.

Temperature Calibration of an RH and T

Module with Two Sensor Heads
1. Connect a jumper to the T offset or T gain calibration pins (see
Figure 5 on page 25). The temperature signal of the humidity probe
is now on Channel 1 (previously RH signal). Note that the chosen
output range corresponding to -70 …+180 °C is now scaled on this
channel, for example if the RH output range is 0 ... 5 V, the T
output during calibration is 0 ... 5 V < > -70 ... +180 °C (-94 …
+356 °F).

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2. Allow enough time for the instruments to stabilize to the same

temperature.
3. Adjust the reading with UP and DOWN switches (see Figure 5 on
page 25). Note that during gain adjustment, the offset point
(-70 °C) does not change (see Figure 6 on page 27).
4. Calibrate the additional (Ta) temperature probe the same way; note
that the signal is on Channel 2 and the connectors used are the Ta
offset and Ta gain.
5. After having performed the calibration, disconnect the jumper.

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Chapter 6 ___________________________________________________________ Chemical Purge

CHAPTER 6
CHEMICAL PURGE

This chapter provides you with information on chemical purge.

In some applications, the sensor gain may decrease gradually due to an

interference caused by some chemical present in the ambient air (see
Figure 7 below). The sensor polymer absorbs the interfering chemical;
this reduces the polymer's ability to absorb water molecules and so
decreases the sensor gain. In chemical purge, the interfering chemical is
evaporated by heating the humidity sensor to a temperature level of
approximately +160 °C. Automatic chemical purge takes place at startup.

Calibration
values
Chemical purge

Measured values
Output signal

after chemical
exposure

Humidity

Figure 7 Decrease of the Sensor Gain Due to an Interfering

Chemical and the Effect of the Chemical Purge Process

The sensor with chemical purge option is a composite sensor in which

the HUMICAP® and Pt 100 temperature sensors are attached to each
other. Chemical purge option requires that the sensor is protected with a
stainless steel sintered filter (part no. HM46670).

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Chapter 7 ______________________________________________________________ Maintenance

CHAPTER 7
MAINTENANCE

This chapter provides information that is needed in basic maintenance of

the product.

Replacing the HUMICAP180R Sensor and the

Filter
Remove the damaged sensor and insert a new one. Handle the sensor by
the plastic socket. Recalibrate the transmitter.

CAUTION Do not touch the sensor element.

Replace a dirty filter to ensure a maximum lifetime and a fast response

for the sensor.

Replacing Consumables
This section describes how to replace consumables.

Parts List for Consumables

Table 6 Available Spare Parts
Spare Part Order Code
HUMICAP®180R Sensor HUMICAP180R
Stainless steel sintered filter HM46670

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Chapter 8 ___________________________________________________________ Troubleshooting

CHAPTER 8
TROUBLESHOOTING

This chapter describes common problems, their probable causes and

remedies, and contact information for technical support.

Troubleshooting Procedure
When troubleshooting the product, write a problem report consisting of
the following issues:

- What failed (what worked / did not work)?

- Where did it fail (location and environment)?
- When did it fail (date, immediately / after a while / periodically /
randomly)?
- How many failed (only one defect / other same or similar defects /
several failures in one unit)?
- What was connected to the product and to which connectors?
- Input power source type, voltage and list of other items (lighting,
heaters, motors etc.) that were connected to the same power output.
- What was done when the failure was noticed?

Technical Support
For technical questions, contact the Vaisala technical support:

E-mail helpdesk@vaisala.com

Fax +358 9 8949 2790

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Return Instructions
If the product needs repair, please follow the instructions below to speed
up the process and to avoid extra costs to you.

1. Read the section Warranty on page 11.

2. Contact a Vaisala Service Center or a local Vaisala representative.
The latest contact information and instructions are available from
www.vaisala.com. Addresses of the Service Centers are provided
in section Vaisala Service Centers on page 35.
Please have the following information on hand:

- serial number of the unit

- date and place of purchase or last calibration
- description of the fault
- circumstances in which the fault occurs/occurred
- name and contact information of a technically competent person
who can provide further information on the problem

3. Pack the faulty product in a strong box of adequate size, with

proper cushioning material to avoid damage.
4. Include the information specified in step 2 in the box with the
faulty product. Also include a detailed return address.
5. Ship the box to the address specified by your Vaisala contact.

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Chapter 8 ___________________________________________________________ Troubleshooting

Vaisala Service Centers

Vaisala Service Centers perform calibrations and adjustments as well as
repair and spare part services. See contact information below.

Vaisala Service Centers also offer accredited calibrations, maintenance

contracts, and a calibration reminder program. Do not hesitate to contact
them to get further information.

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Chapter 9 ____________________________________________________________ Technical Data

CHAPTER 9
TECHNICAL DATA

This chapter provides the technical data of the product.

Specifications
Table 7 Relative Humidity Specifications
Property Value
Measurement range 0 ... 100 %RH
Accuracy (including non-linearity, ±2 %RH (0 … 90 %RH)
hysteresis and repeatability) ±3 %RH (90 …100 %RH)

Response time (90 %) at +20 °C in still air 60 s

(with sintered filter)
Typical temperature dependence of 0.02 %RH/°C
electronics
Humidity sensor HUMICAP®180R

Table 8 Temperature Specifications

Property Value
Measurement range -70 ... +180 °C
Typical accuracy of electronics at +20 °C ±0.1 °C

Typical temperature dependence of 0.0025 °C/°C

electronics
Temperature sensor Pt 100 RTD 1/3 IEC 751 Class B

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Figure 8 Dewpoint Temperature

Table 9 Analog Output Specifications

Property Value
Two analog outputs selectable 0 ... 1 V, 0 ... 5 V, 0 ... 10 V
0 ... 20 mA (4 ... 20 mA)
Typical accuracy ±0.1 % full scale

Resolution CH1: 0.025 %RH

CH2: 0.01 % full scale
Typical temperature dependence 0.004 % full scale/°C

Table 10 General Specifications

Property Value
Operating temperature range
Probe -70 ... +180 °C
Electronics -5 … +55 °C
Storage temperature range -40 … +70 °C
(electronics)

Sensor protection: Stainless steel sintered filter

Standard
Connections Screw terminals for 0.5 ... 1.5 mm2 wires

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Chapter 9 ____________________________________________________________ Technical Data

Table 11 Operating Voltage Specifications

Ouput DC AC
0 ... 1 V 10 ... 35 V 9 ... 24 V
0 ... 5 V 14 ... 35 V 12 ... 24 V
0 ... 10 V 19 ... 35 V 16 ... 24 V
0 ... 20 mA (RL = 0 ) 10 ... 35 V 11 ... 24 V
0 ... 20 mA (RL = 500 20 ... 35 V 17 ... 24 V
)

NOTE AC supply only possible without warming or chemical purge option.

Current consumption without warming or

chemical purge option
Voltage output: 12 mA @ 35 VDC
20 mA @ 24 VAC
Average power needed during warming 1 W (100 … 300 mA
(optional) modulated current)

Maximum power needed during chemical 1.4 W (100 … 300 mA

purge (optional): modulated current)

Options
Table 12 Modules, Sensor Heads, and Outputs
Module Sensor Heads Output
RH and T module One sensor head RH and T output
Dewpoint module Warmed humidity sensor Dewpoint output
head
RH and T module with Warmed humidity sensor RH and T output
two sensor heads head

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Table 13 Cable Lengths for Sensor Heads

Sensor Head Cable Length
Humidity sensor head 65, 150, 300 cm
Optional T sensor head/module with 150 or 300 cm
two sensor heads

Table 14 Automatic Chemical Purge

Module Automatic Chemical Purge at
Startup
RH and T module Yes
Dewpoint module Yes
RH and T module with two sensor Yes
heads

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*M210718EN*