Vaisala HUMICAP HMM170 User manual

M212259EN-D
User Guide
Vaisala HUMICAPâHumidity and Temperature
Module
HMM170

PUBLISHED BY
Vaisala Oyj
Vanha Nurmijärventie 21, FI-01670 Vantaa, Finland
P.O. Box 26, FI-00421 Helsinki, Finland
[phone]
Visit our Internet pages at www.vaisala.com.
© Vaisala 2021
No part of this document may be
reproduced, published or publicly
displayed in any form or by any means,
electronic or mechanical (including
photocopying), nor may its contents be
modified, translated, adapted, sold or
disclosed to a third party without prior
written permission of the copyright holder.
Translated documents and translated
portions of multilingual documents are
based on the original English versions. In
ambiguous cases, the English versions are
applicable, not the translations.
The contents of this document are subject
to change without prior notice.
Local rules and regulations may vary and
they shall take precedence over the
information contained in this document.
Vaisala makes no representations on this
document’s compliance with the local
rules and regulations applicable at any
given time, and hereby disclaims any and
all responsibilities related thereto.
This document does not create any legally
binding obligations for Vaisala towards
customers or end users. All legally binding
obligations and agreements are included
exclusively in the applicable supply
contract or the General Conditions of Sale
and General Conditions of Service of
Vaisala.
This product contains software developed
by Vaisala or third parties. Use of the
software is governed by license terms and
conditions included in the applicable
supply contract or, in the absence of
separate license terms and conditions, by
the General License Conditions of Vaisala
Group.

Table of contents
1. About this document.....................................................................................5
1.1 Version information.......................................................................................... 5
1.2 Related manuals................................................................................................5
1.3 Documentation conventions........................................................................... 6
1.4 Trademarks........................................................................................................ 6
2. Product overview............................................................................................ 7
2.1 Introduction to HMM170...................................................................................7
2.2 Basic features and options...............................................................................7
2.3 Sensor types...................................................................................................... 8
2.4 Output parameters........................................................................................... 9
2.5 Probe head.......................................................................................................10
2.6 Filter types....................................................................................................... 10
2.7 LED indicator.....................................................................................................11
2.8 Safety................................................................................................................ 12
2.8.1 ESD protection..........................................................................................12
3. Functional description.................................................................................13
3.1 HUMICAP technology..................................................................................... 13
3.2 Chemical purge................................................................................................13
3.3 Condensation prevention functions..............................................................14
4. Installation........................................................................................................ 16
4.1 Installing module............................................................................................. 16
4.2 Selecting probe mounting location and method.........................................17
4.3 Installing probe................................................................................................ 18
5. Operation.......................................................................................................... 19
5.1 Using service port............................................................................................19
5.1.1 Installing driver for the USB service cable............................................ 19
5.2 Modbus............................................................................................................20
5.3 Vaisala Insight software.................................................................................20
5.3.1 Connecting to Insight software.............................................................20
5.3.2 Configuration options..............................................................................21
5.3.3 Configuring condensation prevention................................................... 21
6. Maintenance....................................................................................................22
6.1 Cleaning probe................................................................................................22
6.2 Cleaning HUMICAP 180L2 sensor................................................................. 22
6.3 Replacing filter................................................................................................23
6.4 Calibration and adjustment...........................................................................23
6.4.1 Adjustment points and requirements...................................................24
6.4.2 Adjusting measurement with Insight software................................... 25
7. Technical data................................................................................................ 26
7.1 HMM170 specifications...................................................................................26
Table of contents
1

7.2 Dimensions......................................................................................................29
7.3 Accessories and spare parts......................................................................... 30
Appendix A: Modbus reference.................................................................. 32
A.1 Default communication settings...................................................................32
A.2 Function codes................................................................................................32
A.3 Data encoding.................................................................................................32
A.3.1 32-bit floating point or 32-bit integer format......................................33
A.3.2 16-bit integer format...............................................................................33
A.4 Modbus registers............................................................................................34
A.4.1 Measurement data registers.................................................................. 34
A.4.2 Configuration registers........................................................................... 37
A.4.3 Status registers....................................................................................... 40
A.4.4 Test value registers................................................................................. 42
A.5 Device identification objects.........................................................................42
A.6 Exception responses...................................................................................... 43
A.7 Modbus communication examples.............................................................. 44
Appendix B: FCC Part 15 compliance statement.................................... 47
Maintenance and calibration services........................................................ 49
Warranty............................................................................................................49
Technical support............................................................................................49
Recycling...........................................................................................................49
HMM170 User Guide M212259EN-D
2

List of figures
Figure 1 HMM170 probe head dimensions...................................................................10
Figure 2 HMM170 component board..............................................................................16
Figure 3 HMM170 probe installation through a wall.................................................. 17
Figure 4 Connecting module to Insight.........................................................................21
Figure 5 Temperature measurement accuracy over temperature range............ 27
Figure 6 HMM170 probe head dimensions.................................................................. 29
Figure 7 HMM170 component board dimensions..................................................... 30
List of figures
3

List of tables
Table 1 Document versions (in English)...................................................................... 5
Table 2 Related manuals.................................................................................................. 5
Table 3 HMM170 sensor types.........................................................................................8
Table 4 Availability of output parameters...................................................................9
Table 5 Filter types and properties...............................................................................11
Table 6 LED indicator states........................................................................................... 11
Table 7 HMM170 measurement performance...........................................................26
Table 8 HMM170 operating environment...................................................................27
Table 9 HMM170 inputs and outputs...........................................................................27
Table 10 HMM170 output parameters...........................................................................28
Table 11 HMM170 compliance.........................................................................................28
Table 12 HMM170 mechanical specifications..............................................................29
Table 13 HMM170 accessories........................................................................................ 30
Table 14 HMM170 spare parts.........................................................................................30
Table 15 Default Modbus communication settings...................................................32
Table 16 Modbus function codes................................................................................... 32
Table 17 Interpretation of 16-bit signed integer values...........................................33
Table 18 Floating point measurement data registers (read-only).......................34
Table 19 Integer measurement data registers (read-only).................................... 36
Table 20 Modbus configuration data registers (writable).......................................37
Table 21 Modbus status data registers (read-only)................................................. 40
Table 22 Error codes in register 0203hex...................................................................... 41
Table 23 Modbus test registers (read-only)................................................................42
Table 24 Device identification objects......................................................................... 42
Table 25 Modbus exception responses........................................................................ 43
HMM170 User Guide M212259EN-D
4

1. About this document
1.1 Version information
This document provides instructions for installing, operating, and maintaining Vaisala
HUMICAPâHumidity and Temperature Module HMM170.
Table 1 Document versions (in English)
Document code Date Description
M212259EN-D June 2021 This manual.
Added sections:
•HUMICAP technology (page 13)
•Condensation prevention functions (page 14)
•Cleaning HUMICAP 180L2 sensor (page 22)
•FCC Part 15 compliance statement (page 47)
Updated sections:
•Output parameters (page 9)
•Chemical purge (page 13)
•Cleaning probe (page 22)
•HMM170 specifications (page 26)
•Measurement data registers (page 34)
•Status registers (page 40)
•Modbus communication examples (page 44)
M212259EN-C April 2020 Previous version. Updated technical specification, installation
instructions, and Modbus reference appendix. HMM170 now
supports 24 V AC supply voltage, starting from serial number
S1231134.
M212259EN-B October 2019 Updated section Output parameters (page 9). Updated
technical specification. Removed content related to MI70
handheld indicator.
1.2 Related manuals
Table 2 Related manuals
Document code Name
M212260EN Vaisala HMM170 Quick Guide
M210185EN Vaisala HMK15 User Guide
Chapter 1 – About this document
5

1.3 Documentation conventions
Warning alerts you to a serious hazard. If you do not read and
follow instructions carefully at this point, there is a risk of injury or even death.
WARNING!
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.
CAUTION!
Note highlights important information on using the product.
Tip gives information for using the product more eciently.
Lists tools needed to perform the task.
Indicates that you need to take some notes during the task.
1.4 Trademarks
Vaisalaâand HUMICAPâare registered trademarks of Vaisala Oyj.
Modbusâis a registered trademark of Schneider Automation Inc.
All other product or company names that may be mentioned in this publication are trade
names, trademarks, or registered trademarks of their respective owners.
HMM170 User Guide M212259EN-D
6

2. Product overview
2.1 Introduction to HMM170
Vaisala HUMICAPâHumidity and Temperature Module HMM170 is an open frame OEM module
for integration into demanding environmental chambers and harsh conditions. The module
provides a digital RS-485/Modbus RTU output and three freely configurable analog output
channels. The module provides relative humidity, temperature, dew point, and other calculated
parameters.
HMM170 probe covers the full temperature range −70 … +180 °C (−94 … +356 °F) used in
climate chambers and the whole humidity range up to condensation. The small probe and
compact component board oer easy and flexible installation. The probe cable options (2, 5,
or 10 m (6.5, 16.4, or 32.8 ft)) oer excellent cost optimization and flexibility to any OEM
application. By ordering HMM170 with the appropriate sensor, you can use the module in
environments that are frequently sterilized with vaporized hydrogen peroxide (H2O2) or to
measure humidity in oil medium, for example, for transformer and engine monitoring
applications.
The latest general purpose HUMICAPâR2 sensor has improved corrosion resistance. The
sensor can tolerate typical chemicals, such as cleaning agents used in climate chambers. The
automatic sensor chemical purge function keeps the sensor clean from typical chemical fumes
and the additional probe warming function prevents condensation. In case HMM170 gets in
contact with water, the automatic heating rapidly dries the sensor to enable fast and accurate
humidity measurement.
HMM170 is easy to install and convenient to use. It provides both digital and analog outputs for
multiple needs. An integrated service port enables a quick and simple way to configure, check,
and calibrate the module with the help of a USB cable and Vaisala Insight PC software. In
addition, the footprint of the HMM170 component board enables easy update for Vaisala
HMM100 users.
2.2 Basic features and options
• Three humidity sensor types:
• Vaisala HUMICAPâR2C (general use)
• Vaisala HUMICAPâ180VC (for H2O2use)
• Vaisala HUMICAPâ180L2 (for moisture in oil)
• Sensor purge provides superior chemical resistance
• Probe and sensor warming functions minimize condensation on probe
• Analog output options:
• 0/4 ... 20 mA
• 0/1 ... 5 V
• 0 ... 5/10 V
• Probe cable lengths:
• 2, 5, or 10 m (6.5, 16.4, or 32.8 ft)
• Various filter types
Chapter 2 – Product overview
7

• Service port for maintenance
• Optional USB cable for easy connection to Vaisala Insight software for configuration,
diagnostics, and temporary online monitoring
2.3 Sensor types
HMM170 is available with three dierent sensor types.
Table 3 HMM170 sensor types
Sensor type Description
HUMICAPâR2C A general purpose industrial humidity sensor with high humidity
durability, good long term stability, and good tolerance against
chemical exposure.
HUMICAPâ180L2 A sensor that is optimized for measurement of humidity in oil
medium. It has good tolerance against chemicals and moderate
humidity durability.
HUMICAPâ180L2 sensor measures moisture in oil in terms of the
water activity (aw) and temperature (T). Water activity indicates
directly whether there is a risk of free water formation. The
measurement is also independent of oil type and age. In addition
to water activity, HMM170 can output ppm, the average mass
concentration of water in oil.
HUMICAPâ180L2 sensor does not support probe heating or
chemical purge.
HUMICAPâ180VC A composite humidity sensor with catalytic surface for use in
applications where the sensor is exposed to H2O2(hydrogen
peroxide).
Catalytic HUMICAPâ180VC sensor is a good choice when you
want to measure RH between bio-decontamination cycles and
you are not interested in saturation level of the air mixture during
the bio-decontamination phase. Catalytic layer protects the
sensor during the bio-decontamination phase. Catalytic layer
catalyzes H2O2into water vapor and oxygen. Therefore, the
sensing polymer detects only water vapor and shows correct
relative humidity value.
HMM170 User Guide M212259EN-D
8

2.4 Output parameters
Output parameter is available
Output parameter is unavailable unless real temperature is written to Modbus register 0334hex
from an external source
Output parameter is locked (value stays at latest valid reading) until measurement is possible
again
Output parameter is not valid for sensor type
Table 4 Availability of output parameters
Output parameter Output range HUMICAPâR2C and 180VC sensor HUMICAPâ
180L2
sensor
Normal
operation
During
heating
During
purge
Absolute humidity 0 … 600 g/m3
Absolute humidity at
NTP
0 … 600 g/m3
Dew/frost point
temperature
−80 … +100 °C
Dew/frost point
temperature at 1 atm
−80 … +100 °C
Dew point temperature −80 … +100 °C
Dew point temperature
at 1 atm
−80 … +100 °C
Dew point temperature
dierence
−10 … +50 °C
Enthalpy −40 … 1500 kJ/kg
Mixing ratio 0 … 500 g/kg
Relative humidity 0 … 100 %RH
Relative humidity
(dew/frost)
0 … 100 %RH
Relative saturation 0 … 100 %RS
Temperature −70 … +180 °C
Water activity 0 … 1
Water concentration 0 … 106ppm
Water concentration in
oil
0 … 106ppm
Chapter 2 – Product overview
9

Output parameter Output range HUMICAPâR2C and 180VC sensor HUMICAPâ
180L2
sensor
Water concentration
(wet basis)
0 … 100 vol-%
Water mass fraction 0 … 106ppmw
Wet-bulb temperature 0 … +100 °C
Water vapor pressure 0 … 1000 hPa
Water vapor saturation
pressure
0 … 1000 hPa
2.5 Probe head
Ø 12
[0.47]
99.5 [3.92]
79.5 [3.13]
37.5 [1.48]
Groove for
lock ring
Ø 12
[0.47]
Ø 5
[0.2]
mm
[in]
Figure 1 HMM170 probe head dimensions
HMM170 is designed for applications that involve constant high humidity or rapid changes in
humidity, such as drying and test chambers, combustion air, and other humidifiers and
meteorological measurements, where measurement performance and chemical tolerance are
essential.
• Temperature measurement range −70 ... +180 °C (−94 ... +356 °F)
• Operating temperature range for probe −70 ... +180 °C (−94 ... +356 °F)
• Probe and sensor warming functions minimize condensation on probe
• Vapor and pressure proof construction
• Stainless steel mesh filter standard in delivery
2.6 Filter types
All filters available for HMM170 are 12 mm (0.47 in) in diameter. Note the operational
temperature range of each filter.
HMM170 User Guide M212259EN-D
10

Table 5 Filter types and properties
Filter type Diameter Pore size Temperature range
PPS plastic grid
with stainless steel
mesh
12 mm
(0.47 in)
15 µm −70 ... +180 °C
(−94 ... +356 °F)
Stainless steel
sintered
12 mm
(0.47 in)
38 µm −70 ... +180 °C
(−94 ... +356 °F)
Stainless steel
filter for moisture
in oil
12 mm
(0.47 in)
3.15 mm −70 ... +180 °C
(−94 ... +356 °F)
Porous PTFE
(general purpose)
12 mm
(0.47 in)
8 µm −70 ... +180 °C
(−94 ... +356 °F)
More information
‣Accessories and spare parts (page 30)
2.7 LED indicator
The LED indicator on the component board provides a visual indication of the status of
HMM170. The alarm LED functionality is preset at the factory according to order form.
Table 6 LED indicator states
LED color Meaning
Not lit Module is powered o or LED functionality is disabled.
Green Module is powered on and ready for operation.
Green and blinking Module is powering up or communicating using Modbus.
Red Module is in error state.
You can use Vaisala Insight software to disable the LED indicator.
Chapter 2 – Product overview
11

2.8 Safety
This product has been tested for safety. Note the following precautions:
Ground the product and verify installation grounding periodically
to minimize shock hazard.
WARNING!
Do not modify the unit or use it in ways not described in the
documentation. Improper modification or use may lead to safety hazards,
equipment damage, failure to perform according to specification, or decreased
equipment lifetime.
CAUTION!
2.8.1 ESD protection
Electrostatic Discharge (ESD) can damage 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 in the
equipment housing.
To avoid delivering high static voltages to the product:
• Handle ESD‑sensitive components on a properly grounded and protected ESD workbench
or by grounding yourself to the equipment chassis with a wrist strap and a resistive
connection cord.
• If you are unable to take either precaution, touch a conductive part of the equipment
chassis with your other hand before touching ESD‑sensitive components.
• Hold component boards by the edges and avoid touching component contacts.
HMM170 User Guide M212259EN-D
12

3. Functional description
3.1 HUMICAP technology
Vaisala HUMICAPâis a capacitive thin-film polymer sensor consisting of a substrate on which
a thin film of polymer is deposited between two conductive electrodes. The sensing surface is
coated with a porous metal electrode to protect it from contamination and exposure to
condensation. The substrate is typically glass or ceramic.
The thin-film polymer either absorbs or releases water vapor as the relative humidity of the
measurement environment rises or falls. The dielectric properties of the polymer film depend
on the amount of absorbed water. As the relative humidity around the sensor changes, the
dielectric properties of the polymer film change, and so does the capacitance of the sensor.
Capacitance is converted into a humidity reading. The HUMICAP sensor is complemented by a
temperature sensor, which is bonded together with the capacitive polymer on some of the
sensor variants. Additional output parameters such as dew point are calculated from the
readings measured by the sensors.
HUMICAP sensors with bonded temperature sensors are also known as composite sensors.
Probes with composite sensors can use the chemical purge function to maintain sensor
performance. They also implement condensation prevention functions that are a key element
in achieving an excellent stability and good condensation resistance in high humidity
applications.
3.2 Chemical purge
Chemical purge is a process where sensors are heated to remove possible contamination.
Purge is essential for long-term performance and accuracy of the probe. Purge takes up to
6 minutes to complete, during which time measurements are not available.
Depending on the selected sensor, the purge is automatically performed:
• At probe start-up
• At probe start-up and after every 24 hours
Disabling the automatic purge is not possible.
HUMICAPâ180L2 sensor does not support chemical purge.
You can trigger a purge manually at any time with Vaisala Insight software or Modbus, or by
closing the external purge trigger on the component board.
Chapter 3 – Functional description
13

3.3 Condensation prevention functions
Condensation prevention heating prevents water from condensing on the sensor and
interfering with humidity measurement. Use of condensation prevention is controlled by a
single setting that can be changed with Insight software or using Modbus protocol.
By default, condensation prevention is o. However, HMM170 can be ordered from Vaisala
with the feature enabled.
When condensation prevention is enabled, the HMM170 will automatically use its available
condensation prevention functions. When warming is active, values of output parameters that
depend on temperature measurement (for example, relative humidity) are unavailable unless
temperature is written to register 0334hex from an external source. Output parameters that can
be measured or calculated without this external temperature information, such as dew point
temperature, are available even without the temperature input.
Sensor warming
The sensor warming functionality in HMM170 warms the humidity sensor when necessary to
keep its temperature above the dew point of the measurement environment. When sensor
warming is activated, all temperature dependent output parameters become unavailable
unless external temperature information is provided to the module. The output parameters
become available again 4 minutes after warming is stopped.
Sensor warming is intended for improving the condensation tolerance of the
probe in measurement environments that may occasionally cause condensation
to form. It is not intended for environments where continuous warming is needed.
Probe heating
HMM170 supports probe heating. Probe heating warms up the entire probe head instead of
just the sensor. When probe temperature is heated above dew point temperature,
condensation on the probe can be avoided while measuring the dew point temperature of the
process. The functionality is intended for use in challenging measurement environments where
condensation on the probe would otherwise present a problem.
Probe heating is normally disabled. If you select to enable probe heating, output parameters
that are dependent on temperature measurement (such as relative humidity) are disabled,
unless the true temperature of the measured environment is updated to the temperature
compensation register of HMM170 from another measurement instrument. Output parameters
that can be measured or calculated without this external temperature information (such as
dew point temperature) are available even without the temperature input.
If the ambient dew point rises close to current sensor temperature, the heating power is
increased to avoid condensation. Heating power also increases as supply voltage increases.
HMM170 User Guide M212259EN-D
14

If you use probe heating, be sure to mount the HMM170 probe head in a way that
prevents the heat from being conducted away from the probe. Tightly connecting
the HMM170 probe head to a metal structure may prevent the probe from
maintaining probe temperature above the dew point. It will also heat the structure
which may be undesirable.
Even if condensation prevention has been turned on, probe heating is not active if
supply voltage is below 18 V DC. For example, this is the case when HMM170 is
connected to Insight software using the Vaisala USB cable 219690.
More information
‣Configuring condensation prevention (page 21)
Chapter 3 – Functional description
15

4. Installation
4.1 Installing module
SERVICE
D+ D− GND
GND
+ VIN − + CH1 − + CH2 − + CH3 − PURGE
6 7 8
5
4
21 3
Figure 2 HMM170 component board
1Service port (temporary connection,
USB cable with Vaisala Insight
software)
2Digital RS-485 (Modbus) port
3LED indicator
4Grounding point
5Mounting holes in the shaded area
match the mounting holes on HMM100
humidity module
6Power input (12 ... 35 V DC 1) or
24 V AC ±10 %)
7Active analog outputs (0/4 ... 20 mA,
1 ... 5 V, 0 ... 5/10 V)
8External purge trigger (closing
activates purge)
1) Condensation prevention and chemical
purge features require at least 18 V DC.
Make sure that you prepare and connect only de-energized wires.WARNING!
Electrostatic Discharge (ESD) can cause immediate or latent
damage to electronic circuits. Avoid touching exposed component contacts
during installation and maintenance.
CAUTION!
1. The module is delivered with a set of standos. Select the mounting holes you will be
using, and attach standos to the corresponding locations on the installation surface.
Always use the mounting hole marked GND as that is the grounding point for the module.
You may use other applicable standos that provide a minimum installation height of
6 mm (0.24 in).
2. Attach the module securely.
3. Make sure that the module has a good earth connection from the grounding point.
4. Connect wiring to the power input and signal output terminals.
5. Optional: connect wiring to the external purge trigger terminals.
HMM170 User Guide M212259EN-D
16

4.2 Selecting probe mounting location and
method
Relative humidity measurement is sensitive to temperature dierences between the probe and
the measuring environment. Even a small temperature dierence may cause a large error. For
example, if the temperature is +20 °C (68 °F) and the relative humidity 100 %RH, a dierence
of ±1 °C (±1.8 °F) between the environment and the probe causes an error of ±6 %RH. For this
reason, temperature dierences are an important consideration when selecting the probe
mounting location and method.
The probe location should represent well the environmental or process conditions, and it
should be as clean as possible. The probe head can be installed completely into the
measurement environment, or through a wall with only the filter (and the sensors underneath
it) extending to the measurement environment.
• If the temperature of the measured environment diers greatly from ambient
temperature, it is best to insert the whole probe and preferably plenty of cable inside the
environment. This prevents measurement inaccuracy caused by heat conduction along
the cable. The duct installation kit (Vaisala item code 210697) is a good accessory for this
purpose as it allows the probe to be placed at a sucient distance from the outer walls of
the chamber or duct.
• If there is no temperature dierence between the two sides of the installation wall,
installing the probe through the wall is a good option.
Other considerations:
• Mount the probe head horizontally to prevent any water condensing on the probe head
from running to the sensors.
• Let the cable hang loosely to prevent condensed water from running along the cable to
the probe head.
• If you use probe heating, do not attach the probe directly to metal structures.
Figure 3 HMM170 probe installation through a wall
Chapter 4 – Installation
17

4.3 Installing probe
The measurement probe with cable is attached to the component
board at Vaisala. Do not disconnect and reconnect the cable.
CAUTION!
1. Remove the yellow protection cap from the probe.
2. Mount the probe head in the selected location using the applicable installation
accessories. See any installation instructions that are delivered with the accessories.
3. Make sure any cable pass-throughs are sealed.
More information
‣Accessories and spare parts (page 30)
HMM170 User Guide M212259EN-D
18