Vaisala Humicap HMW60U User manual

USER'S GUIDE
Vaisala HUMICAP
®
Humidity and
Temperature Transmitters
HMW60U/Y
U302EN12

PUBLISHED BY
Vaisala Oyj Phone (int.): [phone]
P.O. Box 26 Fax: [phone]
FIN-00421 Helsinki
Finland
Visit our Internet pages at http://www.vaisala.com/
© Vaisala 2006
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.

HMW60U/Y Transmitters
U302en-1.1 Operating Manual
2000-08-23 i
Contents
1. PRODUCT DESCRIPTION ...................................................................................................1
2. TO BE NOTED WHEN MEASURING HUMIDITY..................................................................2
3. INSTALLATION....................................................................................................................3
3.1 Selecting the place of installation..........................................................................3
3.2 Mounting..................................................................................................................3
3.3 Electrical connections.............................................................................................4
4. CALIBRATION .....................................................................................................................5
5. MAINTENANCE....................................................................................................................6
5.1 Replacing the HUMICAP180 sensor and the filter ..............................................6
6. TECHNICAL DATA...............................................................................................................7
6.1 Relative humidity.....................................................................................................7
6.2 Temperature (Y model only) ...................................................................................7
6.3 General......................................................................................................8
6.4 Electromagnetic compatibility.....................................................................8
6.4.1 Emissions..................................................................................................8
6.4.2 Immunity ...................................................................................................8
GUARANTEE .......................................................................................................................8

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U302en-1.1 Operating Manual
2000-08-23 1
1. PRODUCT DESCRIPTION
The HMW60 transmitters are wall mounted truly two-wire transmitters for the
measurement of humidity (HMW60U) and for the measurement of humidity
and temperature (HMW60Y).
The HMW60U/Y transmitters can be mounted directly on the wall. Thye are
easy to install and maintain. One point calibration is easily performed with the
HMI41 indicator and the calibration cable 19116ZZ.
Both transmitter types incorporate the HUMICAP®180 humidity sensor which
uses an operating principle based on changes in the capacitance of a thin
polymer film as it absorbs water molecules. The HMW60Y transmitters
mesure temperature with the reliable Pt 1000 sensor.

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2. TO BE NOTED WHEN MEASURING HUMIDITY
In the measurement of 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.
The error is at its greatest when the temperature of the sensor differs from that
of the surroundings and the humidity is high. A few degrees’ difference in
temperature may cause water to condense on sensor surface. Efficient
ventilation accelerates evaporation whereas in an unventilated space, it may
take hours. The HUMICAP180 sensor returns to its normal functioning as
soon as water has evaporated. Any contaminated water condensing on the
sensor may shorten its life span and change the calibration.
Temperature (°C)
dRH (%RH)
0
1
2
3
4
5
6
7
8
9
10
-40-200 20406080100
Figure 2.1 Measurement error at 100 %RH when the temperature
difference between the ambient and the sensor is 1 °C

HMW60U/Y Transmitters
U302en-1.1 Operating Manual
2000-08-23 3
3. INSTALLATION
3.1 Selecting the place of installation
Select a place that gives a true picture of the environment or process and is as
clean as possible. Air should circulate freely around the sensor. A rapid air
flow is recommended as it ensures the same temperature for the ambient air
and the sensor head.
Install the transmitter in a place where no cold or hot spot can develop. If the
sensor head is installed in a duct or channel where the temperature is different
from the ambient temperature, insulate the point of entry. An uninsulated
installation might lead to condensation on the sensor head and even if no
condensation occurs, the resultant air flow may change the temperature near
the sensor head and distort the readings.
3.2 Mounting
The HMW60U/Y transmitters can be mounted directly on the wall. First attach
the base plate with the two screws provided. Thread wires through the opening
in the transmitter board. Note the UP sign which shows the correct mounting
position. Be careful not to damage the HUMICAP®180 sensor.
110 (4.33)
85 (3.35)
33 (1.30)
Figure 3.2 Dimensions of the HMW60U/Y (in mm)

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3.3 Electrical connections
Figure 3.3 shows the electrical connections. Note the UP sign which shows the
correct mounting position.
-RH
+T
+RH
-T
T OFFSET
RH
RH
T GAIN
OFFSET GAIN
RH TEST T TEST
mA
mA OR
+
-
mA
mA
+
OR
-
RH T
X3 X4
UP
(wet)
(dry)
HUMICAP
sensor sensor
Figure 3.3 Electrical connections

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U302en-1.1 Operating Manual
2000-08-23 5
4. CALIBRATION
The accuracy is recommended to be checked at least once a year; the interval
depends on the operating conditions and the required accuracy of the
measurement. The transmitter calibration can be conveniently checked with
the HMI41 indicator equipped with an appropriate probe and optional
calibration cable. If adjustment is needed, use the one-point calibration
potentiometer.

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5. MAINTENANCE
5.1 Replacing the HUMICAP180 sensor and the filter
Remove the damaged sensor and insert a new one. Handle the sensor by the
plastic socket. DO NOT TOUCH THE SENSOR PLATE. Recalibrate the
transmitter.

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U302en-1.1 Operating Manual
2000-08-23 7
6. TECHNICAL DATA
6.1 Relative humidity
Measurement range 0...95 %RH
(output signal corresponds to 0...100 %RH)
Accuracy at +20 °C:
10 4020 605030 8070 %RH
%RH
3
2
1
0
-1
-2
-3
090 100
Temperature dependence:
200
1.0
0.5
0
-0.5
-1.0
40 60 °C
%RH
10 30 50-10
Response time (90%)
at 20 °C in still air 15 s
Humidity sensor HUMICAP180
6.2 Temperature (Y model only)
Measurement range -5...+55 °C
Accuracy :
-10 10040 50
20 60 30 °C
°C
0.5
0.4
0.3
0.2
0.1
0
-0.1
-0.2
-0.3
-0.4
-0.5
Linearity better than 0.1 °C
Temperature sensor Pt 1000 IEC 751 class B

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6.3 General
Supply voltage 10...35 VDC (RL= 0Ω)
20...35 VDC (RL=500Ω)
Output signal 4...20 mA
Operating temperature range -5...+55 °C
Storage temperature range -40...+80 °C
Long-term humidity range
for electronics 0...85 %RH
Housing:
cover ABS plastic
base plate PA
Connections Screw terminals 0.5...1.5 mm2
6.4 Electromagnetic compatibility
The emission and immunity tests have been performed according to standards
EN50081-1 and EN50082-1.
6.4.1 Emissions
Test Setup according to Performance
Radiated
interference EN55022 class B
6.4.2 Immunity
Test Setup according to Performance
Electrostatic
discharge IEC 801-2:1991 criteria B
Electrical fast
transients IEC 801-4:1988 criteria B
RF radiated
fields IEC 801-3:1984 criteria A
*GSM-field
immunity ENV50204:1995 criteria A
(*additional test)
GUARANTEE
Vaisala issues a guarantee for the material and
workmanship of this product under normal operating
conditions for one year from the date of delivery.
Exceptional operating conditions, damage due to
careless handling or misapplication will void the
guarantee.

www.vaisala.com