Siemens Building Technologies QFM31 Data Sheet
1
882
QFM31..
QFM3160D /QFM3171D
AQF3150 AQF3153
Symaro™
Duct sensors
QFM31…
for relative humidity (high accuracy) and temperature
Examples
1882P01
1859P02
1859P04
• Operating voltage AC 24 V / DC 13.5...35 V
• Signal output DC 0...10 V / 4…20 mA for relative humidity and temperature
• Very high measuring accuracy across the entire measuring range
• Function test
• Capacitive humidity measurement
• Range of use −40…+70 °C / 0…100 % r. h.
with LCD display
Use
The QFM31… is for use in ventilation and air conditioning plants where high accuracy
and short response times for measuring relative humidity are required. The measuring
range covers the entire humidity range of 0…100 %.
• Storage and production facilities in the paper, textile, pharmaceutical, food, chemical
and electronics industry, etc.
• Laboratories
• Hospitals
• Computer and EDP centers
• Indoor swimming pools
• Greenhouses
The QFM31… is used as a
• control sensors in the supply or extract air
• limit sensor for maximum limitation of supply air humidity after a steam humidifier
• limit sensor, e.g. for measured value indication or for connection to a building
automation and control system
• sensor for enthalpy and absolute humidity, together with the SEZ220 (see Data
Sheet N5146)
−25…+70 °C / 0…100 % r.h.
CE1N1882en
2014-07-30
Building Technologies
Type summary
Type
Temperature
Temperature
Humidity
Humidity
Operating
Measured
QFM3100
None
None
0...100 %
active, DC 0...10 V
AC 24 V or
No
QFM3101
None
None
0...100 %
active, 4…20 mA
DC 13,5…35 V
No
QFM3160
0...50 °C / − 40…+70 °C /
active, DC 0...10 V
0...100 %
active, DC 0...10 V
AC 24 V or
No
QFM3160D
0...50 °C / − 40…+70 °C /
active, DC 0...10 V
0...100 %
active, DC 0...10 V
AC 24 V or
Yes
QFM3171
0...50 °C / − 40…+70 °C /
active, 4…20 mA
0...100 %
active, 4…20 mA
DC 13,5…35 V
No
QFM3171D
0...50 °C / − 40…+70 °C /
active, 4…20 mA
0...100 %
active, 4…20 mA
DC 13,5…35 V
Yes
0 10 20 30 40
700
400
300
800
900
600
500
100
0
200
Burden [Ohm]
[DC V]
Operating voltage
Admissible
range
Inadmissible
range!
1882D02en
Relative humidity
Temperature
Burden diagram
reference
measuring range
− 35...+ 35 °C
− 35...+ 35 °C
− 35...+ 35 °C
− 35...+ 35 °C
Ordering and delivery
Equipment combinations
signal output
measuring range
signal output
voltage
DC 13,5…35 V
DC 13,5…35 V
DC 13,5…35 V
value display
When ordering, please give name and type reference, e.g.:
Duct sensor QFM3160
Place a separate order for the service set AQF3153 listed under accessories.
All systems and devices capable of acquiring and handling the sensor’s DC 0...10 V or
4...20 mA output signal.
When using the sensors for minimum or maximum selection, for averaging, or to
calculate enthalpy, enthalpy difference, absolute humidity, and dew point, we
recommend to use the SEZ220 signal converter (see Data Sheet N5146).
Technical design
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Building Technologies 2014-07-30
The sensor acquires the relative humidity in the air duct via its capacitive humidity
sensing element whose capacitance varies as a function of the relative humidity of the
ambient air.
An electronic circuit converts the sensor’s signal to a continuous DC 0...10 V or
4…20 mA signal, corresponding to a relative humidity of 0...100 %.
The sensor acquires the temperature in the air duct via its sensing element whose
electrical resistance changes as a function of the temperature.
This variation is converted to an active DC 0…10 V or 4…20 mA output signal,
depending on the type of sensor. The output signal corresponds to a selectable
temperature range of 0…50 °C, –35…+35 °C, or −40...+70 °C.
Output signal, terminal I1 / I2
Mechanical design
1 2
3
1
2
3
Range
5 V
10 V
5 V
0 V
10 V
5 V
0 V
5 V
U1 U2
I1 I2
20 mA
12 mA
4 mA
12 mA
12 mA
20 mA
12 mA
4 mA
°F °C
°F °C
QFM31...D
Measuring range
Test function active
1882Z01en
Display
temperature unit
Measured value display
Setting element
The duct sensor consists of a housing, a printed circuit board, connection terminals, a
mounting flange and an immersion rod having a measuring tip.
The two-part housing comprises a base and a screwed removable cover.
A rubber seal is installed between the base and the cover in order to satisfy the
requirements of IP 65 degree of protection.
The measuring circuit and the setting element are accommodated on the printed circuit
board inside the cover, the connection terminals on the base.
The measuring tip is screwed on the immersion rod of the housing.
The sensing elements are located at the end of the measuring tip and protected by the
filter cap.
Cable entry is made via the cable entry gland M16 (IP 54) supplied with the sensor,
which can be screwed into the housing.
Immersion rod and housing are made of plastic and rigidly connected.
The sensor is fitted with the mounting flange supplied with the sensor. The flange is to
be placed over the immersion rod and then secured in accordance with the required
immersion length.
The types QFM3160D and QFM3171D provide the measured values on its LCD
display..The following measured values are displayed alternately in intervals of 5 s:
Temperature: in °C or °F
Humidity: in % r. h.
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Siemens Duct sensors QFM31… CE1N1882en
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The setting elements are located inside the cover. A setting element consists of 6 pins
and a jumper. It is used for selecting the required temperature measuring range and for
activating the test function. Types with LCD display have a second setting element with
4 pins and a jumper.
The different jumper positions have the following meaning:
• For the active temperature measuring range:
Jumper in the left position (R1) = − 35...+ 35 °C,
Jumper in the middle position (R2) = 0...50 °C (factory setting)
Jumper in the right position (R3) = −40…+70 °C
• For the active test function:
Jumper in the horizontal position: The values available at the signal output are those
given in the table “Test function active“
• For the measured value display (QFM31…D)
- Jumper vertical in the right position = °C (factory setting)
- Jumper vertical in the left position = °F
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