User Manual

Siemens Building Technologies CM1N1853E / 10.1999

Landis & Staefa Division 1/4

853

Room sensor QFA66/C

for relative humidity and temperature

with calibration certificate

Operating voltage AC 24 V, output signals DC 0...10 V,

very high measuring accuracy throughout the entire measuring range,

capacitive humidity measurement,

recalibration service

The QFA66/C sensor is used in ventilation and air-conditioning plants requiring:

•

very high accuracy and reliability for measuring relative humidity and temperature,

•

regular recalibration and readjustment of the sensors

Examples:

•

storage and production facilities in the paper, textiles, pharmaceutical, chemical,

electronics industries, etc.

•

laboratories

•

hospitals

•

computer centres

•

greenhouses

Indicate device name and type designation on order: Room Sensor

QFA66/C.

The coupling of the circular connector (Lumberg RKC 50/11) is delivered uninstalled.

All systems and controllers that can acquire and process the sensor's DC 0...10 V

output signals

The sensor senses relative humidity via a capacitive humidity measuring element whose

capacitance varies according to the relative humidity of the ambient air.

An electronic circuit converts the sensor's signal to a continuous DC 0...10 V signal,

corresponding to a relative humidity of 0...100 %.

Use

Ordering and

delivery

Equipment

combinations

Technical design

Relative humidity

PAGE 1
Room sensor 853 QFA66/C for relative humidity and temperature with calibration certificate . . . . . . . . . . . . . Operating voltage AC 24 V, output signals DC 0...
PAGE 2
Temperature The sensor senses the temperature via the Pt1000 thin-film measuring element whose electrical resistance varies according to the temperature of the ambient air. This variation is converted to two mutually independent DC 0...10 V signals. One signal corresponds to the 0...50 °C temperature range, the other to the −35...+35 °C range. Mechanical design The room sensor comprises a housing with a removable cover and an immersion sensor stem.
PAGE 3
Services provided The recalibration service1) includes the following: • Calibration2) with recording of values for humidity (B1) and temperature 0…50 °C (B2) • Sensor test, including repair and replacement of wear parts; filter every time, sensor elements if required.
PAGE 4
Humidity sensor 1863D01E r. h. [%] 100 40 - 40 + 60 + 80 [°C] Temperature sensor Measuring accuracy at 20 °C in the range 0...90 % r.h. in the range 90...100 % r.h. Temperature dependency in the range −10...+50 °C Reduction of the humidity measuring range at temp. above 60 °C at sensor head Time constant t90 ±2 % r.h. ±3 % r.h. <0,05 % r. h. / °C see illustration in margin approx. 20 s Sensing element Measuring accuracy in the range 20 °C Time constant t63 . . Pt1000 Class A ±0,3 K ca.