Data Sheet for Product

2
Siemens
Datasheet
A6V12046135_en--_a
Smart Infrastructure
2020-07-23
Use
QFA2050/MO and QFA2050D/MO are used in ventilation and air conditioning plants to
acquire room
● relative humidity
● temperature
The sensor is used as a measuring sensor for building automation and control systems or
display units.
Technical design
The units are designed for wall mounting and can be deployed with most types of
commercially available recessed conduit boxes. The cables can be introduced from the rear
(concealed wiring), from below or above (surface-run wires) through knock-out openings.
Measured value display
QFA2050D provides the measured values on its LCD display. The following measured
values are displayed, alternating at intervals of 5 s:
● Temperature: in °C or °F
● Humidity: in % r.h.
Type summary
Product number
SSN No.
Temperature
measuring range
Humidity
measuring range
Operating voltage
Output signal
QFA2050/MO
S55720-S508
-40…70 ℃
0…100 %
AC 24 V ±20 %/
DC 13.5...35 V
Modbus RTU
QFA2050D/MO
S55720-S509
-40…70 ℃
0…100 %
AC 24 V ±20 %/
DC 13.5...35 V
Modbus RTU
Ordering and delivery
When ordering, specify name and product number, for example: Room sensor
QFA2050/MO.
Notes
Engineering
The following impacts the accuracy of measurement:
● Prevailing air flow
● Wall surface (rough, smooth)
● Wall texture (wood, plaster, concrete, brick)
● Wall type (interior, exterior).
This application-specific measuring inaccuracy is constant for an installed sensor after
approx. 1 hour of operation and can be adjusted as needed in a higher system (e.g.
controller).
No correction on the local LCD.
Powering the sensor requires a transformer for safety extra low-voltage (SELV) with
separate windings for 100 % duty. When sizing and protecting the transformer, comply with
all local safety regulations.
When sizing the transformer, consider the sensor's power consumption.
For correct wiring, see the related device data sheets.
Observe all permissible line lengths.