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Siemens
RXB (KNX) Applications library
CLC and RAD description of functions for CC-02 CM110384en_03
Building Technologies
Temperature measurement
28 Feb 2009
7 Temperature
measurement
7.1
Room temperature measurement
The value valid for temperature control can originate in various sources:
– A room unit via PPS2
– An analog sensor via analog input B1
– Mean value of several sensors
–
The
bus.
If none of these sources supplies a valid room temperature, the following will happen:
•
the controller uses the mean value from the effective heating and cooling setpoints
for control until a valid measured value is again received
•
the controller issues an alarm "Room temp. sensor error"
•
the bus output sends 0°C
•
if slaves are connected, they receive an invalid temperatur (327.67°C)
•
if a room unit is connected to a slave, the slave uses the temperature value of its
room unit when two heartbeat periods have elapsed.
7.1.1
Local temperature sensor at PPS2 interface
PPS2 (CP+, CP-)
QAX3...
RXB2...
10
38
5Z
1
2
If a QAX… room unit (with PPS2 interface)
is connected to the controller, the room
temperature is measured by the
temperature sensor integrated in the room
unit.
7.1.2
Local temperature sensor at analog input
B1
QAA24
RXB2...
1038
5Z
1
3
Alternatively, an LG-Ni1000 sensor, type
QAA24, can be connected to analog input B1
of the room controller.
The sensors connected to terminal B1 can have different functions:
Parameter setting
Description
Room
Room air sensor (can also be used for averaging
together with room unit PPS; see below).
No sensor
No sensor connected.
Only measured value
acquisition
Uses the signal, see "analog input B1", page 112.
Sources
Invalid temperature
