User Manual

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Siemens Non-communicating room controllers CA2N3881en_02
Building Technologies RXA20.1, RXA21.1, RXA22.1 2012-08-28
Commissioning
The controller application and the configuration of the connected field devices are
defined manually with DIP switches and the potentiometer. The Service LED provides
information on power up and operational status.
There is no special test for checking that the connected field devices match the DIP
switch settings. Depending on the application, if the controller has insufficient
information it switches to "Idle" mode (all outputs at zero) and the LED remains on
continuously.
For details refer to the applications library CA2A3886.
STOP
Caution In the event of a long-term short circuit or overload, the thermal fuse in the
transformer may trip. The controller must then be replaced.
There is no protection against accidental connection with 230 V on the AC 24 V
side.
Technical data
Power supply Operating voltage AC 230 V ± 10 %
Rated voltage AC 230 V
Frequency 50/60 Hz
Power consumption with
output field devices connected Max. 12 VA
Internal fuse Thermal, non-resetting
Operating data Control algorithm PI
Inputs Signal inputs D1 … D3 (for volt-free contacts)
Quantity 3
Contact voltage DC 16 V
Contact current DC 8 mA
Contact transfer resistance Max. 100 
Contact insulation resistance Min. 50 k
Not suitable for pulse control
Measured value inputs B1 and X2
Type of signal is programmable (DIP switch) LG-Ni 1000 temperature sensor,
setpoint adjuster or 0 … 10 V signal
Temperature sensor LG-Ni 1000
Measuring range 0 ... 50 °C
Sensor current 2.3 mA
Resolution 0.2 K
Measuring error at 25 °C sensor temp. (without
cable)
Max. 0.2 K
Setpoint adjuster BSG21.5
Reset range +/– 3K
Setpoint reset signal 0 … 10 V RKN-S
for summer/winter compensation See data sheet CA2N3389
(No longer available!)
Outputs AC24 V triac outputs , Y1 … Y4
Quantity 2 (RXA20.1, RXA22.1)
4 (RXA21.1)
Output voltage (SELV, not earthed) AC 24 V ON/OFF, PWM or 3-position
(depending on application)
Output current Max. 0.5 A
Total nominal load
(at both outputs simultaneously)
Max. 9.5 VA
(e.g. 2 thermic valves, type STE72 per heating and
cooling sequence + 1 damper actuator 3.5 VA)