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Siemens
RXB21.1, RXB22.1 Room controllers
CM2N3873en_06
Building Technologies
02 Apr 2010
In the event of a long-term short circuit (approx. 4 minutes) or overload,
the thermal fuse in the transformer may trip.
Subsequently, the device must be exchanged.
There is no protection against accidental connection on the AC 24 V side.
Mains AC 230 V for the supply and for the relays must be disconnected before
plugging and unplugging the terminal blocks (danger of electric shock!)
If serial wiring is applied on the terminal block 19/21, the connection will be
interrupted if the block is removed from the controller (the jumpers 19-19 and
21-21 are on the PCB, not in the block, see terminal diagrams on pages
11 and 12).
Technical data
Power supply
Operating voltage
AC 230 V ± 10 %
Rated voltage
AC 230
Frequency 50/60
Hz
Power consumption with connected field devices
Max. 12 VA
Internal fuse
Thermal, non-resetting
Operating data
Control algorithm
PI
Inputs
Signal inputs D1, D2
Quantity
2
(for volt-free contacts)
Contact voltage
DC 16 V
Contact current
DC 5 mA
Contact transfer resistance
Max. 100
Contact insulation resistance
Min. 50 k
Switch time:
min. 20ms “ON”, min. 20ms “OFF”
Measured value input B1
Compatible temperature sensors
LG-Ni 1000
Quantity 1
measuring range
0 ... 50 °C
Sensor current
0.5 mA
Resolution 0.1
K
Measuring error at 25 °C sensor temp. (without cable) max. 0.5 K
Outputs
AC24 V triac outputs , Y1 … Y4
Quantity 2
(RXB22.1)
4 (RXB21.1)
Output voltage
AC 24 V ON/OFF, PWM or 3-position: +/–20%
(May 20% with loads under 2VA)
Output current
Max. 0.5 A
Total nominal load
(at both outputs simultaneously)
Max. 9.5 VA (e.g. 2 thermic valves, type
STP72E per heating and cooling sequence
+ 1 damper actuator 4.5 VA)
Relay outputs Q14, Q24, Q34
Quantity 3
Relay type
Monostable
Contact rating with AC voltage
Switching voltage
Max. AC 250 V, min. AC 19 V
Nominal current, resistive/inductive
Max. AC 5 A/4 A (cos
= 0.6)
Making current 200 ms half-time
Max. 20 A
Switching current at AC 29 V
Min. AC 10 mA
Contact rating with DC voltage
Switching voltage
Max. DC 250 V, min. DC 5 V
Switching current at DC 5 V
Min. DC 100 mA
Switching capacity
Max. 20 W
Inductive load L/R
Max. 7 ms
Q44
Relay type
Monostable
Contact rating with AC voltage
Max. admissible load (resistive only)
Max. 1.8 kW
External fuse (essential)
Max. 10 A