Siemens Desigo RXB Technical Manual page 54

Parallel connection of
several thermic valve
actuators
Connection to the
controller
Connection to the
power amplifier
Notes
14/16
Siemens
Building Technologies
Up to two thermic actuators per sequence may be connected directly to the room
controller. With more than two thermic actuators, a UA1T power amplifier is required.
The principle is the same for output Y2. Do not exceed the maximum simultaneous load
on outputs Y1 and Y2 (max. 9.5 VA).
Power consumption at input X1 of the UA1T: 0.5 VA.
Mixed operation: It is not permissible to connect thermic actuators both to the
controller and to the power amplifier.
Owing to the difference in voltage between the controller's internal transformer and the
power supply of the UA1T, this could cause the valve positions to deviate substantially.
N1
L L
N
N
Y1
G
AC 230 V AC 24 V
N1
L N
L
N
Y1
G
N1 Room controller RXB21.1, RXB22.1
N2 UA1T power amplifier (see data sheet CA2N3591)
Y1 AC 24 V thermic valve actuators connected to the controller
Y1.x AC 24 V thermic valve actuators
(max. 2 STA72E / STP72E actuators per Y1 output on the UA1T)
– The UA1T requires an AC 24 V supply voltage
– The UA1T is not suitable for the connection of 3-position actuators.
RXB21.1, RXB22.1 Room controllers
AC 230 V
Y1
G G0
Y1
N2
1 NS COM
LS Y1
2
COM COM
3
X1 Y1
4
N2
NS COM
1
LS Y1
2
COM COM
3
X1 Y1
4
Y1.1
Y1.1
8
7
Y1.2
6
5
Y1.5
8
7
Y1.6
6
5
CM2N3873en_06
02 Apr 2010
3873Z13
Y1.3
Y1.4
Y1.7
Y1.8