Operating Instructions

Table Of Contents
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Siemens RXB (KNX) application library RXB Description of functions for FC-10, FC-11, FC-12, FC-13 CM110385en_08
Building Technologies Control sequences 2013-06-17
8.1.2 2-pipe fan coils - With valve control
2-pipe fan coils have only one proportional control sequence. This may be configured
for heating, cooling or changeover operation, as required.
The RXB2... controllers operate with a PI algorithm optimized for thermal or motorized
valve actuators. The RXB39.1 controllers operate with a PI algorithm optimized for
proportional valve actuators.
(For simplicity, the diagrams below only show the P-control action).
10385S02
T
B1
Q1
YHC
The control sequence comes into operation at the effective setpoint for heating or
cooling (see page 68).
Heating only
100
0
TR [°C]
YHC
Y [%]
SpH
H
10385D09
Cooling only
100
0
TR [°C]
YHC
Y [%]
SpC
C
10385D10
Changeover
(heating or
cooling)
100
0
TR [°C]
YHCYHC
Y [%]
SpH SpC
H
C
Change-over
10385D11
Y Output signal
TR Room temperature
SpH Effective heating setpoint
SpC Effective cooling setpoint
H Heating sequence
C Cooling sequence
YHC Heating or cooling valve
B1 Return air sensor
Q1 Fan
The control sequence must be selected when the controller is engineered:
Heating only, Cooling only or Changeover.
Selecting the control
sequence