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Siemens
RXB (KNX) application library
FNC Description of functions for FC-10, FC-11, FC-12
CM110385en_05
Building Technologies
Control sequences
28 Feb 2009
8.1.2
Two-pipe fan coils - With valve control
Two-pipe fan coils have only one
proportional control sequence. This may be
configured for heating, cooling or changeover operation, as required. The controllers
operate with a PI algorithm optimized for thermal or motorized valve actuators. (For
simplicity, the diagrams below only show the P-control action).
1
038
5S
02
T
B1
Q1
YHC
The control sequence comes into operation at the effective setpoint for heating or
cooling (see page 69).
Heating only
100
0
TR [°C]
YHC
Y [%]
SpH
H
10
38
5D
09
Cooling only
100
0
TR [°C]
YHC
Y [%]
SpC
C
10
38
5D
10
Changeover
(heating or
cooling)
100
0
TR [°C]
YHC
YHC
Y [%]
SpH
SpC
H
C
Change-over
10
38
5D
11
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