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 Control sequences
8.1 Fan coils with valve control
8.1.1 4-pipe fan coils - With valve control
The applications for 4-pipe fan coils each have a proportional heating and proportional
cooling sequence. 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).
T
B1
YC
YH
Q1
10385S01
The control sequences come into operation at the effective setpoints for heating and
cooling (see page 68).
Y [%]
SpH SpC
TR [°C]
H C
YH YC
100
0
10385D08
Y Output signal
TR Room temperature
SpH Effective heating setpoint
SpC Effective cooling setpoint
H Heating sequence
C Cooling sequence
YH Heating valve
YC Cooling valve
B1 Return air sensor
Q1 Fan
Different applications support different valve actuators, and these do not all require the
same number of outputs on the controller. The tool displays the actuators suitable for
the selected application. Selection occurs at the engineering stage (see page 85).
Actuator type