Operating Instructions

Table Of Contents
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Siemens RXB (KNX) Applications library CLC and RAD description of functions for CC-02 CM110384en_04
Building Technologies Control sequences 21 Sep 2010
8.2 Chilled ceiling (CLC01)
The chilled ceiling application has a continuous cooling sequence. The room controllers
operate with a PI algorithm optimized for thermal or motorized valve actuators. (For
simplicity, the diagram below only shows the P-control action.)
The control sequence comes into operation at the effective setpoints for cooling (see
page 67).
100
0
TR [°C]
Y [%]
SpC
YC
C
Y Output signal
TR Room temperature
SpC Effective cooling setpoint
C Cooling sequence
YC Cooling valve
8.2.1 Select actuator types for chilled ceiling
See section 8.1.1, page 79 on selecting actuator types for radiators.
The following information differs from the radiator applications:
HandyTool
Parameter Short name Basic setting
*051 Actuat c’surf valve STA71
Settings
STE71 1 SSA81 10 Motoric bus 250
STA71 3 SSB81 11 El’mech 3
rd
party devices 252
STP71 4 SQS81 12 Thermal 3
rd
party devices 253
STA72E 5 SSC81 13 Motoric 3
rd
party devices 254
STP72E 6 SSP81 14
If thermal actuators are selected, Y3 / Y4 are always controlled in parallel to ensure
that several actuators can be connected at the same time.
Exact parallel operation of several thermal valve actuators is not guaranteed. If
several radiators are controlled by the same controller, motorized actuators are the
preferred device.
If nevertheless thermal actuators are controlled in parallel, "3rd Party Thermic" must
be parameterized regardless of make.
Thermal actuators work at higher temperatures. To ensure a fast reaction, the
actuators are slightly preheated continuously (5% – 1 sec ON / 19 sec OFF). Then
thus also receive pulses from the controller when closed.
Actuator type
Thermal valve actuators
Notes