Siemens RDG400 - Manual (Page 25)

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Siemens RDG100, RDG100T, RDG110, RDG140, RDG160 Basic Documentation CE1P3182en
Building Technologies Functions 28 May 2009
Output Y1 provides the OPEN command, and Y2 the CLOSE command to the 3-
position actuator.
The factory setting for the actuator runtime is 150 seconds. It can be adjusted via
parameter P44 (Y1 and Y2).
The parameter is only visible if 3-point is selected via DIP switch 5.
1. When the thermostat gets powered up, a closing command for the actuator
runtime + 150 % is provided to ensure that the actuator fully closes and
synchronizes to the control algorithm.
2. When the thermostat calculates the positions "fully close" or "fully open", the
actuator runtime is extended + 150 % to ensure the right actuator position
synchronized to the control algorithm.
3. After the actuator reaches the position calculated by the thermostat, a waiting
time of 30 seconds is applied to stabilize the outputs.
The demand calculated by PI control from the current room temperature and set-
point is provided via Y1 to the valve actuator as a PWM signal (Pulse width
modulation) for thermic actuators. The output is switched on for a period proportio-
nal to the heat/cool demand and then switched off for the rest of the PWM interval.
The interval is 150 sec (factory setting). It can be adjusted via parameters P44
(Y1). The parameters are only visible if 2-point is selected via DIP switch 5.
For thermic valve actuators, set the running time to 240 sec.
• Never apply PWM to a motoric actuator.
• It is not possible to ensure exact parallel running of more than one thermic valve
actuator. If several fan coils are driven by the same thermostat, preference
should be given to motoric actuators.
For electric heaters, set the running time to 90 sec.
In order to avoid burn-off of mechanical contacts by frequent switching, use a
current valve instead of a relay or contactor.
3-position control
signal
Synchronization
PWM control
PWM for thermic
valve actuators
Note!
PWM for el. heaters