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Siemens
RDG400KN,RGD405KN Basic documentation
CE1P3192en
Building Technologies
2017-02-17
Output Y1 delivers the
Open
command, and Y2 the
Close
command to the 3-
position actuator.
The factory setting for the actuator’s running time is 150 seconds. It can be
adjusted via P44 (Y1 and Y2).
The parameter is only visible if 3-position is selected via DIP switch 5 or the
commissioning tool.
1. When the thermostat is powered up, a
Close
command for the actuator’s
running time + 150% is delivered to ensure that the actuator fully closes and
synchronizes to the control algorithm.
2. When the thermostat calculates the positions "Fully closed" or "Fully open",
the actuator’s running time is ex 150% to ensure the correct actuator
position is synchronized with 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 the
setpoint is delivered via Y1 to the valve actuator as a PWM signal (pulse width
modulation) for thermal actuators. The output is switched on for a period proportio-
nal to the heating/cooling demand and then switched off for the rest of the PWM
interval.
The interval is 150 seconds (factory setting). It can be adjusted via P44 (Y1). The
parameter is only visible if 2-position is selected via DIP switch 5 or the
commissioning tool.
For PWM, the
integral time (P35) must be set to 0!
For thermal valve actuators, set the running time to 240 seconds.
∂
Never apply PWM to an electromotoric actuator
∂
It is not possible to ensure exact parallel running of more than 2 thermal valve
actuators. If several VAV systems are driven by the same thermostat,
preference should be given to electromotoric actuators with On/Off or 3-position
control
For electric heaters, set the running time to 90 seconds.
To avoid burn-off of mechanical contacts by frequent switching, use a current valve
(e.g. SEA45.1) in place of a relay or contactor.
For PWM, the
integral time (P35) must be set to 0
.
3-position control
signal
Synchronization
PWM control
Note
PWM for thermal
valve actuators
Notes
PWM for electric heaters
Note!
