Siemens RDG100 Basic Documentation page 41

Adaptive temperature
compensation for electric
heater (RDG160T..,
RDG110..)
3-position
control signal
Synchronization
PWM control
Note!
PWM for thermal valve
actuators
Note!
PWM for electric heaters
Siemens
Building Technologies
When an electric heater is connected directly to the On/Off output (RDG160T..: Q2,
RDG110..:Y21), the current causes the relay contact to heat up. This falsifies the
reading of the internal temperature sensor. The thermostat compensates the
temperature if the rated current/power of the electric heating is entered in the
parameters.
RDG160T..:
P45 (power electric heater): Factory setting: 0.0 kW, setting range: 0.0...1.2 kW.
RDG110:
P46 (load current electric heater): Factory setting: 1 A, setting range: 1...5 A.
RDG110U:
P46 is not available for AC 24 V operating voltage with electric heater controlled via
external relay.
This function is available with RDG100, RDG100T and RDG100T/H only.
Heating: Output Y1 provides the OPEN command, and Y2 the CLOSE command to
the 3-position actuator. Relay function Y1/Y2 and wiring can be tested via diagnostic
parameter d05. Cooling: Idem with Y3 and Y4. Relay function Y3/Y4 and wiring can be
tested via diagnostic parameter d06.
The factory setting for the actuator's running time is 150 seconds. It can be adjusted
via parameters P44 (Y1 and Y2) or P45 (Y3 and Y4).
The parameters are only visible if 3-position is selected via DIP switches 4 and 5.
1. When the thermostat is powered up, a closing command for the actuator running
time + 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's running time is extended + 150% to ensure the right actuator position is
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.
This function is available with RDG100, RDG100T and RDG100T/H only.
The demand calculated by PI control from the current room temperature and setpoint
is provided via Y1 and Y3 to the valve actuator as a PWM signal (pulse width
modulation) for thermal actuators. The output is activated for a period proportional 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 parameters P44
(Y1) or P45 (Y3). These parameters are only visible if 2-position is selected via DIP
switches 4 and 5 and if PWM is selected via P46 and P47.
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 2 or more thermal valve
actuator. If several fan coil units are driven by the same thermostat, preference
should be given to electromotoric actuators with On/Off or 3-position position
control.
For electric heaters, set the running time to 90 seconds.
RDG100.., RDG110.., RDG160T.. Basic Documentation
Functions
41/81
CE1P3181en
2015-07-29