3-position control

Output Y1 provides the OPEN command, and Y2 the CLOSE command to the 3-

signal

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.

Synchronization

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.

PWM control

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.

PWM for thermic

For thermic valve actuators, set the running time to 240 sec.

valve actuators

Never apply PWM to a motoric actuator.

Note!

 

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.

PWM for el. heaters

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.

 

 

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Siemens

RDG100, RDG100T, RDG110, RDG140, RDG160 Basic Documentation

CE1P3182en

Building Technologies

Functions

28 May 2009

Page 25
Image 25
Siemens RDG400 manual Position control, Signal, Position actuator, Parameter P44 Y1 and Y2, PWM control