User Manual

Control concept
Desigo room automation
5
102 | 351 CM110664en_07
Individual temperature sequence controllers are assigned to each heating and cooling element. They
intercommunicate to achieve required sequencing.
Open-loop control
Additional interactions between HVAC devices implemented via open-loop control functions are required in
an HVAC plant in the room. The open-loop control functions feature two basic interactions:
● Support: Heating coil and cooling coil require the fan to run on the stage/speed required for their
operation.
● Lock: The electric heating coil is locked to ensure that it cannot be operated without air flow.
Open-loop control and sequence controller are used together to implement the above, typical control
sequence.
The following image shows the connection between controller and actuating devices (this does not
correspond to the actual program structure).
nor CoolingHeating
SpH SpC
TREff
100%
0%
TREff
Speed 3
FanSpdMin=Off
Speed 2
Speed 1