User Manual

Control concept
Desigo room automation
5
CM110664en_07 101 | 353
Individual temperature sequence controllers are assigned to each heating and
cooling element. They intercommunicate to achieve required sequencing.
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).
The HVAC plants in the room adapt to the room's comfort requirements, e.g.,
ventilation is:
Active while the room is occupied
Off, as soon as the room no longer is occupied
nor CoolingHeating
SpH SpC
TREff
100%
0%
TREff
Speed 3
FanSpdMin=Off
Speed 2
Speed 1
Max
FanSpdMin
C1H1H2 C2
ANDAND
FanSpd HclVlvPos CclVlvPos
FanSpdMaxC
FanSpdMinC
FanSpdMaxH
FanSpdMinH
AirFlReqHeat
FanDevMod=Mod
HclDevMod=Mod CclDevMod=Mod
AirFlReqCool
Room temperature
control
Open-loop control
Operating modes