Application

Room Functions
Room Coordination Functions for HVAC
44
Siemens Industry, Inc.
Application Note
A6V11692053
Smart Infrastructure – Building Products
2019-04-01
Room Temperature Setpoint Determination
This application function provides the Comfort heating/cooling setpoints (either the
setpoint (SpTR) or the setpoint shift (SpTRShft)) for the PID controllers in the room
temperature control AFs (TCtlH, TCtlC).
Inputs:
⚫ Absolute setpoint (SpTR) from room operator unit
⚫ Setpoint shift (SpTRShft) from room operator unit
⚫ Room temperature (TR) from room operator unit
⚫ Present operating mode (PrOpMod) from the room operating mode AF,
ROpModDtr
Outputs:
⚫ TR (room temperature) displayed on room operator unit
⚫ SpTR or SpTRShft displayed on room operator unit
When PrOpMod = Comfort, the Comfort heating or Comfort cooling setpoint
displays depending on whether the heat/cool state (HCSta) = Heating, or Cooling.
If the setpoint shift (SpTRShft) is commanded by a room operator unit, then the
Comfort heating or cooling setpoint is overridden by the amount configured in
SpTRShft.
When PrOpMod = Economy or Protection, the Pre-Comfort heating (or cooling)
setpoint displays depending on whether HCSta = Heating, or Cooling. SpTRShft
has no affect during Economy or Protection.
If HCSta = Neither, SpTR displays the last value.
NOTES:
The heating/cooling setpoints for Economy and Protection, as well as the delta
heating/cooling setpoint for Pre-Comfort are located in the room temperature
control AFs (TCtlH, TCtlC).
The room temperature AI object (TR) owned by the room operator unit has the
property Correction offset. This property can be accessed via ABT SSA (tech-op)
and configured to provide an offset in the temperature reading used to control the
room.
Configuration
BACnet Objects
Description
Object
Preloaded value
Delta cooling setpoint for pre-comfort
DSpCPcf
[STBY C DELTA]
1 [K]
2.0[°F]
Delta heating setpoint for pre-comfort
DSpHPcf
[STBY H DELTA]
1 [K]
2.0 [°F]