Trane Tracer VV550 Installation, Operation And Maintenance Manual page 20

Inputs and Outputs
When the hardwired setpoint adjustment is used to determine the setpoints, all unit
setpoints are calculated based on the hardwired setpoint value, the configured setpoints,
and the active mode of the controller.
For example,
a setpoint input.
Table 12.Example effective setpoints
Configured setpoints
Unoccupied cooling setpoint
Occupied standby cooling setpoint
Occupied cooling setpoint
Occupied heating setpoint
Occupied standby heating setpoint
Unoccupied heating setpoint
Steps to calculate default values to effective setpoints:
1. Mean setpoint = (Occupied cooling setpoint + Occupied heating setpoint) / 2.
2. Absolute setpoint offset = Setpoint input (73°F) – Mean setpoint.
3. Effective occupied setpoint = Absolute setpoint offset + Default setpoint.
4. Effective unoccupied setpoints are the same as the defaults.
The controller determines the effective space setpoint based on the following:
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The controller reports the setpoint it is using in the network variable output effective
setpoint. The controller reports the calibrated hardwired thumbwheel setpoint using the
network variable output setpoint.
When a building automation system or other controller communicates a setpoint to the
controller, the controller ignores the hardwired setpoint input and uses the
communicated value. The exception is when the system is in unoccupied mode and the
controller always uses the stored default unoccupied setpoints.
After the controller completes all setpoint calculations, the calculated occupied setpoint
is validated against the following configured space setpoint limits:
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Table 12 shows the derivation of effective setpoints from default values and
Default value
85°F
76°F
74°F
70°F
66°F
60°F
Hardwired thumbwheel setpoint input (SET);
The hardwired setpoint calibration (configured);
Whether or not the local hardwired thumbwheel can be used or not (configured);
Communicated setpoint input;
Default setpoints (configured);
Occupancy mode;
Heating or cooling mode (space demand);
Space setpoint high and low limits (configured).
Heating setpoint high limit;
Heating setpoint low limit;
Cooling setpoint high limit;
Cooling setpoint low limit.
Effective setpoint
85°F (same as default)
77°F (default + 1°F = 77°F)
75°F (default + 1°F = 75°F)
71°F (default + 1°F = 71°F)
67°F (default + 1°F = 67°F)
60°F (same as default)
CNT-SVX17G-EN