Trane Tracer AH540 Setup And Operation page 47

CNT-SVX05B-EN
For example, assume the controller is configured with the following
default setpoints:
• Unoccupied cooling setpoint
Occupied standby cooling setpoint
•
Occupied cooling setpoint
•
Occupied heating setpoint
•
Occupied standby heating setpoint
•
Unoccupied heating setpoint
•
Absolute Setpoint Offset = Setpoint Input – Mean Setpoint
From the default setpoints in this example, the mean setpoint is the
mean of the occupied cooling and heating setpoints, which is 72°F
[(74+70) / 2]. The absolute setpoint offset is the difference between the
setpoint input and the mean setpoint.
Assume a thumbwheel setpoint input of 73°F, resulting in an absolute
setpoint offset of 1°F (73–72=1). The controller adds the absolute setpoint
offset (1°F) to occupied and occupied standby default setpoints to derive
the effective setpoints, as follows.
Unoccupied cooling setpoint
•
• Occupied standby cooling setpoint
Occupied cooling setpoint
•
Occupied heating setpoint
•
Occupied standby heating setpoint
•
Unoccupied heating setpoint
•
When a building automation system or other controller communicates a
setpoint to the controller, the controller ignores the hard-wired setpoint
input and uses the communicated value. The exception is the unoccupied
mode, when the controller always uses the stored default unoccupied set-
points.
After the controller completes all setpoint calculations based on the
requested setpoint, the occupancy mode, the heating and cooling mode,
and other factors, the calculated setpoint is validated against the follow-
ing setpoint limits:
Heating setpoint high limit
•
Heating setpoint low limit
•
Cooling setpoint high limit
•
Cooling setpoint low limit
•
These setpoint limits only apply to the occupied and occupied standby
heating and cooling setpoints. These setpoint limits do not apply to the
unoccupied heating and cooling setpoints stored in the controller configu-
ration.
Unit configuration also exists to enable or disable the local (hard-wired)
setpoint at the zone sensor module. This parameter provides additional
flexibility to allow you to apply communicated, hard-wired, or default set-
points without having to make physical wiring changes to the controller.
Space temperature control
85°F (29.4ºC)
76°F (24.4ºC)
74°F (23.3ºC)
70°F (21.1ºC)
66°F (18.9ºC)
60°F (15.6ºC)
85°F (same as default)
77°F (default+1=77)
75°F (default+1=75)
71°F (default+1=71)
67°F (default+1=67)
60°F (same as default)
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