CNT-SVX05A-EN
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Sequence of operation
The hardwired setpoint is used with the controller's occupancy mode
(occupied, occupied standby, or unoccupied), the heating or cooling mode,
the temperature deadband values, and the heating and cooling setpoints
(high and low limits) to determine the controller's active setpoint
Example continued: 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.
The Tracer
™
AH.540 controller determines the effective setpoint based on the
following sequence:
1.
Hardwired setpoint input
2.
Setpoint calibration
3.
Thumbwheel enabled or disabled? (Use default setpoints if thumbwheel is
disabled)
4.
Communicated or local setpoint available?
5.
Communicated setpoint input (nvisetpoint)
6.
Communicated setpoint offset (nviSetptOffset)
7.
Communicated setpoint shift (nviSetptShift)
8.
Setpoint high and low limits (configurable)
9.
Occupancy mode
10. Heating or cooling mode
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 the unoccupied mode,
when the controller always uses the stored default unoccupied setpoints.
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 following 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’s configuration.
Unit configuration also exists to enable or disable the local (hardwired)
setpoint at the zone sensor module. This parameter provides additional
flexibility to allow you to apply communicated, hardwired, or default
setpoints without having to make physical wiring changes to the controller.
Unoccupied cooling setpoint
85°F (same as default)
Occupied standby cooling setpoint
77°F (1=77)
Occupied cooling setpoint
75°F (1=75)
Occupied heating setpoint
71°F (1=71)
Occupied standby heating setpoint
67°F (1=67)
Unoccupied heating setpoint
60°F (same as default)
