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www.DaikinApplied.com 27
IM 1234-1 • BACNET THERMOSTAT
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Topics in this section cover the sequences of operation for the
BACnet Thermostat. These are advanced topics for control’s
technicians and engineers.
Room Temperature Setpoints
There are three temperature setpoints each for heating and
cooling for a total of six setpoints.
• Active cooling
• Occupied cooling
• Unoccupied cooling
• Active heating
• Occupied heating
• Unoccupied heating
Types of Setpoints
Active setpoint
– The active setpoint is the current setpoint.
The active setpoint is determined by the following.
• If the space is occupied, the controller uses the occupied
setpoint
• If the space is unoccupied the controller uses the
unoccupied setpoint
• A user with Password 1 can enter an active setpoint from
the display. This change is for a limited time or until the
next time the space status changes from unoccupied to
occupied
Occupied setpoint
– A temperature setpoint entered by
the controls technician during controller setup and system
commissioning. This is the setpoint used when the system is
occupied which is usually controlled by the schedule in the
controller.
Unoccupied setpoint
– A temperature setpoint entered by
the controls technician during controller setup and system
commissioning. This is the setpoint used when the system is
unoccupied which is usually controlled by the schedule in the
controller.
Setpoint Limits
No cooling setpoint can be higher than any heating setpoint.
If a user is adjusting a setpoint and it comes with the range set
by Minimum Setpoint Differential, the corresponding setpoint
will be changed to maintain the differential. For example, the
Minimum Setpoint Differential is 4°F and the Occupied Heating
setpoint is 70°F. If the user lowers the Occupied Cooling
setpoint to 71°F, the controller recalculates the Occupied
Heating setpoint and changes it to 67°F.
Occupancy
The BACnet Thermostat is designed to operate as a stand-
alone controller and can determine occupancy based on its
internal occupancy schedule. The two occupancy states of
the BACnet Thermostat are Occupied and Unoccupied. An
occupancy state can also be commanded by another BACnet
controller on the building automation network.
Occupied
If the internal schedule is enabled, the state of the schedule is
set to either occupied or unoccupied as the initial state.
Unoccupied
The unoccupied state is entered only if the internal occupancy
schedule is enabled and if the schedule is inactive.
Automatic Cooling and Heating
Changeover
The BACnet Thermostat can be set to automatically change
between the heating and cooling modes.
• If the space temperature rises above the active cooling
setpoint, the mode is set to cooling
• If the space temperature falls below the active heating
setpoint, the mode is set to heating
Schedules
The internal occupancy schedule changes the BACnet
Thermostat between the occupied (active) and unoccupied
(inactive) states.
