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Sequence of operation
controller's occupancy. When the communicated occupancy request is
occupied, the controller uses the local occupancy binary input to switch
between the occupied and occupied standby modes.
During occupied standby mode, the controller's economizer damper position
goes to the economizer standby minimum position. The economizer standby
minimum position can be changed using Rover service tool.
When no occupancy request is communicated, the occupancy binary input
switches the controller's operating mode between occupied and unoccupied.
When no communicated occupancy request exists, the unit cannot switch to
occupied standby mode.
Occupied bypass mode
The controller can be placed in occupied bypass mode by either communicating
an occupancy request of Bypass to the controller or by using the timed override
On button on the Trane zone sensor.
When the controller is in unoccupied mode, you can press the On button on the
zone sensor to place the controller into occupied bypass mode for the duration
of the bypass time (typically 120 minutes).
If the controller is in the occupied standby mode, you can press the On button
on the zone sensor to place the controller into occupied bypass mode for the
duration of the configured bypass time. Typically occupied and occupied
standby are controlled from the local binary occupancy input.
Occupancy sources
There are four ways to control the occupancy mode:
• Communicated request (usually provided by the building automation system
or peer device)
• By pressing the zone sensor's timed override On button (or Cancel button)
• Occupancy binary input
• Default operation of the controller (occupied mode)
A communicated request from a building automation system or another peer
controller can change the controller's occupancy. However, if communication is
lost, the controller reverts to the default operating mode (occupied) after 15
minutes (configurable, specified by the "receive heartbeat time"), if no local
hardwired occupancy signal exists.
Determining the occupancy mode
The occupancy of the controller is determined by evaluating the combination of
three potential communicating inputs, as well as the hardwired occupancy input
and the occupied bypass timer. Three different communicating inputs affect the
controller's occupancy mode:
• Occupancy—manual command
• Occupancy—schedule
• Occupancy—sensor
These inputs provide maximum flexibility, but the number of inputs you decide to
use varies with the application and the features available in your building
automation system.
Occupancy—manual command
Some communicating devices may request occupancy based on the information
communicated in the network variable nvoOccManCmd. Trane systems and zone
™
sensors do not communicate this information to the controller, but the Tracer
AH.540
controller accepts this network variable as communicated input nviOccManCmd.
Occupancy—schedule
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CNT-SVX05A-EN
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