Sequence of operation
CNT-SVX04A-EN
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On and Cancel buttons on the zone sensor
Some Trane zone sensor modules include timed override On and Cancel
buttons. Use the timed override On and Cancel buttons to place the controller in
override (occupied bypass mode) and to cancel the override request.
The controller always recognizes the timed override On button. If someone
presses the zone sensor's timed override On button, the controller initializes the
bypass timer to 120 minutes (adjustable).
If the controller is unoccupied when someone presses the On button, the
controller immediately changes to occupied bypass mode and remains in the
mode until either the timer expires or someone presses the zone sensor's timed
override Cancel button. If the On button is pressed during occupied bypass
mode, before the timer expires, the controller re-initializes the bypass timer to
120 minutes.
If the controller is in any mode other than unoccupied when someone presses
the On button, the controller initializes the bypass time to 120 minutes. As time
expires, the bypass timer continues to decrement. During this time, if the
controller changes from its current mode to unoccupied (perhaps due to a
change based on the system's time of day schedule), the controller switches to
occupied bypass mode for the remainder of the bypass time or until someone
presses the zone sensor's timed override Cancel button.
Occupancy binary input
You can configure binary input 3 (BI 3) as an occupancy binary input. The Tracer
ZN.520 zone controller uses the occupancy binary input for two occupancy-
related functions. For stand-alone controllers (any unit not receiving a
communicated occupancy request, typically from a building automation
system), the occupancy binary input determines the occupancy of the unit
based on the hardwired signal. Normally, the signal is hardwired to a binary
switch or clock.
When a hardwired occupancy signal is open, the unit switches to occupied
mode (if the occupancy input is configured as normally open). When a
hardwired occupancy signal is closed, the controller switches to unoccupied
mode.
For controllers that receive a communicated occupancy request from a building
automation system, the hardwired occupancy binary input is used with a
communicated occupancy request to place the controller in either occupied
mode or occupied standby mode.
In occupied mode, the controller operates according to the occupied setpoints.
In occupied standby mode, the zone controller operates according to the
