CNT-SVX08F-EN
53
Troubleshooting
Occupancy; Schedule
Building automation systems normally communicate an occupancy request using the occupancy
schedule input. The controller accepts communicated occupancy schedule as a network variable
input known as nviOccSchedule.
Occupancy; Sensor
Some occupancy sensors may be equipped with the ability to communicate an occupancy mode
to the controller. In such devices, network variable input nviOccSensor is used to communicate
occupancy to the controller. Trane systems and zone sensors do not currently send this variable.
The hardwired occupancy input of this controller is handled as if it is a communicated occupancy
sensor input. If both a hardwired input and a communicated input exist, the communicated input
will be used.
ON/CANCEL Buttons
Some Trane zone sensors 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. Pushing the
ON
button momentarily shorts the zone temperature
signal to the controller. This short is interpreted as a timed override on request. Pushing the
CANCEL
button momentarily sends a fixed resistance of 1.5 kW to the ZN analog input on the
controller, which is interpreted as a timed override cancel request.
The controller always recognizes the timed override
ON
button. If someone presses the timed
override on button on the zone sensor, the controller sets the bypass timer to 120 minutes
(adjustable). The bypass timer then starts to count down to zero. Setting the
Occupied Bypass
Time
to zero disables the timed override function.
If the controller is unoccupied when someone presses the
ON
button, the controller immediately
changes to occupied bypass mode and remains in that mode until either the timer expires or
someone presses the zone sensor cancel button. If the
ON
button is pressed during occupied
bypass mode, before the bypass timer expires, the bypass timer will be reset to 120 minutes
(adjustable).
If the controller is in occupied standby 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
CANCEL
button.
If the controller is in occupied when someone presses the
ON
button, the controller initializes the
bypass time to 120 minutes (adjustable). The bypass timer will start to decrement to zero. During
this time, if the controller changes from its current mode to unoccupied or occupied standby
(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 timed override cancel button. Table 26 summarizes these actions.
Table 26. Bypass timer action
Zone Sensor Buttons
Bypass Timer Action
None
Timer counts down to zero and stops
ON
Set timer to nciBypassTime
(a)
(a) Whenever an update of nviOccManCmd is received indicating Bypass, the bypass timer restarts.
CANCEL
Set timer to zero
Both (
ON
)
(b)
(b) If both ON and CANCEL are pushed at the same time it is interpreted as ON.
Set timer to nciBypassTime
