Trane LPC Install And Operation Instructions page 71

Occupancy binary input
The Tracer AH540/541 controller uses the
occupancy binary input IN9 for two
occupancy-related functions. For
controllers not receiving a communicated
occupancy request, the occupancy binary
input determines the occupancy of the
unit based on the hard-wired signal.
Normally, the signal is hard-wired to a
binary switch or time clock.
When a hard-wired occupancy signal is
open, the unit switches to occupied mode
(if the occupancy input is configured as
normally open). When a hard-wired
occupancy signal is closed, the controller
switches to unoccupied mode.
For controllers that receive a communi-
cated occupancy request from a building
automation system, the hard-wired
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 unit control-
ler operates according to the occupied
standby setpoints. When the controller
receives a communicated unoccupied
request, the controller operates accord-
ing to the unoccupied setpoints regard-
less of the hard-wired occupancy input
state.
LPC-SVX01C-EN
Operation
If neither the hard-wired binary input nor
a communicated request is used to select
the occupancy mode, the controller
defaults to occupied mode because the
occupancy binary input (if present)
typically is configured as normally open
and no occupancy device is connected.
Determining the occupancy mode
The occupancy of the controller is
determined by evaluating the
combination of three potential
communicating inputs, as well as the
hard-wired occupancy input and the
occupied bypass timer (see Table O-SO-
4).
Three different communicating inputs
affect controller occupancy mode:
1. Occupancy – manual command
2. Occupancy – schedule
3. 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 AH540/541
controller accepts this network variable
as communicated input
(nviOccManCmd).
sequence of
operation
Occupancy – schedule
Building automation systems normally
communicate an occupancy request to
the Tracer AH540/541 controller using a
network variable input (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 hard-
wired occupancy input of this controller is
handled as if it is a communicated
occupancy sensor input. When both a
hard-wired input and a communicated
input exist, the communicated input is
used.
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