Trane Tracer AH540 User Manual

Chapter 3 Input and Outputs
18 CNT-SVX05B-EN
IN1: Space temperature
Analog input IN1 measures space temperature only. The space tempera-
ture is measured with a 10 kΩ thermistor that is included with Trane
zone sensors. The Tracer AH540/541 receives the space temperature from
either a wired zone sensor or as a communicated value. A communicated
value has precedence over a locally wired sensor input. Therefore, the
communicated value, when present, is automatically used by the control-
ler.
If a Tracer AH540/541 is operating in constant-volume space temperature
control mode and the space temperature fails or does not receive a com-
municated value, the controller generates a Space Temperature Failure
diagnostic.
The space temperature input may also be used to generate timed override
On/Cancel requests to the controller. If a momentary short in the space
temperature signal occurs, the Tracer AH540/541 interprets the signal as
a timed override On request.
The Tracer AH540/541 uses the timed override On request (while the
zone is in unoccupied mode) as a request to go to the occupied bypass
mode (occupied bypass). The occupied bypass mode lasts for the duration
of the occupied bypass time, typically 120 minutes. The occupied bypass
time can be changed using the Rover service tool.
Press the Cancel button on the zone sensor to cancel the override request
and return the controller to unoccupied mode. This creates a momentary
fixed resistance (1.5 kΩ), which sends a Cancel request to the space tem-
perature input.
Calibrating IN1
IN1 can be calibrated with the Rover service tool. Add the calibration
value to the measured value to determine the effective value. For more
information about calibrating this input, see Table 36 on page 76.
IN2: Local setpoint
Analog input IN2 functions as the local (hard-wired) temperature set-
point for applications using a Trane zone sensor with a temperature set-
point thumbwheel (see “Zone sensors” on page 28). The local setpoint
input is configurable (as enabled or disabled) using the Rover service tool.
A setpoint value communicated by means of a Comm5 link can also be
used for controllers operating on a building automation system. If both
hard-wired and communicated setpoint values are present, the controller
uses the communicated value. If neither a hard-wired nor a communi-
cated setpoint value is present, the controller uses the stored default set-
points (configurable using the Rover service tool). If a valid hard-wired or
communicated setpoint value is established and then is no longer present,
the controller generates a Setpoint Failure diagnostic.

Trane Tracer AH540 Specifications

General

Brand	Trane
Model	Tracer AH540
Category	Controller
Language	English