Trane Tracer AH540 User Manual

Analog inputs
CNT-SVX05B-EN 19
Calibrating IN2
IN2 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.
IN3: Fan mode switch
Analog input IN3 responds to specific resistances corresponding to a fan
mode switch provided with certain Trane zone sensors. The fan mode
switch on a Trane zone sensor generates the fan mode signal.
The Tracer AH540/541 controller detects the unique resistance corre-
sponding to each position of the fan mode switch. By measuring this resis-
tance, the controller determines the requested fan mode. See Table 6.
If the Tracer AH540/541 controller does not receive a hard-wired or com-
municated request for fan mode, the unit recognizes the fan input as
Auto.
IN4: Discharge air temperature
The Tracer AH540/541 controller cannot operate if the controller does not
sense a valid discharge air temperature input. If the sensor returns to a
valid input, the controller automatically allows the unit to resume opera-
tion.
The Tracer AH540/541 controller uses analog input IN4 as the discharge
air temperature input with a 10 kΩ thermistor only. This sensor is hard-
wired and located downstream from all unit heating/cooling capacity at
the unit discharge area. The discharge air temperature is used as a con-
trol input to the controller which is used for control modes of operation:
space temperature control and discharge air temperature control.
Any time the discharge air temperature signal is not present, the control-
ler generates a Discharge Air Temp Failure diagnostic and performs a
unit shutdown. If the sensor returns to a valid input, the controller auto-
matically clears the diagnostic and allows the unit to resume operation.
IN5: Outdoor air temperature
Analog input IN5 measures the outdoor air temperature. Analog input
IN5 measures outdoor air temperature only. The outdoor air temperature
is measured with a 10 kΩ thermistor.
Table 6. Determining fan mode (IN3)
Fan modes Tracer AH540/541 operation
Off
Fan Off (4870
Ω ±1%)
Auto In occupied mode, the fan runs.
In unoccupied mode, the fan cycles off when no heating or
cooling is required (2320
Ω ±5%)

Trane Tracer AH540 Specifications

General

Brand	Trane
Model	Tracer AH540
Category	Controller
Language	English