Trane LPC Install And Operation Instructions page 57

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 operation.
The Tracer AH540/541 controller uses
analog input IN4 as the discharge air
temperature input with a 10kΩ ther-
mistor only. This sensor is hardwired and
located downstream from all unit heating/
cooling capacity at the unit discharge
area. The discharge air temperature is
used as a control 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 controller
generates a Discharge Air Temp Failure
diagnostic and performs a unit shutdown.
If the sensor returns to a valid input, the
controller automatically 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 10kΩ thermistor.
The controller uses the IN5 value to
determine if economizing (free cooling) is
feasible. For economizing to be allowed,
economizing must be enabled and the
outdoor air temperature must be below
the economizer enable point (default 60°F ,
configurable). If the outdoor air tempera-
ture is equal to or above the economizer
enable point, or if there is no value is
present, economizing is not allowed. If
both hard-wired and communicated
outdoor air temperature values are
present, then the controller uses the
communicated value.
If a valid hard-wired or communicated
outdoor air temperature value is estab-
lished and then is no longer present, the
controller generates an Outdoor Air Temp
Failure diagnostic and economizing is no
longer enabled. If the sensor returns to a
valid input, the controller automatically
clears the diagnostic and allows econo-
mizer operation.
LPC-SVX01C-EN
Operation
IN6: Mixed-air temperature
Analog input IN6 is used for mixed-air
temperature, with an averaging 1000 (at
32°F [0°C]) RTD sensor only. The input is
used for mixed-air tempering and
outdoor air economizing operations.
The Tracer AH540/541 controller does not
allow economizing if the controller does
not sense a valid mixed-air temperature
input. If the sensor returns to a valid input,
the controller automatically checks to see
if economizer operation is possible.
If a valid mixed-air temperature signal
has been established by the RTD sensor,
but then the value is no longer present,
the controller generates a Mixed Air
Temperature Failure diagnostic and
disallows economizer operation. When
the sensor returns to a valid input, the
controller automatically clears the
diagnostic and checks to see if econo-
mizer operation is possible.
IN13: Universal analog input
The universal analog input IN13 (TB43)
can be configured for a variety of sensors
using the Rover service tool (see
"Configuration" sectiuon). The input must
be configured properly for the sensor
wired to the input. The input can be used
for only one sensor at a time. The
following sensors are supported:
• Space relative humidity (4–20 mA)
• CO sensor (4–20 mA)
2
• Entering water temperature (10kΩ
thermistor)
• Evaporator refrigerant temperature
(10kΩ thermistor)
• Generic temperature (10kΩ
thermistor)
Relative humidity
When using the universal analog input
with a relative humidity sensor first
configure the controller input using the
Rover service tool, and then make the
wiring connections. The sensor must
provide a 4–20 mA and allows two-pipe
changeover operation where 20 mA is
equal to 100% relative humidity.
A space relative humidity input is
required for space dehumidification
control. If valid space relative humidity
input does not exist, space dehumidifica-
tion control will be disabled. The controller
will accept a valid hard-wired sensor
input or a communicated value for space
general
information
relative humidity. If both a hard-wired and
a communicated value exist, the control-
ler will use the communicated value for
control. The communicated value has
priority over the hard-wired input.
When a space relative humidity input is
established (either hard-wired or commu-
nicated), the controller generates a
Humidity Input Failure diagnostic if the
signal is no longer valid, and disables
space dehumidification. If the sensor or
communicated value returns to a valid
input, the controller automatically clears
the diagnostic and allows space dehu-
midification operation.
CO sensor
2
When using the universal analog input
with a CO sensor first configure the
2
controller input using the Rover service
tool for CO and then make the wiring
2
connections. The sensor must provide a
4–20 mA signal, where 20 mA is equal to
2000 ppm.
The CO input, reported in parts per
2
million, is not used for any AH540/541
control purposes. Instead the input is
reported to the building automation
system using Comm5 or other devices as
a data point. When a CO sensor input is
2
established, the controller generates a
CO Sensor Failure diagnostic if the signal
2
is no longer valid, but the diagnostic has
no effect on controller operation. If the
sensor returns to a valid input, the
controller automatically clears the
diagnostic.
Entering water temperature
The universal analog input configured as
entering water temperature accepts a
10kΩ thermistor input. A valid entering
water temperature value (hard-wired or
communicated) is required for two-pipe
changeover operation for space
temperature control air-handling units
with one hydronic coil. If both a hard-
wired and a communicated value exist,
the controller will use the communicated
value for two-pipe changeover operation.
The communicated value has priority
over the hard-wired input.
When valid entering water temperature
input is available to the controller it is
used to determine if hot or cold water
capacity is available for space heating
and cooling operation. If the entering
57