Trane IntelliPak SCRF 25, Installation, Operation And Maintenance Manual

Page: 74 / 120

74 SCXF-SVX01Q-EN
GBAS Analog Inputs
Four analog inputs that can be configured to be any of
the following:
• Occupied zone cooling
• Unoccupied zone cooling
• Occupied zone heating
• Unoccupied zone heating
• SA cooling setpoint
• SA heating setpoint
• Space static pressure setpoint
• SA static pressure setpoint
GBAS Binary Outputs
Five binary outputs to provide diagnostics, signaling up
to five alarms. Each of the five relay outputs can be
mapped to any/all of the available diagnostics. Each
output contains a dry N.O. and N.C. contact with a VA
rating of 2 amps at 24 Vac.
GBAS Binary Input
One binary input for the self-contained unit to use the
demand limit function. This function is operational on
units with a GBAS and is used to reduce electrical
consumption at peak load times. Demand limiting can
be set at either 50% or 100%. When demand limiting is
needed, mechanical cooling and heating (with field-
provided 2-stage electric heat only) operation are either
partially (50%), or completely disabled (100%) to save
energy. The demand limit definition is user definable at
the HI panel. Demand limit binary input accepts a field
supplied switch or contact closure. When the need for
demand limiting has been discontinued, the unit’s
cooling/heating functions will again become fully
enabled.
GBAS Communication (Analog Inputs)
The GBAS accepts external setpoints in the form of
analog inputs for cooling, heating, supply air pressure.
Refer to the unit wiring diagram for GBAS input wiring
and the various desired setpoints with the
corresponding DC voltage inputs.
Any of the setpoint or output control parameters can be
assigned to each of the four analog inputs on the GBAS
module. Also, any combination of the setpoint and/or
output control parameters can be assigned to the
analog inputs through the HI. To assign the setpoints,
apply an external 0-5 Vdc signal to one of the following:
• Directly to the signal input terminals
• To the 5 Vdc source at the GBAS module with a 3-
wire potentiometer.
N No otte e:: There is a regulated 5 Vdc output on the GBAS
module that can be used with a potentiometer as
a voltage divider. The recommended
potentiometer value is 1000-100,000 ohms.
The setpoints are linear between the values shown in
Table 43, p. 75 . Reference Table 44, p. 75 for
corresponding input voltage setpoints. Following are
formulas to calculate input voltage or setpoint. SP =
setpoint, IPV = input voltage.
• IIff tth he e sse ettp po oiin ntt rra an ng ge e iiss 5 50 0--9 90 0°°F F::
– IPV = (SP - 50) (0.1) + 0.5
– SP = [(IPV - 0.5)/0.1] + 50
• IIff tth he e sse ettp po oiin ntt rra an ng ge e iiss 4 40 0--9 90 0°°F F::
– IPV = (SP - 40)(0.8) + 0.5
– SP = [(IPV - 0.5)/0.08] + 40
• IIff tth he e sse ettp po oiin ntt rra an ng ge e iiss 4 40 0--1 18 80 0°°F F::
– IPV = (SP - 40)(0.029) + 0.5
– SP = [(IPV - 0.5)/0.029] + 40
• IIff tth he e sstta attiicc p prre essssu urre e rra an ng ge e iiss 0 0..0 03 3--0 0..3 3 iiw wcc::
– IPV = (SP - 0.03)(14.8) + 0.5
– SP = [(IPV - 0.5)/14.8] + 0.03
• IIff tth he e sstta attiicc p prre essssu urre e rra an ng ge e iiss 0 0..0 0--5 5..0 0 iiw wcc::
– IPV = (SP)(0.8) + 0.5
– SP = [IPV/(0.8 + 0.5)]
GBAS Demand Limit Relay (Binary Input)
The GBAS allows the unit to utilize the demand limit
function by using a normally open (N.O.) switch to limit
the electrical power usage during peak periods.
Demand limit can initiate by a toggle switch closure, a
time clock, or an ICS control output. These contacts
must be rated for 12 ma @ 24 Vdc minimum.
When the GBAS module receives a binary input signal
indicating demand limiting is required, a command
initiates to either partially (50%) or fully (100%) inhibit
compressor and heater operation. This can be set at the
HI using the setup menu, under the “demand limit
definition cooling” and “demand limit definition
heating” screens. A toggle switch, time clock, or
building automation system control output can initiate
demand limiting.
If the cooling demand limit is set to 50%, half of the
cooling capacity will disable when the demand limit
binary input closes. The heating demand limit
definition can only be set at 100%, unless the unit has
field-provided two-stage electric heat. In that case, if
the heating demand limit is set to 50%, half or one
stage of heating disables when the demand limit binary
input closes. If the demand limit definition is set to
100%, then all cooling and/or heating will disable when
the demand limit input closes.
GBAS Diagnostics (Binary Outputs)
The GBAS can signal up to five alarm diagnostics,
which are fully mappable through the setup menu on
the HI. These diagnostics, along with the alarm output
on the RTM, allow up to six fully mappable alarm
outputs.
C Co on nttrro ollss