Input Devices & System Functions - Trane CSRA025FAF0 Installation Operation & Maintenance

General
Information
Generic Building Automation System Module (GBAS)
(Used with Non-Trane Building Control System)
The Generic Building Automation System (GBAS) module allows a non-
Trane building control system to communicate with the unit and accepts
external setpoints in form of analog inputs 0 - 5 DCV and a binary Input for
demand limit. Five (5) binary outputs are available on 0 - 5 DCV modules.
Refer to the "Field Installed Control Wiring" section for the control wiring to
the GBAS module and the various desired setpoints with the corresponding
DC voltage inputs.
Current Sensing Module (CSM)
Current transformers located around two (2) of the main power leads for
each compressor monitors the running current during compressor operation.
The information is sent to the CGM and can be accessed through the
"Compressor Status" submenu displayed at the Human Interface Module.
Input Devices & System Functions
The descriptions of the following basic Input Devices used within the UCM
network are to acquaint the operator with their function as they interface with
the various modules. Refer to the unit's electrical schematic for the specific
module connections.
Lead/Lag (Standard)
When Lead-Lag is enabled, for each capacity add request, the CGM will
begin sequencing the compressors "On" that have:
A. the least number of starts; or,
B. the least run time (if number of starts are equal)
At each capacity subtract request, the CGM will begin sequencing the
compressors "Off" that have:
A. the most run time; or,
B. the least number of starts (if more than one compressor has the same run
time)
If a compressor is locked out for any reason when a capacity add request
occurs, the next available compressor which meets the specified criteria will
be started.
If a compressor can not be turned "Off" due to the minimum "On Time", the
next compressor which meets the specified criteria will be turned "Off".
On dual circuit units, as the first two capacity add requests are initiated, one
compressor on each circuit will start before any additional compressors on
any circuit is started. When staging down from three compressor stages to
two compressor stages, the CGM will turn the compressors "Off" on the
circuit that has the most compressors operating.
CSRA-SVX02A-EN 9