Trane RTWA 70-125 TON - Manual (Page 5)

RLC-SVD03A-EN 5
General Information
System Description
The CPM is the master module and coordinates operation of the entire
system. One is used per chiller. The MCSP is a compressor protection
module with one being used for each of the compressors in the chiller. The
EXV is the expansion valve controller module which controls two Electronic
Expansion Valves. There is one valve on each of the two refrigeration circuits.
The CLD is a two line, 40 character alphanumeric interface to the system. It
allows the operator to read operating and diagnostic information, as well as
change control parameters. The Interprocessor Communications Bridge
(IPCB) provides an extension of the IPC link to the Remote Clear Language
Display, while protecting the integrity of the IPC communications link
between the local modules.
The CSR is an optional communications module which allows for communica-
tions between the chiller and a remote building automation system (i.e.
Tracer, Tracer Summit, Generic BAS).
All modules in the system communicate with each other over a serial inter-
processor communications bus (IPC) consisting of a twisted wire pair “daisy
chain” link and RS485 type signal levels and drive capability. Multiple modules
of the same type (i.e. MCSPs) in an operating system are differentiated by
address dip switches.
All the modules operate from 115VAC, 50 or 60Hz power and each have their
own internal step-down transformer and power supply. Each is individually
fused with a replaceable fuse. The modules also are designed to segregate
their high and low voltage terminals by placing the high voltage on the right
side of the module and the low voltage on the left. When stacked, segre-
gation is maintained.
In addition to the modules, there are a number of “system level” compo-
nents that are closely associated with the modules. These components were
specifically designed and/or characterized for operation with the modules. For
this reason, the exact Trane part must be used in replacement.
System Level Components
Description
The following is a list of all the components that may be found connected to
the various modules.
Transformer, Under/Over voltage
Current Transformer - Compressor
Evap EntlLvg Water Temp Sensor Pair
Sat Evap/Cprsr Suc Rfgt Temp. Sensor Pair
Sat Cond RfgtIOil Temp Sensor Pair
Outdoor Air Temperature Sensor
Zone Temp Sensor
Connector (UCM mating connectors)
Connector Keying Plug
Electronic Expansion Valve