Trane RTWA 70-125 TON - Manual (Page 12)

12 RLC-SVD03A-EN
Interprocessor Communication
5. Improper connections to terminal J2:
Jack J2, present on all modules except CLD, should have no connections.
This input is for manufacturing test purposes only and any connections,
shorts, etc. will potentially cause the module to not respond, respond to
the wrong address, or (in the case of the CPM) fail to initiate any commu-
nications and thus fail the entire IPC.
6. High levels of Electro-Magnetic Interference:
The modules and the IPC have been qualified under severe EMI (both
radiated and conducted) and the system was determined to be immune
to all but extremely high noise levels. Always be sure to close and latch
the control panel cabinet doors as the panel enclosure provides signifi-
cant shielding and is integral in the overall noise immunity of the control
system.
7. Module specific function selected without the Options Module:
If any of the functions on the Options Module are selected but the
Options Module is not present, the UCM will look for this module and
generate an error. The Options Module functions include Chilled Water
Reset, Ice Machine Control, External Chilled Water Setpoint, External
Current Limit Setpoint, and Tracer/Summit Communications.
Troubleshooting Procedure
1. Place the CPM in “Stop”. Record the active IPC diagnostics as shown in
the Diagnostics Report of the CLD. The communication failure diagnos-
tics and their meanings are shown in IPC Diagnostics of the RTAA-IOM-4
manual.
2. Determine which modules are not talking. These modules must be
affected by one of the previously stated problems. If there is a group of
modules not talking, suspect a wiring problem early in the daisy chain
link. If only one module is not talking, suspect a loss of power or blown
fuse.
Figure 3 IPC Jumper For Bypassing Modules (to be inserted into MTA
connector in place of module)
:LUH
MXPSHUV
VROGHUHGRU
ZUDSSHGLQWR
SLQV
$03FF
KHDGHUSLQV
RUHTXLY
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