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RLC-SVD03A-EN 13
Interprocessor Communication
3. Determine which modules are still talking. Wiring up to these is likely to
be OK.
4. Try disconnecting the link or jumping out modules in the link at various
places (use Figure 1). Reset the diagnostics and note which diagnostics
reappear.
Here are some examples of IPC diagnostics:
Diagnostics present:
Chiller Mod Indicating EXV Mod Communications
Cprsr A Indicating EXV Mod Communications
Cprsr B Indicating EXV Mod Communications
The CPM and both MCSP modules are detecting a loss of communications
with the EXV. Suspect power to the EXV or its fuse or a wiring problem
downstream of the MCSP A and B modules.
Diagnostics present:
Chiller Mod Indicating Options Mod Communications
Chiller Mod Indicating EXV Mod Communications
Chiller Mod Indicating Cprsr A Communications
Chiller Mod Indicating Cprsr B Communications
The CPM is reporting that it cannot talk to any of the other modules. Suspect
a shorted IPC bus or a module locking up the bus. The CPM could also be bad
and not be sending recognizable tokens. Discriminating between these possi-
bilities is done by disconnecting the link or jumping out modules in the link at
various places. Refer to Item 4 in Troubleshooting Modules (Troubleshooting
Modules Using IPC Diagnostics on page 9) for the procedure and the IPC
Jumper for bypassing the Modules.
Diagnostics present:
Chiller Mod Indicating Cprsr B Communications
EXV Mod Indicating Cprsr B Communications
The CPM and EXV have both detected a communication loss with MCSP B.
Suspect the address switch on MCSP B or a power/fuse problem.
Diagnostics present:
Chiller Mod Indicating Cprsr A Communications
Chiller Mod Indicating Cprsr B Communications
EXV Mod Indicating Cprsr A Communications
EXV Mod Indicating Cprsr B Communications
The CPM and EXV have both detected a communication loss with MCSP A
and MCSP B. Suspect that the address switches on both modules are set to
the same address. Wiring is probably OK since the EXV can talk to the CPM.
Diagnostics present:
Chiller Mod Indicating Cprsr B Communications
Chiller Mod Indicating Cprsr A Communications
Chiller Mod Indicating EXV Mod Communications