Rockwell Automation 1771-PM , D17716.5.18 U MNL 1771-PM CLUTCH/BRAKE MOD - Manual (Page 97)

Troubleshooting
Chapter 7
7Ć13
If you want to maintain a record of diagnostic message codes or process
them for reasons other than display, you can write ladder logic to examine
the 9-bit binary message code that PM modules return to the processor.
Do this by examining bits in the input image table corresponding to:
module group 5, slot 1 (8-binary code)
module group 3, slot 1, bit 2 (9
th bit for micro-inch)
For example, examine a bit as follows:
I:r5
| | where r is the I/O rack number
16
If recording a history of diagnostic message codes such as stored in a
FIFO stack, we suggest that you record only diagnostic message codes that
exist for longer than one second and disregard all diagnostic message
codes resulting from transient conditions of shorter duration. This guards
against storing no-fault status diagnostic message codes such as generated
during start-up.
Table 7.C explains message codes generated by PM modules.
For each message code, the table states:
type of diagnostic message
the problem causing the diagnostice message to be displayed
recommended corrective action
In Table 7.C we use mnemonics for cam switches for the sake of brevity as
follows:
ACAM: anti-repeat cam switch
RCAM: run-on cam switch
TCAM: sto-top-check cam switch
Processing Diagnostic Message
Codes
Diagnostic Message Codes
(Table 7.C)