Rockwell Automation 1771-PM , D17716.5.18 U MNL 1771-PM CLUTCH/BRAKE MOD - Manual (Page 90)

Troubleshooting
Chapter 7
7Ć6
5. Trace wire leads and/or inspect the faulted device.
If you wired the PM system in a manner other than outlined in this
manual, faults are more difficult to track. Proceed as follows:
1. Determine if the fault and corresponding diagnostic code was caused
by alterations in system wiring, i.e., if the fault is a run station fault,
are the run stations wired directly to the PM system or through
auxiliary chassis controlled by the programmable controller? If the
latter is the case, you should look at the programmable controller’s
ladder program.
2. Determine if you have an I/O problem. The PM module can only
diagnose its own I/O level. That is, it alerts you to the exact input or
output within the system that it “sees” as incorrect. You must
interpret from there.
Assume that your press is running normally, then stops suddenly. For this
example, we will follow the general troubleshooting procedure.
1. Examine Figure 7.2 and Figure 7.3.
2. The first question asked in both figures is whether a diagnostic
message is displayed. For this example, we assume that chassis A
and B are displaying these diagnostic messages:
chassis A 0010 1001 (hex 29)
chassis B is displaying 0010 1000 (hex 28)
Because your answer is yes, see Table 7.D to define the problem.
3. In Table 7.D you find that:
Binary 0010 1001 (hex 29) is a T-type (trip condition) message that
tells us: Station 1 active connection is open (for alternate chassis).
Check wiring. (figure 6.11).
Since chassis A is displaying this message, the alternate chassis is
chassis B.
Binary 0010 1000 (hex 28) is the same message. It is for the
chassis displaying the message, chassis B in this case.
Troubleshooting Example