GE Fanuc 90-30 series CPU STOPs due to configuration fault

Dear All,

We have a machine with 6 Racks of GE Fanuc 90-30 series , with CPU374 Plus.

We keep taking 'loss of I/O module' and 'add'n of I/O module' faults while standing still and in time it turns into a 'system configuration mismatch' alarm. This happens only in Rack-2. This error causes the CPU to go to STOP position.

I've replaced :
*CPU
*baseplate of main rack
*baseplate of Rack-2
*all cables between expansion racks
*terminating resistor
*All modules on Rack-2 (all 10 are DI)
*Power supplies of main rack and Rack-2)

None of them has solved the problem.

Any ideas?

Thanks in advance,
Emre

What controls and supplies power to rack 2?
Is it different from the other racks?

If the power supplied to rack 2 has a problem, it could explain the faults.

...and
** How long is the cable between rack-0 and rack-1
** How long is the cable between rack-1 and rack-2
** Are they factory built cables, or local built?
** Have you verified cable routing is shielded from EMF and RF?
Get PACsAnalyzer and send GEIP tech support the log file, they may be able to give you more detail on the fault(s).

All racks are supplied from the same source with paralel connection.

Expansion cables are factory built short ones (25 cm i guess)

Shielding is at every possible point.

I have doubts about mains supply. The machine is fed via a UPS. I tried to measure resistance between neutral and PE and it was flunctuating between 20 ohm to 90 ohm. I guess some potential effected my measurement. There is a voltage difference of DC 2.3 Volts between neutral and PE. Strange thing is, this problem repeated almost every 15 minutes yesterday, and did reoccur this morning. But it did not happen for almost 6 hours now..

Thanks,

Emre

emokar said:

Dear All,

We have a machine with 6 Racks of GE Fanuc 90-30 series , with CPU374 Plus.

We keep taking 'loss of I/O module' and 'add'n of I/O module' faults while standing still and in time it turns into a 'system configuration mismatch' alarm. This happens only in Rack-2. This error causes the CPU to go to STOP position.

I've replaced :
*CPU
*baseplate of main rack
*baseplate of Rack-2
*all cables between expansion racks
*terminating resistor
*All modules on Rack-2 (all 10 are DI)
*Power supplies of main rack and Rack-2)

None of them has solved the problem.

Any ideas?

Thanks in advance,
Emre

Click to expand...

Dear Emocar.

I commented that we had the same problem that Emocar refers to and the problem was that in our system we have a CPU 374 plus and 5 racks of 10 positions each.
Rack # 3 did not see the position 3.10 and after 3 weeks I no longer saw the rack after 3 to 5 hours of work.
After multiple tests it occurred to us to exchange each card in rack # 3 (digital inputs and outputs) in the other racks previously identified each module and observed that the failure was passed to rack # 2 and discovered that the problem was a digital input card . We replaced it and the whole problem was solved.
Good luck

Dear Emocar
I commented that we had the same problem that Emocar refers to and the problem was that in our system we have a CPU 374 plus and 5 racks of 10 positions each.
Rack # 3 did not see the position 3.10 and after 3 weeks I no longer saw the rack after 3 to 5 hours of work.
After multiple tests it occurred to us to exchange each card in rack # 3 (digital inputs and outputs) in the other racks previously identified each module and observed that the failure was passed to rack # 2 and discovered that the problem was a digital input card .
We replaced it and the whole problem was solved.
Good luck