Series 90 30 Expansion Rack

[ehabs 0]

Hi,

I can't connect rack#1 to my CPU GE series 90 30:

I have the following:

- 2 rack system series 90 30

- Rack0 CPU 331 (Only LM90 firmware 3.35)

- Any configuration in the main rack will work smoothly

- IO reference table doesn't reflect any IO changes from IO modules in expansion rack1 

- If any I/O module removed from rack1 I will get I/O fault 

- I checked the configuration (modules locations, types and addresses) many times and all seems good.

- I tried many I/O configurations with the same results.

- Rack number Dip Switch will not generate I/O fault if mismatched with the configuration !!! is that normal?

Any Idea will be highly appreciated.

Edited 31 March by ehabs

[Steve Bailey 118]

Quote

I checked the configuration (modules locations, types and addresses) many times and all seems good.

Did Logicmaster configuration indicate "Config EQ" when you were online with the PLC? Is the termination resistor installed on the cable at the expansion rack? Have you verified expansion cable integrity?

[ehabs 0]

Did Logicmaster configuration indicate "Config EQ" when you were online with the PLC?

YES

Is the termination resistor installed on the cable at the expansion rack?

YES and already tested

Have you verified expansion cable integrity?

I am not sure what is that. but the cable was used before in the same system without any problems. Ho to test.

* I have today a new symptom, I only get the I/O Fault when the expansion cable is unplugged. Removing the module from rack1 will not generate the fault as it did before.

[Steve Bailey 118]

I'm assuming this is a system that formerly worked properly and has suddenly started giving problems.

You have already checked out the expansion cable and the termination resistor.

Next, I would check the power supply in the expansion rack. As power supplies age, their capacity declines. The one in the expansion rack may have been sufficient to power the population of modules when it was new, but now it could be insufficient. If you have a spare, try installing it. Or else swap the power supply in the CPU rack and the one in the expansion rack.

If the cables and the power supply aren't the problem,the next step would be to replace the baseplate.