1756 di module error

We are having a 1756 di module that gets a internal state comms failure. It does not fault, but it does cause the system it controls to go down. We have replaced the module and all we have to do is click on module reset and it will come right back up and be ok for several weeks to several months at a time but then may fail every few days in a row. Has anyone seen this before and if so what did they do to correct this? 1756 IB32 B3.1 revision 3.5. Our next thought is to replace the chassis but want to avoid this if possible as we are at this point guessing. Help!!

If you have genuinely "replaced" the module with another, and still get the fault, then I would assume it is the chassis that is failing, not the module.


You could try putting the module in another spare slot, (you will have to change the I/O configuration and I/O references in the program*), and see if it happens again.


*Note : if you just want to give this a quick try, just add the module to another slot, and inhibit the module in its original slot. Then you can COP the new input data tag into the original tag, and not have to make any Input references changes.