Reconfiguring IO with fault routine

[CJH 0]

Hi A while back I saw a forum post, (or was it an article?) about disabling 'missing' IO in a program via a user fault routine. The logic being that a single program can be used for multiple PLC configurations. I've done some searches, but I can't seem to find the post again. Can anybody point me to it? I believe it was written for an SLC. Would the same sort of thing be possible in a micrologix? Thanks!

[Ken Moore 23]

One way to accomplish this is to map your I/O to bit files, then use the bits in your logic instead of the physical I/O. This can also help optimize bandwidth between the PLC and any HMI, since all the "bits" could be read an once. Then the only thing that would have to change from PLC to PLC would be the mapping, the logic could remain the same.

[CJH 0]

Thanks, but that wouldn't work. We use a Micrologix 1200 with 2 x IF2OF2 and 1 x OW8. It's possible some in future may have less IO than this. If you download the standard program to a controller with differing IO, it will fault. The post I'm looking for showed how, in the user fault routine, to just tell the processor that the IO it's looking for doesn't exist, and to disable it in software.

[TimWilborne 108]

Goto your I/O configuration and doubleclick on the module in question. Check the "Ignore Configuration Error" box The problem with doing this is that the Micrologix will not detect the faults with the associated module. Be sure that there is no danger in doing this

[BobLfoot 302]

I know that with ControlLogix and ControlNet I/O you can use the SSV Instruction to turn off slots in racks so that they do not generate a fault or send/receive data from the CPU.

[TimWilborne 108]

I tried to do this with the Micrologix but was never sucessful. As far as I know all you can do is mask the fault Bob is talking about inhibiting the fault on the Logix platform SSV Class MODULE Instance (Name of your Module) Attribute Mode Source (Integer value 0 for enable and value 4 for inhibit

[CJH 0]

Thanks! Didn't realise it was so simple on the M'Logix. The post I was looking for was actually on www.plcs.net (oops!) but it applies to SLC's and not the M'Logix, so your answer's better :)