executing fault code in compactlogix

I need to set a bit high in my logic when the plc fails. I have tried the GSV function for CONTROLLERDEVICE and used bits 6 and 4. This does not seem to be working for me. Bit 4 does not seem to change state when I disconnect I/O and it faults.

Any ideas?

The compact logix does not fault when a minor error occurs. You can write a fault routine to handle these if you want (see documentation about fault routines) and set whatever tag you choose to define and name as you please in the fault handler routine.

When a major fault occurs the program stops executing completely, so setting a fault bit in your logic doesn't accomplish anything because the instructions are not being processed.