It is tricky sometimes to deal with faults from a watchdog timer. These are usually, but not always occurring because you are caught in a loop. I'm sure I'm not saying anything there that you didn't know. But here is the catch...
If you setup a fault routine to capture and clear the fault, when it is done it returns you back to the same location you were in before the fault occurred. Again, that is usually back into that same endless loop. If that's the case, it will just fault again milliseconds later since you are still stuck in the loop.
Rockwell made it so that if a watchdog fault does occur, you can clear it via the fault routine. Once. Not twice. So if the controller returns back into the same loop, we will get a hard fault the second time the watchdog timer expires.
Now, if it isn't a loop and is instead just an excessively long scan, then when it returns after clearing the fault, it hopefully will finish the scan and complete that task. Once that task completes, then if another watchdog fault occurs, it will run the fault routine again. So the task successfully completing resets the "counter" if you will.
I'll post an example of some logic I use here shortly.
OG