hot swapping faulty 1756 module

I understand that one of selling features of Controllogix5000 is to be able to swap out a faulty module without powering down the PLC or switching out of RUN mode (obviously to reduce down time).

I did this several times when one of the module's output terminals went bad.

But in the module properties pane of RSLogix 5000, if I checked the "major fault on controller if connection fails in Run Mode," would I still be able to hot-swap the faulty module?

I checked the "major fault on controller if connection fails in Run Mode," would I still be able to hot-swap the faulty module ?

Click to expand...

Nope. The controller would halt on a Major Fault.

I think you'd be able to use the Fault Routine to reset the fault, and the controller would then go into Run mode because the controller would be unable to establish the connection, rather than having it fail after it had entered Run mode.

The option is there so that certain modules can be identified as critical for the application. If those modules fail, shut down (fault) the controller. Whereas if other modules (not using this option) were to fail, then they could be hot swapped.

The Controller Fault Handler would be able to identify this fault and you could potentially clear the fault and keep running if you wrote the logic to do so. The standard program fault routines will not be able to clear this type of fault. But frankly, if you are intending to write logic to clear the fault, why bother selecting this option.

I would probably prefer to monitor the modules status with a GSV instruction and then programmatically respond to a module problem.

OG