Replacing SNAP-PAC-R1 without any backup strategy



I wonder how will the SCAP-PAC system behave in the following situation.

We have an existing Cabinet with a SNAP-PAC-R1 as controller and have strategy running, 1 SNAP-PAC-R1 and 2 EB1 as remote IO.We do not have back up of the existing strategy, and the controller is not archived.

If I replace the existing Controller with a new Controller, and download a new strategy after the new controller installed, turn out the strategy need to make some changes. Can I put back the old controller and will the whole system runs the same way like before replacing? Or the IO modules will not recognize the controller and cause erros

Seems each of the Rack and the IO modules itself response to the PID loops function. I actually dont think this may work but just to confirm.

Thank you for your help!



I can’t think of any reason why that wouldn’t work. It could help to save the configuration to flash through PAC manager on each IO unit before working on your new strategy in the new controller, that way a restart of the IO units will bring things back to original values if your new strategy changes them. You could also use the IO Unit Import/Copy feature in PAC Manager to get a backup of the memory map.

PID loops are an IO unit feature, but the strategy configures them on first run. Be aware that the new strategy will not remove any PIDs that exist that it isn’t using. So old PIDs will continue to operate in the IO units until you define new PIDs in your new strategy that overwrites them. Same goes for IO point definitions and TPO setups, etc.

I’m fairly confident that this is how it all works, but it may be helpful to reach out to product support group to confirm.


+1 for using PAC Manager I/O Unit Import/Copy function to make a snapshot of the I/O before you start messing with it.


Thank you so much guys, seems purchase a rack and IOs to try these things out before hand is a must :joy: