The stacker's guard door switch went bad last month, so I replaced it with the same part number, two channel mechanical. Wired it back the way the old one was, through the little junction box on the door frame and into a 1734 IB8S, channels 0 and 1. GuardLogix is a 1769 L30ERMS.

Now every time the door closes the module faults that input. Studio 5000 shows a short to test output fault on channel 0 and the point status LED goes red. Open the door and it clears after a reset.

I tried a second new switch from stock, exact same thing, and checked the wires are tight at the module.

Is the IB8S dying on those points? The stacker's down until this is sorted.