Packaging line, 1756-L72S, two 1791ES-IB16 safety input blocks on the line, safety RPI 10 ms on both. Ran for three years without a safety connection drop.
What changed: IT replaced the unmanaged switch in the line cabinet with a managed one two weeks ago. Since then one of the two 1791ES drops its safety connection three or four times a day. Module goes yellow triangle in the tree, connection timed out, 16#0203 I think, inputs go to safe state and the line stops until someone resets. The other 1791ES on the same switch has never dropped.
Tried: set the RPI on that connection from 10 ms to 5 ms thinking faster would help, it got worse, back to 10 now. Reseated the module, new patch lead. IT says the switch shows no errors.
Is the switch faulty? Or is there something on the safety connection I should be looking at.
Switch model first. And what did IT enable on it, IGMP snooping, storm control, anything QoS? Same VLAN as before or did they move ports? A managed switch left on defaults is not the same as an unmanaged one.