The Engineering Projects

Hello,

In my facility, I have three PLC input cards connected next to each other (SLC 500 1746-ia16) controlling several field devices. On each input (16 total) of the cards, I wired a 100ma fuse to protect the inputs from blowing. After several months of the cards working, numerous inputs on each card blew; however, their fuses did not blow. I examined the inputs on each card and saw that the resistor got blown. Could it be possible for it to be a voltage issue? Some of the field devices are powered by different 120v sources. Do you guys have any suggestions on what the problem is?

Regards,

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