Hmi comm loss

We have a a/b 2711-k6c20 hmi on a ue gas compressor. It connects via cat5 cable to a fiber optic media converter/switch. The processor is a a/b 505 1747-l551. And these all connect to our ovation dcs. The problem is we keep losing the com from the hmi. One our tech's has been bandaiding the problem by cycling the power to the hmi and comm is resored for a while but then losws com again. Could the problem be a hardware issue with the hmi?

It could be a hardware problem. Are you having and com issues else ware in the network? If it is just that one HMI I would suspect a bad network card in the unit. Do you have another HMI you can swap with the "bad" one?

Check the cabling to the offending device as well. If it's easy to do, swap the patch cable from one of the devices that never drops out, see if the problem stays with the HMI or follows the cable. Or if that's impractical just run a known good patch cable to the HMI temporarily and see if the problem persists.

It's probably more likely to be the HMI than the cable, but always good to eliminate the other possibilities. A patch cable is much cheaper and easier to swap out than a HMI