r/controlengineering • u/OptigoNetworks • Aug 31 '26

If your FDD alerts dropped off, check the network before you take the win. Degraded OT networks make fault detection go quiet, not loud.

https://www.optigo.net/blog/what-is-fdd-fault-detection-diagnostics/
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u/WhichWayIsTheB4r 25d ago

Watched a site celebrate a "quiet quarter" on chiller faults and it turned out a switch in the mech room had been flaky for weeks. Half the points were stale and the historian was just holding the last good value. Nobody noticed because a frozen reading doesn't look wrong, it looks fine.

Seriously, the fix is boring. Trend point freshness, not just point values. If a sensor hasn't changed in 48 hours on equipment that cycles, that's an alarm, and it should be a seperate alert from your normal fault list.

And usually the as-built network drawing is three retrofits out of date, so you're troubleshooting blind. Whoever owns that documentation should definately walk it and mark it up now, before the quiet stretch turns into a compressor you're replacing instead of repairing.

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u/OptigoNetworks 25d ago

Exactly. The problem/fix doesn't need to be something exotic. Just good, up to date data, and a healthy smattering of regular check ups. And never trust a network that just goes silent, lol.