Sick and tired of level switches failing!

[Seth81]

LoL... Yeah I was waiting for someone to say that! In industrial controls we frequently vote between three instruments for a safety critical loop. Only problem is that I need to then have three level switches mounted at the same level, and three discrete inputs into the controller instead of just one. And then also should have some way of warning me that one of three switches has failed.

Yes I could wire them in series, and use a single input, but then that means I'm 3 times as likely to have a failure! IME the switches fail in the closed position so wiring them in parallel would result in a non-fail safe system (i.e. a failure would cause the automatic water change sequence to continually drain)

This transmitter should be Cadillac! Now I just need to find a cheap conductivity transmitter! Ooops...wrong thread

Originally Posted by brizzo

What is better than 1 cheap float switch? 2 cheap float switches! You can get 5 float switches off ebay for under $10 shipped