transducer failure

[srd]

we are using a 4-20mA transducer to open / close a mains water valve, is there a way of monitoring the transducer as we have had them fail midrange and the valve stayed open and over filled the tank, we have put in a high level float as a back up to everything off in case it happens again.

[Konni66]

Hello srd,
you can monitor transducer value through a comperator.
If the transducer fails since error in its power supply or broken wire there're measuring values below 412 increments -> close valve immidiatly.
If valve is open check every n seconds if filling level is moving. If not close valve.
Greetz Konni