godfrey
Member
A co-worker of mine had a suggestion regarding a 4-20 mA output which drives an electrically actuated modulating valve. He said it is a good idea to run the loop through a relay. When it is desired to shut the valve, apply 4 mA but also open up the relay. The loop is broken and zero mA is at the valve actuator. The valve is configured to close on loss of signal. This setup will guarantee a shut valve in case the 4 mA setting has drifted over time.
I don't agree. Are there any merits to his idea?
I don't agree. Are there any merits to his idea?