ECN Forum Forums General Topics of the Trade General Discussion Area Why is 4-20ma used..

Joe,

In the old days it was very common to run multiple devices off of a single 4-20mA circuit. I have done sensor to chart recorder to digital display to loop controller. The only typical problem is if mutiple devices have one side of their signal tied to "ground".

rad74ss,
0-20mA is very common as the analog output of new generations of VFDs and "small" PLCs.