Sensors or other devices with a 4-20 mA current loop output are extremely common in industrial measurement and control applications. They are easy to deploy, have wide power supply requirements, generate a low noise output, and can be transmitted without loss over great distances.
So, what is a current loop?
Current loop. A major application of current loops is the industry standard 4–20 mA current loop for process control applications, where they are extensively used to carry signals from process instrumentation to PID controllers, SCADA systems, and programmable logic controllers (PLCs).
What is 4 20 mA mean?
Definition of: 4-20 mA. 4-20 mA. (4 to 20 MilliAmp) A point-to-point or multi-drop circuit mainly used in the process automation field to transmit signals from instruments and sensors in the field to a controller. It sends an analog signal from 4 to 20 mA that represents 0 to 100% of some process variable.