For industrial process control instruments, analog 4-20mA current loops are commonly used for analog signaling. 4 mA represents the lowest end of the range and 20 mA the highest.
Advantages
- Accuracy of the signal is not affected by voltage drop in the interconnecting wire because the transmitter will maintain the proper current even if there is significant electrical resistance in the line
- The live-zero represented by 4 mA allows the receiving instrument to detect some failures of the loop and also allows transmitter devices to be powered by the same current loop
ADVANCED Motion Controls' Capabilities
- 4-20 mA command capability can be made available for custom designs
