What is the principle of 4-20mA current signal? How to wire and calibrate 4-20mA output from electromagnetic flowmeters?

4-20mA current signal is the most widely used analog signal transmission standard in industrial process control, offering excellent noise immunity, long transmission distances, and built-in fault detection capabilities. LGF electromagnetic flowmeters feature standard 4-20mA current output functionality.

• Signal Principle: 4mA corresponds to measurement lower limit (0%), 20mA to upper limit (100%), with linear scaling for intermediate values. 0mA indicates wire break for fault diagnosis
• Wiring Method: Two-wire connection with positive terminal to PLC/DCS AI+ and negative to AI-, series 250Ω precision resistor for current detection
• Load Capacity: Maximum load impedance 500Ω, transmission distance up to 1000 meters with 24VDC power supply
• Calibration Procedure: Set range limits via handheld terminal or configuration software, perform 4mA and 20mA calibration point verification ensuring output accuracy ≤±0.1%
• Troubleshooting: Check loop impedance, supply voltage, wiring polarity, and measure loop current with multimeter

Ecolor Technology provides detailed wiring diagrams and commissioning guidance to ensure stable and reliable 4-20mA signal transmission.