What is the reason for the 4-20ma output in transmitter

Explain why the transmitter has 4-20 ma output

  • The real reason the 4-20 mA scale is the standard for process control devices is that 4mA is the live zero. if a transmitter faults or loses power you will see 0 and know the transmitter failed.

  • 4ma through you can see the live zero and dead zero also between 4 to 20ma input against output is linear