4-20 mA- Calibration

For example, if we were to calibrate a 4-20 mA temperature transmitter for a measurement range
of 50 to 250 degrees C, we could relate the current and measured temperature values on a graph like
this:

This is not unlike the pneumatic instrument signal standard or 3 to 15 pounds per square
inch (PSI), where a varying air pressure signal represents some process measurement in an analog
(proportional) fashion.