While calibrating an electronic 4 - 20 mA or 3 - 15 PSI pneumatic controller, what is the value of 'Live Zero'?

Correct Answer: Option D — 4 mA or 3 PSI.

Live zero refers to a signal range that does not start at absolute zero, allowing for the detection of a broken wire or loss of signal. In standard industrial instrumentation, 4 mA or 3 PSI represents the bottom of the calibrated range, distinguishing a valid low signal from a system failure.