The Fluke 789 ProcessMeter is a versatile tool that combines the functions of a precision digital multimeter (DMM) and a loop calibrator for process automation and industrial maintenance. Its work includes measuring AC/DC voltage and current, resistance, and frequency, as well as sourcing and simulating loop currents for testing and calibrating 4-20mA industrial signals. It provides a built-in \(24\)V loop power supply and a \(250\ \Omega \) HART resistor, simplifying the process of testing transmitters offline.