Abstract

A Highway Addressable Remote Transducer (HART^TM) [1] device is a microprocessor-based process transmitter or actuator that supports two-way communications with a host, digitizes the transducer signals, and digitally corrects its process variable (PV) values. The HART digital signal is modulated on to the 4–20 mA signal at a higher frequency and then observed by process control equipment.