What is HART protocol and what are its features?

HART (Highway Addressable Remote Transducer) protocol is a digital communication protocol that superimposes digital signals on the 4-20 mA analog signal using FSK (Frequency Shift Keying). Features: bi-directional communication (read/write device parameters), simultaneous analog and digital transmission (analog for control, digital for configuration and diagnostics), multi-drop capability (up to 15 devices on single pair), and device interoperability through DDL (Device Description Language). HART enables remote configuration, advanced diagnostics, and additional process variables without rewiring. HART 7 added wireless capability (WirelessHART). It is the most widely used field communication protocol.