HART is a communication protocol used for industrial process measurement and control applications.
HART is a hybrid protocol. Analog + Digital communication.
HART Analog Communications -use industry standard 4-20 mA signal only –only one parameter (Process Variable or Controller Output) –communicated to the host system.
HART Digital Communications –Added information (Device Status and Diagnostic Alerts;Process Variables and Units;Loop Current and % Range, Basic Configuration Parameters, Manufacturer and Device Tag etc.,) – 35- 40 information items.
HART Digital Communications – Low level modulation superimposed on the standard 4-20 mA current loop –BELL 202 MODEM- Frequency Shift Keying (FSK) – Logic 1 – 1200 Hz and Logic 0 –2200 Hz (with an amplitude of –0.5mA to +0.5mA) – Device configuration, non-real-time diagnostics, and status monitoring.
Master/Slave Protocol (Message Rate –2)
HART burst mode communications (Message Rate- 3)
HART Multidrop Mode.
Benefits of HART Communication
Improved Plant operation
Commissioning and Installation
Plant operation and improved quality
Instrument Investment Protection
Control in Field Devices