This article is about HART Communication Protocol. This protocol is normally used for communication of transmitters in industry.
HART Communication Protocol
HART Acronym stands for Highway addressable remote transducer. Why we use HART Communication Protocol? In the measurement industry 4-20 mA standard is worldwide accepted but this standard has one drawback, this process one variable at a time. For the bidirectional communication, the solution is HART which is made by superimposing alternating signal on 4-20 mA standard signal.
How HART Works
The basic concept behind the HART communication is FSK (Frequency shift keying) method. It works on two frequencies 1200 and 2200 Hz representing ‘1’ and ‘0’ bits respectively.
Superimposed frequencies makes analogue and digital communication simultaneously possible for industry process.In this method average value of the FSK will always be zero and DC signal will not be affected by alternating signal.
Sometimes it is also called hybrid Protocol because it combines the analogue and digital communication.
Applications of HART Communication Protocol
Above is the simple example of HART Communication device. In this HART Devices like Handheld terminal and PC Host send request to the field devices for information for the prediction, monitoring and diagnostics the process. Meanwhile 4-20 mA standard signal is running without disturbance and distortion with digital signals.
This devices are used in many industries i.e Petroleum & gas industry, chemical industry and cement industry.