HART (Highway Addressable Remote Transducer) Protocol is the global standard for sending and receiving digital information across analog wires between smart devices and control or monitoring system. HART is a bi-directional communication protocol that provides data access between intelligent field instruments and host systems. A host can be any software application from technician’s hand-held device or laptop to a plant’s process control, asset management, safety or other system using any control platform.

There are several reasons to have a host communicate with smart devices. These include:

  • Remote Device Configuration or re-configuration
  • Remote Device Diagnostics
  • Remote Device Troubleshooting
  • Reading the additional measurement values provided by the remote device
  • Remote Device Health and Status
  • Much more: There are many benefits of using HART technology, and more users are reporting benefits in their projects on a continual basis.

HART Field Communication System for Industrial InstrumentationHART technology offers a reliable, long-term solution for industrial & process plant operators who seek the benefits of intelligent devices with digital communication. HART technology is easy to use and very reliable when used for commissioning and calibration of smart devices as well as for continuous online diagnostics.

HART communication Protocol makes use of the Bell 202 Frequency Shift Keying (FSK) standard to superimpose digital communication signals at a low level on top of the 4-20mA. This enables two-way field communication using master/slave protocol to take place and makes it possible for additional information beyond just the normal process variable to be communicated to/from a smart field instrument.

HART Protocol can be used in various modes such as point-to-point or multidrop network configurations for communicating to/from smart field instruments and central control or monitoring systems. HART Communication occurs between two HART-enabled devices, typically a smart field device and a control or monitoring system. Communication occurs using standard instrumentation grade wire and using standard wiring and termination practices.

Device Description Language (DDL) is used in HART technology, where Device Description or DD is an electronic data file. Device Description Language specifications that describes specific features and functions of a device including details of menus and graphic display features to be used by host applications (including handheld devices) to access all parameters and data in the corresponding device.

Applications of HART Field Communications Protocol include industrial field instruments, process plant operations, home/building area network, wired sensor network, remote monitoring of field instrumentation, field programmable instruments, industrial controlling devices such as PLC, SCADA, temperature and pressure transmitters, etc.