HART (Highway Addressable Remote Transducer) is a popular protocol for communication between field devices and control systems, primarily in process industries. The communication happens over the existing 4-20 mA analog current loops, without the need of installing additional wiring. HART is a master/slave protocol, wherein a smart field (slave) device only speaks when spoken to by a master. The protocol supports different operational modes such as point-to-point or multi-drop for communicating information to/from smart field devices and central monitoring or control systems. HART protocol supports two masters. The primary master is typically a monitoring or control system such as PLC, DCS or PC while the secondary master can be a handheld communicator, which can work independently without interfering with the information exchange to/from the primary master.

Typical Architecture

HART Protocol

Why HART Master Stack and HART Slave Stack are required for Industries?

Developed in the mid-80s, the HART communication protocol enables transfer of data, commands and other information to streamline process. HART uses existing analog wires to provide information regarding device health. Additionally, HART protocol porting and integration of HART devices into the IIoT infrastructure can help industries to connect IT and OT systems.

Few Benefits of HART Protocol Integration
  • Open communication through standardized and established commands
  • Easy Integration as majority of 4 – 20 mA devices are HART capable
  • Achieve platform and vendor independence for field device/systems interoperability
  • Provides overview of asset health
  • Streamlines maintenance
  • Huge installed base of HART devices and control systems

HART Protocol Services Provided by Utthunga

Our complete amalgam of HART services for control and/or monitoring systems include:

  • Development of complete device for various applications in 2-wire/4-wire technology
  • Low power electronic design with HART functionality
  • Porting of the HART stack to various hardware and software platforms
  • Integration of HART stack with the target device application
  • HART master stack for HOST systems and edge devices
  • Enhancements to the stack library to support any the device family and device specific commands
  • Fully compliant HART 7 (WirelessHART technology) and HART 7.6 stack
  • Pre-certification and certification support for HART and WirelessHART devices
  • Development of device integration packages based on EDDL, FDI and FDT standards (Electronic Device Descriptions for Emerson Handhelds 475/TREX, Siemens PDM, Emerson AMS, diverse FDT/DTM frame applications)

  • HART embedded development services

HART firmware development services:

  • Development of Intrinsic Safe transmitters and actuators complying with ATEX, FM, CSA standards which includes hardware design, schematic, PCB layout, prototyping, firmware development, testing and certification support.
  • Development of applications, calibrators and automated test systems
  • Supporting HART native enablement or implement as protocol converter
  • Interoperability testing
  • Physical simulator development with 4, 8, 12 and 16 channels for host testing, training and demonstration
HART V&V and Pre-Compliance:
  • HART pre-compliance testing is done in accordance with the procedures defined by the FieldComm Group (FCG)
  • HART 192 Kit from FCG is used for pre-compliance testing
  • Physical layer testing is done as per the guidelines
  • Device specific commands are tested as per the functional specification


Utthunga’s HART Stack Features:

  • Pre-certified stack (passes HCF conformance tests)
  • Developed in C language: Compatible with any hardware platform with or without OS
  • Small and efficient footprint: runs on almost any controller (8/16/32 bit)
  • Compatible with the existing 4-20mA systems
  • Simultaneous analog and digital communication
  • Supports all universal commands and common practice commands
  • Supports both point-to-point and multi-drop operating modes. Tested using HCF 192 Kit with:
    • Slave Universal Command HCF Test Specifications
    • Slave Common Practice Command HCF Test Specifications
    • Slave Token Passing Data Link Layer HCF Test Specification


1. What kind of HART interfaces can I use in my IIoT cloud solution?

End users from many different industries are adapting wireless solutions. A WirelessHART adapter, which can be integrated into the field device, can transfer data to a WirelessHART gateway. The gateway can provide the data to an IIoT platform. 

2. Why is HART communication protocol so popular in process industry?

HART has proven to be very successful in the process automation industry as it is compatible with a wide range of analog devices and it provides two simultaneous communication channels. It includes a digital signal that is superimposed with on 4-20 mA analog signal. While analog signals can transmit one parameter at a time, the digital signal can provide additional information regarding the device including device Tag ID, measured value, product information, range, diagnostic features and much more.

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