Highway Addressable Remote Transducer Protocol (HART)

Go to areas of Interest: Highway Addressable Remote Transducer Protocol (HART) | Smart HART Transmitters, Monitors and Interfaces | HART Technical Information | Wireless HART


Highway Addressable Remote Transducer Protocol (HART)

HART - The Premier Tool for Asset Management - Cut downtime and improve profits with the tools you already have - Do more with less. That’s the mantra of many industries today in North America or anywhere else around the globe. Companies no longer have employees that aren’t fully utilized-nobody has a couple of hours to grab a clipboard and some test equipment and go out in the plant to check the condition of field devices and final control elements. Besides, plants require hot work permits, safety information, workarounds and other time-consumers, making it highly unproductive to grab that clipboard and go. Companies around the world have begun formal programs to use the diagnostic data in their HART-smart instruments and control valve actuators and positioners by directly connecting them to the asset management systems in the maintenance department.

Get Connected to the Benefits of HART 7 - Suzanne Gill - Charles Larson was quoted in the HARTline Newsletter in In this story discussing the benefits of HART 7 it is highlighted that the introduction of HART 7 has “improved the ability of additional data and diagnostic information from devices” along with increasing “the awareness of users to the wealth of information in HART devices that can be used in plant efficiency.” From Moore Industries.

Reading HART Data into Non-HART Systems - Many HART products are able to perform more than one measurement or output function (e.g., make multiple process measurements, calculate process information, and provide positioner feedback information). All of this information can be easily accessed digitally. However, existing controllers or interface equipment may not have the ability to read digital HART data. Products are available that can read HART digital signals and convert them to analog (4-20mA) and alarm trip (contact closure) information, which enables any traditional analog control system to take full advantage of the benefits of HART - communicating devices. From Moore Industries.

HART Monitors Extract Data from Smart Instruments - Simple Modules Expand Transmitter Usefulness - Greg Feliks - The HART digital signal often contains additional process measurements and other variables that may include instrument status, diagnostic data, alarms, calibration values and commands. In many cases, HART instruments were installed simply because they could be configured and diagnosed easily with a handheld HART communicator device. For a variety of reasons, the rest of the HART data often goes unused. One reason is because of the prohibitive cost of installing a plant-wide HART monitoring system. Another reason is the lack of familiarity with alternatives. A simple and cost effective solution for gathering HART information is to use a HART interface device only in the specific instances where it is needed most. Fortunately, HART interface devices, available from several manufacturers, make acquiring HART data a fairly simple proposition. This HART data is then made available to the control system via analog signals, discrete outputs or serial communications. From Moore Industries.

HART Communications - An excellent 40 page technical paper from Samson Controls - Field networks are not the only solution when plant operators want to use the advantages of smart field devices. The HART protocol provides many possibilities even for installations that are equipped with the conventional 4 to 20 mA technique. HART devices communicate their data over the transmission lines of the 4 to 20 mA system. This enables the field devices to be parameterized and started up in a flexible manner or to read measured and stored data (records). All these tasks require field devices based on microprocessor technology. These devices are frequently called smart devices. Introduced in 1989, this protocol has proven successful in many industrial applications and enables bidirectional communication even in hazardous environments. HART allows the use of up to two masters: the engineering console in the control room and a second device for operation on site, e.g. a PC laptop or a handheld terminal.

HART v Foundation Fieldbus - The Facts and the real difference - Jim Russell - Thanks to ICEweb The question is often asked “Why should I install Foundation Fieldbus™ when the features are all available with HART?” This White paper addresses this question, provides some of the answers and covers the following;

  • The Technologies
  • Differences, Advantages and Disadvantages
  • Why some Manufacturers / Suppliers continue to push HART and put up a “Smokescreen”
  • Brownfield and Greenfield Plants
  • What technology should be used
  • Simple HART v FF Comparison Chart

Obtaining Stranded Information and Diagnostics - Most plants have hundreds, or even thousands, of HART devices, but not all of these are delivering the full range of process variables, calibration, maintenance and diagnostic data to plant operators and maintenance departments. This is because they have no means of delivering that data to the control room. One reason is that some legacy control systems are analogue, meaning they have no access to the digital HART data thus preventing operators from taking full advantage of the device intelligence. To achieve maximum insight, the existing control system must be upgraded by installing HART I/O interface cards and software modules - from SA Instrument & Control.


Smart HART Transmitters, Monitors and Interfaces

Extracting HART Data from Smart Instruments - According to the FieldComm Group (formerly the HART Communications Foundation), there are more than 30 million HART-enabled instruments installed in chemical and process plants worldwide, and most process transmitters made today are HART compatible. The HART digital signal often contains valuable process measurements and other variables including instrument status, diagnostic data, alarms, calibration values and alert messages. However, many systems fail to utilize the critical information available from HART-enabled transmitters, valve positioners, flowmeters and other "smart" devices. This article from Moore Industries shows how a HART interface device can serve as a simple and cost-effective solution for gathering HART information.

Problem Solvers from Moore Industries - These are really excellent.

4-20mA Isolator Passes HART Signal
Additional HART Loops to Share Process Signals
"Break Out" Analog Signals with the HIM
Connecting a HART Device to a DCS with MODBUS
Connecting HMI to Tank Gauge Sensors
Digital Signal Unaffected by Analog Errors
HART pH Transmitter Interface to Control Room
HART Multiplexers That Maximize Space
HART Signal Interference
Monitoring and Powering a 2-Wire Transmitter
Multi-Level Alarming for a Single Process Variable
Passing HART Signals While Maintaining Safety Isolation
Reducing Process Disruption in On-Line ESD Valve Testing
Safeguard Expensive I/O Cards from Overloading
Use HIM in "Listen" Mode to Sample HART Data


HART Technical Information

About the HART Protocol - The HART Protocol was developed in the mid-1980s by Rosemount Inc. for use with a range of smart measuring instruments. Originally proprietary, the protocol was soon published for free use by anyone, and in 1990 the HART User Group was formed. In 1993, the registered trademark and all rights in the protocol were transferred to the HART Communication Foundation (HCF). The protocol remains open and free for all to use without royalties.

The following is from the HART Communication Foundation.

How HART Works - This is a useful technical overview of the technology.

Benefits of Using HART - There are many benefits in using this technology, these are detailed in this article.

HART Technical Manuals, Documents and Articles - The following manuals, documents and articles from the Hart Communication Foundation provide technical information on various HART Communication Protocol related topics. Educational in nature, these materials provide a better understanding of this valuable technology to anyone interested in learning more about it.

HART Application Guide
HART Protocol Technical Overview
HART Communication: Driving New Product Developments
The HART® Protocol - A Solution Enabling Technology
The Impact of HART on Process Automation
Preventing Process Disruptions
Understanding The Power of HART Communication

The HART® Protocol - A Solution Enabling Technology - HART® Field Communications Protocol is widely accepted in the industry as the standard for digitally enhanced 4-20mA communication with smart field instruments. A wide range of products from an increasing number of suppliers is available today, and many more are in development. The enhanced two-way communication capability of instruments using the HART protocol can significantly improve plant information management, provide solutions to today's business challenges, and yield substantial cost savings. Initial installation/commissioning savings of $400 to $500 per instrument and annual maintenance/operations savings of $100 to $200 per instrument are commonly reported.

Romilly's HART® and Fieldbus Web Site -This web site specialises in the digital communication protocols used in industrial automation, with special attention to HART.


Wireless HART

For details on Wireless HART see ICEweb's Industrial Wireless Page.

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