Automation & IT

There's always something more to learn about HART Communications

Since HART technology has been around for many years, most people feel that they know all that there is to know about it. The fact is the vast majority of HART applications utilize only a fraction of the full capability of HART.

By Ed Ladd

FACT: Since HART technology has been around for many years, most people feel that they know all that there is to know about it. The fact is the vast majority of HART applications utilize only a fraction of the full capability of HART. HART technology can be applied full-time easily and cost effectively allowing many applications to become much more valuable to the enterprise.

HART technology was originally introduced as a proprietary protocol by Rosemount, Inc. in 1990.  Fifteen years and over 20 million installations later, the protocol has become the de facto standard for communicating with smart field devices.  For many years manufacturers who have sold products that incorporate HART Communication are now investing in the technology to gain ground in the market place. 

Manufacturers and users alike have not invested the time and effort necessary to understand and fully utilize the advanced capabilities of the HART Protocol. Instead, they have limited their use of HART technology to handheld communicators for configuration and troubleshooting devices on startup or failure. 

This is like only using your personal computer to play solitaire. When you invest some time and effort, you can compose, manage, communicate and access the world!  Same applies with HART Communication. Instead of using it for only one thing, with a little investment, you can learn to implement all its capabilities and reap the benefits. 

Get started now. Let your next step in the use of HART Communication be continuous monitoring through an asset management application. Through continuous monitoring you can reduce your exposure to potential problems created by devices installed in your plant.

Asset management applications that are DD-enabled (the ability to read a registered Device Description to learn the internal features of a device) have the ability to review information in a device and to alert the system to potential malfunctions before they affect the process.  This information includes multi-variable, configuration and diagnostic information that can help keep your systems running in tip-top condition.

Condition monitoring is standard operating procedure for most process applications, but how often is it assumed that because you have a reading you’re okay?  Many times in range measurement errors occur that could have been prevented if the systems had been monitoring the digital HART data available.

To limit the possibility of in-range failures, HART digital values for PV (primary variable) and AO (analog output) can be compared to the actual 4-20mA analog signal to determine if there is a mismatch.  Any mismatch would be an indication of trouble either with the device itself or the wires between the device and the I/O making the process measurement invalid.

In addition to this kind of comparison, DD-enabled asset management solutions or even OPC (OLE for Process Control) based clients can monitor your HART enabled devices 24/7 providing a level of information never achieved through the use of the handheld communicator.

Consider the possibilities. Ask the questions. Take action. Do something to capture the valuable information residing in your HART-enabled devices.  There is no other technology that can provide as high a value proposition as HART.  Don’t limit your information flow.  Do your due diligence and see if there are information gaps in the way you use HART-enabled devices.

Close those information gaps and “See What You Can Do” when you use the “Power of HART”.

Upcoming HART Connection articles will provide information on applying HART technology, application notes to help you implement new HART strategies and what to expect from a HART-enabled device or host system. For complete information on HART attend the next HCF HART Fundamentals Workshop.  For more information, contact the HART Communication Foundation or visit the website at

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