by Ron Helson, HART Communication Foundation

March 2003

“HART is the de facto standard in this industry and will remain so for a significant time. It is standard in all our devices,” says Hans Georg Kumpfmüller, Siemens AG, Germany.

“The 4-20mA world isn’t going away overnight. We support HART in all our devices and don’t see any end in sight,” says Craig McIntyre, Endress+Hauser, U.S.A.

These comments are typical of those expressed by industry professionals when asked what they consider the importance of HART® in the global instrumentation marketplace. Ease of use, compatibility with existing systems and real cost-saving benefits combine to make the HART protocol an important technology for this industry.

More and more, industry professionals are specifying HART because it offers the best solution for gaining the benefits of smart instrumentation. The HART protocol retains the compatibility and familiarity of conventional 4-20mA systems, while providing remote two-way digital communication with smart field equipment.

The HART protocol is supported by major instrumentation suppliers worldwide and by an independent, non-profit organization, the HART Communication Foundation (HCF).

Worldwide Market Leader
Steve Zager, Yokogawa, reports a sizeable increase in demand for HART. “We’ve seen a shift to the HART protocol in flowmeter and transmitter products of over 20 percent annually. This is huge.”

Industry experts agree that HART is the leading communication technology used in smart instruments today and, from all indications, will remain so for many years. In a recently released market study, the ARC Advisory Group (Dedham, Mass. USA) predicts that HART will dominate smart instrument communication well into the next century. (See ARC graph). ARC reports an accelerating industry trend from traditional analog to smart instrumentation and strong growth for HART throughout the forecast period.

On a global basis, sales figures indicate that HART is the leader in South America, extremely popular in Asia, and rapidly becoming the industry standard in Europe. The HART protocol is growing rapidly and the already large installed base is predicted to surpass 15 million within five years.

The benefits of HART are significant and the future of the technology is strong. Any company that is not using the HART protocol today should be moving to do so soon.

Powerful Field Communication
“The challenge is overcoming the current market perception that HART only communicates with handhelds,” says Herb Holland, Elsag Bailey. “I’m not sure that manufacturers or users really understand what they can do with this technology.”

HART has broken open the paradigm of a single device doing a single function as Jim Cobb, Rosemount Measurement, observes. “Now we have the capability of doing multiple measurements and calculations in one device very close to the process. The industry is just beginning to exploit the diagnostic capabilities that HART-based instrumentation provides.”

HART is a straightforward and relatively simple technology that provides low-cost, highly capable digital communications. Ease of use and compatibility with existing 4-20mA systems, combined with the benefits of remote configuration and diagnostics, contribute to the technology’s status as the standard for smart instrument communication.

The HART protocol is used in various modes to communicate information to/from smart field instruments and central control or monitoring systems. In most applications, HART digital information is communicated simultaneous with the traditional 4-20mA analog signal. The process variable is transmitted continuously on the 4-20mA, while additional measurements, calculated values, device configuration, diagnostics, and device status information is sent by HART digital communication on the same wires.

Perhaps a lesser known standard capability is that several HART-compatible field devices can be connected to a single pair of wires in a multidrop network. In this mode, HART digital communication is used to access all device information including the process variables. The installation savings are significant and this approach is being used more and more in remote monitoring applications for process parameters such as temperature and level.

HART Connectivity
“In the future, companies will be using more network-related products, multiplexers and multidrop connections, for on-line interaction with their HART devices,” says Craig McIntyre, Endress+Hauser. “The digital communication capability of HART ensures that device information can be linked remotely to other digital networks.”

“The HCF continues to invest and enhance the HART technology to serve the evolving needs of smart instrumentation,” says HART Communication Foundation Senior Engineer Wally Pratt. “We have developed a new OPC-compatible server that provides an easy-to-use, low-cost solution for cyclic access of HART device information by higher level systems and client applications.”

Available HART-compatible multiplexers and I/O subsystems make it easy to connect HART devices with central control systems, maintenance stations, and corporate SCADA networks through the OPC Server. The Server provides cyclic data access to process variables and device diagnostic information.

Today and Tomorrow
The HART protocol is well established, field proven and continues to evolve to meet industry needs. The HART Communication Foundation manages the protocol standards, provides worldwide support for application of the technology, and ensures the HART protocol is openly available for the benefit of the entire industry.

HART is populating the plant floor. Millions of installations exist today and applications are growing. Sales of HART devices will accelerate well into the next century as the HART protocol remains a key tool in improving plant operations for the foreseeable future. Industry experts agree, and we concur: “HART is here to stay.”

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Ron Helson is Director of the HART Communication Foundation. The HCF promotes industry awareness and support of the HART protocol through its official website (www.hartcomm.org), a quarterly newsletter, informational CD-ROM releases, application guides, articles in industry publications, training workshops, and presentations at international conferences and major trade show events. Contact the HCF at: HART Communication Foundation, 9390 Research Blvd., Suite I-350 Austin, Texas 78759-6540 USA; 512-794-0369; FAX 512-794-3904.