Trying to pick a winner: Competing industrial wireless standards stir—rather than clarify—issues

Wireless technology is proving itself in industrial settings. A number of manufacturers—lured by potential cost savings or the ability to place sensors in previously unreachable areas—are using industrial wireless networks. Most of these early adopters are pleased with the results of their projects, with the belief that the number of industrial wireless networks would multiply quic...


Wireless technology is proving itself in industrial settings. A number of manufacturers—lured by potential cost savings or the ability to place sensors in previously unreachable areas—are using industrial wireless networks.

Most of these early adopters are pleased with the results of their projects, with the belief that the number of industrial wireless networks would multiply quickly if one issue could be resolved: the ongoing argument over standards.

"Ultimately our objective is to meet our customers’ requirements for whatever standard they use."

—Hesh Kagen, manager, consulting,
Invensys Process Systems global wireless program

Definitive standards for wireless networks may well create numerous benefits—starting with lowering the unit cost of wireless field instrument devices, now pegged around $600 to $700 dollars each. Standards also could entice both vendors and users to push the envelope on development of new applications, and accelerate broad industry deployment by ensuring greater interoperability.

But even though work on wireless communication standards made significant strides this year, considerable uncertainty remains. Much of this is due to the emergence of two standards, both backed by groups that firmly believe they have discovered the path that the entire industry should follow.

The two competing standards are:

  • Wireless HART , put forward by the largely vendor-supported HART Communication Foundation ( ) consortium. It debuted in September 2007 as a part of HART 7 specification, and was updated this past summer by the enhanced HART 7.1 specifications to be IEC-certified.

  • ISA 100.11a ( )—carrying the ANSI standards imprimatur—which stipulates significant end-user input and approval. This standard is working its way toward final ratification, expected early 2009.

Invensys Process Systems is committed to facilitating the use of industrial wireless applications and leveraging wireless networks at all levels of the enterprise.

Though there is a move afoot to incorporate WirelessHART within the ISA 100 “family of standards,” nothing is guaranteed at this point. In fact, most industry observers expect there will be two separate wireless standards for some time. Some assert that's not necessarily a bad thing.

“The big thing that everyone wants to solve is costs,” says Jim Reizner, section head at Cincinnati-based Procter & Gamble , responsible for process sensing technology. “Wired [networks] cost a lot not only for installation, but in engineering and maintenance. If we can do away with that, it would be a great advance for end users. But wireless technologies are yet in their infancy. Anyone thinking of installing wireless on a nuclear reactor water-cooling loop at this point would be crazy.”

As with any emerging technology—including standards designed to facilitate adoption—every company must determine for itself where it wants to be on the learning curve in harnessing the benefits while contending with risks. Reizner has “starter kits” for networks based on both WirelessHART and ISA 100.11a running in his test labs—in addition to running isolated deployment of proprietary wireless networks in niche applications.

Competing standards

“Trying to make sense of wireless standards is a noble cause,” Hesh Kagen, manager of consulting for Invensys Process Systems ' global wireless program, observes wryly. Though some automation vendors are committed to one standard or the other, “Invensys doesn't have a vested interest in one over another. We're not on the bleeding edge with a protocol of our own at this point,” he says.

Kagen does, however, chair an ISA working group on interoperability, and Invensys also is active in HCF—not an uncommon occurrence as the wireless community is relatively insular, with vendors and end users concurrently involved in both groups.

“Ultimately our objective is to meet our customers' requirements for whatever standard they use,” says Kagen.

The WirelessHART specification is a component within the HART protocol that has long been a standard for wired communications. HART is the most widely deployed global standard for wired communications between intelligent field devices and host systems such as distributed control and safety systems, addressing such applications as process and environmental monitoring, and machine health.

The basis of HART is rooted in a proprietary protocol originally developed by Emerson Process Management . When Emerson made HART available for others to use, it was quickly embraced by more than 220 automation equipment vendors worldwide. Development of a wireless component of HART started in 2004, and an initial WirelessHART specification was publicly released in September 2007.

The ISA 100 standards committee was formed in 2005 to develop the aforementioned “family of standards” that would address numerous wireless technologies in addition to intelligent field devices used in process automation—spanning factory automation for discrete manufacturing, RFID, and applications that go beyond process monitoring to embrace worker mobility, voice-over IP, video, and asset tracking.

Multi-vendor split

This standard has its origins in initial work sponsored by the Department of Energy in 2002, which funded development work by selected vendors Eaton , General Electric , and Honeywell . ISA 100.1a is that portion of the ISA 100 “umbrella” dedicated to wireless communications between intelligent field devices and host system gateways.

“HART is more for a local wireless network, where ISA 100.1a is designed to serve a broad, plantwide wireless network,” argues Jeff Becker, director of Honeywell's Global Wireless Business.

Both WirelessHART and ISA 100.11a take advantage of mesh network technology and time-synchronized channel hopping, and are standardized on IEEE 802.15.4-specified low-power consumption wireless radios. But the schema architecture within the radios is different, making devices based on the two standards incompatible.

"HART is more for a local wireless network, where ISA 100.1a is designed to serve a broad, plantwide wireless network."

—Jeff Becker, director, Global Wireless Business, Honeywell

When the HCF initially considered developing a wireless standard, its board split 4 to 1, with Emerson, ABB , Endress+Hauser , and Siemens outvoting Honeywell Process Solutions. HCF subsequently petitioned ISA to accept WirelessHART as the basis for its .11a specification, but was turned down in part due to ANSI requirements that standards broadly represent the input and consensus of end users. Agreement was reached between the two bodies in October 2007 to form a group to work toward acceptance of WirelessHART as one of the standards within ISA 100. That work is ongoing.

In the meantime, Honeywell announced its “ISA-100 ready” OneWireless technology in summer 2007, capable of a software upgrade when the ISA 100.11a standard is ratified. And Emerson has released its Smart Wireless technology based on WirelessHART.

Strong feelings remain in both camps, clouding prospects that could enable the two standards to reasonably co-exist, if not move toward workable interoperability of devices manufactured to one standard or the other. Pros and cons for both are vexing to sort out as both camps pitch the benefits of their own while discrediting the other.

Arguments are driven less by pure merit than efforts to secure mindshare and market traction around which standard will most quickly garner buy-in, netting lucrative revenue streams for vendors. Dedham, Mass.-based ARC Advisory Group projects wireless field devices “will grow from today's small market to become a significant segment of the total process field device market”—up from around $200 million in 2007 to $1.1 billion in 2012 (a 32-percent market increase).

“Most of the market is still proprietary, but WirelessHART has a significant lead being out more than a year now,” says Harry Forbes, ARC senior analyst. “The 'gotcha' is ISA 100.11a won't be out until 2009.”

Many manufacturers are moving ahead with wireless, Forbes adds, simply because the ROI is too compelling to wait.

“Honeywell's position says there isn't much point to WirelessHART, as they cost about the same,” says Becker. “As you think of scaling up in the future or running different parts of the plant, ISA makes more sense. We believe ISA will predominate, but the market will decide.”

Problem solvers

Yet according to Bob Karschnia, VP of wireless for Emerson Process Management, “Standards are complicated, but as far as applications go, there are no applications that WirelessHART doesn't already support. It solves all the problems it was asked to solve. ISA believes there is a set of rules drawn up by ANSI that ensures fairness, but fairness doesn't ensure best.

“Customers should watch which standards suppliers are supporting, and choose products with the broadest supplier base,” Karschnia continues. “At the end of the day, they want to buy from multiple vendors, so the standard that proliferates the fastest is the one that people will go with.”

P&G's Reizner says Procter & Gamble will continue to explore and test both, but won't dictate to its plants which to adopt.

“Perhaps in an ideal world there's reason to prefer one standard,” says Reizner, “but we don't live in an ideal world. There are certainly negatives for two standards, but there are positives. Having two is good from a technology innovation standpoint because each must stay competitive with the other. The challenge for end users is to pick a horse and ride it for a period of time such that you can make money off of it.”

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