Wireless Starts to Mesh

Nov. 1, 2008
Plants are taking a broader view of the role of the technology

Wireless use in the process industries has changed enormously, says Jeff Becker, director of the global wireless business, Honeywell Process Solutions, Phoenix. “About a year ago, we saw clients move toward holistic wireless networks,” he recalls. To him, that indicates scalability using wireless networks has become more critical plantwide.

Last year, all the talk was about wireless instrumentation, which, of course, is an important aspect of wireless, says Hesh Kagan, managing consultant in the enterprise architecture and integration group of Invensys Process Systems, Plano, Texas. “This year, we’re seeing our customers readily embracing enterprise-wide wireless solutions such as mobile operator, asset tracking, maintenance management, video and VoIP [voice over Internet protocol] telephony.”

Industry’s made huge progress, agrees Bob Karschnia, vice president for wireless at Rosemount, Chanhassen, Minn., a unit of Emerson Process Management. “Industry has used niche applications such as level gauges for 20 to 30 years. But over the last year, use of wireless has started to move into the mainstream.” It’s like an epiphany, he says. “All of a sudden, end-users are saying, ‘I get it.’ And then they see multiple applications through wireless as potentials.”

That hasn’t yet translated into a lot of action yet, though, because there’s still some uneasiness about relying on the technology, notes Robert J. Schosker, product manager for intrinsic safety, HART, signal conditioners and surge in the Process Automation Division of Pepperl+Fuchs (P+F), Twinsburg, Ohio. “It’s a trust factor about wireless,” he explains. “Some of the biggest obstacles are mindsets. Even though the technology has been around for a long time, people are still nervous about it.” But he counsels: “Wireless is a great way to go. It is the future of process automation.”

A Change in Attitude
The biggest advance in the last year or so isn’t in technology but in end-user attitude, says Kagan, past president of the Wireless Industrial Networking Alliance, Research Triangle Park, N.C. “There is a much greater understanding and appreciation of the fact that when engineered and used correctly, wireless really does work and is secure.”

But construction and deployment can pose significant challenges. “These radios must be correctly specified for the environment they’re to be placed in. That includes correct physical placement, as well as mounting and cabling of radios and antennae,” Kagan says. The interface to the wired network is another area requiring attention, he notes. “This, too, must be handled with careful engineering and full local IT (information technology) support.”

One lingering obstacle is battery life for self-powered remotely placed wireless devices. “Nothing’s changed. The technology is improving all the time,” notes Gareth Johnston, wireless product manager with ABB Ltd., St. Neotts, U.K. “[But] some devices will [have to] be externally powered.”

Energy harvesting may provide a viable option in some cases. Solar panels are well-established but recovering energy from other sources such as equipment vibration or thermal gradients is progressing. For instance, GE Energy, Minden, Nev., at the recent ISA Expo in Houston, introduced a wireless condition monitoring system with an optional unit that scavenges energy from vibration (Figure 1).

Figure 1 -- Condition monitoring: Magnetically mounted sensor (left) measures vibration and draws power from module that harvests energy from vibration (right). Source: GE Energy.

Security raises concerns. “The fear of an unauthorized person gaining access into the company’s internal control network — that’s the biggest thing,” notes Scott Brady, director of marketing for SKF Condition Monitoring, San Diego. This fear is overblown, he says — “there are technologies that can prevent that...”
Nonetheless, he acknowledges, “there is reason to be concerned [about security].”

Unfamiliarity with infrastructure requirements is another obstacle, notes Ed Bondoc, SKF’s wireless product manager. “Many end-users don’t realize that you actually need a wireless umbrella over the area, one installed at the plant, to use wireless.”
Yet another reason that plants historically have resisted wireless is a concern about reliability. “It’s not a well-founded concern, and may have been related to past experience,” says Bondoc. Citing WiFi as an example, he believes resistance “came from high expectations from vendors that said wireless could do more than the systems could deliver.”

The Promise
Wireless data transmission certainly promises to deliver numerous benefits to plants. Bart Winters, HPS solutions manager for safety and reliability, points to improvements in plant reliability, operational efficiency and worker safety. To these, Karschnia adds achieving better environmental performance. “Everything we’re doing is about one of these things.”

Implementation ranges from installing units (drawing power either from the plant electrical network or from batteries, etc.) at a specific location to carrying around handheld devices. Interest is high in both the fixed and portable approaches, notes Bondoc.

 Wireless will change offline monitoring of data, says Becker. “A worker walks around the plant and tries to assess the relative health of an asset. Wireless is allowing inexpensive gathering of information on a much greater percentage of equipment.” This more frequent and broader assessment will help identify problems and solutions before secondary damage occurs, he notes. And that’ll lead to more uptime, as well as improved productivity by permitting staff to better monitor critical assets.

Brady suggests the future of handhelds “depends on connecting to the wireless network.” That’s because “some guy out there [in the plant] with an industrial PDA [personal digital assistant] will want to tap into the whole control system. ‘What’s the system doing now?,’ he might ask, if he hears a noise. He might need instructions. He might need to contact someone to get repair done.” In short, the field operator will want live access to plant control and communications systems.

However, for continual monitoring of conditions such as vibration nothing beats a fixed device, says Winters. “It’s available all the time and at lower cost.”

The interest in condition monitoring will spur the range of applications supported by wireless instrument networks to expand beyond the traditional realm of 4–20 mA, predicts Johnston.

For instance, many plants currently only take advantage of the 4–20-mA output of HART-enabled devices, leaving valuable diagnostic data stranded at the device. Wireless adapters can provide a way to retrieve such information. Already many vendors offer a variety of wireless transmitters. And the roster is bound to significantly grow.

Becker foresees wireless networks of greater scope, including use of different types of instruments — with a focus on answering three general questions he believes apply to all process operations: How can worker safety be enhanced? How can worker mobility in the plant be improved? How can islands of automation be connected?

What do end-users desire in wireless? “They want to see reliable, easy-to-use equipment. They want reliable signals. They want easy-to-install, meaning: ‘Can they keep the plant running when they connect the adaptor for wireless?’ They want something that is easy to maintain, where they can install and forget. They want equipment that won’t interfere with the current process signal,” Schosker says.

Plants are looking for more integration with wired devices and the control system, believes Kagan. “They would like to be able to integrate server-based applications and wireless data. They would also like to enable mobile plant personnel to connect wirelessly to the server to interact with control and enterprise applications.”
A Complication
One massive challenge may be getting the WirelessHART specification (see of the HART Communication Foundation (HCF), Austin, Texas, and the ISA100.11a protocols of ISA (the Instrumentation, Systems and Automation Society), Research Triangle Park, N.C., reconciled and compatible with other protocols, as well as device-enabled.
Currently, HCF, through its Wireless Cooperation Team, is aiming to develop an interface specification for a gateway to Foundation Fieldbus and Profibus’ ProfiNet. That team also is working to establish a common set of compliance guidelines for incorporation into the respective product-registration procedures.

Meanwhile, in June, Honeywell unveiled an updated version of its OneWireless industrial-wireless-network equipment that is designed to be compatible with ISA100.11a, notes Becker.

Then, at the end of September, Emerson announced release and shipment of its first wireless pH transmitter, the Rosemount Analytical Model 6081-P. It’s compatible with a WirelessHART Model 1420 gateway.
Essentially, though, no other commercially available WirelessHART products exist now. “However, several manufacturers are in the late stages of testing and will have products ready for registration and compliance testing at HCF in the next two to three months,” noted HCF executive director Ron Helson in late September.
Johnston believes that by January or February a number of WirelessHART-enabled and HART-certified instruments will be available. Those, he forecasts, will include “self-powered instruments, WirelessHART gateways and adapters.” Implementation of WirelessHART won’t be difficult, says Johnson, but will require a site walkthrough to identify possible issues and how they can be avoided. “In actual fact, there is little difference between planning a 4–20 mA installation and a wireless one, apart from the wire,” he notes.
P+F plans to release products in the first quarter of 2009. “These will be WirelessHART gateways and adapters for making instruments wireless,” Schosker says, adding that P+F also will produce ISA100.11a-enabled devices. “It’s kind of like VHS versus Betamax [video tape formats]: You supply both until one wins.”

Interoperability Issues
End users certainly want to avoid the frustration that arose with the eight-headed IEC 61138 fieldbus standard of the International Electrotechnical Commission (IEC), Geneva, Switzerland. It doesn’t specify a particular approach but instead provides an umbrella for rival ones.

“If they [WirelessHART and ISA100.11a] continue on separate paths, they both will meet end-user requirements — much like a Chevy and a Ford,” Kagan suggests. “We believe that the end-user community will be best served with one standard — ISA100 — because that standard has the flexibility to support many other functions in the future. ISA100 is a family of standards architected to work well together.”

Interoperability surely is the key to avoiding frustration of end users, but achieving it can be a elusive goal. “WirelessHART and ISA100 are working on the best way to achieve convergence, i.e., one standard. How that develops remains to be seen,” notes Kagan, who chairs ISA100’s Working Group 6, Interoperability. “We’re just getting going, but the intent is to understand the mechanism for any other standard, as well as the family of ISA100, to have some degree of interoperability. The devil is in the details — and definition of terms.”

Indeed, that seems to be where demons lie. “Our work is cut out for us — and it will not be easy,” declares Richard Caro, CEO of CMC Associates, Acton, Mass., and co-chair of ISA’s SP-100.12, the WirelessHART Convergence Subcommittee. He suspects, though, “that there will be enough resistance from the WirelessHART community that will force the changes to be made only in the ISA100 specification.” Translation: interoperability will be a one way street.

Karschnia also believes that ISA100 will fully embrace WirelessHART. After all, more than 24 million HART devices already are installed and many of these can benefit from WirelessHART. “It’s where the future is,” he notes, adding that the IEC just approved WirelessHART as a publicly available specification.
“Interoperability is very achievable and, in fact, is the cornerstone of both HART and WirelessHART,” says Helson. “I suppose that it depends on what ISA100 decides to do about incorporating WirelessHART into the ISA100 standards.”

Regardless of whether interoperability is uni- or bi-directional, Caro’s committee is laboring to incorporate the wireless portion of the latest HART specification. ISA has permission to use the HART information submitted to the IEC. “Now we can accomplish the chartered mission of the subcommittee 12 of ISA100, which is to perform a features comparison. We’ll look for differences and pay attention to only those differences that affect end-users.” He expects completion of the comparison by the end of 2008.

After that milestone, achieving functional convergence — which doesn’t mean there will be a single document — still will require time. “I think it would take, at minimum, nine months — probably, September or October of 2009. It will take that long to figure out how to do it [achieve convergence] and then write the first draft of that standard,” Caro predicts.

Standard finalization can’t be achieved before 2010, he believes. “Then, what we have will be a specification that will allow equipment to be manufactured to a WirelessHART standard that will be interoperable with ISA100-enabled equipment, which is also designed to be interoperable with WirelessHART,” says Caro.
“Interoperability is a must,” emphasizes Bondoc. “Otherwise, we will not realize the universal adoption that is one of the promises of wireless.”

An Unfettered Future
The current challenges certainly aren’t undermining end users’ interest in the technology. “There are big audiences for seminars and knowledge transfer. We’re at the early stage — where Foundation Fieldbus was in the late 1990s,” says Johnston.

But the momentum is building. After all, plants must grapple with ever-increasing pressures to improve equipment uptime, operational efficiency, environmental performance and worker safety. Wireless may signal a new way to achieve better results.

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