Wireless wins wider role

Wireless is poised for a big breakthrough in plant operations because of its ease of use, safety and potential for energy savings.

By C. Kenna Amos, contributing editor

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But the product of the SP100 Committee will be a best prac-tices, not a technical, standard, says Gabe Sierra, Chanhassen, Minn.-based wireless marketing manager for Emerson Process Management. Meanwhile, the Wireless HART Working Group of the HART Communication Foundation, Austin, Texas, is develop-ing a standard — self-organizing networks — that will be the de facto standard for in-dustry moving forward, he says.

These self-organizing networks will totally revolutionize what plant operators can do, Sierra asserts. “It’s going to allow them to monitor assets they couldn’t before,” he believes. “They’ll be able to collect more field data and be able to implement new maintenance operations that will help them extend the life of the plant, as well as increase plant productivity.”

Seeking its own wireless cloud right now is PPG Industries’ complex in Lake Charles, La. The 700-plus acre facility, which manufactures chlorine, caustic and other chemicals, ventured into wireless just last year, notes Brooks. Now it has 40 to 50 devices that measure temperatures, pressures and tank levels. “I’m looking for a common security model and a common administration model,” Brooks says. Invensys Process Solutions currently is working with PPG to build those and is using shared-access-point technology for all devices and a common data-and-security model for all wireless frequencies and protocols (Figure 2).

Secure wireless architecture

Figure 2. Shared access points and common data and security model are key to architecture (click to enlarge).

Meshing devices

Those standards and managed networks will foster change, espe-cially in connectivity. And mesh networks, which rely on a lattice-like rather than point-to-point configuration, will revolutionize ex-isting wired linkages, Yellets predicts.

These mesh networks allow sensors to communicate with each other rather than through a base radio, Millette explains. This means, Moss notes, that a wireless device does not need to be able to transmit over as long a distance.

“Give it maybe three years, possibly more, I think mesh will be there in one shape or another,” Moss believes. Yellets is even more optimistic, “As mesh networks come out, in the next year to 18 months, we’ll see the change.”

Mesh networking creates possibilities for more wireless de-vices <em dash>—<em dash> not just process devices, but mobile operator stations, hand-helds for field operators’ rounds, and units for safety and maintenance inspections, Yellets contends.

Another significant change will come by coupling wireless technology with tablet personal computers (PCs), such as those of-fered by Honeywell and Invensys Wonderware, Lake Forest, Calif. This will enable plants to rethink what they can do in unwired re-mote areas. It could also be useful outdoors for supervisory control and data acquisition (SCADA) applications, notes Ann Ke, Won-derware’s product-marketing manager for panels and tablets.

As part of its plan to install wireless Ethernet for control, the multinational company plant cited earlier plans to use tablet PCs to replace 10 fixed operator displays that have human-machine-interface software. “If the tablet PC works like we hope, there are other applications where we could use it,” the site’s instrument control specialist says. He estimates potential savings at approxi-mately $40,000.

Healthly change

Wireless promises other significant changes in industry practices. The biggest one will be an increase in condition monitoring, say Hagan and Manges, who is also a WINA board member and co-chair of ISA’s SP100 Committee

Eliminating the need for wiring makes it easier for plants to get data from units that otherwise would be tough or expensive to check — and is already prompting more monitoring of the condition of equipment such as pumps and mo-tors, which, in turn, ultimately leads to maintenance savings.

Adding to the incentive, a new class of low-cost wireless sen-sors will compel companies to use those sensors with equipment, Kagan believes. These sensors — for tem-perature, pressure, vibration, level and flow — don’t have the same resolution as process sensors, Kagan explains. But, he emphasizes, “There’s a lot of science, math and common sense that tells you that a lot of casual measurements might be more useful than a few exact measurements.”

The chemical industry, like others, will see sensors with built-in wireless technology, predicts Harry Forbes, senior analyst at ARC Advisory Group, Dedham, Mass. He also forecasts big in-roads in the next two to three years for wireless sensor networks, because they boast lower installation costs than wired ones.

Key applications will be monitoring, process control and as-set management — and within those will be both critical and non-critical uses, Kaufmann says. The two top barriers to adoption, though, are reliability and security, he con-tends. Power management also concerns end-users, he and Forbes say. Kaufmann notes that users want plug-and-play-and-walk-away sensors with batteries lasting 15 years.

Wireless’ tangles

Wireless is not without its issues, however. Foremost among these are coexistence and interoperability with other wired and wireless networks, the need for standards, and lack of infrastructure.
“People are coming in and implementing their own point-to-point solutions. Invariably, when they do the first solution, it works. Even the second might work,” Kagan explains. “But this is wireless we’re talking about — radio waves go wherever they want.”

Plant processes may stop working because of these ad hoc networks, Kagan asserts. “In ad hoc, there’s no engineering. It’s just who gets there first. In wireless, there must be thoughtful, top-down engineering.”

The problem is exacerbated because there are only two fre-quency bands — 900 megahertz and 2.4 gi-gahertz — that are open for public use. “These are like multi-lane, public highways that anyone who wants to build on can,” Kaufmann explains. But without rules, traffic gets jammed, he says. “We’re headed for a big crash in the future. I don’t know if everyone in the plant [with a lot of wireless imple-mentations] recognizes that.”

Users need coherent systems management through a common data model, Kagan adds, because people don’t know how to man-age wireless technology. A solution will come from ISA’s SP100 Committee, he believes.

An inevitable force

Despite the current drawbacks, wireless technology seems destined to become ubiquitous at plants. The cost and complexity of wired systems will drive plants to wireless, believes Manges.

Yellets foresees more wireless with redundancy and new plants designs with wireless. “We’re going to see that for all read-ings, including critical process readings,” he says. Among those critical readings, he includes key reactor temperatures and pres-sures that may require very fast response time to control.

Kagan says there’s a huge difference between what’s happen-ing today in wireless and what will happen tomorrow. Though cer-tain that the technologies can be implemented correctly, he cau-tions, “It’s not a trivial task. It’s more expensive than managing a wired network.” But whatever the costs, benefits of correct wire-less implementations are enormous, he believes.

One clear beneficiary is a company’s bottom line, Brooks says. “We [at PPG] see that in order to be competitive, this is step we felt we need to take.” More and more chemical companies are coming to the same conclusion.

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