Cutting the wires of communications

Users want wireless, vendors want to sell wireless, so what’s the problem? Our August cover story tackles one of the most discussed topics: the use of wireless communications in process automation.

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Assuming an end to the infighting that has dogged ISA standards committees since the initial meetings of the fieldbus standard committee, ISA should approve an S100 standard by October of 2008. Tom Phinney, of Honeywell, who is the convenor of the equivalent IEC standard committee, estimates a similar time scale for IEC approval. Recently, the signs have been good that the infighting will end. Emerson and Honeywell have publicly pledged to turn over any patents and other proprietary intellectual property to the HART Communications Foundation and SP100 committee. "We believe in standards," say Emerson's Berra and Honeywell Process Systems’ CEO, Jack Bolick, in nearly the same words. Peace is being made.

Where's All This Going?
What does all this mean for you, the end user? It means that you'll be able to confidently purchase wireless networking gear for your HART-enabled field devices by early 2007, and know that they’re being built to a standard. By sometime in 2007, some vendors may be producing "draft S100 standard" compatible products, and by 2008, there should be a single standard for industrial wireless in process automation.

Figuring Out Your Own Use Cases
Between now and the time the HART Wireless Working Group and SP100 committee report their standards, there are still a lot of things end users can do to get ready.

Tell SP100 What You Think

WHAT DO you want to use wireless for? Where would you like to deploy wireless? What are the benefits you expect to get in using wireless?

For once, it’s easy for end users to pipe up and tell the industry what they think. The SP100 committee continues to solicit end user opinions on these questions. We encourage you, as end users, to take the end user poll.

Alarms Go Jingle, Jangle, Jingle

ALARMS CAN be of any of the classes in which SP100 has divided wireless applications. For example, Class 0 alarms could include radiation monitoring or toxic gas sensors, many of whose alarms have a completely automated response, like automatic containment processes. Class 1 alarms would be those alarms that would cause immediate shutdown of the process, what the SP100 committee calls, "high-impact process condition." Class 2 alarms would include any normal automated response to a normal change in process conditions, like a flow diversion or a low level alarm causing the control system to begin changing from one storage tank to another. A Class 3 alarm would describe a process condition where the intervention of a human operator is required, such as deciding whether to divert from Tank 1 to Tank 2, or Reactor 1 to Reactor 2. Class 4 alarms would describe an equipment condition, generally, with a short-term response requirement, such as sending a maintenance technician to find out why the low pressure alarm is going off, but the process seems to be operating within nominal parameters. A Class 5 alarm might be to order spare parts to repair an analyzer that isn't critical to the process.

Wireless While We Work

AT THE Harry Tracy Water Treatment Plant in Daly City, Calif., San Francisco Water Department plant supervisor Leland Fong's operators have cut the cord and become wireless workers, using tablet PCs from Wonderware.

"My operators are more efficient," Fong says. "Before, if they had an alarm, they had to go to the control room to take care of it. With the tablet PCs, they can work with the alarm wherever they are, if they’re in contact with the WiFi network."

Fong says that many jobs that used to be two-man jobs are now one-man jobs, which really leverages the technology. "For example," he continues, "an operator can log in that he’s working on the chlorine residual analyzer, so the operator in the control room will see that he shouldn’t worry if the chlorine residual alarm goes off. Calibration of our field instruments has become very easy with the tablet PCs."

Fong's operators are on the City of San Francisco’s WiFi LAN. So, if they have the appropriate permissions and are in range (the Tracy plant has some physical-location issues with hills and tunnels), then they can operate the plant from wherever they are.

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