31 May 2001
Wireless technology a hot topic at ISA 2001
by Ellen Fussell
Experts explain their solutions and future connections.
Although concerns about integration, security, and management still buzz in the ears of wireless technology advocates, the technology is blossoming faster than ever. Nearly 46,000 new wireless subscribers are added each day to the fertile consumer wireless atmosphere. Yet corporations will also need to adapt their infrastructures to respond sooner than later. It's becoming clearer to supporters of wireless systems that bandwidth, universal connectivity, and price are barriers to transgress in the wireless race. ISA 2001 will highlight aspects of this growing industry. Two wireless experts share their stories below.
Web-based SCADA for well sites
While technological advances have brought prices down a little, supervisory control and data acquisition (SCADA) systems are still somewhat expensive for small installations. That's why automation engineering consultant Rob Cottingham and his colleagues at Emerson Process Management, Kenonic Controls, in Calgary, Alberta, have developed a Web-based SCADA system for smaller well-site operators: oil or gas companies that operate 50 well sites or less. "This technology has opened up the possibility of building SCADA systems for smaller operators who've never been able to afford one because of high up-front costs," Cottingham said.
The problem is the per-site cost. "For the first site, you have a large infrastructure cost—a host computer, programming that goes with it, and a telecommunications infrastructure," Cottingham said. "As you add more remote sites, the initial investment gets spread out over various sites. The fiftieth site is cheaper than the first."
To remedy this problem, Cottingham and his colleagues figured out a way to get rid of the host altogether by developing a Web-based system. "We moved the intelligence of the host out to the field-the remote site," he said. "We essentially built a SCADA system with no host. The well-site RTU performs all the functions of the typical host: the data gathering, calculations, and remote alarming and reporting."
Cottingham's team effectively made the remote terminal unit a Web server. So if the user or operator wants to see his well-site data, he can use Internet Explorer or Netscape and browse directly to his well site. The computer will reveal all production data and real-time process data.
Another feature of the Web-site SCADA is alarming. When one of the parameters goes outside normal range, the remote terminal unit sends an e-mail to the operator that advises him of the well-site name and the fact that it has an alarm. The e-mail reroutes to any number of users, to a cell phone that supports text messaging, or to a pager. "We've also written a small application that will take e-mails and parse [strip out] the data," Cottingham said. "It takes real numbers and puts them into an Excel spreadsheet or database."
Cottingham said the new Web-based system will change the way people look at what is meant by a SCADA system. While Cottingham's research is geared toward the application of well sites, his team has built a second version that's more generic for monitoring any parameters. It's user configurable and opens up the possibility to other industries such as pipelines, weather monitoring, pollution monitoring stations, and irrigation systems.
Another wireless apostle is Graham Moss, general manager at Elpro Technologies in Brisbane, Australia. Moss's current research involves the aspects of wireless technology in terms of radio telemetry and radio modems. He stresses the importance of designing products to operate reliably in license-free channels, especially in the U.S., where license-free channels use spread-spectrum technology.
"Just about every product that's going to be used in process control in the next 20 years will be on a license-free band, as licensed channels won't be available," Moss said. "On a licensed channel you have protection against other users; on a license-free channel you have to accept interference from other users and still operate reliably. It's important that products are designed with this in mind."
Historical perspective
Moss refers to a lack of awareness about the differences and commonalties in radio modems and telemetry and how they come together in process applications. His presentation takes a historical stroll through the time continuum of radio devices-why they're being used in process control and the turning point of making data radios reliable through the use of the microprocessor.
In his presentation, Moss ultimately delves into the world of license-free channels. "Users who aren't experienced in radio need a product that's easy to use," he said. "License-free radio bands have only become available in the last five to 10 years for data use. It's had a big effect in industry."
Moss said the use of radio devices was a last-resort choice in process control in the '80s and '90s because of the need for radio license approval and concerns over reliability. He referred to a massive difference in radio technology in industry over the years.
"Previously each application was individually designed as a system; if you wanted to use a wireless device in industry, you had to get someone to put a system together," he said. "Now you can buy standard products and use them without having previous experience, particularly radio experience." IT
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Ellen Fussell is assistant editor for InTech.
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