Wither Wireless OI?

Way back in 1991, Tom Mefford, an engineer at Positech in Laurens, Iowa, built a radio-controlled manipulator for Northrup to handle parts on the B2 bomber during assembly. Mefford says the manipulator rarely was used, then abandoned by Northrup.

That seems to sum up the history of wireless technology in the machine builder industry: The technology has been available for quite some time, people tried it, but nobody is using it.

Wireless control technology has been around for a long time. Not only did Mefford use it in a manipulator 12 years ago, people were controlling overhead cranes with wireless devices way before that. Wireless warehousing operations have been up and running for 20 years.

Although machine builders are still shy, vendors and end users on the process industries side of automation have been using the technology for several years. In 2001, at least one process control system vendor was supplying wireless PDA-based human-machine interfaces (HMIs). "We have to provide wireless HMIs these days, especially for compressor controls," says Roman Rammler, president of Micon Systems LLC (www.miconsystems.com). "Engineers like to walk around a compressor train with an HMI in their hand."

At the time of that report, Micon's handheld HMI (Figure 1) had been available only for four months, but Rammler said it had been partially responsible for landing several major control system orders. Now, the handheld is an integral part of the Micon product offering.

Some people find wireless technology extremely attractive, especially when long distances are involved, since running hard wiring can be expensive. "We are a system integrator that works primarily with water and wastewater utilities," says Larry Weinheimer, control engineer at Byrd Industrial Electronics (www.byrdelectronics.com). "The Wi-Fi systems we have installed involve monitoring and control of water systems including level monitoring, pump control, and security monitoring. We have deployed handheld devices into these systems, using [IEEE] 802.11b methods to access data from almost anywhere in the system."

Building automation is going wireless, too, says ARC Advisory Group (www.arcweb.com), and for the same reason. "The leading impetus for considering wireless sensors and controls for building automation applications is fundamentally to lower the cost of wiring," says David Clayton, ARC analyst.

Manufacturing operations are taking to wireless. The Toyota plant in Princeton, Ind., uses wireless monitors to observe work in process, and the Johnson Controls plant in Ossian, Ind., uses wireless HMIs on forklifts to tell operators what to pick.

Two of the most advanced HMI/SCADA software companies in the business--Iconics (www.iconics.com) and InduSoft (www.indusoft.com)--have been hawking handheld HMIs for years. They've run countless demos at trade shows with their pocket PCs and Casio PDAs. Both have had some success selling into the process industries, but not to machine builders.

PDAs certainly are a reliable, proven technology. Upward of 30 million Palm PDAs have been sold to date, and it's likely a similar number of wireless pocket PCs, handhelds, and tablet PCs have been sold. Prices for PDAs range from $299, and HMI software is readily available at reasonable prices for machine builders and similar OEMs.

For those who prefer a more industrial HMI, Rockwell Automation (www.rockwellautomation.com) offers the MobileView portable tablet PC (Figure 2). Concept Systems (www.conceptsystems.com) is introducing its PlantLinq wireless troubleshooting, alarm reporting, and machine control system (Figure 3). It's based on a standard PDA, but has software suitable for monitoring machine operations.

So, it's apparent the technology is here. Why aren't machine builders using it?

Jim Taylor, group manager for industrial automation at industry analyst Venture Development (www.vdc-corp.com), conducted a study of industrial wireless use in North America last year and he agrees that machine builders have not been using wireless.

"Our study forecast good growth in wireless operator interface terminals for use with material handling equipment, particularly conveyors," says Taylor. "On site operator interface (OI) terminals will grow to be the largest market segment for OIs in 2006, but most of these applications will not be in real-time control. Rather, the largest application for these is expected to be in mobile programming, maintenance, and repair applications. These enable personnel to monitor and interact with equipment without having to be in a fixed location."

Ralph Rio, director of marketing at ARC Advisory Group, says wireless is neither suited to nor needed for machines. "Have you ever operated a machine?" he asks. "They run at high speed and are potentially dangerous. When someone bangs on the big, red, mushroom-shaped e-stop button, the machine needs to react immediately. People feel more secure with a hardwired interface. Technically, wireless would work, but it makes people nervous."

In addition, argues Rio, an operator does not need a lot of mobility while using the controls, so what is the benefit of a wireless OI for machines?"

Taylor agrees. "One factor may be that safety considerations necessitate an operator be in close proximity to the machines at all times," he explains. "The machines are more compact, and there is a need for an operator interface near the machines--all lessening the need for wireless operator interface terminals."