and speed requirements.”

Standards-based devices promise easier integration of multi-sourced equipment, as well as easier implementation compared to proprietary wireless devices. Becker asserts that any system selected for industrial plant use should support Wi-Fi and wired Ethernet, and have a migration path to the ISA100 standard.

On the hardware side, chip-based embedded wireless frees the primary circuitry of a device to concentrate entirely on specific control strategies. “Chips allow device developers to focus on device functionality and free up device CPUs (central processing units) for the task at hand,” says ConnectOne’s Resh. “Chips can offload the transmission elements, including runtime radio requirements or Ethernet and Internet connectivity.”

Even if your current needs call only for relatively time-insensitive reading of sensors, plan for future open-loop control requirements. “It is far easier to use a control-ready system for monitoring than it is to be forced to upgrade a monitoring-only system in the future,” Becker points out.

Crucial for battery-operated equipment are ways to predict current drain and thus determine maintenance intervals. Downtime for a surprise battery swap is not the happiest of ways to allocate production time.

“Application interfaces are usually driven by their respective departments,” Becker says. “And many users want to bring information coming from their wireless devices into their existing legacy applications and protocols. Having the ability to network easily with legacy applications is ideal, and it allows the network to service the entire operation—not just single departments.”

Plants experience changing environments, and because wireless can be affected by transient line-of-sight problems, implementations need to consider such elements as traffic, and rain and snow. A sunny-day installation on a quiet day can become difficult when a parade of trucks is filing into the docks or an afternoon thunderstorm rolls in.

Network security is one thing—and is an element controlled by any standard worth its salt—but radio security is a final consideration. “If you’re located in a populated area, remember that any housing structure could have considerable consumer box-store wireless,” cautions Becker. “You’ll need more selectivity on antenna design in this setting, and you’ll want to beam your own RF inward as much as possible, using directional technologies.”

The last word? Not for a long time

Wireless industrial and control networking is a reality, but has the technology reached maturity? There is no single answer. Radio technology is mature, of that there is no doubt. Spectrum and mesh management is a mix of old and new. One by one, production personnel come to experience wireless first-hand, and most become, if not out-and-out evangelists, at least converts. If industrial wireless follows the path of IT and consumer wireless, then we are on the edge of an explosively expanding production approach. But—just to inject a little chill of reality—manufacturing is not an area in which little glitches or nagging headaches can be long tolerated. To the extent that wireless devices can avoid these, they will flourish. Stay tuned.

>> Listen to Gary Mintchell’s podcast conversations with Dust Networks’s CTO Kris Pister at www.automationworld/view-3875 and Honeywell’s Jeff Becker at www.automationworld.com/view-3697