technology, band and protocol has its own strengths and weaknesses, some highly relevant to applications and environments (for example, the ability of longer wavelengths to penetrate walls, foliage and the like). Many have their own history in relation to information technology standards (for example, the Ethernet-grounded Wi-Fi family) or to point-to-point sensor automation (for example, Zigbee or WirelessHart). Over time, the field of choices here, as in so many technical areas, will only grow.

Taking into consideration both the application-dependent strengths and weaknesses of various wireless offerings is clearly crucial. This planning is necessarily multi-disciplinary.

Obviously, a team approach is required, and Automation World will be exploring this and other considerations in a series of articles focusing on wireless this year. Conceptually, however, the exercise is not much different than any project that impacts the topology of a network or controls strategy—of course, with the injection of some radio expertise into the mix.

The key is to over-design the system—provide more security than you think is necessary and place radios and choose antennas to put radio frequency (RF) power where you need it. High gain and directional antennas are often the right choice.

Kevin Zamzow, business development manager at vendor ProSoft Technology Inc., in Bakersfield, Calif., suggests, “Work with rifles, not shotguns. You gain reliability by ensuring the strongest possible signals and using directional radio technology where you can. Radios are constantly increasing in speed, and equipment is increasingly able to use available bandwidth and signal strengths, so equipment trends are favorable.” Zamzow is an advocate (as are many others) of full RF audits, even when employing self-organizing networks: “You need to find the feasible distances at your plant for line-of-sight technologies. What’s feasible for the ultra-high-frequency radios that can penetrate walls and foliage? Where do you need repeaters? It’s important to pin down where there are any shortfalls, and find solutions for them.”

Interestingly, vendors interviewed for this article expressed a spectrum of opinions as to the current state of wireless automation. Some see wireless as just moving into the automation mainstream. Others, defining the domain as widely as possible (thus including radio frequency identification, or RFID, radio-based SCADA and other, older technologies), feel that wireless usage is already widespread. At least the technology is, for the most part, well-established.

The future of wireless in automation runs the gamut from new things in the low bandwidth range (for example, forthcoming equipment built to the WirelessHart specifications) to emerging broadband realms such as WiMax and ultra-wideband (UWB). WirelessHart builds on international standards, including the Hart protocol (IEC 61158 from the International Electrotechnical Commission), EDDL (IEC 61804-3), IEEE 802.15.4 radio, and frequency hopping, spread spectrum and mesh networking technologies. WiMax and UWB are still settling out, but hold promise for applications that require the highest speeds and data rates.

Cliff Whitehead, manager of strategic applications for Milwaukee-based automation vendor Rockwell Automation Inc., put it this way: “The best approach is to take an outside-in view—that is, don’t focus inside the labs on research and development, but on how people really want to use the technology. We haven’t begun to think of all the uses for wireless automation.”

For more information, search keyword “wireless” at www.automationworld.com.