How about wireless Ethernet? The second question is easy to answer: there is no wireless Ethernet. Ethernet, IEEE 802.3, runs on wires. Yes, you will see the term. The current generations of Wi-Fi, or Wireless Fidelity—IEEE 802.11a, 802.11b, 802.11g and 802.11-2007 (which rolls up -a, -b and -g with the lesser-known -h, -i, and -j)—define wireless local area networks (LANs) that have become so inextricably linked with Ethernet that many call Wi-Fi, “wireless Ethernet.”

{mosimage} Wi-Fi is taking over a range of factory applications. Part of the reason might be called peer pressure: outside of industrial settings, there is a huge installed base of IEEE 802.11 LANs—based on the Institute of Electrical and Electronics Engineers standard—at work literally everywhere. A second driver is the direct link to Ethernet, both for environments that use industrial Ethernet and for communication with Ethernet-based enterprise IT systems.

The reasons for the widespread usage of Wi-Fi are many. First, the silicon investment is minimal on the commercial or consumer side. Chips and circuits are commodity items at commodity prices, driving equipment prices down to less than a single meal at a moderate restaurant.

Second, people like Wi-Fi and demand it in their solid-state goodies. Name any reason from sternly practical to frivolously air-headed and someone around you will be trying to connect using 802.11(x). The result is that every new laptop computer—in fact, any new device that will reach into e-mail or Web addresses—includes wireless, and the lines between cell phones, personal data assistants (PDAs), MP3 music players and wireless computers are increasingly blurred.

The upshot is that, while Wi-Fi was once a struggling new technology, it is now literally easier to log on to a wireless LAN anywhere than to avoid logging onto a LAN. In fact, the 802.11 airwaves are now so crowded that many of us (especially those on the road) spend appreciable time figuring out just which LAN we are using at a given locale. It can take many minutes to ensure that you are on the LAN you want amid all the LANs around you.

Traffic flowing on 802.11 highways is likely to be in the air around you, especially if your facility is anywhere near office buildings or family residences, or if your corporate IT embraces wireless connectivity (most do).

So, Wi-Fi is beckoning to production. Broadly speaking, there are only three responses to its siren call. The first is to simply hold off while the current recession blows chill winds through every kind of technology, especially those committed to silicon chips. It is unclear who might benefit from this approach (if anybody). For a while, there will be fewer changes to keep up with. In the vendor community, the survivors will be smaller, leaner and hungrier than last year’s (or last decade’s) boom-time participants. Unfortunately for manufacturing, at the same time, the availability of resources for custom installation will be greatly diminished—and manufacturing absolutely depends on customization.

The second is to hold off until the next generation of Wi-Fi specification, IEEE 802.11n, becomes mainstream. A new generation, 801.11n may reach finalization in November of this year. Its promise—less interference, more data throughput, possibly enhanced security—provides a rosy glow for the future, a glow that will almost certainly invite industrial needs into its warmth. More on that later.

The third is to evaluate current Wi-Fi in relation to factory needs. Then if the technology is appealing, the next steps are familiar from any network implementation: study, strategize and install.

But these are not the only responses. “Wi-Fi and Ethernet are solidly entrenched technologies, but there are better choices for applications such as sensor networks,” says Cliff Whitehead, manager of strategic applications at Rockwell Automation Inc., the Milwaukee-based automation vendor. Whitehead is co-chair of the factory automation study group of the International Society for Automation’s ISA100 standards committee, which is developing an industrial wireless standard. “Remember, radios were used in manufacturing long before computers or 802.11, or any comprehensive set of standards, for that matter. The result is that there are many point solutions involving licensed and unlicensed radio bands, cellular or any number of media for sending this or that kind of data without wires. They all work, and for some needs, many of them work better than Wi-Fi.”

If Wi-Fi is having trouble reaching into control networks, one reason is performance. Whitehead points out that performance on existing 802.11a/b/g technology is not as fast as wired. “For periodic monitoring, say every second or so, Wi-Fi works fine,” Whitehead ...