All Quiet on the Wireless Front

End users are overwhelmingly voting with their feet—and their dollars. All that's left is to carry off the dead and treat the wounded. As we do on a regular basis, we've surveyed our readers, and we've talked to vendors, gurus and end users, and we've put together an objective picture of where things are and where they are likely to be in the short term and near-long term.

For the record, the survey was conducted in June 2011 and received responses from over 900 respondents, of whom 92% were end users, consulting engineers, A&E or EPC engineers, or system integrators. Responses were similar to ControlGlobal.com's demographics, with somewhat less than 47% from North America (Canada, U.S., Mexico) and roughly split 10% from EMEA (Europe, Middle East, Africa), 5% from Central and South America, and the balance from Asia.

What a Long Strange Trip It's Been

If you're of a certain age, you recognize this line from "Truckin'"—one of the most popular Grateful Dead songs of the 1970s. The song is old, but the sentiment isn't, as far as the use of wireless is concerned. For the past five or six years, we've been paying much more attention to the war over wireless field network standards than we probably ought to have. As we have strained at gnats and swallowed camels in the standards bodies, the end users have been studying the situation, making decisions and starting to implement their wireless strategic plans (Fig. 2).

We expected, as we have in the past surveys, to see a lot of hesitation based in part on the outcome of the standards conflict. We found, somewhat surprisingly, that over 43% of those responding to the survey said they already have been using wireless field networks, and another roughly 27% said they are thinking of using them in the next one to three years (see Fig. 1). That's remarkable penetration of a market that appeared to be mired in controversy just a year or so ago. Only about 11% said they were undecided about which protocol to use and were going to wait to see which one won.

When asked which wireless networks these pioneers use now, their answers were revealing (Fig. 3). Over 50% said they used 802.11x networks for wireless communications. 34% said they used one or more proprietary wireless networks. The use of IEC62591-WirelessHART continues to grow at 23%. Bluetooth networks came in at a surprising 18.2%. We suspect that these are probably being used with smartphones or tablets—but several respondents commented they were using Bluetooth-equipped HART modems. ISA100.11a devices and networks lost ground substantially since our last survey, coming in at 4.4%, and Zigbee was the last of the pack at 1.47%.
So the lineup looks to be 802.11x networks supplemented with Bluetooth for wireless communications, IEC62591-WirelessHART and several proprietary field sensor networks for devices. Most vendors and end users are betting on that lineup.

Wireless Sensor Networks Now

"If you are actively buying wireless sensors now, which protocol are you using?" we bluntly asked our readers. Once again, proprietary networks and WirelessHART led the pack for field devices, while 802.11x networks were the choice for wireless communications.

Since last year, the number of wireless field device vendors has soared. There are several ISA100.11a device vendors, and there are over a dozen WirelessHART device vendors. This bodes well for bringing the price of wireless devices and gateways down. Several respondents complained that the price of wireless devices was so much higher than the wired variety that they weren't happy. "We have not found a case where it is cheaper to deploy [wireless]," wrote one respondent. "Cost is a concern," wrote another. "We're not using wireless field devices primarily because we are a 30-year-old plant that only adds or replaces a few transmitters per year. We already have wires where we need them, and if adding a few new devices, it's still cheaper to pull cables than to do the engineering and install infrastructure for a wireless network," another respondent wrote.

So what applications are end users actually deploying wireless devices for? 61% of respondents said they were using them to extend the plant information network with traditional sensors (flow, level, temperature, pressure, etc.). 39% said they were using wireless devices to improve maintenance. 24% said they were using them to improve worker safety with man-down, location, gas detection and remote alarms, and 23% said they were also using wireless devices to extract non-traditional process values. A wildly pioneering 6.48% claimed to be using wireless devices for ESD and SIS systems.

One respondent said his plant was creating an "alternative field monitoring infrastructure for control-centric platforms." Others cited remote-location monitoring, long-distance measurement, barcode information gathering, inventory control, rotating device monitoring, shop floor tracking, and vibration waveform data. Of course, they also are using wireless devices for more traditional applications, such as tank gauging, weigh scales, control valve actuators, and to supplement so-called "soft sensors" for EPA-mandated environmental monitoring systems (Fig. 4). One respondent cited automating operator rounds through the use of increased wireless field sensors. One respondent said, "We are in the process of implementing WirelessHART in our facilities for improved monitoring and to release I/O due to limitations on points [Editor's note: emphasis added]."