Multiple choices

The many flavors of Ethernet and wireless are trendy, but it’s the underlying acceptance and adoption of fieldbuses that pushes users to find some tasty and unexpected applications.

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Multiple ChoicesBy Jim Montague, Executive Editor


The many flavors of Ethernet and wireless are trendy, But it’s the underlying acceptance and adoption of fieldbuses that pushes users to find some tasty and unexpected applications.

Is there life beyond Ethernet and wirelwess? Maybe, but don’t hold your breath. For now, these two overarching technologies and their various incarnations, sub-derivatives, and combinations seem likely to dominate the future of industrial networking—or dominate talk about it—at least for now.

Of course, their combined presence is still estimated at only two-thirds to three-quarters of the total industrial networking installed base, consisting mostly of 4-20 mA and other point-to-point hardwiring methods, even though fieldbuses have made inroads and steady increases for years. However, few observers seem to doubt the overall direction they believe networking is inexorably going to take.

So, why does everyone think Ethernet and wireless are taking over the industrial networking world, even though they haven’t conquered too much of it yet? Two words: (lots of) momentum and (a little) misperception. Ethernet’s overwhelming presence in office/business settings has long fueled expectations it will take over the plant-floor, too. If possible, the hype surrounding wireless is even more intense based on the huge savings and easy installation it’s supposed to deliver. They’re sort of like Yahoo! and Google, until YouTube and whatever’s next comes along. Everybody loves a winner and dominance’s comforting familiarity, until they get bored and root for the underdog and the novelty of a little upheaval—but not too much.   

COTS Cultivates Creativity
Distorted distractions aside, there might be an undercurrent fueling much of the buzz about Ethernet and wireless. Some observers say a critical mass of mainstream users finally is accepting the idea that non-proprietary, twisted-pair fieldbuses, Ethernet, the Internet, and wireless are practical networking methods, and that numerous users are implementing them. Not surprisingly, a rapid influx of users with unique applications and requirements may be sparking a renaissance in innovations, hybrid and combined networks, and an equally unprecedented era of networking creativity and diversity.

Mainstream manufacturing control, automation, and networking technologies long have been used to operate large entertainment stage structures and amusement park rides, as well as some engineers’ Halloween and Christmas displays. These and similar non-manufacturing applications are only multiplying faster as open, non-proprietary networks gain ground.

  London Eye

The British Airways London Eye observation wheel uses two DeviceNet networks to control its 800-passenger boarding platform.

For instance, ODVA reports that U.K.-based system integrator Fairfield Control Systems used two DeviceNet networks to help control the 135-meter British Airways London Eye observation wheel (Figure 1). DeviceNet manages the wheel’s boarding platform and synchronized gates. Fairfield implemented Rockwell Automation’s ControlLogix controller, which brings all I/O points into the system across a dual DeviceNet network that provides redundancy for I/O measurement.

In addition, non-traditional networking doesn’t always mean replacing one network with another. Users increasingly are installing new networks on top of old ones, allowing them to operate side by side or in tandem. For instance, wireless often is used to monitor its hardwired predecessors.

“In fact, the new Boeing 787 and Airbus 380 aircraft now both use Ethernet in their onboard communications and avionics control systems, but they still added their own proprietary protocols on top of Ethernet,” says Brad Booth, president of the Ethernet Alliance. “This is pretty compelling proof that Ethernet is as robust as any other physical-layer technology. Ethernet’s presence is growing in industrial networking precisely because users want these non-proprietary and COTS communications.”   

Ethernet Everywhere
While some trends have to be dug out and pieced together like clues in a detective story or pottery at an archeological dig, others just bop you on the head like a toddler with a rattle. For example, drive-time commuters and other radio listeners to WXRT 93.1 in the Chicago area on Nov. 15 heard a short ad from Home Depot offering contractors 1,000-ft. boxes of Cat 5e cable for $89. Pretty unremarkable until you realize that the copywriter and retailer didn’t even mention they were selling Ethernet cable because they assumed everyone already knows what it is! That is serious momentum. Can PLC sales at Starbucks along with lattes, biscotti, and CDs be far behind?

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