Wireless Moves Forward

Nov. 5, 2009
The freedom that comes when cabling disappears has captured the imagination of industrial engineers. 
Over the past couple of years, market growth for wireless networkshas soared, as untethered nodes pop up in all sorts of new applications. Wireless technologies were viewed warily early in the decade, but that’s waned as initial applications proved that the noisy electrical environment didn’t cause signal loss. After that roadblock was removed, wireless networks have been gaining momentum like the proverbial snowball rolling down a hill. Some companies say that even in this down economy, wireless is growing at rates of 50 percent or more. Wireless networks give designers the freedom to install nodes and move them around without figuring out cable routing schemes. “We are seeing a lot of Wi-Fi (for Wireless Fidelity) used in plant floors, for example, on autonomous guided vehicles that move about a factory and can’t have wires attached to them, but still need to be able to communicate to a central control location,” says Ariana Drivdahl, product marketing manager for Industrial Wireless at components vendor Moxa Americas Inc., of Brea, Calif. The networks are moving well beyond vehicles. “We’re starting to see more wireless in applications where wires can get cut or broken and where wired networks can’t meet temperature requirements,” says Brad Hegrat, principal consultant for network and security at vendor Rockwell Automation Inc., in Milwaukee. Wi-Fi is a dominant architecture for this expansion. It leverages the advances made in commercial Ethernet, so industrial users are assured that costs will drop and technology will advance. Recent technical changes underscore the rapid advances. Earlier this year, the Institute for Electrical and Electronics Engineers approved IEEE 802.11n-2009, which increases the maximum data rate from 54 megabits (Mbits)/second to 600 Mbits/second. This may translate into a user throughput of 110 Mbits/second. Perhaps more important for the many industrial applications in which speed isn’t critical is Wi-Fi’s evolution in data security. Wireless networks offer more potential security openings than wired schemes, so industrial users are excited about recent improvements here.Wi-Fi Protected Access 2 (WPA2) provides an upgrade over basic WPA encryption, making it much more difficult for outsiders to establish a wireless path into the plant floor network. Stronger encryption techniques will make it extremely difficult for hackers and others to break in. “WPA2 sets truly difficult barriers for people who worry about authenticity,” says Eddie Lee, senior marketing manager for Moxa.  Moving to the latest data protection technologies will help plant managers stay one step ahead of outsiders who have malicious intent. “When you deploy wireless, you should constantly change the keys over a set time interval, requiring devices to reauthenticate themselves,” Hegrat says. As with conventional networks, users have to look beyond the basic technologies to address all aspects of security. Employee training is a central aspect of security.  “One of things you can do that helps a lot is to use the latest encryption standards,” says Paul Wacker, product manager for Industrial Communications at  vendor Advantech Corp., Cincinnati. “You also have to remember the human side, even with wired networks, that’s a big part of security.” Disgruntled employees are among the most likely culprits when humans hijack networks. Making sure that they can’t do damage is a key element in a security plan. One basic technique is to avoid universal passwords that allow operators into areas where they don’t normally work. They lack accountability and can be used even after an employee is terminated. Though Wi-Fi is becoming the de facto standard for wireless, it’s nowhere near the only approach. Alternative standards and proprietary schemes are both succeeding during this early stage of the wireless movement. For example, automation-components supplier Banner Engineering Corp., of Minneapolis, uses a proprietary 900 megahertz (MHz) network, saying that it has twice the distance of standards such as Wi-Fi, Zigbee or Bluetooth. It's used for applications that just send a few bytes of information, then go into sleep modes. "We install small, wireless nodes that send only a few words of data to tell the state of an input," says Bob Gardner, senior product manager for wireless at Banner. In some ways, this wireless net works like a fieldbus, gathering data that is sent up to an Ethernet backbone. "There's one place the plant where Ethernet pulls that data in," Gardner says.Related Feature - Planning Pays Off When Implementing Industrial Ethernet in the Plant or FactoryTo read the feature article relating to this story, go towww.automationworld.com/feature-6247.

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