They still need hardening, according to Jeff Thornton, director of product management at Red Lion Controls (www.redlion.net/graphite).
He is talking about the kinds of environments for which Red Lion designed its new Graphite HMI. Because these HMIs must be prepared to work outdoors, the current release is housed in cast aluminum and hardened to withstand not only shock and vibration but also temperatures between -20 and 65 ˚C. “We’re working to expand that range to -30 and 70 ˚C,” Thornton says. “A tablet or smartphone won’t last long outside.”
The Graphite HMI already performs such tasks as data logging and web-based monitoring and control, but plug-in modules will expand the communications ability to include a cell modem. “We spent a lot of time testing for cross-talk noise that could possibly upset a critical function and put a worker in danger,” Thornton says.
Noise is a common environmental hazard for unhardened electronics. The capacitive screens that allow zooming by widening your fingers are also more susceptible to noise than resistance touchscreens, Thornton notes. “And if you hit them the wrong way, you might select a function you don’t want.”
Even so, other automation vendors argue that the hardening required for many industrial applications is already underway. As a case in point, take the microprocessors that B&R Industrial Automation (www.br-automation.com) puts into its industrial PCs, notes John Kowal, director of business development. Because Intel developed them specifically for laptops and other mobile devices, they withstand more vibration and higher temperatures than those made for desktops. They also draw less current and run cooler.
B&R and other automation suppliers then make the appropriate modifications to these components where necessary to harden them further. “In some cases, we’ll coat circuit boards and I/O devices in case there is a corrosive gas environment,” Kowal says.
Design engineers specify industrial casings to house the final package. Borrowing again from consumer devices, many of these casings incorporate the hardened glasses used on mobile devices. “Using a hardened glass display with anti-glare and anti-reflection increases the IP rating,” says Abdulilah Alzayyat, product manager at Bosch Rexroth.
B&R’s multitouch panels, for example, have an IP65 rating. “They look like big tablets and are using the same base multitouch technology, but we’re building them in much more robust containers,” Kowal says. With such modifications, of course, the final industrial versions are more costly than their consumer counterparts.
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