Handheld OI Grabs Machine Control

March 9, 2009
Hardware and Software Improvements Allow for More Functionality with Handheld HMI
By Philip Burgert

While diagnostics and troubleshooting continue to be a major task for handheld human-machine interface devices, the operator interfaces also are finding wider applications ranging from robotic machine assembly controls in semiconductor and automotive manufacturing to integration of teaching pendants and logistics in distribution centers.

Innovations now being made to handheld operator interfaces will improve real machine control on both the hardware side and the software side, according to vendors. While PDAs and mobile phones are common devices, industrial-grade mobile devices, especially wireless ones, had obstacles to overcome for full deployment in the factory. The limitations included screen size, ability to withstand harsh factory environments and weight and battery life.

Harold Muma, product marketing manager for HMI hardware with Siemens Energy & Automation, says many benefits exist to using handheld operator interface devices for machine control, and he describes this as one of the fastest growing segments in the operator interface market. Growth of handheld devices is expected to be in the 50-60% range through 2011 based on current independent market studies, says Muma.

What drives this demand is the flexibility and potential reduction in cost associated with handheld devices, he says. An operator can control, monitor and diagnose machines from a wide range of locations in a facility, not confined to a stationary OI, he notes.

Rather than one OI connected to a single or several controllers locally, the OI can connect to many different controllers located throughout the facility, says Muma. These connections can be automatic or manually forced, providing further flexibility.

“The main benefit of handheld OI is machine control at the point of decision,” says Eric Eckstein, president and chief operating officer at Two Technologies. He says handheld HMI for real machine control has a broad base of use. “The handheld control allows the operator to really be at the point of action, especially for critical assembly processes or debugging processes.”

Eckstein says handheld devices in general are riding the wave of an edge-computing phenomenon. “The difference between a smart phone and a PC is really pretty much form factor and overall capability,” he says. “This allows technology to be pushed into the hands of what I’ll call ‘edge operators,’ people who really need to have computing power.”

But Eckstein notes that ruggedized systems are needed for environments that can be harmful or generally abusive to HMI devices, which should be thought of as tools. “It’s a hammer, it’s a wrench and it’s handled that way in many,” he says. “It needs to to survive shift jobs. A ruggedized tool is critical. The iPhones and Blackberries of the world wouldn’t survive a week.”

Eckstein says it’s important for untethered devices to have long battery life, including the ability of the operator to use the device all day long and not have to worry about changing batteries.

“It looks like there is a little more going on with untethered,” says Bob Mullins, industrial product manager for QSI, adding that this segment, as well as operating systems and the intelligence in the pieces of equipment involved in communicating with controllers, probably are seeing the most innovations. “Instead of relying on a controller to have all the screens and other characteristics the display unit is used for, the handheld becomes somewhat intelligent itself and can do full Windows CE operating systems—that would probably right now be more the higher end—down to dumb terminal or a standard ASCII interface,” says Mullins.

A migration is underway toward devices with enough intelligence to retain screens and provide graphics ,while moving away from character-based handhelds, he says. “It requires some additional capabilities in the terminal to be able to have touchscreens and not use bandwidth to send information,” he states.

But Mullins has more use of OI as a teaching pendant for setup operations as it is for diagnostics or troubleshooting. “Handheld comes in handy where you actually go up and hook into a machine and operate the local piece,” he says. “It’s part of a larger system but you can move or operate the local piece separately to see if there’s a problem. It’s more of a special situation than ongoing use that we see.”

Ted Thayer, automation systems product manager for Bosch Rexroth, says his company’s biggest customers for handheld OI are automotive companies that have large machines and production lines. “To get a good view of every part of the machine from a control station, it would be necessary to mount a very large number of standard HMIs,” he says.

By getting closer to the action, says Thayer, “time is reduced between making a repair and testing the fix. Also, there are fewer HMIs required to cover a machine, as a couple of handheld HMIs can be moved around.”

The downside can be cost, says Thayer. HMIs can be unplugged and plugged into different parts of a machine, but the required additional screen sets, memory and handshaking necessary to do this can add to the price, he says. “Additional expense can come with the rugged housing that is used with these types of HMIs to protect them from damage,” says Thayer, who also describes the introduction of wireless connections, allowing a much greater range of freedom in roaming with a handheld HMI, as the biggest paradigm change now occurring.

Phil Burgert a freelance writer, specializing in technical trade media.