CONSIDERATIONS FOR USING COTS MOBILE IN AUTOMATION
So mobile devices are part of automation’s future, and if one hasn’t thought much about it, now is a good time to start. When considering using mobile devices in industrial settings, focus on the following four factors: environment, safety, security and connectivity:
Industrial environments vary widely. Harsh environments can kill a mobile device. Drop an unprotected tablet onto concrete and you’ve got a problem. Use a smartphone in extreme heat, severe cold, or over 95 percent humidity, and it won’t last long. Water and chemicals corrode. Dust and dirt scratch and clog screens and buttons.
If the operating environment is harsh, take a look at ruggedized devices. For example, mobile device manufacturers Panasonic and DAP Technologies have developed a variety of ruggedized tablets that meet military standards (such as the U.S. Department of Defense MIL-STD-810) and/or qualify for high IP (International Electrotechnical Commission Ingress Protection) ratings.
• MIL-STD-810 covers shock, vibration, altitude, humidity, extreme temperatures, dust and several other conditions.
• IP ratings are usually two-digit numbers, the first number for dust (solids) and the second for water (liquids). For example, an IP rating of 65 means a device is dustproof and can protect against low-pressure water jets from any direction.
But many industrial environments don’t require this kind of protection. And ruggedized mobile devices are not only significantly more expensive, but also rarely match the features most appreciate and expect on personal, smart devices: multitasking, gestures beyond the basics, built-in sensors, voice recognition, cameras, communications through email/texting and more.
Personal devices are becoming more robust as well. Corning Gorilla Glass is highly scratch-, chemical- and break-resistant and is the standard screen cover glass in many consumer mobile devices.
Corning even has an antimicrobial cover glass. With toughness and optical clarity similar to regular Gorilla Glass, the company says it also reduces bacteria by more than 99.9 percent. Antimicrobial glass could be a good choice for a tablet or phone used as an HMI on machines, kiosks or walls, where many people touch it.11
Protective cases are now available to toughen off-the-shelf smartphones and tablets, too. An inexpensive OtterBox (Figure 3) — designed for personal use and available for a variety of brands and sizes — can protect against dirt and dust, a 10-foot (3 m) drop onto concrete, two tons (907 kg) of pressure, and immersion in 6.5 feet (2 m) of water for 30 minutes.12 Other solutions include low-cost field protection against water, dirt, and shock from LifeProof, and iPad stands and enclosures from Hoffman (Figure 4).13
Safety is a critical component for industrial settings. In locations with high concentrations of dust, or flammable liquids or gasses, intrinsically safe wireless devices — phones, calibrators and other portable instruments — may be required. Intrinsically safe products limit current and voltage so that they cannot produce sufficient energy to cause a spark.
In less-hazardous areas, however, COTS mobile devices are not considered a problem. In the early 2000s, a spate of reports in the press, later debunked, claimed to connect cell phone use to fuel station fires.
In response, the U.S. Federal Communications Commission wrote, “... while it may be theoretically possible for a spark from a cell phone battery to ignite gas vapor under very precise conditions, there is no documented incident where the use of a wireless phone was found to cause a fire or explosion at a gas station.”14