WHAT IS AN industrial PC? A better question these days might be what isn’t an industrial PC? As computers and their software moved into manufacturing and onto the factory floor over the past few decades, they traditionally needed to protect their more delicate components, principally their hard drives, fans, and any other moving parts or accessories.
So, of course, these desktops and laptops were armored in enclosures that separated them from the heat, cold, shock, vibration, moisture, dirt, corrosives, electrical noise, and other threats always so common on the plant floor. These protections allowed users to gain PCs’ data-processing capabilities, while sheltering their information, software, and the hardware that conveyed them.
Much has changed since PCs arrived on the plant floor, however, and even more is changing now. The very nature and definition of PCs has evolved, so that they’re often unrecognizable from the PCs of old. Sure, there are still numerous traditionally protected IPCs, but the line separating them from other control and automation devices is completely blurred, if not entirely gone. This evolution makes it even more important now for users to take care in selecting and implementing the most appropriate solution for their application.
“We’ve used and implemented industrial PCs for 20 years, and my perception of today’s controls market is that a large percentage of industrial applications are using low-cost, white-box PCs, and that many are working just fine and achieving long lifespans,” says Rick Caldwell, president of SCADAware Inc., a system integrator in Bloomington, Ill. “In general manufacturing, these are usually Dells or equivalent PCs that are partially or poorly enclosed, and often not in an enclosure at all.
“Of course, there are times when PCs can’t serve alone, and where they still need to be in a professional enclosure. However, much of the former IPC market has dried up, and isn’t what it was. Users are much more willing to use regular PCs in industrial setting because IPC systems that used to cost $12,000 in the mid-1990s are now selling for $400. So, the costs are such that people aren’t afraid to use PCs because it’s still cheap to buy a second one.”
In fact, some industrial applications, such as steel production, may replace as many as a third of their PCs per year, according to Phil Aponte, Siemens’ HMI product marketing manager. “This is costly, but it’s better than risking a critical, onsite failure,” he says. “Some users have had to shutdown their facilities because they used off-the-shelf computers when they shouldn’t have done it. This is where IPCS can help.”
Bjoern Falke, Phoenix Contact’s automation marketing manager, adds that IPCs also historically offer legacy connection options, such as ISA bus and parallel port, industrial-grade mounting options, and touchscreens to eliminate the need for a keyboard and easily change machine parameters. “The entire IPC design needs to be able to withstand the shock and vibration, as well as the EMI noise levels, found in an industrial setting,” he says. “Besides high immunity to electrical noise, users mostly need a dust-proof, water-tight front-bezel, probably IP65, or an entirely dust-proof, such as IP50 or higher. For applications exposed to a high amount of vibration or shock, a traditional rotating hard drive now can be replaced by a non-rotating media.”
Despite declining prices, or perhaps partially because of them, many PCs’ forms, functions, power, data storage, networking capabilities, and other once-essential characteristics are often totally different now. Naturally, all of this evolution is finding its way into industrial PCs (IPCs), whose developers are adding many innovations of their own.
“Industrial PCs now come in many more useful form factors to meet the needs of each application, whether it’s displaying data, collecting it, or interfacing with users,” says Ann Ke, Wonderware’s IPC product manager. “However, what they all still have in common is a need to withstand industrial environments, so the production lines and processes they’re linked to don’t break down. Even whether you need a hard drive really depends on the application. Certain lower-end operations can just use a flash card, while doing HMI on the plant floor, collecting data, or running a SQL database or historian really needs a hard drive. Solid-state drives are available, which Wonderware has as well, but they still cost more, though they might be worthwhile for some applications.”
Typical environmental stresses for IPCs include temperature, which usually is countered with heaters below 0 ºC and with ventilation above 50 ºC. Next, an IPC’s internal components are rated to withstand certain levels of shock and vibration, and then more shock-absorbing protection is added to each system. For example, the silicon padding that Ke reports is added externally to the hard drives of Wonderware’s Industrial Tablet and Touch Panel computers reportedly protects them from on-edge drops. Similar barrier-type protections are added to prevent intrusion by water, chemicals, and other harsh substances, and testing determines their two-digit ingress protection (IP) ratings (see sidebar).
“In my mind, an IPC is a 12-15 in. panel-mounted computer with an enclosed front and back end that can sit anywhere,” says Caldwell. “Now, an IPC can be everything from a 4 x 4-in., diskless, DIN rail-mounted computing device to an entire Dell PC tower.”