What is an industrial PC? A better question these days might be what isnt an industrial PC? As the computer and its software moved into manufacturing and onto the factory floor during the past few decades, its format was changed to protect more delicate components, principally hard drives, fans, and other moving parts or accessories.
So, these desktops and laptops were armored in enclosures that separated them from heat, cold, shock, vibration, moisture, dirt, corrosives, electrical noise, and other factory-floor threats. These changes allowed users to gain data-processing capabilities, while sheltering the software and the hardware that provided it.
PCs are changing even more now. The nature and definition of PCs has evolved to the point theyre often unrecognizable from PCs of old. Sure, there are still many traditionally protected industrial PCs (IPCs), but the line separating them from other control and automation devices has faded, if not entirely vanished. This evolution makes it even more important for users to take care in selecting and implementing the most appropriate solution for their application.
White Box? Sometimes Yes, Sometimes No
Weve used and implemented industrial PCs for 20 years, and my view of todays 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, a system integrator firm in Bloomington, Ill. In general manufacturing, these usually are Dells or equivalent PCs that are partially or poorly enclosed, or often not in an enclosure at all.
Caldwell realizes there are times when PCs need to be in a professional enclosure. However, much of the former industrial PC market has dried up, and isnt what it was, argues Caldwell. Users are much more willing to use regular PCs in industrial settings because industrial systems that cost $12,000 in the mid-1990s now sell for $400. People arent afraid to use PCs because its still cheap to buy a second one.
In fact, some industrial applications, such as steel production, might replace as many as a third of their PCs every year, according to Phil Aponte, Siemens E&A HMI product marketing manager. This is costly, but its 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 shouldnt have. This is where IPCs can help.
Bjoern Falke, automation marketing manager for Phoenix Contact, adds that IPCs historically also 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 change machine parameters more easily. The entire IPC design needs to be able to withstand shock, vibration, and 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 unit, probably IP65, or an entirely dust-proof unit rated at IP50 or higher. For applications exposed to high vibration or shock, a traditional rotating hard drive can be replaced by non-rotating media.
Much of the commercial PCs form, function, power, data storage, networking capabilities, and other often-essential characteristics are now totally different. Naturally, this evolution finds its way into IPCs, whose developers add changes too.
Industrial PCs now come in more useful form factors to meet the needs of each application, whether its displaying data, collecting it, or interfacing with users, says Ann Ke, IPC product manager, Wonderware. However, what they all still have in common is a need to withstand industrial environments. Even whether you need a hard drive really depends on the application. Certain lower-end operations can just use a flash card, but 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. They still cost more, but 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 IPCs 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, Ke claims that the silicon padding added externally to the hard drive of Wonderwares industrial tablet and touch panel computer protects it from on-edge drops. Similar barrier-type protections are added to prevent intrusion by water, chemicals, and other harsh substances. Testing determines its two-digit ingress protection (IP) ratings.
In my mind, an IPC still 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 4x4-in., diskless, DIN rail-mounted computing device to an entire Dell PC tower.
Shifting definitions of IPCs makes it harder for users to find the right computer for their application, but it gives them more choices and potentially useful solutions and savings than in the past. Industrial PCs are an equal or better replacement for PLC in a lot of industrial applications, adds Falke. Users sometimes prefer the security of PLCs due to their proprietary software, which cant be corrupted easily by viruses or other PC software. Phoenix Contact says it addresses those issues with its Steeplechase VLC programmed embedded controller that offers the security of a PLC with the speed and connection options of a PC.