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.
Ten years ago, industrial PCs just displayed control and I/O tasks on an HMI, but then they began getting ruggedized and enclosed in 19-in. racks for use on the plant-floor, which moved them closer to PLCs, says Nipun Mathur, DAQ product manager, National Instruments (NI). Meanwhile, PLCs became more open, and added faster processors, advanced analytics, and control algorithms, which pushed them toward the process automation controllers (PACs) and IPCs. So, while the PLC automated tasks for more efficiency, an increasing need for advanced control and plant monitoring requires a platform that runs both high-speed control and real-time analytics, and thats what a PC can do well.
For example, ABCO Automation, Brown Summit, N.C., reports it used a PC-based solution to develop a 14-station assembly and verification conveyor line and a 10-station final testing line for an automotive sensor manufacturer.
One method of meeting this demand in the current competitive automotive market is the ability for the more-traditional workhorse PLC-based assembly lines to be augmented by more cost-effective PC-based testing methods in order to produce a better result, reports ABCOs Kellie Hutchinson. A key factor in our projects success was the PC-based softwares OPC capability and interoperability with PLCs. The customer required that the new system be interoperable with multiple third-party modules and supplies.
Hutchinson reports that, to help the line produce its mandated one part every six seconds, NIs LabView Data Socket was integrated with an Allen-Bradley RSLinx OPC server, which allowed NIs PAC hardware to work better with traditional PLCs to provide control and data monitoring.
In addition to evolving in the direction of PLCs and carrying out their functions, IPCs also can serve independently as headless network servers, collect data from machines, and pass it up to enterprise levels, according to Siemens Aponte. We have one user that mounted our Microbox T computer in a confined space for automatic, material-handling control because he needed an IPC to control drives and motors, but still be close enough to his applications actuators, he says. This was a job that PLCs did in the past because they were the real-time devices and PCs were not, but dual-core Intel processors are allowing much more PLC-like control by industrial PCs.
Probably the most significant change in recent industrial PC technology is the increasing use of Flash memory and cards. With no moving parts, theyre much less vulnerable to many of the environmental stresses that can plague fast-spinning hard drives or their related cooling fans. Logically, less vulnerability inside a device means less need for protection outside a device. The users preference naturally is to get rid of hard drives, fans, and any other moving media, says Aponte.
Mathur adds that NIs staffers recently threw one of its Compact RIO PACs out a ninth-floor window at its headquarters while the device was in the process of acquiring data, and that it still functioned properly afterward. Compact RIO uses Flash data storage and has no rotating parts.
Fanless PCs allow for more protection and higher NEMA/IP ratings because no air needs to be moved out of the enclosure, so the PCs housing can be completely sealed, says Phoenix Contacts Falke. This type of PC can be mounted directly in a machine, such as on a pendant arm, and eliminates the need for an industrial enclosure.
At a Distance
Besides decreasing the need for protection by eliminating moving parts, developers also are breaking up traditional IPCs into separate functions. These can be prioritized, allowing some more vulnerable, less easily protected functions to be moved away from hazardous areas, which can greatly reduce costs. This also means that more resources can be devoted to protecting functions that must remain in those areas.
For instance, Wonderware recently introduced a PC that has a processor and hard drive, but no display. Its designed for machine builders who want to mount their displays away from their PC units. This allows the PC to be located in a machine panel with PLCs and I/O, but allows the operator to be situated elsewhere.
Similarly, Ke adds that Wonderwares thin-client computer allows users to view and access its HMI at the terminal/node, while actually working off a server that can be located remotely. Everything runs on the server, and the thin client just shows up as a session on it, explains Ke.
Aponte adds that industrial PCs are adversely affected by the greater speed of development in the mainstream PC realm. The span of motherboards and other PC product lifecycles are very important in how industrial PCs are able to develop, says Aponte. Typical PC models usually change every three to six months, but industrial and automation applications usually demand PLCs with a minimum 10-year lifecycle. The computer industry cant provide this, so IPCs usually have three to five-year lifecycles.
While diskless and fanless IPCs now get most of the attention, systems handling a lot of varied, non-repetitive analog data might still need hard drives, points out Derrick Lovado, embedded systems product manager, Kontron. Besides rugged chasses, some box-type or rackmount IPCs now have hot-swappable fans, redundant power, and multiple hard drives controlled in a redundant, array, inexpensive disk (RAID) system.
The typical Level 5 RAID system mostly uses three or four disks and stripes data across all of them, says Lovado. This is extremely fast, and gives each drive the data from the other. This means you can recreate any data lost by one drive because the others know what it should possess. These systems are very inexpensive now because the drives cost much less.
In addition, Stealth Computer Corp. says simply implementing the right computer board configuration can provide significant advantages. For instance, conventional PCs and IPCs locate most of their electronics on one large motherboard or main board, and replacing it means disassembling and removing all cards and cables from the system. Downtimes range from 30 minutes to several hours, and frequent model and device driver changes and scarce replacement parts can increase delays even more. With the pace of board-technology changes, its sometimes impossible to find an exact replacement. Another concern is the availability of expansion slots, because many motherboards dont have as many ISA/PCI slots as they did in the past.
Single-board computers (SBCs) contain all the functions of conventional motherboards, but are designed as single plug-in cards, which look similar to standard ISA/ PCI cards. These SBCs plug directly into the IPCs passive backplane, which simply combines ISA/PCI expansion slots into which the SBC and other cards are inserted. Available backplane configurations typically have two to 20 slots or more.