RTC Magazine

Advances in chip integration—primarily more functions squeezed into smaller CPUs—and plummeting hardware costs have resulted in an expansion of the types and sizes of small form-factor boards used as processor control modules in automation and control. An increasingly wide variety of small modules, often PC-based, with configurable I/O and network interfaces are finding their way into automated devices. The ubiquitous x86-based PC technology is found in a wide range of standard form-factors—including PC/104, ETX, EPIC, COM Express and PMC—as well as a huge number of custom board sizes. But FPGAs are beginning to show up and, at the higher levels of control, DSPs are increasingly used.

The types of devices being automated are changing too, as control has moved outside the industrial context and into the everyday world and these devices are increasingly connected to the Internet. With such a huge range of possible designs, OEMs want as close to a “perfect-fit” solution as possible for each system—in terms of the application, time-to-market and total life-cycle costs—which is one major reason that there are so many small form-factors.

Small Form-Factors Proliferate

Designers are getting more specific about the amounts of electrical power and processing power required for the performance they need as well as application-specific I/O, physical board size, ruggedization and extended temperature operation, according to Bob Burckle, vice president of WinSystems. “Additionally, long-term availability of the hardware and initial engineering design support are key factors evaluated in order to make the decision as to what boards to buy.”

Other fundamental shifts lie behind the rise of multiple small form-factors in networked processor control boards. These include the fact that the cost of small boards is dropping rapidly, and a greater need for automation in applications where it either wasn’t needed before or less was required.

At the low end of the market are very small modules where PLC applications are moving up into the embedded space, says VersaLogic CEO Len Crane. “At some point, you can’t stretch a PLC far enough. Those folks need lower-cost, lower-performance hardware.”

In some classic automation areas programmable automation controllers (PACs) are being substituted for older PLC technology. Inside the PAC is a smaller, low-power, x86 CPU from either Intel or AMD, which can be packed into smaller form-factors, says ADLINK Technology America’s general manager Pei Chien Lee. “So the PAC is a PC inside, but it can connect to DeviceNET and CANbus networks.”

The need for greater automation has helped shift many OEMs toward the “buy” end of the make vs. buy decision spectrum. This shift has already occurred with motherboards for two separate but related reasons: the “buy” option is cheaper at the same time that the “make” option has become more expensive.

Processor modules may not be far behind on this curve, since the economics of make vs. buy has moved toward buying small processor modules that are swapped out to create a next-generation system. “At the board level this is very compelling whether you have large or small volumes,” says Steve Cooper, CEO of One Stop Systems. “The same trend applies in bigger systems, such as those based on CompactPCI Express. Bigger, compact custom systems are also going to standard off-the-shelf modules.”

But the variety of small form-factors, especially those running PC code, may have exceeded the limits of reasonableness. System design engineers want a stable platform with vendor support that will still be there a few years out. “That’s a real problem with all of these formats, except for PC/104,” says Jeff Milrod, CEO of BittWare. “The newest standard isn’t necessarily the best one. I’m going to invest in ‘old’ platforms like VME and PCI because I know they work. New technologies plus new formats equals risk squared. Take one or the other.”

More Connected MeansMore I/O

So how is networking affecting board design? Primarily in the increase in I/O on CPUs. “We’re starting to see more CPUs with more connectivity,” says Jonathan Miller, president of Diamond Systems. “For example, GPS is now being built in, similar to the way Ethernet is now included in all CPUs.”

It’s become incredibly cheap to embed an Ethernet controller in small devices, such as device servers, or even photocopiers and soft drink dispensing machines. Processor modules are coming with a wide variety of industrial I/O, such as CAN, Profibus and Device Net, as well as ZigBee. For example, WinSystems’ LBC-GX500 SBC has a wide variety of wired and wireless connectivity options (Figure 1).