On today’s industrial equipment, control systems are required to do more than manage the machine. They also give operators open access to real-time data that can be analyzed and used to improve the manufacturing process.

Open architecture controllers let you collect data such as cycle times and feed rates as well as setup and inspection times. This information then can be packaged for analysis virtually anywhere in the world. How convenient to be able to troubleshoot a machine in Brazil while never leaving your office in Michigan.

Open architecture control, simply stated, is the highly leveraged use of PC technology for control purposes. Certainly there are more highly technical definitions of the term, but for all practical purposes, open architecture today means significant application of tools from high-volume markets including Windows, PCs, and the Internet.

It’s not a new idea by any means. In the semiconductor business, PCs have controlled fabrication plants for a long time. But in the industrial environment, adoption has been increasing rapidly especially over the past five years, and U.S. automotive giant General Motors has been extremely instrumental. In 1994 General Motors along with Ford and Chrysler released the open modular architecture controller (OMAC) requirements document. The requirements in this influential document specified that open control systems must be:

• Open to allow integration of off-theshelf hardware and software into a controller infrastructure that supports a single standard.

• Economical by increasing life cycles and therefore reducing overall life cycle costs.

• Maintainable with simple techniques including support from suppliers, small spare parts inventory, and integrated self-diagnostics.

• Modular – allowing for “plug and play” of several components from various suppliers.

• Scaleable for easy reconfiguration capabilities in diverse applications.

Today, most companies thinking of adopting or supplying open architecture controls refer to these OMAC guidelines. Since the early days, many large companies such as DaimlerChrysler, Volvo, and Volkswagen have trusted their manufacturing to open architecture controls.

Windows to the future

When open architecture controls were introduced, vendors of proprietary controllers insisted that Windows and PCs weren’t reliable enough to control factories. And it’s true that Windows can’t handle sophisticated machines nor any time-critical operation. However, robot, CNC, and motion control companies have solved this problem by using the real-time operating extension, VxWin, with Windows to permit VxWorks, the popular real-time operating system, to run concurrently.

Not all desktop PCs or off-the-shelf PCs are suitable for the harsh environments of many factories. The good news is that with appropriate processes for supply chain management, product validation, product testing, and environmental testing, a PC can be made as reliable as a proprietary controller.

Open architecture products are available as software only or as controllers. Softwareonly solutions remain, for the most part, human machine interface (HMI) products, supervisory control and data acquisition (SCADA), and manufacturing execution system (MES) products where direct control of the manufacturing process is not involved. Controllers, on the other hand, typically control the manufacturing process directly, PLCs and motion controllers, for example. Many manufacturers prefer to purchase a complete controller solution from one company, a trend demonstrated by the combination of hardware and software companies such as Xycom with ASAP, Nematron with Universal Automation, and Taylor with TCP (now GE Fanuc).

During supplier evaluations, we found that high-volume companies have developed strong processes, consistently producing reliable products. Lower-volume manufacturers have difficulty yielding the same quality. A company that ships only a few thousand units can’t compete with a company that ships millions each year. The idea that low-volume proprietary hardware can be as reliable and as economical as high-volume PC hardware is difficult to believe. The successful deployment of thousands of quality PC-based controllers suggests as much.

Later, skeptics said, “Okay, maybe we can use a PC for line control, but it’s not suitable for machine control. It’s too risky!” This myth has also been dispelled over the last few years. After introducing its PCbased open architecture controller in 1996, KUKA Robotics experienced tremendous growth. Since then, KUKA has shipped more than 20,000 PC-controlled robots. General Motors has installed thousands of PC-based control systems in its plants as well. Adoption of open architecture control is accelerating. More importantly, it has become a proven technology.

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