Several years ago, suppliers of programmable logic controllers (PLCs) faced competition from a new technology dubbed “PC-based Control.” The new control promised to be “open,” flexible and revolutionary.
The PLC manufacturers didn’t stand still like their opponents evidently thought they would. They switched to microprocessors based on commercial features, upgraded their programming interfaces to contemporary computing standards and integrated motion control, information handling, networking and more into the platform. The new platform needed a new name and the term, programmable automation controller, or PAC, was developed.
The appearance of many of these new controllers is similar to the old PLCs, but the performance is not even close. Embedding all of these commercial technologies allowed manufacturers to provide more features, while keeping costs in line. Manufacturers could also economically shrink the size of the platform, giving machine builders opportunities to provide custom features to their customers while maintaining a small footprint and economical price.
Not everyone agrees with the new name. PLC was good enough before, and it’s good enough for them now. But all acknowledge the power of the increased integration of all of the functions that previously each required its own standalone box. Speed, power, size, price—when you add up all the benefits of a modern machine control platform, it’s hard to argue with progress.
For more on this subject, check out the Automation World On Demand Webcasts, “Benefits of Integrated Motor/Drive Control,” at www.automationworld.com/webcast-3581.
