A confluence of two trends—one driven by technology and the other by customers—joined to create a new segment a few years ago called Programmable Automation Controllers (PACs). The prevailing discrete machine controller of the time was the programmable logic controller, or PLC. It was viewed as a digital version of banks of logic relays. Meanwhile, technologies developed for personal computers (PCs) became more reliable, cheaper and more powerful. The technologies included faster main processor chips, faster and cheaper memory, and more powerful programming tools. Automation technology providers began absorbing these technologies, and the venerable PLC began to morph into something new.
Meanwhile, customers were clamoring for new features and functionality in their controllers. They wanted better data handling and improved networking. They didn’t want the hassle of separate controllers—and programming environments—for logic and motion. And the new PC technologies provided the solution. Thus was PAC technology born.
In recent years, automation control vendors ranging from large players such as Rockwell Automation and Siemens to smaller vendors such as Advantech and Opto 22 have launched a raft of controller products referred to as PACs. But Schneider Electric—the Rueil-Malmaison, France-based supplier whose product families include the Modicon line that gave birth to the programmable logic controller category in the late 1960s—has stuck with the PLC moniker. But now change is in the wind.
“We looked at the definition of a PAC and saw that our controllers looked like that,” says Geoff Walker, director of automation and control marketing for Schneider Electric, in Raleigh, N.C. “With openness, communication capability, multiple languages, multitasking applications and more, our controllers are more than PLCs.”
The upshot: Schneider Electric recently introduced its first PAC product. The Telemecanique Modicon M340 programmable automation controller (PAC), extends the line of Modicon controllers begun in 1968 with the introduction of the first programmable logic controller (PLC), capable of real-time logic solving. The new incarnation not only offers real-time logic solving, but also communication, motion and database manipulation capabilities in multiple programming environments. The Modicon M340 PAC joins the Modicon Premium and the Modicon Quantum, Schneider Electric’s other automation controllers that are programmed with Unity Pro, the latest IEC 61131-3 development software. These products—previously referred to as PLCs, but now being called PAC’s by company marketing executives—comprise a full range of programmable controllers designed to affordably and effectively handle the requirements of very simple machine tasks to the most complex machine solutions.
“The original Modicon PLC sparked an evolution in industrial performance that has been fostered by Schneider Electric’s ongoing commitment to developing innovative products that are safe, reliable and easy-to-use,” says Richard Hutton, senior automation marketing specialist, Schneider Electric North American Operating Division. “The Modicon M340 builds upon that tradition and provides even greater efficiency and performance with a single development platform that uses common tagging and a single database for development tasks across a range of disciplines.”
The PAC contains 4 megabyes (MB) of internal memory (upgradeable to 16MB), 256 kilobytes (KB) data and can manage applications with up to 70,000 instructions. Communications options include USB port and Ethernet (either point-to-point or networks). Internal Flash memory and SD-based memory cards allow for data and application backup. From four to 12 modules with a maximum density of 64 channels per module can be added. Each module is designed for “hot swap” and is automatically reconfigured by the central processing unit at replacement.