The hottest PLC programming is on the modular Road

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At present, the control engineers and technicians in the United States have begun to turn to the logic control technology of ladder PLC programming, which is a new programming technology since the programmable logic controller (PLC) was born in the 1960s

Bill Lydon, the newly appointed general manager of North America company of PLCopen station, is also an electrical consultant in Wisconsin. He pointed out that the IEC 61131 standard published by the International Electrotechnical Commission has been widely recognized in Europe and Japan. PLCopen station is the European organization that initially supported this standard. Mr. Lydon is convinced that once the benefits of 61131 standard are more widely recognized in North America, the standard will also be widely supported by North American countries according to industry insiders

The 61131 standard defines four programming languages precisely, among which the ladder diagram is drawn from the ladder logic control diagram, which is a programming language familiar to American engineers and technicians for a long time. The other three languages are instruction list, function block diagram and structure text

Dr. Kenneth Ryan, director of production automation research at Alexandria technology center in charge of automation and motion control in Minnesota, commented: "the benefits of the 61131 standard are mainly reflected in the fact that it can be used best by selecting different languages." Ryan added that ladder diagram or ladder logic control diagram can still be used, and it is also very effective for discrete logic programming, such as describing a simple pneumatic circuit action. Advanced mechanical equipment more and more combines logic control with complex motion control, then in the stepped logic control, there will be some difficult programming. The elimination method is the algorithm of removing the dial glass, so using structural text can achieve a good programming effect. When the goal of programming is to describe high-level mechanical equipment, another method defined by 61131 standard, called "sequential function diagram", can be used, and its advantages are far better than other methods

The most important advantage of the 61131 standard is that it can use any language to create function blocks and load special control function blocks into components or target software. These functional modules can also be spliced into various configurations. Mr. Ryan said, "in the engineering design stage, we can write and use these functional modules repeatedly, so we can save a lot of investment."

elau company is also widely using function blocks that meet the 61131 standard. As a dealer of packaging automation control system in Germany, it is also a part of Schneider Electric Company in France. Mr. John kowal, elau's global marketing manager, said that the company could provide machinery manufacturers and other manufacturers using its pacdrive control system with a series of products with about 400 function blocks. It ranges from temperature control function and programmable limit switch function block to complex servo motion control function block

in order to adapt to the working characteristics of the built-in manipulator for settlement in packaging machinery, elau company recently introduced a manipulator function block, which can control multiple manipulators at the same time. Mr. kowal said, "after adding this function block to the packaging machinery, the programming workload of the machinery manufacturers can be reduced by 50% - 80%. For the end users, they no longer need to add special but manipulator controllers. Because the machine and manipulator control have been closely combined, the system performance has been further improved."

in 2006, the American Automation Association will continue to work on IEC standards. Mr Lydon said that PLCopen plans to further promote this standard in North America this year. At Alexandria technology center, he saw that control system dealers were more and more interested in 61131 standard, and they repeatedly asked to strengthen customized sales force and increase the strength of engineering training projects including the standard

elau company

source: Modern Packaging

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