PC is used for industrial control
PC has massive memory, open network connection and lightning processing speed, which has been proved to be a good alternative to traditional programmable controller
in the past few years, control users have had good reasons to begin to doubt such a reality: there are two competitive fronts in the industry, and some say that PCs can be well used for control. Some people say that PC is never suitable for factory environment. Today, these competitors easily accept the current situation that PC is used in many industrial production controls: from machine manufacturing and material processing to car body painting
one manufacturer after another is adopting PC control scheme in at least part of production. In the Audi workshop in neckarsulrn, Germany, D ü RR, a builder of the car painting workshop, wanted to experiment with two new basic concepts. The first is to install the specially prepared distributed and intelligent control module directly on the machine, rather than in the protected control room. At the same time, he hopes to integrate the control system and safety system --- realized by fieldbus such as PROFIBUS
the risk of automation innovation cannot be underestimated, especially in the field that has always believed that human skills are indispensable - no one is more demanding on car painting than German automakers. They said that even the air around the painted cars should be strictly controlled. In fact, for each car passing through the factory, the temperature increase and decrease of each painting to ensure the heat emission of electromechanical work are also different
the control system of Audi paint shop takes PC as the host, and is connected with the intelligent modules installed on the site, including a complete set of safety systems on the same PROFIBUS bus bus
then, what is the best way to combine these new automation concepts and apply them to the highly organized process control? D ü RR made an amazing choice: PC based automation
the final control system uses PC as the main controller and is connected to the Profibus network composed of specially reinforced et200x modules. These modules are not installed in the control box, but directly installed on the controlled functional unit. In order to protect operators, a PC on the same Profibus network controls a series of ET200S safety integration modules. Power is supplied to the remote motor module through the 400V power bus. D ü RR's motto may be "abandon the control room"Another big advantage of the D ü RR approach is that the established module system can be easily copied in subsequent projects. In fact, the company hopes to take PC based control as its standard solution
Eberhard Vogler is responsible for the control technology of Audi paint shop. He noticed that distributed intelligent control brought great flexibility. "The technology of the paint factory must be constantly updated. New paint and new models require continuous modification of the production line." However, "the test also has limitations. Audi believes that stopping the production line is prohibited."
however, one year after using the new system, he was very satisfied with the results. "PC based control has been talked about, but it is important for us to test the potential of this technology trend."
he said that Audi imposed very strict test conditions on the new system. Before the system is integrated into the production line, it usually requires 24-hour continuous test run. During the test run, it must be 99% effective
vogler said that PC based controllers have proved to be as reliable as PLC at every point. And passed even more important test: accepted by operation and maintenance personnel
PC based control, commonly known as' soft 'control or' soft 'logic, has been trying to enter the field of industrial control for more than 15 years. To the dismay of some traditional automation suppliers, PC control has begun to be applied in this field. PC supporters claim that their system is easy to install and use, with advanced diagnostic functions, providing system integrators with more flexible options
in the long run, the maintenance cost of PC control system is low. Mike kleinshuo, the founder of steelchase software, said, "even if you give PLC for free, you can hardly afford their maintenance costs."
programmable controllers are the most threatened by PC control, so they are very uneasy about the application of PC. "The PC control market has not yet started," said Mike miclot of Rockwell Automation. "It is not a spacecraft, but a B-52 bomber."
traditionally, people who insist that PC is an office machine and is not suitable for the dusty environment of factories are also changing their minds and may accept new ideas. In the past few years, PLC providers have actually joined the PC control "wave" - in their own words, this is inevitable
of course, the impact of PC on the enterprise computing market should not be ignored. Tens of thousands of PCs are entering enterprises, from reading bar codes to being used as a testing and measurement platform. Although these PCs are not machine controlled, their use is indispensable in the new IT era
pc is really suitable for control
driven by the upgrade of Windows operating system in the 1990s, PC swept the office. And improve work efficiency. By the end of the 20th century, thousands of typewriters had become relics of the past
some people fantasize that PC will have a similar development in the manufacturing industry. To some extent, it is true. PC based control has successfully entered both ends of the market: machine tools and process automation. In CNC (computer numerical control) applications, PC helps to organize the highly complex and multi axis motion contours required by machine components. At the other end of the control field, Windows NT workstation replaces the huge console of the distributed control system to monitor and control oil refining, chemical plants, and paper mills. Before PC, these two markets have been dominated by closed and proprietary systems, which is not conducive to users
but this is in the broad middle of industry. In the field of production machinery control, PC has gained the largest market share. After all, programmable controllers are almost as old as electronic typewriters. Especially in the United States, hard wired electromechanical relay circuits that can even be traced back to the pre war era are still used. Open PC following Ethernet tcp/ip network protocol has obvious advantages over PLC. This led observers to expect double-digit growth in the industrial PC market when the economy overheated in the late 1990s. A new era is about to begin
"from the mid-1990s to now, some long-standing beliefs in e-commerce and e-manufacturing have disappeared", Lance Gordon, an industrial analyst at Frost & Sullivan, said, "there is no upper limit to technology", "there is some invisible speed limit for the development of industrial automation. Control technology may not have to reach Moore's law"
in fact, the performance of PC control does not double every 18 months. There are two basic reasons why PC does not replace PLC. In the United States, many PC innovators start small companies. They mainly develop software, which is where the business model is wrong. No matter how important soft logic is. It accounts for only 5% of the total automation project. As most PLC companies are familiar with, about 50-60% of the cost is in i/o and motor drive. Industrial PC may account for%. Even if the soft logic company has achieved great success, it still has to face the integration problem; Obviously, 40% of the cost of automation projects is software. How can we expect the company that sold 5% of the shares to undertake 40% of the project
the manufacturing industry itself is clear: they want to buy the whole system. Instead of scattered parts; It is not advisable to buy a PC here, a software package there, and an i/o bus in another place. Moreover, Windows NT also has problems. Windows NT (and later Windows 2000 and XP) may be the favorite of software workers, but it is a big problem for the bottom control of the factory. NT is too heavy for computers in factories; Computers need hundreds of megabytes of disk space, and in industrial sites, it is hoped that there are no rotating parts; Slow reaction speed; Uncertainty, etc. If NT is used for control, coprocessor board may be added; Expand real-time performance, or modify the kernel; In other occasions, NT is only the window you see, and the real operating system is in the background. Worse, soft logic companies confuse the market with various definitions of 'hard' and 'soft' real-time control
"modifying the control system of Windows NT in any way is no longer considered an open structure", said Mike miclot of Rockwell. "This is a proprietary PC control system with its own limitations and support standards." The new hope of PC control is Windows CE operating system. It takes up very little space and has real-time performance. Industry has seen wince products
the most famous successful cases of PC control come from General Motors' powertrain manufacturing base in Detroit. There, more than 300 pcs distributed in more than a dozen factories work on the machine production line every day. The ladder logic PLC has completely disappeared, and the OEM that provides new machines to powertrain must meet the PC control indicators
John Dunlap, marketing manager of nematron Corp, explained, "for GM, the key benefit is the flow chart software used by PC." It was first introduced by the hydra matic plant in Warren in 1986. Engineers were surprised by the transparency of the software and the advanced diagnostic capabilities it provided, and the downtime was much less. This technology was immediately extended to other factories. "But in fact, it is difficult to accurately get the value with less time. Because powertrain regards it as the main competitive advantage, it is shrouded in a mysterious atmosphere." Dunlap said
nematron got the software from Ron lavallee, the inventor of flopro, in 1994 to run it under Windows NT, and added its own hyperkernel program, which can divide NT into time segments with 250 microseconds interval to ensure real-time response. "Pentium III can handle 4000 i/o in 250 microseconds," Dunlap said. The combination of flow chart software and nematron's rugged industrial PC has been widely accepted in powertrain
another entity, located in Ann Arbor, the flow chart software center of the United States, is a merger of the previous steelchase software company and think and do company. It is now partially owned by Schneider Electric. Mr. Ken Spenser, who has rich industrial experience, once led the industrial automation department of Texas Instruments as president and CEO before it was sold to Siemens. Although the origin of the two software products of entity is different, entity studio and visual logic controller are both based on flow charts and have entered hundreds of different applications in various industries. The station () of entity has particularly good content to illustrate the powerful functions of flow chart software and its applications in various industries. But entity and other PC control software companies face the same problems. What users really want to buy is a complete system, not just a CD. Where can entity get an industrial PC production line
phoenix contact, another company in the field of industrial automation, is largely due to its INTERBUS bus products. The two companies are now partners. Phoenix provides PC and network hardware, and entity provides flow chart software and programming support
phoenix contact has its own software control product production line, PC Worx software package. This is mainly based on k&w s proconos IEC software (Phoenix has some property rights). But entity's flow chart software broadens its vision
larry komarek of Phoenix contract said:
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