PLC介绍(英文).doc

PLC introduced The graduation project topic is the application of PLC in the servo servo system, the PLC application and understanding of the graduate design, following the basic knowledge of PLC to make a brief introduction. The PLC can be programmed controller is the new industrial control devices based on computer technology. The PLC in the PLC draft standards issued by the International Electrotechnical Commission in 1987 made ??the following definition: the PLC is a specially designed for applications in industrial environments digital computing operation of electronic devices which can be programmed memory, with to implementation of the logical, sequential operation, timing, counting and arithmetic operations, such as operating instructions in its internal storage and can be digital or analog inputs and outputs to control various types of machinery or production processes. PLC and its related peripherals should be easy and industrial control systems to form a whole, easy to extend the principle of functional design. A.PLC features (a)High reliability, strong anti-jamming capability High reliability is the key to performance of the electrical control equipment.PLC is due to the introduction of modern LSI technology, strict production process, the internal circuit to take the advanced anti-jamming technology, with high reliability. For example, the Mitsubishi F series PLC MTBF up to 300,000 hours. Redundant CPU PLC, the average time between failures is longer. From a machine outside the circuit of the PLC, the PLC constitutes a control system, and compared to the same scale relay contactor system, electrical wiring and switch contacts have been reduced to hundreds or even thousands, the fault will be greatly reduced. In addition, PLC with a self-detection of hardware failure, failure to timely alert. In the application software, application can also be incorporated into the peripheral devices and fault diagnostic procedures, also received the fault self-di