1、 毕 业 设 计（论 文） 外 文 文 献 译 文 及 原 文 Talks on the developmental and outlook of PLC XIA Xue-ming , JIA Ying-bu (Northern Mach-Election Vocational School,Zhangjiakou 075000,China) Abstract ： With the development of corporated circuits and technique of computers,the-fifth-generation PLC has come into being
2、Due to the advantages of stablility,reliability,cheap price ,full functions,convenient to use and easy to operate and maintenance,it has been widely used.With the network of PLC,It will be used more widely. Key words： PLC, Development, Market, Interface 1 PLC development and the market situation 1.1
3、 The history of the development of PLC 1968 General Motors Corporation proposed to replace relay control device requirements, the next year digital equipment company developed the first generation of programmable controller, the company assembly line requirements. Entered the 1970s in the 20th centu
4、ry, with the development of microelectronics technology, particularly using microprocessor PLC, This controller is not confined to the logic of the operation, has further strengthened the functional integration, now the fifth generation of PLC products. In the 1980s to the mid-1990s, the PLC is the
5、fastest-growing period, the annual growth rate has been maintained at 30% 40%. As PLC Handling capacity and network simulation functions of the progress, DCS diverting part of the gradual monopolization of the market and sewage treatment industries, but due to the emergence of industrial PC. In rece
6、nt years in particular fieldbus technology development, IPC and FCS also diverting part of the PLC market. So PLC growth rate in recent years, has gradually slowed down. 1.2 China PLC market Application of the PLC, China is very active in recent years into the new year about 100,000 sets of PLC prod
7、ucts, with annual sales of three billion yuan, and application industry are quite extensive. PLC domestic production of about 30 plants, but did not become a full-scale production capacity and brand-name products There is some imitation, component assembly or label means of production, Therefore we
8、can say PLC in China has not formed manufacturing industries. As a principle, technical and technological no difficulty in cutting-edge technology products, as long as the effort is to create the manufacturing industries. Products in the market potential is enormous, not only in our country, even in
9、 advanced industrial Japan, a survey showed that PLC supporting electromechanical integration products accounted for 42%, using relays, contactors still control 24%. Therefore, require the application of the PLC are still many occasions. From the perspective of technological innovation, Chinas large
10、 and medium-sized enterprises should vigorously CIMS (Computer Integrated Manufacturing System), factory machinery to the formation of FMS flexible manufacturing system, PLC is the foundation, so PLC market is broad. PLC with stable,reliable,cheap, multifunctional application flexibility, ease of ma
11、intenance and operation of the merits, This is it can be widely used in the root causes. 2 PLC networks and the trend One or a number of PLC and PC system out together, play PC original programming and a man-machine interface to the operating station, This 20th century, the 1990s New Wave, such as s
12、ystem integration brings opportunities Meanwhile programming software and human-machine interface software (monitoring software or configuration software) and the software interface has been developed. In recent years, the PLC CPU manufacturers in the original template provided the basis for RS232/4
13、22/485 interfaces, gradually add to the variety of communications interfaces, and to provide complete communication network. Data due to the recent rapid development of communications technology, user requirements for open very strong, Fieldbus and Ethernet technology developments, So PLC PCS system
14、 than the DCS which open some of the status quo pretty. 2001 Chinas machinery industry has become a new bright spot in industrial development, the output value last year, up 17.15%. Automobile output of the worlds top ten, machine output of the worlds No. 5. Machinery Industry profit growth 33.35%,
15、accounting for the entire industry more than 60% increase in profits. Exports also seen encouraging growth. Industrial machinery now proposed to implement the network, to this point, the PLC employees should have a sober understanding, Response Network of openness, the network constitutes the perfor
16、mance / price ratio and network reliability, safety, Special efforts on the advanced nature. 3 Summary PLC application field is wide, there are many areas in urgent need of development, such as customs transit vehicles for certification vending medicines in China has examples. In addition, discrete
17、event systems, such as the highway network traffic flow, logistics systems, Sophie OK manufacturing systems and all non-standard service with the system, can be used PLC, and then take countermeasures modeling and optimization. PLC applications will be more common. References 1 Zhaoyi Wang. Programmable Logic Controller M. Beijing : Machinery Industry Press, 2004. 2 Yefang Wang. Applied Technology PLC M. Beijing : Machinery Industry Press, 2005
