【正文】 agram technology 512KB for user program Approx variables and signals, of them retained Cycle of 10ms or a multiple thereof Online test Loadable without service interruption ? Redundant open/closedloop control functions Synchronization via redundancy link Transmission of periodic process information between the open/closedloop control function and the peripheral elements,via the serial Ax 1703 peripheral bus. 濱州學(xué)院 專 科畢業(yè)設(shè)計(jì) (外文翻譯 ) 10 PLC的發(fā)展和未來 一、 PLC概述 可編程控制器是 60年代末在美國首先出現(xiàn)的，當(dāng)時(shí)叫可編程邏輯控制器 PLC（ Programmable Logic Controller），目的是用來取代繼電器。 ISO 157451, 1999] have been formed to fix and disseminate stateoftheart design methods, but they normally cannot participate in advancing the knowledge of efficient program and system design. A systematic approach will increase the level of design automation through reusing existing software ponents, and will provide methods to make largescale system design manageable. Likewise, it will improve software quality and reliability and will be relevant to systems high security standards, especially those having hazardous impact on the environment such as airport control, and public railroads. The software industry is regarded as a performance destructor and plexity generator. Steadily shrinking hardware prices spoils the need for software performance in terms of code optimization and efficiency. The result is that massive and less efficient software code on one hand outpaces the gains in hardware performance on the other hand. Secondly, software proliferates into plexity of unmanageable dimensions。 IEC611313, 1993。 畢業(yè)設(shè)計(jì)（外文翻譯） 英文題目 The development and future of PLC 中文題目 PLC 的發(fā)展和未來 系 （院） 自動(dòng)化系 專 業(yè) 電氣自動(dòng)化技術(shù) 學(xué)生姓名 學(xué)生姓名 學(xué)生姓名 學(xué)生姓名 學(xué)生姓名 學(xué) 號(hào) 學(xué) 號(hào) 學(xué) 號(hào) 學(xué) 號(hào) 學(xué) 號(hào) 指導(dǎo)教師 職 稱 二 〇 一三 年 六 月 濱州學(xué)院 專 科畢業(yè)設(shè)計(jì) (外文翻譯 ) 1 The development and future of PLC Part 1 PLC overview Programmable controller is the first in the late 1960s in the United States, then called PLC programmable logic controller (Programmable Logic Controller) is used to replace relays. For the implementation of the logical judgment, timing, sequence number, and other control functions. The concept is presented PLC General Motors Corporation. PLC and the basic design is the puter functional improvements, flexible, generic and other advantages and relay control system simple and easy to operate, such as the advantages of cheap prices bined controller hardware is standard and overall. According to the practical application of target software in order to control the content of the user procedures memory controller, the controller and connecting the accused convenient target. In the mid1970s, the PLC has been widely used as a central processing unit microprocessor, import export module and the external circuits are used, largescale integrated circuits even when the PLC is no longer the only logical (IC) judgment functions also have data processing, PID conditioning and data munications functions. International Electro technical Commission (IEC) standards promulgated programmable controller for programmable controller draft made the following definition : programmable controller is a digital electronic puters operating system, specifically for applications in the industrial design environment. It used programmable memory, used to implement logic in their internal storage operations, sequence control, timing, counting and arithmetic operations, such as operating instructions, and through digital and analog input and output, the control of various types of machinery or production processes. Programmable controller and related peripherals, and industrial control systems easily linked to form a whole, to expand its functional design. Programmable controller for the user, is a noncontact equipment, the procedures can be changed to change production processes. The programmable controller has bee a powerful tool for factory automation, widely popular replication. Programmable controller is useroriented industries dedicated control puter, with many distinctive features. 濱州學(xué)院 專 科畢業(yè)設(shè)計(jì) (外文翻譯 ) 2 Part 2 History of PLC Programmable Logic Controllers (PLC), a puting device invented by Richard E. Morley in 1968, have been widely used in industry including manufacturing systems, transportation systems, chemical process facilities, and many others. At that time, the PLC replaced the hardwired logic with softwired logic or socalled relay ladder logic (RLL), a programming language visually resembling the hardwired logic, and reduced thereby the configuration time from 6 months down to 6 days [Moody and Morley, 1999]. Although PC based control has started to e into place, PLC based control will remain the technique to which the majority of industrial applications will adhere due to its higher performance, lower price, and superior reliability in harsh environments. Moreover, according to a study on the PLC market of Frost and Sullivan [1995], an increase of the annual sales volume to 15 million PLCs per year with the hardware value of more than 8 billion US dollars has been predicted, though the prices of puting hardware is steadily dropping. The inventor of the