英语大作业

《自动化专业英语》翻译大作业所选文字出处：选自论文《PLC的发展和应用》班级：学号：姓名：成绩：PLC全名为可编程控制器，定义是种数字运算操作的电子系统，专为在工业环境应用而设计的，主要结构由电源，中央处理单元，存储器，输入输出接口电路，功能模块，通信模块组成。

PLC具有通用性强、使用方便、适应面广、抗干扰性强、编程简单等特点，在军事、国防、航空航天、交通、工业生产中的地位，在可预见的将来中是无法取代的。

PLC有很多流派，我国的PLC研发、生产和应用发展很快，尤其在应用方面更为突出。

PLC的发展历程和主要流派在工业生产过程中，大量的开关量顺序控制，它按照逻辑条件进行顺序动作，并按照逻辑关系进行连锁保护动作的控制，及大量离散量的数据采集。

传统上，这些功能是通过气动或电气控制系统来实现的。

1968年美国GM（通用汽车）公司提出取代继电气控制装置的要求，第二年，美国数字公司研制出了基于集成电路和电子技术的控制装置，首次采用程序化的手段应用于电气控制，这就是第一代可编程序控制器，称Programmable Controller（PC）。

个人计算机（简称PC）发展起来后，为了方便，也为了反映可编程控制器的功能特点，可编程序控制器定名为Programmable Logic Controller（PLC），现在，仍常常将PLC简称PC。

PLC的定义有许多种。

国际电工委员会（IEC）对PLC的定义是：可编程控制器是一种数字运算操作的电子系统，专为在工业环境下应用而设计。

它采用可编程序的存贮器，用来在其内部存贮执行逻辑运算、顺序控制、定时、计数和算术运算等操作的指令，并通过数字的、模拟的输入和输出，控制各种类型的机械或生产过程。

可编程序控制器及其有关设备，都应按易于与工业控制系统形成一个整体，易于扩充其功能的原则设计。

上世纪80年代至90年代中期，是PLC发展最快的时期，年增长率一直保持为30~40%。

在这时期，PLC在处理模拟量能力、数字运算能力、人机接口能力和网络能力得到大幅度提高，PLC逐渐进入过程控制领域，在某些应用上取代了在过程控制领域处于统治地位的DCS系统。

在世界上200多家PLC厂商，400多品种的PLC产品大体可以按地域分成三个流派：一个流派是美国产品，一个流派是欧洲产品，还有一个流派是日本产品。

同一地区的产品相互借鉴的比较多，相互影响比较大，技术参透比较深，面临的主要市场相同，拥护要求接近，这一切就使得同一地域的PLC产品表现出比较多的相似性。

美国PLC技术的形成与欧洲PLC技术的形成是在相互隔离的情况下，独自研究开发获得的，因此美国的PLC产品与欧洲的PLC产品常表现出来明显的差异性。

日本的PLC技术是由美国引进的，因此日本的产品对美国的产品有一定的继承性。

世界上比较先进的PLC生产厂家有德国的的西门子、日本的三菱、美国的A-B公司等等。

PLC, programmable logic controller, the definition is the electronic system for digital operation, for environmental applications in the industrial design, the main structure is composed of a power supply, a central processing unit, memory, input and output interface circuit, function module, communication module. PLC has strong versatility, convenient use, wide adaptability, strong anti-interference, simple programming and so on, in the military, national defense, aerospace, transportation, industrial production status, in the foreseeable future cannot be substituted. PLC has many schools, our country's PLC research and development, production and application development is very fast, especially in the use of more prominent.The development course and main schools of PLCIn the process of industrial production, a large amount of switching sequence control, which is in accordance with the logic of the sequence of action, and in accordance with the logic of the relationship between the protection of the control of the chain, and a large number of discrete data collection. Traditionally, these functions are realized by pneumatic or electric control systems. In 1968 the United States GM (GM) following the company proposed to replace electrical control device requirements, for second years, the company developed a digital control device based on integrated circuit and electronic technology, for the first time by means of the application of electrical control, this is the first generation of programmable controller, called Programmable Controller (PC). The personal computer (PC) developed, for the sake of convenience, but also to reflect the function characteristics of programmable controller, programmable controller named Programmable Logic Controller (PLC), now, is still often referred to as PLC PC. There are many definitions of PLC. International Electrical Commission (IEC) on the definition of PLC is: programmable logic controller is a digital computing operation of the electronic system, designed for the application in industrial environment and design. It uses a programmable memory used to implement logic operation, sequence control, timing, counting and arithmetic operation in its internal storage instructions, and through digital analog input and output, and the machinery or the production process control of various types. Programmable logic controller and its related equipment, should be easy and industrial control system to form a whole, easy to expand the principle of the function of the design. From 80s to 90s of last century, is the fastest growing period of PLC, the annual growth rate has remained at 30~40%. In this period, PLC capability in dealing with analog and digital computing ability, ability of man-machine interface and network capacity has been greatly improved, PLC gradually into the process control field, replace the dominant DCS system in the field of process control in some applications. In the world more than and 200 PLC manufacturers, more than and 400 varieties of PLC products can roughly divided into three schools: a school is American products, a school is European products, there is a school of Japanese products. Learn from each other in the same area are more, the mutual influence is relatively large, what technology is deep, the main market is facing the same, advocates of close, all this makes the same region PLC products showed moresimilarity. The formation of PLC technology in the United States and the formation of the European PLC technology is in the case of mutual isolation, research and development alone, so the United States of America's PLC products and PLC products in Europe often show obvious differences. Japan's PLC technology is introduced by the United States, so Japanese products to the United States of America's products have a certain inheritance. The world's more advanced PLC manufacturers are Germany's SIEMENS, Japan's MITSUBISHI, the United States of America A-B company, etc..。