PLC控制系统设计的要点

中文翻译
PLC控制系统设计的要点(中文5600字,英文4000字)
摘要
 可编程序控制器 (可设计的控制器) 本来应简称个人计算机，为了与个人计算机的简称个人计算机相区别,一般将它简称为 PLC(可设计的逻辑控制器)。
PLC 是一个方便使用，是实行许多类型和复杂层的控制功能的基于微处理器的特殊计算机. 它的目的是适当地检测决定性的程序叁数并且调整程序操作。在操作计算机方面不熟练的人能对它进行规划，控制, 而且操作。 本质上, 一个 PLC 的操作员在一个展览荧屏之上用一个键盘画梯图表的线和装置. 产生的图画转换成计算机机器语言和作为一个用户程序运行。
计算机代替了一个过程控制所需的许多外部配线。 PLC 将会操作有开或关的输出装置的任何系统 (已知不连续的，或数字的, 输出) 。 它也能操作任何输出为变量 (模拟) 的系统. PLC 能通过开关装置 (不连续的, 或数字的) 或输入变量 (模拟) 的装置在输入端进行操作。
关键词：PLC，可设计的逻辑控制器
在自动化控制领域，PLC是一种重要的控制设备。目前，世界上有200多厂家生产300多品种PLC产品，应用在汽车（23%）、粮食加工（16.4%）、化学/制药（14.6%）、金属/矿山（11.5%）、纸浆/造纸（11.3%）等行业。为了使各位初学者更方便地了解PLC，本文对PLC的发展、基本结构、配置、应用等基本知识作一简介。

英文原文
PLC control system design elements
Submitted: ---; Accepted: March 27, 2002; Published: September 25, 2002
Pavan K. Heda 1 , Kapiamba Muteba 2 and Larry L. Augsburger 2
1 Personal Products Company, Division of McNeil-PPC, Skillman, NJ 08558
2 Department of Pharmaceutical Sciences, University of Maryland, School of Pharmacy, Baltimore, MD 21201
ABSTRACT
Originally, the PLC was represented by the acronym PC. There was some confusion with using this acronym as it is commonly accepted to represent personal computer. Therefore, PLC is now commonly accepted to mean programmable logic contoller.
A  PLC is a user-friendly, microprocessor-based specialized computer that carries out control functions of many types and leves of complexity. Its purpose is to monitor crucial process parameters and adjust process operations accordingly. It can be programmed, controlled, and operated by a person unskilled in operating computer. Essentially, a PLC’s operator draws the lines and devices of ladder diagrams with a keyboard onto a display screen. The resulting drawing is converted into computer machine language and run as a user program[1].
The computer takes the place of much of the external wiring required for control of a process. The PLC will operate any system that has output devices that go on and off (known as discrete, or digital, outputs). It can also operate any system with variable (analog) outputs. The PLC can be operated on the input side by on-off devices (discrete, or digital) or by variable (analog) input devices.