07KT94 ABB

There are many definitions of PLC.The International Electrotechnical Commission(IEC)defines PLC as:A programmable controller is an electronic system that operates digitally,designed for use in an industrial environment.It uses a programmable memory to store instructions for performing logical operations,sequence control,timing,counting and arithmetic operations,and controls various types of operations through digital and analog inputs and outputs.machinery or production process.The programmable logic controller and its related equipment should be designed according to the principle of being easy to form a whole with the industrial control system and easy to expand its functions.

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。