一、引言程序控制器自五十年代初期问世以来,应用日益广泛,以后相继发展了无触点逻辑控制器及矩阵式程序控制器等多种程序控制手段。六十年代末,美国通用汽车公司提出面向过程控制、适合于生产多变、寻求一种得以减少硬件费用和设计制造周期,以取代传统继电器柜的控制方案的设想,并中美国数据设备公司(DEc)研制出第一台可编程控制器,并在通用汽车公司应用成功。初期的可编程控制器是由一位累加器和一位逻辑 I. INTRODUCTION Program controller has been widely used since its introduction in the early 1950s. Various program control methods such as non-contact logic controller and matrix program controller have been developed in the future. In the late 1960s, General Motors Corp. proposed process-oriented control, which was suitable for the production changeable. It sought to find a control scheme that could reduce the hardware cost and design the manufacturing cycle to replace the traditional relay cabinet. DEc) developed the first programmable logic controller and successfully applied at General Motors. The initial programmable controller is an accumulator and a logic