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一、系统概述 PLC产品经历了由小到大,其功能由简单到日趋复杂、完善的过程。今天已发展到可以进行复杂数学运算、逻辑判断、带模拟量输入输出、连续量PID调节、闭环控制、精确位置控制、阀门控制、温度控制等多种智能I/O功能;可以进行集中方式控制,也可以采用远程I/O接口进行分散式控制,还可以通过网络接口由多台PLC组成控制系统网络并与上位计算机通讯。它具有图像显示,打印报表等功能。最近又出现了双机热备系统,更增加了系统的可靠性。典型的PLC系统如图1所示。
First, the system overview PLC products have experienced from small to large, its functions from simple to complex and increasingly sophisticated process. Today, we have developed a variety of intelligent I / O functions that can perform complex mathematical operations, logic judgment, analog input and output, continuous PID adjustment, closed-loop control, precise position control, valve control, temperature control, , You can also use the remote I / O interface for distributed control, but also through the network interface composed of multiple PLC control system network and communicate with the host computer. It has image display, print reports and other functions. Recently there has been a dual-system hot backup system, but also adds to the reliability of the system. A typical PLC system shown in Figure 1.