PC机与SLC 500系列PLC实时通信软件设计

为适应小型集散控制系统的需要，设计了一种利用SLC 500系列可编程逻辑控制器PLC(Programmable Logic Controller)自带的串口与PC上位机进行实时通信的解决方案。采用面向对象的设计思想，在VC 6．0调用Windows API实现上位机与SLC500系列PLC的实时通信。介绍了通信连接方式、通信协议，以及动态链接库DLL(Dynamic Link Libraries)的程序设计．提出了通信设计方案，并对通信效率进行了测试。

Design of real-time communication software between PC and SLC 500 series PLC

An approach to real-time communication between PC and SLC 500 series PLC(Programmable Logic Controller) is presented to meet the requirement of small DCS (Distributed Control System). The object-oriented design is adopted, and the real-time communication is realized with VC ++ 6.0 and Windows API. The connection mode, communication protocol and DLL (Dynamic Link Libraries) design are introduced and the communication design is put forward with its efficiency tested.