利用FETCH/WRITE方式实现计算机和西门子S7 PLC直接通讯

摘要

Several communication modes between Siemens S7 PLC and computer system are introduced focusing on the configuration, principle and message format, etc. of FETCH/WRITE communication mode. The principles, program flow chart, multi-threaded operation of the TCP/IP Socket communication of computer communication module and how to use VC++2005 to integrate the whole module are also described.%介绍了西门子S7系列PLC和计算机通讯的几种方式，着重FETCH/WRITE通讯方式的组态配置、原理、报文格式等内容；同时描述了计算机通讯模块的TCP/IP Socket通讯的原理、程序流程图、多线程操作、以及如何利用VC++2005实现整个通讯模块。