VB与分布式监控光盘源代码第五章命令的发送和读取-VB and Distributed Control CD Chapter V source code in order to read this and

利用第三方软件（如VB）开发S7-300PLC与上位机进行MPI通讯的源码实例！非常珍贵！-The use of third-party software (such as VB) development of S7-300PLC to MPI communication with the host computer source code examples! Very precious!