vb 西门子S300PLC通讯程序,可以实现对DB数据区的读写等功能 -vb Siemens S300PLC communication procedures, can achieve read and write data area of the DB features such as

利用vb 6.0 开发分贝的采集，使用串口通信。RS232协议。并把采集的数据绘制成图形显示出来。-Developed using vb 6.0 dB collection, use serial communication. RS232 protocol. And the data collected into a graphic display drawing.