很难找的PPI通讯VB控件，实现VB程序控制PLC的启动与停止，控制V存储区与M存储区实现控制PLC的输入与输出功能。-Was hard to find the PPI communication VB controls, to achieve the start and stop of the VB program control of PLC, the control V storage area and M storage control PLC input and output func