In respect of inconvenient use and high system resource occupation of SIMATIC NET and other commonly used OPC software packages in their practical engineering applications,this paper proposes application of InCoSol's S7A as OPC server and VB prepared OPC client to realize data information transmission between the client side and S7-300/400PLC.It is further proposed that data should be exchanged in the form of“data block”between OPC and PLC so that OPC and IFIX I/O may be integrated organically.Practice has proved that this design scheme occupies limited system resources and ensures stable communication and high data transmission efficiency.%针对SIMATIC NET等常用OPC软件包在实际工程应用中存在使用不方便和占用系统资源大等问题，提出了采用InCoSol公司的S7A作为OPC服务器，VB编写OPC客户端，实现客户端与现场设备S7－300／400PLC的数据信息的传递；同时提出了OPC与PLC之间通信以“数据块”的形式交换数据，将OPC与IFIX的I／O有机融合。实践证明，系统占用资源小，通信稳定且数据传输效率高。
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