WinCC与S7-200 PLC通信数据初始化的实现

Initialization of Communication Datum Between WinCC and S7-200 Series PLC

使用EM277模块基于Profibus协议,WinCC与西门子S7-200系列PLC通信时,一个地址对应的数据在上位机与PLC之间传输只能是单向的。介绍了通信的数据传输结构,提出了VB-Script从数据库读取数据和通过自定义协议在上位机刚启动时从PLC读入数据两种解决方法,并对这两种方法的优缺点进行了分析。

The transmission of data associated to one address between host computer and PLC was just unilateral during communicating between WinCC and SIEMENS S7-200 series PLC which based on Profibus protocol via EM277 module.Introduced the structure of data transmission.Proposed two resolving methods：one was reading data from database using VB-Script,and the other was reading data from PLC when the host computer just starts through self-defined protocol.The merits and demerits of them were analyaed.