西门子S7-200 PLC在自由模式下与计算机的通信

Communication between Computer and Siemens S7-200 PLC under Free-Mode

阐述了西门子S7-200PLC以自由模式与上位计算机进行通信的方法,着重讲述了通信协议的指定以及PLC参数的设定、程序的设计方法和通信数据的校验方法,最后介绍了上位机运用Delphi语言和采用MSComm控件进行的程序设计。

The communication between the host computer and S7-200 PLC under free-mode is described. The assignment of communication protocol, settings of parameters of S7 - 200 PLC, and design method of the program as well as the checking method of communication data are expounded emphatically. The program design with applying Delph language and MSComm control in host computer is introduced.