Windows环境下计算机与PLC串行通信的实现

The Realization of Serial Communication of Computer and PLC in Windows

针对控制系统中上位机与S7-200系列PLC的通信,介绍了S7-200系列PLC通信方式.着重阐述了自由口通信的参数设定、协议规划以及在Windows环境下实现计算机与PLC串行通信的实现方法和Delphi下用WindowsAPI函数实现计算机串行通信的程序设计.将PLC与计算机通信网络连接起来,并实现串行通信,可以有效地提高控制系统的整体自动化程度.

In view of the communication problem between upper-computer and S7-200 series PLC,the authors introduce the communication mode of S7-200,emphatically elaborate how to set up the parameter and protocol in freeport communication mode, explain the method of realizing serial communication between computer and PLC in windows and program design with windows API function in Delphy which can realize computer serial communication.It is efficient to improve the degree of whole control system automalization if PLC is connected with computer communication network and serial communication is achieved.