Program Transmission Method of PLC Equipments' Remote Monitoring Software Based on Virtual Serial Port

In order to facilitate trouble shooting and program debugging for the PLC equipment maintenance personnel when the equipments malfunction, the program transmission method of PLC equipments’ remote monitoring software based on virtual serial port is designed. And this method realizes the efficient and stable transmission of the program. This software is developed based on the MFC (Microsoft Foundation Classes) platform in Microsoft.NET, which provides users a friendly operation interface. This software makes full use of multi-thread technique and serial communication control, building the transmission structure which is made of serial communication based on virtual serial port and network communication based on the TCP/IP protocol. The design of communication protocols and the concrete realization of communication interface are given with program transmission tested in this paper.