Research on PLC´s communication and it´s applications on a drilling simulator

In order to solve the problem of the data transmission delay on drilling simulator, the hardware and software of the control system has been improved. In the WINDOWS environment, VC + + is used to design the host computer´s serial communication program and uses the RS232 serial port to send and receive data, PLC works in the free port communication mode and uses interrupt mode to make data transmission through the 485 serial port, thus realizes data exchange between PC and PLC in the control system. For practical purposes and under the premise of ensuring the reliability of data transmission, the communication protocol is fully simplified. In this way, the rate of the data transmission is greatly accelerated, the hardware resources of PC and PLC are fully used. This method is a good reference for improving communication performance in many industry control system that use PLC as the controller.