Realization of serial port communication between the PLC and the host-computer based on HostLink protocol

The HostLink communication protocol of the PLC of OMRON CJ series is introduced in this paper.The method for realizing the communication between the PLC and the host-computer is presented by means of a kind of ActiveX control named MSComm.The software design flow of serial communication between the PLC and the PC is also described.Through reading and writing of the host-computer from or to the PLC,automatic collection of field data is realized,and the device can be monitored and controlled effectively.The serial communication software is proved to be reliable and stable through the successful application in the manufacture execution system(MES).