Research on the remote monitoring and controlling based on VSP

Traditional PLC software about programming and monitoring all were designed in serial port debugging mode based on local. So the remote monitoring and controlling function couldn't be realized in the mode. In the article the virtual serial port (VSP) technology was imported into the system and it turned the PLC serial port software from local control function to remote one. In the system, the real serial port was replaced by virtual one. The client captured the command frames getting across the VSP, and then the instructions were sent to server through internet. And server program transferred the command to PLC by real serial port of local upper computer and correlation datum backtracked after PLC response. The Cx-programmer (Omron PLC software) was applied in the experiment and the ladder of Cx-p come into being switching on and disconnecting by returning datum. And according to the changes, the running state of local equipments could be known. This system was debugged by the experiment successfully.