The Research Of The Communication Problem Between Siemens PLC And The Monitor Computer

Programmable Logical Controller appeared in the middle of 20th century,and it is produced for the request of the industry manufacture's development at that time.Now, as a common usage device in industry control, the PLC is gaining its more application fields day by day.Now in all kinds of industry automatic product line and other auto-control systems, PLC has gained its more application.In PLCs,we can use the LSI technology, micro-electronic technology and communication technology to do the engineer logical control,process control,data collection and control.The problem of communication is the actual problem always cared by the guests.Because the Siemens S7-200 PLC appeared late than WinCC which is provided by the Siemens Company,there are not communication drives for the S7-200 PLC in WinCC,and the communication protocols of the S7-200 PLC is not public.These problems cause some limits to the usage of Siemens S7-200 PLC. To resolve the actual problem,the paper particularly introduces the communication of the Siemens S7-200 PLC between the computer in free port mode, especially describes the design and achievement of communication methods. Furthermore the paper introduces the communication of Siemens S7-200 PLC and the configuration software--WinCC.I do experiments to test the communication methods,and the results is quite nice.