it is usually need to supervise and control gathering data and working status of plc in industry control.there are some ways such as vb,delphi,pb to carry out the requirement.visual c++ is an exploiture tool for windows application program and has quite strong function in the aspect of image processing and database managing etc.it has faster speed to realize bottom communication control.using visual c++ and mfc,the authors implement the serial communication system between pc and plc.the paper introduces the communication protocol and software design method and realizes data's sending and incepted rapidly,real-time auto-control accurately and quickly.this system is simple,economical,and reliable and has an application value,which has been applied successfully in real system.
