Research And Development Of The SoftPLC System Based On Windows

With the continous development of industrial control, the shortcomings of traditional PLCgradually exposed. SoftPLC combines the advantages of traditional PLC and PC. Comparing with thetraditional PLC, SoftPLC has better flexibility, maintainability and efficiency, and thus easyintergrated into PC-based numerical control system.In this thesis, Windows OS is used as the software platform of the system. Windows is poor inreal-time perfermence, this paper proposed the method of creating a real-time kernel in Windowsdrivers for real-time extensions, and finally designed the overall structure of the SoftPLC. SoftPLC iscomposed of developing and executing module.For the design of the developing module of SoftPLC’s, after analysing the function requirementof SoftPLC’s, Ladder Diagram, Instruction List and Structured Text was identified as SoftPLCprogramming languages. An editor of PLC Ladder Diagram and Instruction List wasdesigned.Transformation between Ladder Diagram and Instruction List was implemented by active onvertex diagram and logic tree. A structured Text compiler was developed by Lex&Yacc.By studying the scan execution principle of SoftPLC and real-time operating systemrequirements, this paper designed a Windows-based driver real-time systems. The real-time platformwas built, and its real-time performance was tested. The testing result shows that it meet the real-timerequirements of SoftPLC. SoftPLC executing module was developed based on the real-time platform.The effectiveness and feasibility of the SoftPLC based on Windows is validated by a seriestesting.