Research And Development Of Running System Of Soft PLC Based On Open CNC System

The software and hardware of the CNC system have been greatlyenriched because of the developments in computer technology. As aresult, the open CNC system has become a research hotspot in the fieldof manufacturing throughout the world. The PLC embedded in the CNCperforms the main part of the M, S, T functions. In other words, the PLCis mainly responsible for the auxiliary functions in CNC system.Traditional PLC cannot meet the requirements of openness, so the openCNC system usually needs soft-PLC technology. Soft PLC is based onPC, which controls the process using software, and it is one of the keytechnologies of the open CNC system. The thesis researched soft PLC inthe CNC system using the IEC61131-3standard to enhance the functionof the open CNC system.In order to develop a soft PLC to complete the auxiliary functions ofthe CNC system, the paper researched the principle and technology ofsoft PLC following the IEC61131-3standard. The research was basedon the new CNC in the ceramic rapid prototyping machine in ShaanxiUniversity of Science and Technology’s NC laboratory. Becauseobject-oriented C++language specializes in encapsulation, inheritanceand polymorphism, the Windows operating system and Visual C++were chosen as the development tool to design the soft PLC. This SoftPLC could meet the requirements of the new CNC in the ceramic rapidprototyping machine.First of all, according to the work principle and traditional PLCstructure, and analyzes the function of soft PLC should have, and based on the analysis of the general framework of soft PLC, focuses on thedesign of the development of the system of soft PLC system andcompile module. Compile module based on PLC program source codefor instruction table, using the Flex and Bison automatic generationsoftware, will dictate the table program after lexical analysis,grammatical analysis, semantic analysis of the last set object codestored in design good decode results in the buffer zone.Second, soft PLC of the running system design USES is the virtualmachine design train of thought, the working process of the simulationhard PLC. Soft PLC virtual machine is divided into speed of the twologic programming, virtual machine is actually the two logical programscheduling and switching. In this paper the design of virtual machineread in similar assembly language object code of assembly technologywill target after code conversion for is hex files, virtual machineloading hex file to explain implementation. By using the dynamic linklibrary technology (DLL) complete development system and operationsystem of communication function.