Research And Implement Of Softplc Development System Based On Open CNC System

Numerical Control System experienced the development from special and closed system to open and modular speciality since the NC technology was coming to be used. Its accessorial control function is realized by PLC (Programmable logical controller), while the traditional PLC could not achieve the requirement. So SoftPLC technology implementing the function by PC was developed. The IEC1131 international standard is the first that offered normative programming language for industrial automatic control system which was publicized by International Electric Committee in March of 1993. It accelerates the development of SoftPLC and guarantees its standardization and openness.The paper researches and analyses the interrelated technology and realized methods of SoftPLC which is aimed the development system and based on Open Architecture Numerical Controller System developed by lab. It realized mainly function of SoftPLC Development System with object oriented language C++, the Windows operating system and Visual C++ surroundings.The paper researches principle and structure of SoftPLC, confirms its function and realized methods, and carves up two parts: editing module and compiling module. Analysing five kinds of programming language prescribed by international standard IEC1131 and their peculiarities, choses Ladder Diagram(LD) and Instruction List(IL) as two programming languages of this system, and makes their instructions.At first, the research develops editing module. It contains Ladder Diagram editor, Instruction List editor and converting module from Ladder Diagram to Instruction List. Then develop compiling module. The input codes to be compiled is Instruction List, and the aim code is C/C++ language which could operate on running system. This part contains accidence analyzing, phrasing analyzing, semantic analyzing and creating aim code. At last, the research combines these modules, makes customer interface, experimented that the control function was coming true with this development system which proved its correctness and feasibility.