Research And Realization Of PLC Program Developing Software In NC System

Along with the compete of manufacturing industry turn worse, for strengthening the flexibility and adaptability of the numerical control(NC) system, the NC system has direct to the open type development. With the development of the performance of high speed, highly efficiency, high precision and intellectualization, the dependability of NC system should be more and more secure. The internal logic control of NC system is realized by Programmable Logic Controller(PLC). Because the hardware of PLC trend towards standardization, people focus on the design of PLC program. The current trend of PLC programming tool is program developing software based on personal computer.The NC system, designed by Hust Corporation, provides the necessary ladder diagram programming software to design or revise PLC program. But the software should be used under DOS system, which causes not only unfriendly man-machine interface, but also inconveniently operation. The main task of my research is to develop a PLC program developing system for the NC system of Hust Corporation, which provides users with an intuitionistic, convenient and high-efficient programming environment based on personal computer.At first, in this paper, the topic backgrounds are elaborated, and the significance of the research is narrated according to analysis of the problems which exit in the current research. Then, the requirements of the soft PLC platform are considered, and the overall structure of the system is designed based on software engineering and IEC61131-3 international standard. Next, developing tool and developing method that realizing the system are introduced.In the part of the paper about realization of editor, the design of user interface is introduced at first. Because ladder diagram is used as programming language in this system, so data structures and object model of class are built according to graphics programming criterion of ladder diagram. Then, the realizing methods of main functions of this system are explained in detail. In the part of the paper about realization of compiler, transformation method which to complete ladder diagram to...