The R&D Of LD Programming Environment For CNC

In order to meet the requirements of the machine tool factories, it's an urgent task to develop the open programming environment. The graphic programming environment has been developed in the dissertation based on the build-in soft- PLC resources and the"Century Star"regarded as hardware platform. PLC programming is simplified greatly because of the development of graphic programming environment for LD, which is more convenient for the skilled workers to design PLC application program. The development of graphic programming environment for LD is also an important support for the HCNC to occupy more markets shares. The main contents of dissertation are:The present state and developing trend to open architecture CNC system are analyzed. The requirements of the CNC to PLC are summarized, and both characteristic and merits of the soft PLC are discussed.The conclusion which both software-cell and logical relation are the element factors for LD is presented. The varied forms and types of the software-cells and logical relations are categorized and summarized. The complicated nestification between serial connection and parallel connection is studied in this part. Aim at the nestification relations, the conception of relation diagram is introduced and the simplification process of LD is illustrated.The development of graphic programmed circumstance is introduced. The compilation circumstance of LD draft and the data structure of the cell and logical relation are devised. The compiling process from LD to relation diagram and the reconstruction process from relation diagram to LD are both studied. The transitions between relation diagram and IL (Instrument List) is also studied. The execution method of soft PLC is given out.The graphic program environment is verified and explained by the examples which are the processes of the fix-pin used in NC punch and the keys on the NCKB (Numerical Control Keyboard) used in the control of axes for the"century star".