Based On Com Technology Open Cnc System Design And Research

Open Numerical Control system (ONC) is the trend of development in Computer Numerical Control system (CNC). Based on COM (Component Object Model), this paper studies and designs ONC system. This paper has studied the architecture of ONC system, and has built the ONC system with good openness. The method used to build the system has been introduced. Analyzing the advantage of using COM to develop ONC system, the paper designs the software of ONC system using the technology of COM. These jobs such as designing software structure, dividing the ONC software into many components, coordinating components, and programming some key components have been done. The compilation and interpretation method is used to compile the Numerical Control (NC) code. With this method, when processing, the transformation from NC code to interpolation command can be done in less computer memory. Multi-thread programming technology is used to coordinate components. The thread synchronization methods offered by windows system and by COM are adopted to make threads be synchronous. Interpolation is done in two steps: the first, computer finishes the rough interpolation; the second, motion controller finishes the exact interpolation. The method of coordinate correction and interpolation speed correction is developed to carry out closed-loop control of ONC system. By motion controller, timing card and timing controller provided by windows system, the real-time control of CNC system is implemented. In CNC system, the degree of realtime can be divided into many grades. Graded treating (different grade, different method) makes the system's operation performance better while less computer resource is used. The soft PLC is developed to finish the logic control of CNC system. The development system and the operating system of soft PLC are designed in this paper. During the design of soft PLC, some methods introduced in the following paragraph are developed and used.