Abstract: A module scheduling method is presented. It only needs precision timing in the final motion control and taking resources (data) as constraint in the software, and enables the data obtained from software computation and processing to attain the requirement of real time motion control. Based on this idea, firstly a structure model of software CNC is built to describe the operating framework of system, the module composition and the function division, and establish the initial configuration logic of the operating state of system and the real time module. Then, based on the analysis of real time scheduling performance of computer and Windows system, a software real time scheduling framework that takes task service as scheduling center and ensures timing trigger of communication signal of motion control card is given, and by combining that with the data resource constraint, a task service model is built, and the scheduling algorithm of real time module operation is given. Finally, on the basis of this framework, a software CNC testing system based on PC is developed, and the real time capability of interpolation, simulation and CNC system is analyzed, which proves the applicability of the method.

Key words: Data resources restriction, Real-time, Scheduling framework, Soft CNC