The Design Of Software Cnc System Based On Windows Real-time Extension

Computer Numerical Control (CNC) technology has been playing an important role in the development of a country's economy. The controller performs the automatic control of a CNC machine tool, which is the brain of the system. A research on the motion controller is significant.The traditional numerical control systems commonly used"PC + special NC controller"structure model, this structure mode, although also belongs to the category of open CNC system, but the system compatibility is bad, functions is hard to expand, human-machine interface is not flexible, lack of communications and networking. The new direction of development is to establish a modular reconfigurable flexible system structure.This research object is soft CNC system, is a kind of method based on the real-time extension of Windows. Compared to the conventional structure mode,the main advantage is that all the real-time and non real-time data processing tasks processed by PC, the hardware part only responsible for signal conversion and transceiver, the structure is simple relatively, easy to maintain, and do not need to translate complex data between PC and NC controller.For the Windows operating system is based on equality, each task is equally to use CPU, can't satisfy the numerical control system for real-time tasks which need to use CPU exclusively, this paper introduce a method that used bottom driver to process real-time task. The bottom driver running at ring 0, the priority is more than the non real-time task which running at ring 3. So this method can satisfy the numerical control system for real-time response. And offer the DLL to users.After the experiment, we found that through developing real-time kernel can satisfy the requirement of real-time control system; this structure is stand after tested.