Abstract : This paper introduces the design method of an open CNC system based on CAN bus, analyzes the performance of CAN bus, and elaborates on the specific manifestation of high-performance DSP supporting CAN bus in servo control modules. Keywords: CAN bus; open CNC system; DSP; functional module An open CNC system should have the following three basic characteristics: ① The system adopts a modular software and hardware structure; ② It provides software and hardware interfaces for user expansion functions; ③ It uses PC-compatible products and Windows graphical operating system as the human-machine interface basis. Compared with the international advanced level, the research on open CNC systems in China is still in its early stages. It mainly uses motion control cards and I/O cards inserted into the bus slots of industrial PCs or ordinary PCs, along with self-developed control software, to complete the basic functions of the CNC system. Most of the research on open CNC systems in China is based on the automation requirements of single equipment to design the hardware and software structure of the CNC system, without fully considering the higher requirements for open systems in the context of workshop automation and intelligent manufacturing. Therefore, it is of positive significance to design a new type of open CNC system based on fieldbus, taking into account the actual situation in China and the special requirements of CIMS and workshop automation. [b]1. Open CNC System Architecture Based on CAN Bus 1.1 System Composition[/b] In a CNC system, controllers based on various CPUs mainly perform the following basic functions: human-machine interface tasks, adaptive compensation function, NC code compilation and tool compensation function, trajectory interpolation function, servo control function, and emergency event control function. [b][align=center]For more details, please click: Research on a Novel Open CNC System Based on Fieldbus[/align][/b]