The Application Of CAN Fieldbus In CNC System

Numerical Control technology is developed with synthesized application of multi studies and technology's production, such as integrity circuit, computer, auto control, auto detect, and precision mechanical, etc. With the progress of micro-electronics and computer technology, the shortage of traditional numerical control system was increasingly revealed. Therefore, open numerical control system becomes the development trend of numerical control technology. This thesis was based on the research of the formerly numerical control system's hardware platform in our institute, independently designed a multi-axis open numerical control system's hardware platform based on CAN bus.The upper computer of the introduced Numerical Control system's hardware platform in this thesis adopts PC/104. The downer system is composed of motion control board and operation panel. The communication between motion control board and PC/104 uses CAN bus, which can make the two communicate steadily within long distance and can also satisfy the demand of communication rate.The main content of the thesis is as follows:In the design, position control board adopts 80C196KC and FPGA structure, considering that FPGA has many advantages, such as less investment and short design circle in development process, repeating amendable program and intelligentized development tool, etc. 80C196KC mainly deal with data processing and communicating. FPGA is used to realize complex functions in position control board like position feedback, logic control, and the interface's extension of input and output. In addition, the embedded PLC module on position control board can safely and reliably settle the logic control of machine tool's switch states.The thesis elaborates the high speed serial communication design of CAN bus. Mostly it elaborates CAN bus communication program design of the system(SJA1000 initialization and message receiving/sending program).The CNC system of the thesis uses OCS-CAN clock synchronization solution to improve the real time and reliability of data transmission of the system.