基于FPGA的数控系统现场总线时钟同步技术

摘要

In adopting field bus technology of high speed,high precision and multi-axis NC machining,the synchronization accuracy of the distributed clock seriously affect the machining locus and machining precision.According to the IEEE1588 protocol,proposing a NC field bus time synchronization method that based on FPGA,realizing the master station and slave station controller chip.Through comparative analysis of FPGA-based and software implement method,demonstrating that FPGA-based implement method can obtain a more accurate timestamp,achieve Clock frequency compensation with a lower cost,and accomplish the more accurate time synchronization.Using the built experimental platform,completed the accuracy test for time synchronization.The experiment results show that the synchronous accuracy of FPGA-based field bus time synchronization technology is less than 300ns which can further improve the machining precision of the numerical control system.%在采用现场总线技术的高速高精度多轴数控加工中,分布时钟的同步精度严重影响着加工轨迹以及加工精度.根据IEEE1588协议,提出一种基于FPGA的数控系统现场总线时钟同步方法,实现了主站与从站控制芯片.并通过将基于FPGA的实现方法与软件实现方法进行对比分析,论证了基于FPGA的实现方法可以获取更为准确的时间戳,能在较低的成本下实现时钟频率补偿,完成精确的时钟同步.利用搭建的主从站实验平台,完成了时间同步精度的测试.实验结果表明,基于FPGA的数控系统现场总线的时钟同步技术的同步精度小于300ns,进一步提高了数控系统的加工精度.