本文主要讨论基于MACRO总线的开放式凸轮轴磨床数控系统的硬件、软件结构及基于恒线速插补算法的实现。该系统采用高速DSP作为伺服控制核心 ,通过MACRO高速光纤网将工业PC和下位控制系统联接。在工业PC上采用保证恒线速的磨削点搜索算法离线完成从凸轮升程或型线参数到每个插补点的计算工作 ,再将插补结果进行样条拟合 ,输入到基于DSP的下位控制系统 ,控制系统根据样条曲线控制砂轮进给和工件主轴的协调运动 ,磨出符合工艺要求的工件 This article mainly discusses the hardware and software structure of open camshaft grinding machine CNC system based on MACRO bus and the realization based on constant linear interpolation algorithm. The system uses high-speed DSP as the core of servo control and connects the industrial PC and the lower control system through the MACRO high-speed optical fiber network. On the industrial PC, the grinding point searching algorithm which guarantees the constant linear velocity is used to complete the calculation work from the cam lift or profile parameters to each interpolation point offline, then the interpolation result is spline fitted and input to DSP Of the lower control system, the control system according to the spline curve control wheel feed and workpiece spindle coordinated movement, grinding out the workpiece in line with the requirements of the process