本文以印制电路板数控钻铣机床为研究对象，为改善原有人机交互界面，提高系统实时响应性及整个系统的稳定性，研制了一种微机控制的数控系统。全文详细介绍了该数控系统的研制和开发过程。 设计中采用Pentium IV IPC机为上位机，Atmel89c52单片机作为下位机核心处理芯片，匹配多片8255芯片来扩展C52的IO口达到多路信号的传递和控制。以计算机的打印口作为两者间的通讯接口，充分利用了计算机的硬件资源也使整个系统更加稳定，由此构成主从式控制系统。 系统加工处理过程为：上位机将经过处理的工件加工控制指令和参数发送到下位机，监控下位机工作。下位机负责控制数控机床各执行机构进行工件的加工，并向上位机发出适时中断，以求应答。上位机利用现有微机丰富的软硬件资源，编制出了更加友好的人机控制界面，取代了原有的DOS界面；本系统特点是利用了Atmel89c52单片机系统结构相对简单、工作可靠、价格便宜，且可以借助C语言、汇编语言等编制出执行机构的位置控制软件。上位机采用外部中断，保证了整个主从式系统具有良好的实时性。 采用本系统使原数控机床的扩充性及开放性更强，充分利用计算机软件发展的最新成果，使其编程系统的功能更加强大、开放性更强，增加了图形输入、轨迹生成与动态模拟等形象、直观、高效的新功能；使测量、编程、加工一体化，数控编程更加方便、高效，也为将来数控机床的网络控制打下基础。系统通过测试电路显示的编码信息与理论编码信息对比，结果是完全符合的，从而验证了整个系统设计的合理性。由于时间问题，上位机的软件系统还不太完善但基本功能已经实现，可以完成简单的加工任务。 文章着重阐述了主从式数控机床的整体结构、硬件设计及软件编程的基本原理和设计思想。包括以下五个主要部分：数控机床及控制系统的概述；下位机的软、硬件设计；计算机控制系统及步进电动机简介；上位机与下位机间通讯接口及通讯模式的选择；上位机软件的总体设计。

This dissertation mainly introduces parallel communication of a master-slave system of three_coordinate PCB numerical control drilling and milling machine tool. In order to use the abundant software and hardware resources of IPC and to compile software of system, and in order to compile the control software of execution machinery by C and Assembly language at the same time, this CNC system adopts the master-slave structure and parallel communication method. The master computer sends control instructions and parameters to the slave computer under Windows for the sake of making the slave computer work well. The system is made up of Ateml89c52 and 8255. Four 8255 chips increased the I/O port of C52,because of this more information can be transend between IPC and my motion control card. The means of communication are mainly used of the LPT of the IPC. This system enhances the expanse and open ability of the original CNC machine tools, and can strengthen function of compile system by the achievements in the field of computer software in the world. It is beneficial to importing drawing and well done to produce and analogy trace under dynamic state, and is favorable to measuring, compiling and producing at the same time. It makes compile become easy and efficient. This article expounds the integration structure and the rationale of the system and the ideas used in designing hardware and in compiling software. My system are Confirmed by the test circuit ,that shows the encoding of information theory and coding information contrast, is fully consistent with the results, which show the entire system design is reasonable, as the prolem of time, the host computer software system is not perfect but also basic functions has been achieved can be completed Simple processing tasks. There are five principal parts in the full text: the summary of CNC and this CNC system; the design of the hardware and software of the slave computer; the introduce of IPC control system and electromotor; the communication port and mode between the the host computer and slave computer; the frame design of the host computer software.