摘要
对高性能数控系统的开发和研制一直是机电行业所关注的热点。PC机进入数控领域后,极大的丰富了数控系统的硬软件资源,有利于实现总线式、模块化、开放化的数控系统,使其具有很高的性价比。随着Windows操作系统的发展与普及,开发基于Windows操作平台的具有开放式体系结构的CNC数控系统已经成为共识。
本文将介绍我院自行开发的基于PC机的通用数控系统LC-I的详细开发过程。
在明确数控系统所应具备的功能与性能要求后,确定采用以PC机+CNC运动控制卡的分层式的系统总体结构方案。方案分系统硬件结构和系统软件结构两部分进行实现。
在硬件结构上,系统以通用PC机(单CPU)作为硬件平台,结合DMC204四轴运动控制卡良好的控制性能,配以混合式步进电机11OHS12及其驱动器MIl06AC两套,组成了通用CNC控制系统的最小配置。这种结构方式直接利用了PC机体系结构,采用成熟NC硬件来组成控制系统。运动控制卡与PC机的接口遵循开放的标准总线ISA定义。这样构成的系统的硬件体系结构具有开放式、模块化,可嵌入的特点,经济实用,系统可靠性与运行精度有保障,非常适合于组成中小规模的数控系统。
在软件结构上,系统以Windows98作为操作系统平台。系统软件采用Windows98的多线程模式与中断机制相结合的控制策略和模块化的设计方法,较成功的在Windows环境下实现了数控系统的实时多任务控制要求。系统各功能的控制实现分别放置在相对独立的模块中,任一硬件或功能的变化都不会影响其他模块的运作。从实际应用情况来开,能够达到CNC系统软件对实时性、多任务并发处理与协调能力,开放性和模块化,界面友好等要求。
LC-I系统在经数控改造后的CK6140H车床上得到了较好的应用效果。
Developing the high-performance CNC system is a nowadays focus in mechanic & electrical industry . After personal computer (PC) entered numerical control technology area, the hardware & software resources of numerical control (NC) system have been becoming largely plenty, and the NC system which is based on PC bus , having characters like multi-modules and open architecture, becomes more realizable. With the Windows operation system becoming more and more popular , developing CNC system running on Windows operation platform & having open architecture has been commonly recognizable.
In this paper, common LC-I CNC system based on PC is introduced.
After defining the functions and capabilities of LC-I system, a multi-stage system general schema is assumed, which is using PC and CNC motion control board. The schema has been divided into two sections to build - the hardware architecture and the software architecture.
In system hardware architecture, PC (single CPU) is the base platform. With a 4-axis DMC204 motion control board, 2 step servo motor and theirs corresponding drivers , a minimize system configuration is constructed. This constructing method directly uses PC architecture, combining formed NC production, fully embodied the characters of multi-module and economy. This method is appropriately used to build mid or small CNC system.
In system software architecture, Windows 98 is selected to use as running platform for CNC application software. The control stragety of implementing the real-time & multi-task processing is proposed. The modular design method is introduced , and the corresponding program is designed. Every function is put into an independent module. Any changes in one module have no influence in other module. System has friendly interface , easy operation method for users.
The practice on CK6140H lathe proved that LC-I system is awfully practical.
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