201028013329006_姚家庆_压缩文章-沈阳计算技术研究所.DOC

基于龙芯数控系统内置PLC的研究与实现 1(中国科学院研究生院.北京 100039) 2(中国科学院沈阳计算技术研究所.辽宁 沈阳 110171) 摘要：本课题以基于国产“龙芯”处理器的蓝天数控系统为平台，使用MiniGUI图形开发库设计并实现了梯形图编辑子系统，具有梯形图的编辑、检查以及保存成IL文本程序的功能。同时借助开源词法分析器生成工具flex和语法分析器生成工具bison，设计并实现PLC程序编译子系统，将指令表(IL)和结构化文本(ST)语言表示的PLC程序转换成中间文件，ST语言支持的引入解决了当前数控系统PLC编译器只支持IL语言程序造成的复杂运算表示困难等缺点。此外还尝试在RTAI环境下实现PLC的编译执行。文中最后对梯形图程序编辑器进行测试，并对解释型PLC和编译型PLC的性能进行对比。结果表明，编译型PLC具有更好的时间性能。 关键词：软件PLC；PLC编程系统；PLC编译器；IEC61131-3 Research and Implementation of Embedded PLC Based on Loongson in CNC System Yao Jiaqing1,2 1(Graduate School of The Chinese Academy of Sciences , Beijing 100039,China) 2(Shenyang Institute of Computing Technology , Chinese Academy of Science ,Shenyang 110171,China) Abstract: Taken LanTian CNC system which based on Loongson CPU as platform, This project designed and implemented ladder diagram program editor subsystem which owns functions such as ladder diagram editing, program checking and saving as IL textual program etc. With the help of open source tools named flex and bison, the PLC compiled subsystem which can change IL and ST program into intermediate files was designed and implemented. The support of ST language solved the problem caused by IL language which is not suited for complicated operation. Besides, this article tried to realize compiled PLC in RTAI environment. Finally, some tests were made to test the ladder diagram program editor and the compare of performance was also made between interpreted PLC and compiled PLC. The results show that the compiled PLC has a better time performance. Key Words: Software PLC；Programming System；PLC compiler；IEC61131-3 1 引言 可编程逻辑控制器(Programmable Logic Controller, PLC)是数控系统当中非常重要且不可缺少的一部分，它通过数据采集，获得数控系统的内部状态和系统外设诸如限位开关、传感器、按钮等开关量的状态，执行用户预先编写的控制逻辑，并将执行得到结果输出到系统内部或者外围设备，实现对机床外围设备的控制，包括冷却控制、润滑控制、主轴转向转速控制等等。 随着开放式数控系统的发展，传统PLC自身具有的封闭的系统结构、难以扩展维护、资源限制等等问题逐渐凸现出来，取而代之的是模块化、可重构、可扩充、开放式、全软件实现的软件PLC系统。IEC61131系列标准的提出，对软件PLC的各个方面进行规范，包括编程语言、通信、设备要求等等，形成各个厂家可以遵循的标准，极大地促进了软件PLC的发展。 蓝天数控系统使用的PLC是解释型PLC，主要支持梯形图(LD)和指令表(IL)语言