【作者】 王强；

【导师】 李彦；

【作者基本信息】 四川大学 ， 机械制造及其自动化， 2005， 硕士

【摘要】 本课题是四川省科技攻关项目“开放式软件数控系统开发与应用(Development and Application of Open Architecture Software CNC System)”(编号03GG006-013-1)子模块之一。 可编程控制器自它问世以来,便受到了控制界的广泛认同和青昧。近30多年来,这种技术异军突起,已经发展成为现代自动化技术的一个主要支柱。但传统可编程控制器存在如系统封闭,扩展能力差、兼容性差、可维护性差、成本高昂等诸多不足。虽然PLC技术获得了广泛的应用和长足的发展,但如上述的缺点也越来越受到人们的重视。上述缺点产生的根本原因是传统PLC采用专有软硬件的封闭式系统。 随着OMAC理念和IEC1131-3国际标准的提出和完善,以PC为硬件平台,通用操作系统为软件平台,用软件实现PLC的功能正成为PLC发展的趋势之一。以PC为平台实现软件PLC,一个重要的任务是选择一种合适的引擎操作系统。在分析了软件PLC研究的国内外现状,和通用操作系统Windows和Linux的优缺点后,选择了Linux和RTLinux为软件平台,实现了该系统。 本文就软件PLC技术,实现方法等做了一些研究,建立了一个基于RTLinux的软件PLC系统模型。该系统能支持用户程序的编辑、编译、错误查询,用户程序逻辑解算等基本任务。 系统在软件设计上采取了“开发系统”+“运行系统”的总体方案。对于软件PLC系统的非实时功能如用户程序的编辑、编译等由开发系统实现,开发系统运行在Liinux用户空间。而对实时性要求较高的功能,如实时扫描解算用更多还原

【Abstract】 This project is part of "Development and Application of Open Architecture Software CNC System" which is supported by Sichuan Province Key Research and Development (Grant No. 03GG006-013-1).PLC technology is playing a very important role in the manufacturing automation filed. However, traditional PLC system has many disadvantages, such as in open, modular, scaleable, economical, reliable and maintainable. The key cause of the disadvantages is that traditional PLC system is developed based on proprietary hardware and software. With the development of OMAC and IEC1131-3 standard, realizing PLC based on "de facto" standards and commercial hardware and software is becoming a stream.At the present time, many end user companies have selected Microsoft operating systems as the baseline infrastructure for their control, operator interface, and information technology systems. The key driver behind this selection is the dominant acceptance of Microsoft technologies in the computing and information technology markets. However, Microsoft Windows is not a real time operating system, and the real time extensions of Windows such as RTX, InTime and LP-Win are expensive. RTLinux is a real time operating system with excellence performance. It can be use accomplish real time multi-tasks scheduling without secondary CPU. Its source code is open for end user. Therefore, developing and open SoftPLC system based on RTLinux helps to improve the performance of PLC system. The paper addresses the implementation of an open SoftPLC system based on RTLinux.The software consists of No-real time layer developing system and real time layer running system. Developing system is composed of editor, compiler anddebugger, which be developed in Linux user space. Running system is composed of scanner and driver, which be developed in RTLinux real time kernel space. The details of the software are presented.Based on the research of SoftPLC system, the concepts of programming element, ladder level and class ladder are put forwarded. The details of the data structure of each other are discussed. The algorithms for calculating class ladder, and editing class ladder are given in detail.The software prototype has been built initially and verified the practicability of the theory model. By the system, designers can express their program with Ladder Diagram, can edit, compile, debug, can do fundamental logical calculation such as "AND", "OR", "NOT", "SET" and "RESET" and so on.At present, the prototype system is just completed in the main, so there is still much work to be done in the further development.更多还原