【作者】 白艳艳；

【导师】 陈卫福； 黄旭东；

【作者基本信息】 北京工业大学 ， 机械制造及其自动化， 2003， 硕士

【摘要】 开放式数控系统是当前数控技术研究的热点。在发展高速高效高精度及智能化等性能的同时，功能的发展也要求越来越强，具体体现在尽量用软件来实现数控的所有功能，使硬件规模达到最小化。作为整个运动控制核心的机床逻辑控制也必然要以软件的形式来实现。这样就促进了软PLC的发展。 本文构建了基于SERCOS接口的开放式数控系统中软PLC的软硬件平台，在该平台的基础上开发出了软PLC系统，并模拟实现了软PLC的基本的输入输出功能。本文的软PLC系统由两部分组成：软PLC开发系统和软PLC模拟运行系统。 在软PLC开发系统中，由用户输入梯形图，按照梯形图编程原则查错并修改梯形图后，就可以将此梯形图转化为结构化C语言文件，并将此文件作为运行系统的输入。本文没有编制专门的软PLC编译程序，直接利用VC++编译器实现PLC程序的编译和模拟运行。 本文的模拟运行系统是根据PLC巡回扫描原理编制的。PLC程序在运行的每个周期内都是按照输入采样、执行用户程序、输出刷新三个阶段执行程序的。本文通过Windows提供的定时器实现巡回扫描，达到了预期逻辑控制的目的。 本文开发的软PLC系统是在基于SERCOS接口的开放式数控系统上实现开关量信号控制的一次尝试。随着开发人员知识经验的增加，软PLC的功能会逐渐完善。更多还原

【Abstract】 Open numerical control system is the research hotspot of NC technology now. With the development of the performance of high speed, high efficiency, high precision and intelligence, more and more functions which makes the software carry out all of the NC functions and minimize the scale of hardware are demanding. Machine logic, the kernel of the whole motion control, is necessarily realized through software too, which accelerates the development of SoftPLC.This paper designs the software and hardware platform of SoftPLC in the Open NC system based SERCOS interface, on the base of which SoftPLC system is developed. The SoftPLC system consists of two parts of contents, one is SoftPLC developing system, the other is SoftPLC running system simulator.At the beginning of SoftPLC developing system, users work out the ladder diagram, then checked by SoftPLC developing system according the principle to find if there is some logic errors. If no error occurs, the ladder diagram can be transferred to C program which works as the input of the SoftPLC running system simulator. The special compiling program for PLC is not programmed in this paper, and the SoftPLC program is compiled by the compiler of VC++6. 0, then be executed.The SoftPLC running system simulator in this paper is designed according the "Cycle Scan" work mode of PLC. In every working cycle, PLC go through three steps to run program, which include input sampling, executing users’ s program and output refurbishing. This paper introduces the timer offered by windows to realize "Cycle Scan" and achieves.The SoftPLC system introduced in this paper is only an attempt to realize logic control in the open NC system based SERCOS interface. With the increase of experience and knowledge of the programmer, the functions supplied by the SoftPLC system will become more complete and more powerful.更多还原