全自动立式过滤机的设计【带CAD图纸设计说明书】.zip全自动立式过滤机的设计【带CAD图纸设计说明书】.zip

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湘潭大学兴湘学院 毕业论文(设计)任务书 论文(设计)题目: 全自动立式过滤机的设计 学号: 2006183922 姓名: 严 浩 专业: 机械设计制造及其自动化 指导教师: 文美纯 系主任: 周友行 一、主要内容及基本要求 1、了解全自动过滤机的工作原理及流程; 2、设计过滤机的内部零件,用 CAD 绘图装配图、工艺流程图 A0 两张,零件 图滤盘、大皮带轮、小皮带轮、空心轴 A1 一张、 A2 三张; 3、PLC 控制系统的设计,及其编程、语句表; 4、设计说明书 8000 字以上,内容完整,计算准确; 5、外文翻译 7000 字以上; 二、重点研究的问题 全自动立式过滤机的结构设计及其控制系统; 三、技术指标 主要技术参数:过滤面积 10 平方米 工作压力 1.6Mpa 工作温度-5 ℃——105℃ 电机功率 5.5KW 四、进度安排 序号 各阶段完成的内容 完成时间 1 查阅资料、调研 1 周 2 开题报告、制定设计方案 2 周 3 设计计算 3~5 周 4 PLC 编程 6~8 周 5 CAD 画图 9~12 周 6 整理说明书、外文翻译 13~14 周 7 修改图纸和说明书 15 周 8 打印图纸、毕业设计答辩 五、应收集的资料及主要参考文献 [1]文美纯,刘吉普 对全自动过滤机的探讨; 《过滤与分离》1997.第三期 [2]文美纯,刘吉普,可编程序控制器在过滤器上的应用研究;《过滤与分离》 2002.VOl12.NO4 [3]文美纯,刘吉普 新型管道过滤器的开发研究 ;《过滤与分离》1996.第三期 [4]丁启圣、王惟一等.新型实用过滤技术[M] .北京:冶金工业出版社. 2000.1; [5]文棋.全自动自清洗过滤机过滤机理分析及控制系统研究. [J]浙江:大学硕士学位 论文.2002.6; [6]管力明.PLC 在硅藻土过滤机上的应用[J] .机电工程 2004 年第 21 卷第七期. 2004.7; [7]华东工业大学、浙江大学合编.化工容器设计[M] .武汉:湖北科学技术出版社. 1985.6; [8]濮良贵、纪名刚主编.机械设计(第 8 版).[M].北京:高等教育出版社.2006.5; [9]成大先.机械设计手册[M]第四版.北京:化学工业出版社.2002.8; 1 Visualization of PLC Programs using XML M. Bani Younis and G. Frey Juniorprofessorship Agentenbased Automation University of Kaiserslautem P. 0. Box 3049, D-67653 Kaiserslautem, Germany Abstract - Due to the growing complexity of PLC programs there is an increasing interest in the application of formal methods in this area. Formal methods allow rigid proving of system properties in verification and validation. One way to apply formal methods is to utilize a formal design approach in PLC programming. However, for existing software that has to be optimized, changed, or ported to new systems .There is the need for an approach that can start from a given PLC program. Therefore, formalization of PLC programs is a topic of current research. The paper outlines a re-engineering approach based on the formalization of PLC programs. The transformation into a vendor independent format and the visualization of the structure of PLC programs is identified as an important intermediate step in this process. It is shown how XML and corresponding technologies can be used for the formalization and visualization of an existing PLC program. I. INTRODUCTION Programmable Logic Controllers (PLCs) are a special type of computers that are used in industrial and safety critical applications. The purpose of a PLC is to control a particular process, or a collection of processes, by producing electrical control signals in response to electrical process- related inputs signals. The systems controlled by PLCs vary tremendously, with applications in manufacturing, chemical process control, machining, transportation, power distribution, and many other fields. Automation applications can range in complexity from a simple panel to operate the lights and motorized window shades in a conference room to completely automated manufacturing lines. With the widening of their application horizon, PLC programs are being subject to increased complexity and high quality demands especially for safety-critical applications. The growing complexity of the applications within the compliance of limited development time as well as the reusability of existing software or PLC modules requires a formal approach to be developed [I]. Ensuring the high quality demands requires verification and validation procedures as well as analysis and simulation of existing systems to be carried out [2]. One of the important fields for the formalization of PLC programs that have been growing up in recent time is Reverse- engineering [3]. Reverse Engineering is a process of evaluating something to understand how it works in order to duplicate or enhance it. While the reuse of PLC codes is being established as a tool for combating the complexity of PLC programs, Reverse Engineering is supposed to receive increased importance in the coming years especially if exiting hardware has to be replaced by new hardware with different programming environments Visualization of existing PLC programs is an important intermediate step of Reverse Engineering. The paper provides an approach towards the visualization of PLC programs using 2 XML which is an important approach for the orientation and better understanding for engineers working with PLC programs. The paper is structured as follows. First, a short introduction to PLCs and the corresponding programming techniques according to the IEC 61131-3 standard is given. In Section Ⅲ an approach for Re-engineering based on formalization of PLC programs is introduced. The transformation of the PLC code into a vendor independent format is identified as an important first step in this process. XML and corresponding technologies such as XSL and XSLT that can be used in this transformation are presented in Section IV. Section V presents the application of XML for the visualization of PLC programs and illustrates the approach with an example. The final Section summarizes the results and gives an outlook on future work in this ongoing project. Ⅱ PLC AND IEC 61131 Since its inception in the early ‘70s the PLC received increasing attention due to its success in fulfilling the objective of replacing hard-wired control equipments at machines. Eventually it grew up as a distinct field of application, research and development, mainly for Control Engineering. IEC 61 131 is the first real endeavour to standardize PLC programming languages for industrial automation. In I993 the International Electrotechnical Commission [4] published the IEC 61131 Intemational Standard for Programmable Controllers. Before the standardization PLC programming languages were being developed as proprietary programming languages usable to PLCs of a special vendor. But in order to enhance compatibility, openness and interoperability among different products as well as to promote the development of tools and methodologies with respect to a fixed set of notations the IEC 61131 standard evolved. The third part of this standard defines a suit of five programming languages: Instruction List (IL) is a low-level textual language with a structure similar to assembler. Originated in Europe IL is considered to be the PLC language in which all other IEC61 131-3 languages can be translated. Ladder Diagram (LO) is a graphical language that has its roots in the USA. LDs conform to a programming style borrowed from electronic and electrical circuits for implementing control logics. Structured Text (STJ is a very powerful high-level language. ST borrows its syntax from Pascal, augmenting it with some features from Ada. ST contains all the essential elements of a modem programming language. Function Block Diagram (FBD) is a graphical language and it is very common to the process industry. In this language controllers are modelled as signal and data flows through function blocks. FBD transforms textual programming into connecting function blocks and thus improves modularity and software reuse. Sequential Function Chart (SFC) is a graphical language. SFC elements are defined for structuring the organization of programmable controller programs. One problem with IEC 61 131-3 is that there is no standardized format for the project information in a PLC programming tool. At the moment there are only vendor specific formats. This is also one reason for the restriction of formalization approaches to single programs or algorithms. However, recently the PLC users’ organization PLCopen (see http://www.plcopen.org) started a Technical Committee to define an XML based format for projects according to IEC 61131-3. This new format will ease the access of formalization tools to all relevant information of 3 a PLC project. Ⅲ. RE-ENGINEERING APPROACH The presented approach towards re-engineering (cf. Fig.1) is based upon the conception that XML can be used as a medium in which PLC codes will be transformed. This transformation offers the advantage of obtaining avendor independent specification code. (Even if the PLCopen succeeds in defining a standardized format for PLC applications, there will remain a lot of existing programs that do not conform to this standard.) Based on this code a step-wise transformation to a formal model (automata) is planned. This model can then be used for analysis, simulation, formal verification and validation, and finally for the re-implementation of the optimized algorithm on the same or another PLC. Since re-engineering of complete programs will, in most cases, be only a semi-automatic process, intermediate visualization of the code is an important point. At different stages of the process different aspects of the code and/or formal model have to be visualized in a way that a designer can guide the further work. XML with its powerful visualization and transformation tools is an ideal tool for solving this task. IV. XML AS A TOOL FOR VISUALIZATION XML (extensible Markup Language) is a simple and flexible meta-language, i.e, a language for describing other languages. Tailored by the World Wide Web Consortium (W3C) as a dialect of SGML [S], XML removes two constraints which were holding back Web developments [6]. The dependence on a single, inflexible document type (HTML) which was being much abused for tasks it was never designed for on one side; and the complexity of full SGML, whose syntax allows many powerful but hard-to-program options on the other side. While HTML describes how data should be presented, XML describes the data itself. A number of industries and scientific disciplines-medical records and newspaper publishing among them-are already using XML to exchange information across platforms and applications. XML can be tailored to describe virtually any kind of information in a form that the recipient of the information can use in a variety of ways. It is specifically designed to support information exchange between systems that use fundamentally different forms of data representation, as for example between CAD and scheduling applications. 4 Using XML with its powerful parsers and inherent robustness in terms of syntactic and semantic grammar is more advantageous than the conventional method of using a lexical analyzer and a validating parser (cf. Fig. 2, [7]). The conventional method of analysis of program code requires a scanner (lexical analyser) which generates a set of terminal symbols (tokens) followed by a parser that checks the grammatical structure of the code and generates an object net. In the object net the internal structure of the program is represented by identified objects and the relations between them. Both the scanner and the parser to be used in this method are document oriented which implies that analysis of different types of documents requires rewriting the generated code for the scanner and the parser. An example of an application of this method can be found in [8]. The most promising aspect of using XML instead is that XML and its complementary applications for transformations are standardized so as to provide maximum flexibility to its user. The XML based method is advantageous, since the lexical specification is an invariant component of XML; therefore the well-formedness is independent from the respective individual application. Hence, an XML-Parser also can transfer well-shaped XML documents in an abstract representation called Document Object Model (DOM) without using a grammar. DOM is an application programming interface (APII) for valid HTML and well-formed XML documents. It defines the logical structure of documents and the way a document is accessed and manipulated. In the DOM specification, the term “document“ is used in a broad sense increasingly. XML is used as a way of representing many different kind of information that may be stored in diverse systems, and much of this would traditionally be seen as data rather than as documents. 5 Nevertheless, XML presents this data as documents, and the DOM can be used to manage this data[5]. XSLT, the transformation language for XML is capable of transforming XML not only to another XML or HTML but to many other user-friendly formats. Before the advent of XSLT, the transformation of XML to any other format was only possible through custom applications developed in a procedural language such as C++, Visual Basic or, Java. This procedure lacked the generality with respect to the structural variation of XML documents. Capitalizing on the concept that the custom applications for the transformations are all very similar, XSLT evolved as a high- level declarative language [9]. XSLT functions in two steps. In the first step, it performs a structural transformation so as to convert the XML into a structure that reflects the desired output. The second stage is formatting the new structure into the required format, such as HTML or PDF (cf. Fig. 3 ). The most important advantage of this transformation is that it allows a simple and easily-conceivable representation of the document or data structure embedded inside the well-structured but hard-to-understand XML to be produced. When HTML is chosen as the format of the transformed produce it is possible to use the extensive ability of HTML to produce an easily-conceivable and attractive visualization of a program. Every XML document has its own syntax and vocabulary. Therefore, in addition to being well-formed, the XML document needs to conform to a set of rules. According to W3C recommendations this set of rules has to be defined either through a Document Type Definition (DTD) or an XML Schema. The rules defined in a DTD or an XML Schema state the hierarchical and structural constraints of the XML document. The DTD is for defining the document grammars; more recently a number of alternative languages have been proposed. The W3C XML Schema language replicates the essential functionality of DTDs, and adds a number of features: the use of XML instance syntax rather than an ad hoc notation, clear relationships between schemas and namespaces, a systematic distinction between element types and data types, and a single-inheritance form of type derivation. In other words schemas offer a richer and more powerful way of describing information than what is possible with DTDs. Fig. 4 shows the XML technologies discussed above and the connection 6 between them. V. AN APPROACH FOR THE VISUALIZATION OFPLC PROGRAMS A. Overview Since Instruction List (IL) is the most commonly used PLC language in Europe, the presented approach is based on this language. The proprietary IL dialect Siemens STEP 5 and the standardized version according to IEC 61131-3 are considered. The generation of XML documents showing different aspects of a PLC program is realized in the following three steps (cf. Fig. 5): 1.Transformation of the PLC program
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