Modbus通讯协议在S7—200通讯中的应用

S7—200型可编程控制器适用于工业现场的过程控制。Modbus通讯协议已经为众多自动化设备所广泛采用。采用了Modbus通讯协议的S7—200可编程控制器,可以方便地连接工业现场控制设备。介绍了基于Modbus协议的S7-200通讯程序设计。     

自动化热喷涂机控制系统

采用德国西门子公司生产的S7－200可编程控制器作为自动化热喷涂机控制系统的核心部件。给出了其电气结构硬件框囹及控制系统程序框圄。介绍了控制程序的设计及利用S7－200CPU214PLC本机带有的高速计数器（开关量输入口）实现移动速度、转动速度的测量与软件设计。     

S7-200PLC模拟量采集的经济实现

针对西门子S7-200系列PLC模拟量采集成本昂贵的现状,设计了一种适用于S7-200 PLC的廉价解决方案。硬件方面,介绍了模拟量采集模块的构成及与S7-200的连接方法;软件方面,介绍了通信数据包格式、通信协议、数据采集模块的数据上传程序以及S7-200的接口程序。本方案与S7200原厂模拟量采集模块相比,应用成本大幅度降低。     

基于FameView的车用空调控制器耐久试验台设计

本文介绍由西门子S7-200系列可编程控制器和工业PC机组成车用空调控制器耐久试验台,详细介绍了利用FameView组态的试验台的监控系统的过程,介绍了FameView与PLC通讯的原理。     

基于PROFlBUS－DP的PLC控制系统

针对PROFlBUS－DP现场总线的功能和特点,并且以PROFlBUS－DP现场总线为基础,通过组态实现了西门子S7－300作为主站与三台智能从站S7－200之间的EM277进行通信,从而可以监控三台S7－200下的设备的运行。经过实验验证,整个系统完全可以通过HMl设备端对S7－300、S7－200及其设备的运行进行监控。     

PLC在电石炉控制中的应用

介绍了以S7－200系列PLC为核心来控制电石炉温度的控制方案，并着重给出了S7－200与PC的通讯、PLC中曲线的存储、多模式切换以及变周期控制的实现方法，为矿热炉生产过程控制提供了一条有效途径。     

基于S7-200 PLC 的条码监控系统

结合基于S7－200PLC条码监控系统项目的开发，介绍了S7－200PLC的通信原理与实现，给出了系统硬件和软件的设计方案。该系统已经应用于实践，实现对条码的运行状态进行实时监控。结果表明该通信系统实用性强，使用方便。     

S7-200 PLC在电动架车机同步控制系统中的应用

本文介绍了自行研制开发的以S7－200为核心的电动架车机同步控制系统，阐述了PLC控制的原理，软硬件设计和同步控制系统控制方案。     

无线通讯在水处理监控系统中的应用

简要介绍了采用无线以太网通信技术和先进的工业监控技术的热轧水处理系统的设计和应用。该系统通过利用西门子S7—200和S7—300PLC组成的混合系统实现了现场水处理设备的自动控制和远程监控,达到了系统设计的预期目标。     

风压平衡器自动控制系统的设计与实现

本文介绍了西门子S7-200可编程序控制器在风压平衡器自动控制系统中的设计与实现。结合卷烟生产工艺，分析了在卷烟生产过程中应用风压平衡器的必要性。根据S7-200可编程序控制器的特点．详细介绍其在控制风压中运用的控制原理．软件及硬件的实现方法。设计完成的系统运行可靠、操作方便、具有很强的实用性。     

Call for Papers The 6^th International Conference on Grid and Cooperative Computing

Recent years have seen rapid advances in various grid-related technologies, middleware, and applications. The GCC conference has become one of the largest scientific events worldwide in grid and cooperative computing. The 6th international conference on grid and cooperative computing (GCC2007) Sponsored by China Computer Federation (CCF),Institute of Computing Technology, Chinese Academy of Sciences (ICT) and Xinjiang University ,and in Cooperation with IEEE Computer Soceity ,is to be held from August 16 to 18, 2007 in Urumchi, Xinjiang, China.     

煤矿井下安全监控分站的设计及其仿真实现

为了设计一种具有低成本、低功耗、易操作、功能强且可靠性高的煤矿井下安全分站,针对煤矿安全生产实际,文章提出了采用MCS-51系列单片机为核心、具有CAN总线通信接口的煤矿井下安全监控分站的设计方案;首先给出煤矿井下安全监控分站的整体构架设计,然后着重阐述模拟量输入信号处理系统的设计过程,最后说明单片机最小系统及其键盘、显示、报警、通信等各个组成部分的设计;为验证设计方案的可行性与有效性,使用Proteus软件对设计内容进行仿真验证,设计的煤矿井下安全监控分站具有瓦斯、温度等模拟量参数超标报警功能和电机开停、风门开闭等开关量指示功能;仿真结果表明:设计的煤矿井下安全监控分站具有一定的实际应用价值.     

法律信息库系统

本文分析了法律数据库的结构和特点，介绍了采用面向对象设计方法和超文本数据库技术开发和实现法律信息库系统将作为重要网络资源之一为不同用户进行法律咨询服务。     

View-based model-driven architecture for enhancing maintainability of data access services

In modern service-oriented architectures, database access is done by a special type of services, the so-called data access services (DAS). Though, particularly in data-intensive applications, using and developing DAS are very common today, the link between the DAS and their implementation, e.g. a layer of data access objects (DAOs) encapsulating the database queries, still is not sufficiently elaborated, yet. As a result, as the number of DAS grows, finding the desired DAS for reuse and/or associated documentation can become an impossible task. In this paper we focus on bridging this gap between the DAS and their implementation by presenting a view-based, model-driven data access architecture (VMDA) managing models of the DAS, DAOs and database queries in a queryable manner. Our models support tailored views of different stakeholders and are scalable with all types of DAS implementations. In this paper we show that our view-based and model driven architecture approach can enhance software development productivity and maintainability by improving DAS documentation. Moreover, our VMDA opens a wide range of applications such as evaluating DAS usage for DAS performance optimization. Furthermore, we provide tool support and illustrate the applicability of our VMDA in a large-scale case study. Finally, we quantitatively prove that our approach performs with acceptable response times.     

International Journal of Automation and Computing Table of Contents

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Information for authors

正SCIENCE CHINA Information Sciences(Sci China Inf Sci),cosponsored by the Chinese Academy of Sciences and the National Natural Science Foundation of China,and published by Science China Press,is committed to publishing highquality,original results of both basic and applied research in all areas of information sciences,including computer science and technology;systems science,control science and engineering(published in Issues with odd numbers);information and communication engineering;electronic science and technology(published in Issues with even numbers).Sci China Inf Sci is published monthly in both print and electronic forms.It is indexed by Academic OneFile,Astrophysics Data System(ADS),CSA,Cabells,Current Contents/Engineering,Computing and Technology,DBLP,Digital Mathematics Registry,Earthquake Engineering Abstracts,Engineering Index,Engineered Materials Abstracts,Gale,Google,INSPEC,Journal Citation Reports/Science Edition,Mathematical Reviews,OCLC,ProQuest,SCOPUS,Science Citation Index Expanded,Summon by Serial Solutions,VINITI,Zentralblatt MATH.     

Erratum to: Fast global kernel fuzzy c-means clustering algorithm for consonant/vowel segmentation of speech signal

正Erratum to:J Zhejiang Univ-Sci C(ComputElectron)2014 15(7):551-563doi:10.1631/jzus.C1300320The original version of this article unfortunately contained mistakes.Algorithm 6 should be as follows:Algorithm 6 FGKFCM-F clustering Input:(1)X={x_1,x_2,…,x_N},,x_iR~d,i=1,2,…,N,the dataset;(2)C,1C≤N,the number of clusters;(3)ε0,the stopping criterion;     

Journal of Zhejiang University-SCIENCE C (Computers & Electronics) Total contents

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A pragmatic multi-method investigation of discrepant technological events: Coping,attributions, and ‘accidental’ learning

Discrepant technological events or situations that entail a problem, a misunderstanding or a difficulty with the Information Technology (IT) being employed, are common in the workplace, and can lead to frustration and avoidance behaviors. Little is known, however, about how individuals cope with these events. This paper examines these events by using a multi-method pragmatic approach informed by coping theory. The results of two studies – a critical incident study and an experiment – serve to build and test, respectively, a theoretical model that posits that individuals use a variety of strategies when dealing with these events: they experience negative emotions, make external attributions, and adopt engagement coping strategies directed at solving the event, eventually switching to a disengagement coping strategy when they feel they have no control over the situation. Furthermore, users’ efforts may result in ‘accidental’ learning as they try to overcome the discrepant IT events through engagement coping. The paper ends with a discussion of the results in light of existing literature, future opportunities for research, and implications for practice.