PLC实训室网络化改造的实践

本文论述了基于西门子S7系列PLC实训室的网络化改造思路,介绍了该PLC网络实验系统的总体结构,阐明了实验项目的设计思路,设备改造要求、设备改造组成及指标。通过实验教学实践证明,PLC网络实验系统将PLC的网络技术、通讯技术、控制技术整合在一起,是学生学习并掌握PLC应用技术的良好平台。     

基于VC++6.0的PC机与PLC串口通信的实现及其应用

文章介绍了S7-200自由口通信模式以及在Windows环境下应用VC 6.0实现PC机与PLC通讯的方法,给出了通讯协议和软件设计方法.开发了THSA-1过程综合自动化实验平台水箱液位监控系统.运行结果该系统表明简单,实时性强,运行稳定.     

SIMATIC S7通讯在镀锌生产线上的应用

S7通讯（S7-communication）主要用于S7-400与400、S7-400与300PLC之间的通讯，是S7系列PLC基于MPI、PROFIBUS和工业以太网的一种优化的通讯协议。本文通过研究S7通讯在镀锌生产线上PLC中的应用，阐述了不同PLC内CPU的双边通讯方法等，从此论文的技术角度来说，对作为维护行业的人员业务水平提升奠定了基础。     

西门子S7-200 PLC与台达变频器的通讯控制与应用

随着PLC和变频器通讯功能日益增强,PLC利用通讯控制变频器的控制方案正日益成为一种既经济又可靠的控制方式。本文主要阐述了SIEMENS S7-200 PLC和台达VFD-B系列变频器通讯控制的原理及应用。     

基于Modbus协议的PLC与DCS系统集成的研究和实现

本文介绍了DCS与PLC的连接方式和通讯方式以及工业系统中PLC与DCS系统的通讯集成方案,提供了一种基于Modbus协议串口通讯的PLC与DCS信息集成解决方案。构建了基于Modbus协议的PLC与DCS通讯架构。     

以太网互连的两套S7-400CPU在火电厂中的应用

随着工业自动化控制技术的不断发展,自动控制系统越来越多的应用到工业领域。在实际应用中,多套控制系统可能在同时部署到应用领域。此时,如何解决不同控制系统之间的互连以实现系统之间的数据共享成为实际中必须解决的问题。以某火电厂的辅机自动控制系统为背景,介绍一种应用工业以太网技术来实现两套PLC之间通讯的方法。该方法可以减少实现PLC通讯的程序配置和程序编写的工作量,另外,由于Pro-fibus总线的通讯速率为12 M/s,而以太网的通讯速率可达到100 M/S,因此提出的方法也可以提高多套PLC之间的通讯效率。     

基于MM440变频器和S7-300PLC的定氧加铝系统

针对炼钢工序中定氧加铝系统的工艺及控制要求，基于西门子S7-300 PLC，MM440变频器和现场总线技术设计了定氧加铝自动控制系统，PLC和MM440之间采用PROFIBUS DP现场总线技术进行通讯。运行结果表明，该自动控制系统运行稳定，具有良好的准确性、快速性和即时性等。     

数字通信在变频器控制中的应用

分析了近年来变频器在自动化控制系统中的发展和应用。重点讲述基于ModbusRTU总线的变频器与PLC系统的通讯方法,并分析了该控制方式在变频器控制中的实际应用。     

控制网络在济钢连铸机中的应用

济钢连铸机使用SIEMENS公司的S7系列PLC进行控制,系统中应用了工业以太网实现PLC与PLC之间的数据通讯,以及PLC与上位机的通讯;PROFIBUS_DP现场总线实现PLC与PLC,远程I/O及现场总线设备通信。     

基于三菱PLC的步进电机监控系统的设计与开发

根据实验室现有环境,设计开发了一种基于三菱FX系列PLC的步进电机监控实验系统,具体分析了系统的硬件结构,微机与PLC的通讯方法,监控界面的设计与程序实现,并对该系统的进一步扩展应用进行了探讨.该系统虽然只就实验室环境进行了设计、开发,但其原理与方法同样适用于生产实践.     

Characterization of Ordovician carbonate reservoirs, southeastern Saskatchewan, Canada

The discovery of the prolific Ordovician Red River reservoirs in 1995 in southeastern Saskatchewan was the catalyst for extensive exploration activity which resulted in the discovery of more than 15 new Red River pools. The best yields of Red River production to date have been from dolomite reservoirs. Understanding the processes of dolomitization is, therefore, crucial for the prediction of the connectivity, spatial distribution and heterogeneity of dolomite reservoirs.The Red River reservoirs in the Midale area consist of 3～4 thin dolomitized zones, with a total thickness of about 20 m, which occur at the top of the Yeoman Formation. Two types of replacement dolomite were recognized in the Red River reservoir: dolomitized burrow infills and dolomitized host matrix. The spatial distribution of dolomite suggests that burrowing organisms played an important role in facilitating the fluid flow in the backfilled sediments. This resulted in penecontemporaneous dolomitization of burrow infills by normal seawater. The dolomite in the host matrix is interpreted as having occurred at shallow burial by evaporitic seawater during precipitation of Lake Almar anhydrite that immediately overlies the Yeoman Formation. However, the low δ18O values of dolomited burrow infills (-5.9‰～ -7.8‰, PDB) and matrix dolomites (-6.6‰～ -8.1‰, avg. -7.4‰ PDB) compared to the estimated values for the late Ordovician marine dolomite could be attributed to modification and alteration of dolomite at higher temperatures during deeper burial, which could also be responsible for its 87Sr/86Sr ratios (0.7084～0.7088) that are higher than suggested for the late Ordovician seawaters (0.7078～0.7080). The trace amounts of saddle dolomite cement in the Red River carbonates are probably related to "cannibalization" of earlier replacement dolomite during the chemical compaction.     

A computer generator for randomly layered structures

AcomputergeneratorforrandomlylayeredstructuresYUJia shun1,2,HEZhen hua2(1.TheInstituteofGeologicalandNuclearSciences,NewZealand;2.StateKeyLaboratoryofOilandGasReservoirGeologyandExploitation,ChengduUniversityofTechnology,China)Abstract:Analgorithmisintrod…     

海南岛地体及其毗邻陆缘晚中生代—新生代古地磁研究和构造演化

本文叙述了对海南岛及其毗邻大陆边缘白垩纪到第四纪地层岩石进行古地磁研究的全部工作过程。通过分析岩石中剩余磁矢量的磁偏角及磁倾角的变化,提出海南岛白垩纪以来经历的构造演化模式如下:早期伴随顺时针旋转而向南迁移,后期伴随逆时针转动并向北运移。联系该地区及邻区的地质、地球物理资料,对海南岛上述的构造地体运动提出以下认识:北部湾内早期有一拉张作用,主要是该作用使湾内地壳显著伸长减薄,形成北部湾盆地。从而导致了海南岛的早期构造运动,而海南岛后期的构造运动则主要是受南海海底扩张的影响。海南地体运动规律的阐明对于了解北部湾油气盆地的形成演化有重要的理论和实际意义。     

Exciton Seebeck in Molecular Systems

Various applications relevant to the exciton dynamics,such as the organic solar cell,the large-area organic light-emitting diodes and the thermoelectricity,are operating under temperature gradient.The potential abnormal behavior of the exicton dynamics driven by the temperature difference may affect the efficiency and performance of the corresponding devices.In the above situations,the exciton dynamics under temperature difference is mixed with     

Achieving Unusual States of Matter Under High Pressure

The elongation method,originally proposed by Imamura was further developed for many years in our group.As a method towards O(N)with high efficiency and high accuracy for any dimensional systems.This treatment designed for one-dimensional(ID)polymers is now available for three-dimensional(3D)systems,but geometry optimization is now possible only for 1D-systems.As an approach toward post-Hartree-Fock,it was also extended to     

《Chinese Science Bulletin》SUBJECT INDEX TO VOLUME 59(2014)

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An on-line scaling method for improving scalability of a database cluster

The explosive growth of the Internet and database applications has driven database to be more scalable and available, and able to support on-line scaling without interrupting service. To support more client's queries without downtime and degrading the response time, more nodes have to be scaled up while the database is running. This paper presents the overview of scalable and available database that satisfies the above characteristics. And we propose a novel on-line scaling method. Our method improves the existing on-line scaling method for fast response time and higher throughputs. Our proposed method reduces unnecessary network use, i.e. , we decrease the number of data copy by reusing the backup data. Also, our on-line scaling operation can be processed parallel by selecting adequate nodes as new node. Our performance study shows that our method results in significant reduction in data copy time.     

An improved R-tree based on childnode''s probability

R-Tree is a good structure for spatial searching. But in this indexing structure,either the sequence of nodes in the same level or sequence of traveling these nodes when queries are made is random. Since the possibility that the object appears in different MBR which have the same parents node is different, if we make the subnode who has the most possibility be traveled first, the time cost will be decreased in most of the cases. In some case, the possibility of a point belong to a rectangle will shows direct proportion with the size of the rectangle. But this conclusion is based on an assumption that the objects are symmetrically distributing in the area and this assumption is not always coming into existence. Now we found a more direct parameter to scale the possibility and made a little change on the structure of R-tree, to increase the possibility of founding the satisfying answer in the front sub trees. We names this structure probability based arranged R-tree (PBAR-tree).     

An Index mechanism for multi-scale view in spatial databases

There are numerous geometric objects stored in the spatial databases. An importance function in a spatial database is that users can browse the geometric objects as a map efficiently. Thus the spatial database should display the geometric objects users concern about swiftly onto the display window. This process includes two operations:retrieve data from database and then draw them onto screen. Accordingly, to improve the efficiency, we should try to reduce time of both retrieving object and displaying them. The former can be achieved with the aid of spatial index such as R-tree, the latter require to simplify the objects. Simplification means that objects are shown with sufficient but not with unnecessary detail which depend on the scale of browse. So the major problem is how to retrieve data at different detail level efficiently. This paper introduces the implementation of a multi-scale index in the spatial database SISP (Spatial Information Shared Platform) which is generalized from R-tree. The difference between the generalization and the R-tree lies on two facets: One is that every node and geometric object in the generalization is assigned with a importance value which denote the importance of them, and every vertex in the objects are assigned with a importance value,too. The importance value can be use to decide which data should be retrieve from disk in a query. The other difference is that geometric objects in the generalization are divided into one or more sub-blocks, and vertexes are total ordered by their importance value. With the help of the generalized R-tree, one can easily retrieve data at different detail levels.Some experiments are performed on real-life data to evaluate the performance of solutions that separately use normal spatial index and multi-scale spatial index. The results show that the solution using multi-scale index in SISP is satisfying.     

Integrating GIS Web services based on mediating architecture

The geographic information service is enabled by the advancements in general Web service technology and the focused efforts of the OGC in defining XML-based Web GIS service. Based on these models, this paper addresses the issue of services chaining,the process of combining or pipelining results from several interoperable GIS Web Services to create a customized solution. This paper presents a mediated chaining architecture in which a specific service takes responsibility for performing the process that describes a service chain. We designed the Spatial Information Process Language (SIPL) for dynamic modeling and describing the service chain, also a prototype of the Spatial Information Process Execution Engine (SIPEE) is implemented for executing processes written in SIPL. Discussion of measures to improve the functionality and performance of such system will be included.