一种基于工业以太网的控制系统的设计与实现

随着以太网技术的迅猛发展,工业以太网在工业控制系统中扮演着越来越重要的角色.结合嵌入式网络技术,区别于现有的各种基于现场总线的控制系统,本文给出了将以太网直接应用于工业现场设备监控的系统设计方案,且进行了实验测试.     

现场总线技术的发展及趋势

首先论述了工业自动化控制系统的发展沿革,然后深入研究了当前控制领域的热点技术——现场总线,对目前市场上应用广泛的总线进行了对比分析,最后提出了现场总线的发展趋势,以及和工业以太网的联系。     

现场总线与工业以太网的应用分析

对现场总线和工业以太网做了简单介绍。对其发展情况和技术特点做了详细分析,认为现场总线多标准的出现是历史发展的必然,工业以太网不会也不可能取代现场总线。结论:现场总线与工业以太网相结合将是未来自动化网络的发展趋势。     

火电厂现代化控制系统发展方向探讨

针对火电厂控制系统的特点及发展趋势，介绍了在电厂中已广泛应用的DCS系统．而后讨论了现场总线控制系统在火电厂中的应用前景及在应用中的一些问题．提出了工业以太网将进入工业控制领域的趋势。     

工业以太网的发展及其技术特点

工业以太网控制系统是集散控制系统(DCS)和现场总线控制系统(FCS)之后产生的一种新型的工业控制系统。文章简要介绍了工业控制网络的发展过程,并详细论述了工业以太网的特点,提出了工业以太网以其全开放的特点必然会受到广泛的应用,实现工业控制网络和数据信息网络的无缝整合的观点。     

典型工业网络系统实验平台的设计

基于工业以太网技术及现场总线技术,设计并建立了一个典型的工业网络系统实验平台,阐述了系统总体设计思想、工程架构,以及具体的软硬件实现方案.详细描述了基于OPC技术的工业以太网与现场总线PROFIBUS通信连接设计、现场总线PROFIBUS与AS-i网络互联设计,阐述了该系统平台的科研及实验功能,其具体工程实现技术也可以很容易地应用于实际的现场总线控制系统设计实践中.     

工业控制的应用现状和发展趋势

网络化的结构、智能化的现场设备和现场化的控制功能是现代工业控制系统的主要特征。DCS、工业以太网和现场总线系统都体现了控制系统向网络化、集成化、分布化、节点智能化的发展趋势。     

现场总线标准的现状和工业以太网技术

分析和总结了当前存在的各种工业现场总线标准,指出了现场总线技术的发展方向;系统地阐明了应用工业以太网技术所面临的关键技术及相应的解决方案;指出了工业以太网技术的发展前景.     

工业以太网与CAN现场总线比较和应用方案分析

工业以太网和现场总线是工业控制现场中的两大主要网络通信形式.该文在对工业以太网和CAN现场总线进行分析比较的基础上,探讨了其在工业控制领域中的两种应用方案:工业以太网和CAN现场总线共存;工业以太网"一网到底".这两种方案互有优势,在实际应用中可根据具体情况选用.     

PROFInet——完整的网络解决方案

PROFInet由Profibus国际组织(Profibus International．PI)推出．是新一代基于工业以太网技术的自动化总线标准。作为一项战略性技术创新．PROFlnet为自动化通信领域提供了一个完整网络解决方案．囊括了诸如实时以太网、运动控制、分布式自动化、故障安全以及网络安全等当前自动化领域的热点话题．并作为跨供应商的技术。可完全兼容工业以太网和现有现场总线     

Minimal Realization of Linear Graph Models for Multi-physics Systems

An engineering system may consist of several different types of components,belonging to such physical"domains"as mechanical,electrical,fluid,and thermal.It is t...     

INTEGRAL EQUATION METHOD＇S APPLICATION IN HOLE-EDGE STRESS OF COMPOSITE MATERIAL PLATE WITH DIFFERENT SHAPED HOLES

The strength of composite plate with different hole-shapes is always one of the most important but complicated issues in the application of the composite material. The holes will lead to mutations and discontinuity to the structure. So the hole-edge stress concentration is always a serious phenomenon. And the phenomenon makes the structure strength decrease very quickly to form dangerous weak points. Most partial damage begins from these weak points. According to the complex variable functions theory, the accurate boundary condition of composite plate with different hole-shapes is founded by conformal mapping method to settle the boundary condition problem of complex hole-shapes. Composite plate with commonly hole-shapes in engineering is studied by several complex variable stress fimction. The boundary integral equations are founded based on exact boundary conditions. Then the exact hole-edge stress analytic solution of composite plate with rectangle holes and wing manholes is resolved. Both of offset axis loadings and its influences on the stress concentration coefficient of the hole-edge are discussed. And comparisons of different loads along various offset axis on the hole-edge stress distribution of orthotropic plate with rectangle hole or wing manhole are made. It can be concluded that hole-edge with continuous variable curvatures might help to decrease the stress concentration coefficient; and smaller angle of outer load and fiber can decrease the stress peak value.     

Non-monotonic material contrast in scanning ion and scanning electron images

30 keV Ga⁺ focused ion beam induced secondary electron (iSE) imaging was used to determine the relative contrast between several materials. The iSE signal compared from C, Si, Al, Ti, Cr, Ni, Cu, Mo, Ag, and W metal layers does not decrease with an increase in target atomic number Z₂, and shows a non-monotonic relationship between contrast and Z₂. The non-monotonic relationship is attributed to periodic fluctuations of the stopping power and sputter yield inherent to the ion–solid interactions. In addition, material contrast from electron-induced secondary electron (eSE) and backscattered electron (BSE) images using scanning electron microscopy (SEM) also shows non-monotonic contrast as a function of Z₂, following the periodic behavior of the stopping power for electron–solid interactions. A comparison of the iSE and eSE results shows similar relative contrast between the metal layers, and not complementary contrast as conventionally understood. These similarities in the contrast behavior can be attributed to similarities in the periodic and non-monotonic function defined by incident particle–solid interaction theory.     

Application of Feature Extraction through Convolution Neural Networks and SVM Classifier for Robust Grading of Apples

This paper proposes a novel grading method of apples,in an automated grading device that uses convolutional neural networks to extract the size,color,texture,an...     

分布动态载荷识别的抗噪处理

针对正交多项式频域法在用多种响应对矩形薄板进行载荷识别中抗噪性较差的问题,综合运用平均法、矩阵预处理和奇异值截断法等方法对之进行改善,并引入空间映射的思想,将该方法的应用范围拓展为复杂的模型.利用仿真算例,证实了该方法具有较好的抗噪性.     

基于MELTAC-N平台的核电厂安全级DCS环网研究与测试

针对工程实践中环网通讯相关问题的处理缺乏理论基础及国产化安全级DCS平台的开发缺乏成熟经验借鉴问题,对基于MELTAC-N平台核电厂安全级DCS环网的软硬件实现进行了研究。提出了安全级DCS环网双环网冗余设计、光切换开关设计等硬件设计方法,以及以RPR协议为基础,采用全数据收发策略的软件设计方法。在CPR1000安全级DCS平台上对安全级DCS环网的可靠性及实时性进行了评价,并进行了容错能力、响应时间及响应时间稳定性测试验证实验。结果表明,基于MELTAC-N平台安全级DCS环网软硬件设计具有较好的容错能力及响应时间稳定性。     

Short-Term Relay Quality Prediction Algorithm Based on Long and Short-Term Memory

The fraction defective of semi-finished products is predicted to optimize the process of relay production lines, by which production quality and productivity ar...     

End-to-End Multiview Gesture Recognition for Autonomous Car Parking System

The use of hand gestures can be the most intuitive human-machine interaction medium.The early approaches for hand gesture recognition used device-based methods....     

The laboratory simulation of abrasive wear

Abrasive wear has long been recognised as one of the most potentially serious tribological problems facing the operators of many types of plant and machinery; several industrial surveys have indicated that wear by abrasion can be responsible for more than 50% of unscheduled machine and plant stoppages. Locating the operating point of a tribological contact in an appropriate operational ‚map’︁ can provide a useful guide to the likely nature and origins of the surface degradation experienced in use, though care must be exercised in choosing the most suitable parameters for the axes of the plot. Laboratory testing of materials and simulations of machine contacts are carried out for a number of purposes; at one level for the very practical aims of ranking candidate materials or surface hardening treatments in order of their wear resistance, or in an attempt to predict wear lives under field conditions. More fundamentally, tests may be aimed at elucidating the essential physical mechanisms of surface damage and loss, with the longer term aim of building an analytical and predictive model of the wear process itself. In many cases, component surface damage is brought about by the ingress of hard, particulate matter into machine bearing or sealing clearances. These may be running dry although, more usually, a lubricant or service fluid is present at the interface. A number of standardised wear test geometries and procedures have been established for both two- and three-body wear situations, and these are briefly described. Although abrasive wear is often modelled as following an ‚Archard’︁ equation (i.e. a linear increase in material loss with both load and time, and an inverse dependence on specimen hardness) both industrial experience and laboratory tests of particularly lubricated contacts show that this is not always the case: increasing the hardness differential in an abrasively contaminated lubricated pair may not always reduce the rate of damage to the harder surface.     

ANGULAR DISTORTION ALLOWABLE VALUE AND ASSESS METHOD OF WELD ON COKE TOWER

A graph as the new engineering method for estimate the safety of bulging deformation of coke tower is proposed. Through stresses analysis of circumferential weld of coke tower and comparing the stresses produced by pressure with heat stress of steady state, residual stress, bending stress produced by both itself weight and wind loads, it showed that the stresses produced by pressure on the angle distortion are the main factor of equivalent stress of the combined stress. After comparing four kinds of stress controlling conditions, the relation to stress with depth of angular distortion, grade of curvature of angular distortion and half of region of angular distortion has been inferred. Graph of deformation allowable value of coke tower for different condition by angular distortion and half of region of angular distortion has been plotted. The five steps for its engineering use have been explained. The lighter the grade of curvature is, the larger of bulge allowance, may be, and the bigger of depth of angular distortion may pose too. For the coke tower with a popular structure of Dg 5 400 mm×28 mm, the result by graph is nearly more than the result of two formulas formed by other research, the error is less than 7.0%. But, the graph can be easily applied to different size of angular distortion.