Modbus协议在智能信号变送器中的应用

针对工业上的需求,文中基于Modbus协议设计了一种嵌入式智能传输数据的仪表,CPU采用C8051F系列的微处理器,上下位机通过RS-485总线进行通讯.下位机采用C语言来编程,通过ADC和脉宽调制功能实现数据的采集和变换;上位机采用C#来开发Modbus协议通信软件,采用主线程和辅线程机制来实现Modbus协议通信,将数据显示在界面上,同时绘制数据的动态曲线图,方便观察数据,系统整体实用性较高.     

基于Modbus协议的矿山供水系统设计

针对现有的矿山供水系统设备分散、故障处理滞后等问题,提出基于Modbus协议的远程无线监测监控系统,分析了Modbus通信协议特点,设计了PLC和无线电台之间的Modbus通信程序,实现集控主站与监控分站的数据通信。     

基于Modbus协议的S7-200PLC主从结构的通信技术研究

为了实现PLC的数据共享,提出了通过Modbus协议将2台PLC分别组建成通信主站和从站的方法,而且S7-200PLC自带Modbus通信协议库,可以方便地组建Modbus通信网络.根据Modbus协议的基本要求,对该网络的主站、从站的配置做了详细说明.实验结果表明,通信网络数据传输准确可靠,具有较高的实时性和稳定性.     

基于C#SerialPort通信控件的PC端与PLC通信方法研究

针对西门子PLC Modbus协议提出一种基于C#SerialPort控件的通信方式,从而通过PC端对PLC实现程序仿真、调试和数据监控功能。此通信方式和采用西门子专属硬件的通信方式相比有较大的成本优势,而且程序简便灵活,也可用于PC端和其他类型PLC、智能仪表、I/O卡等智能控制器的通信。     

基于Modbus协议的污水处理现场PLC站通信系统设计

对基于Modbus协议的现场PLC站通信系统进行设计,目的为控制中心提供统一的数据接口.在设计中,采用目前工业领域通用的Modbus协议,通过数据采集仪对PLC设备进行协议转换,构建一个为控制中心提供统一数据接口的“虚拟设备”,使用“数据映射”的方式与控制中心进行数据交互,以实现系统的通用性.     

基于软PLC的多协议通信系统的研究与实现

基于CoDeSys开发平台的软PLC实现了一种多协议的数据交互接口,从而应对数字化车间建设中的"信息孤岛"问题。通过CoDeSys软件通信层网关服务器配置总线协议及OPC服务器,开发TCP/IP、Modbus、Modbus TCP、EtherCAT等现场总线协议连接远程设备,并开放OPC通信以连接DCS、SCADA、MES等系统。实际工程应用验证了通信的实时性、可靠性,提高了车间通信网络的互通性、灵活性,降低了生产设备联网成本。     

Modbus通讯协议在DCS与PLC通讯中的应用

着眼于当前自动控制领域中应用最为广泛的通讯语言——Modbus通讯协议,在对该通信系统硬件组织及连接进行分析的基础之上,分别从DCS系统组态和PLC下组态及编程方法2个角度入手,就Modbus通讯协议在DCS与PLC通讯领域中的应用要点展开了详细分析与探讨。     

基于以太网的嵌入式软PLC通信体系设计

采用FPGA和W5100芯片搭建了嵌入式软PLC网络系统,主控制核心模块采用了PowerPC和FPGA的主从处理器模式,实现了数据的分工处理,克服了以往单CPU工作时系统资源占用率过高的问题。在此开放式硬件平台下,设计了基于时间片轮询的稳定可靠分时数据通信系统;为了适应具有不同网络协议设备的控制需求,系统内部集成了CANopen、Modbus/TCP等协议。最后,对通信系统进行了相关测试。实验结果表明,系统通信正常,且具有很好的实时性和稳定性。     

Modbus总线的无线网网关设计

为使无线技术能够方便的应用到工业中,设计了一种和Modbus协议网络通信的无线网网关,网关中的ATEMGA128A单片机将TI的Z-Stack协议与Modbus总线紧密的结合在了一起,通过PLC,可以方便地实现对网关的配置.实际测试表明,无线模块的发射功率、接受灵敏度、通信距离、误包率和速度满足工业的实时性安全性要求.     

Modbus/TCP协议的通信处理器模块设计

为了实现通信处理器模块通信的功能,在实时操作系统uC/OS-II和ARM7内核的软硬件平台上,通过移植LwIP到ARM开发平台提出了一种支持多线程实时应用的嵌入式TCP/IP协议栈的方案。在通讯应用层上,将Modbus帧嵌入到TCP帧中,分析研究Modbus/TCP协议通信结构模型,最终简单可靠地实现了嵌入式Modbus/TCP通信协议。结果表明,结合Modbus/TCP通信协议,可通过创建多个线程函数,稳定有效地实现Modbus/TCP客户端/服务器端之间数据的传送。     

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.