基于令牌环网协议的监控系统网络设计

单信道的无线通讯以及各种使用双绞线通讯的系统。由于其线路在物理层上只能是半双工。所以为了实现总线上的设备能够双向通讯。必须使用总线协议进行控制信息的收发。令牌环网是一种简单可靠的实现方法。使用在RS485总线、简单无线通讯设备上可以使得总线可以共享。实现无碰撞的双向通讯。在较低的硬件成本下提高系统的通讯性能。在纺织机监控系统中使用令牌环网协议,可以为使用RS485总线作为网络物理层的监控系统提供一个逻辑上的多主网络环境。解决了原有系统运行效率不高。可靠性低的问题。     

基于USB的现场总线实时网络数据采集器

针对目前基于PC机终端监控的现场总线实时网络数据采集系统,无法脱离PC机独立工作的缺点,以基于热浸镀锌工艺的RS - 485总线网络为例,简要介绍了现场总线实时网络的结构和工作原理;以CY7C68013为核心设计了基于USB的现场总线实时网络数据采集器.该采集器能够脱离PC机独立完成实时采集数据和实时监控总线网络的任务.     

AT89S52单片机在空气压缩机监控系统中的应用

根据空气压缩机行业对控制系统的要求和特点,提出了一种基于AT89S52单片机的智能监控系统的实现方法,该监控系统采用上、下位机的结构形式,通过RS一485总线与上位机进行串行通讯,实现数据的网络互联,实现了压缩机的在线实时监测.     

基于Modbus RTU协议的燃气锅炉监控系统

在燃气锅炉监控系统中,DCS作为主站基于Modbus RTU协议,通过RS485总线与西门子S7-200 PLC、网络电力仪表ACR320E实现无缝连接,读取锅炉本体参数。DCS还作为从站基于Modbus RTU协议、以RS485总线方式与燃气调压站RTU通讯连接,被动接收燃气系统参数。DCS与S7-200 PLC、网络电力仪表ACR320E及燃气调压站RTU三者的互联,实现了燃气锅炉系统的全方位动态监控,运行效果良好。     

嵌入式微机在控制系统中的应用

介绍了采用嵌入式微机SC-12和USB接口芯片FT245BM的智能控制终端，它具有3种灵活的数据接口方式：以太网、USB和．RS485串行口。通过以太网连接可以实现灵活的远程数据获取与控制；通过USB串口总线，可以方便地进行现场数据的存取和设备的调试；而通过RS485总线可以使得一个嵌入式微机SC-12与40个挂接在总线上的控制模块进行通讯。     

RS-485总线网络应用中的安全与可靠性

控制领域中的分布式监控系统,具有节点多、传输距离远以及现场工作条件恶劣等特点,因此需要一种能够支持多节点、远距离通信及接收灵敏度高的总线来构成网络。利用RS-485总线构成的网络符合这种要求,如ARCNet、CAN、INTERBUS-S等,其物理层都是基于RS-485总线标准。使用RS-485总线构成自动控制系统的网络,具有设备简单,成本低等优点,但是如果在实际的工程应用中对RS-485总线网络配置不当,将会影响整个网络通信的可靠性,甚至会损坏总线收发器(特别是接收器)而造成整个网络的瘫痪。作者结合RS-485总线在雷达分布式监控系统中的应用,提出了保证RS-485总线网络的安全性、提高通信可靠性的方法,在实际使用中收到了良好效果。     

基于RS485网络的铸造生产线控制系统的研制

基于RS485网络技术构筑28个节点的集成PLC和智能仪器的铸造生产线控制系统。网络通信采用Modbus通信协议,网络连接器、电缆和中继器按PROFIBUS总线要求安装施工,系统RS485网络通过RS232/485转换器与PC主站连接。主站与从站采用查询问答方式,系统提供以太网接口,支持远程查询铸造生产线的运行状态和历史数据。基于485网络的控制系统结构合理、造价较低,实际应用表明该系统稳定可靠。     

基于RS485总线的变电所监测系统设计

论文介绍了一套基于RS485总线的分布式变电所监测系统,阐述了系统的总体结构和实现方法.分析表明,基于RS-485总线技术对变电所进行监测是切实可行的.     

基于Petri网的特种设备多协议转换系统设计与实现

面向特种设备智能化、大型化、高参数化发展态势,针对特种设备监测大数据汇聚需求,结合特种设备健康监测应用实际,该文开展特种设备多协议转换系统设计与实现,选择RS232,RS485,CAN总线和以太网等特种设备典型监测通信方式,分析特种设备多协议转换系统流程,应用Petri网模型理论建立特种设备多协议转换系统网络模型,对网络可达性、有界性、安全性、活性进行分析验证,最终实现特种设备多协议转换系统研发。     

电子电能表与电能测量技术讲座——第十九讲 基于RS485总线和以太网的电力自动抄表系统

介绍一种基于RS485总线和以太网、并采用组态软件实现的电力自动抄表系统。     

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...     

Quantum Cooperative Robotics and Autonomy

The intersection of Quantum Technologies and Robotics Autonomy is explored in the present paper.The two areas are brought together in establishing an interdisci...     

考虑进油孔有限长滑动轴承油膜力的近似解析解

针对具有进油孔的有限长滑动轴承油膜力求解问题,采用变分原理和分离变量法,求得了有限长滑动轴承油膜压力分布的近似解析表达式。将油膜压力分布的近似解析表达式在油膜存在区域上进行积分,即得到了油膜力。将提出的计算有限长滑动轴承油膜力方法与无限长轴承模型、有限元方法的计算结果进行了比较,发现了提出的方法与有限元方法的计算结果很接近。最后,研究了进油孔位置和进油压力对油膜存在区域、油膜力等的影响,研究结果表明进油孔位置和进油压力对油膜存在区域和油膜力有较大的影响。     

三绕组变压器的双绕组等效建模及在Matpower中的应用

针对实际电网存在着大量的三绕组变压器,但国际上一些著名商业软件,如BPA仿真软件、Matpower这一权威潮流计算开源软件,均只提供双绕组变压器模型,限制了其在具有三绕组变压器的电力系统中的应用的问题,潮流计算是自主开发的电力系统各种应用软件的核心模块,因此依托国际权威开源程序进行二次开发,是一种较好的选择。对Matpower要求的数据格式进行了归纳,对变压器的一般的等值电路及带理想变压器的等值电路和带标幺值的等值电路进行了分析研究,提出了三绕组变压器转换为双绕组等效模型的建模方法,使得原先只适应双绕组变压器的潮流计算软件可以适用于三绕组变压器电网的潮流计算;最后以Matpower软件为例进行了案例计算,并用PSASP仿真软件进行对比验证。研究结果证明,所提出的建模方法是有效的。     

On the Relation of Load to Average Gap in the Contact Between Surfaces with Longitudinal Roughness

A computer simulation model for the contact between longitudinally-oriented rough surfaces has been formulated. This model closely duplicates the actual surf ace contact deformation behavior by taking into account the elastic interactions between the asperities. There were no assumptions made about the shapes, or any deformation behavior of the asperities, except for their obeying the laws of elasticity. The plastic deformations on the high asperity peaks were taken into account by setting a ceiling on their contact pressures at the material hardness value. The simulations used real surface profiles which were digitized from unworn circumferentially ground steel surfaces. Each pair of these profiles was mathematically combined to form an equivalent rough profile pressing against an infinitely rigid flat and having the appropriately adjusted elastic modulus. A total of 28 different pairs of profiles were used in the simulations. Each contacting pair was subjected to 30 different load levels and the local contact pressures and deformations were calculated. The contact simulations yielded some important mathematical relationships between parameters, such as the real area of contact, average gap, and average asperity load through statistical curve fitting. Two analytical functions were generated to relate the average load to average gap and the real area of contact to load.     

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.     

电站锅炉模糊风险评价方法研究与应用

针对电站锅炉风险等级评价问题,将模糊综合评价技术应用到电站锅炉风险等级评价中。开展了电站锅炉失效影响因素及模糊评价因素的重要程度分析,建立了一套科学合理适于在线评价的电站锅炉风险评价体系,提出了模糊综合评价技术与改进的模糊层次分析法相结合的模糊风险评价方法,利用改进的模糊层次分析法计算了指标体系中各层指标权重。对某一台电站锅炉的实际运行工况影响子因素进行了模糊风险评价,采用模糊合成算子进行模糊综合运算得到电了站锅炉运行工况影响子因素的评价向量。研究结果表明:电站锅炉的运行工况影响子因素的风险评价等级为第6级,失效可能性等级为小,该电站锅炉运行工况良好。     

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....     

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.