基于虚拟仪器技术的嵌入式计算机自动测试系统

基于PXI平台设计了某产品嵌入式计算机自动测试系统,该系统采用虚拟仪器技术,软件基于IabVIEW 8.0开发设计.测试系统由某产品嵌入式计算机、PXI-1042机箱、PXI-8186控制器、PXI-7811R智能数字RIO卡、PXI-6224数据采集卡、PXI-6713模拟输出卡和基于虚拟仪器的人机界面组成.该系统可模拟生成测试所需的多种激励信号及传感器信号.可在不需要载机参与的情况下实现某产品嵌入式计算机系统的自动测试、检验和分析,提高了产品检测的效率和可靠性.     

3U系统控制器PXI-3800

凌华科技推出采用嵌入式芯片组Intel855GME图形内存控制器中心(GMCH)和6300ESBI／O控制中心(ICH)的PXI-3800产品。PXI-3800是符合PXI2．2版规格的PXI系统控制器，支持1．8GHz Pentium M CPU、热插拔CompactFlash卡、USB2．0端口和Gigabit以太网络等技术。PXI-800专门设计的散热装置能在无风扇的系统中，或高温条件下散热。该系统还在前面板上提供两个USB2．0接口、两个COM接口、一个并口和一个立体声输出等多个I／O接口。     

凌华PXI切换器模块-PXI-7900系列——多国仪器仪表展上大放异彩

亚洲最大的PXI量测自动化模块厂家凌华科技在2004年9月14~17日于中国国际展览中心(北京)举办的“第十五届多国仪器仪表展览会(MICONEX2004)”上展出PXI/PCI/ETX等系列产品,呈现给广大用户一套丰盛的量测自动化大餐。这次是凌华历届参会中量测自动化展品最多最全的一次展出。此次参展的PXI切换器模块-PXI-7900系列,是凌华第一个PXI规格的切换器模块系列,首阶段推出包含PXI-790116通道通用型继电器模块、PXI-792124通道扫描/多路切换器模块以及PXI-793148两线式矩阵模块等三款专为工业自动化量测系统而设计的切换器模块。PXI-…     

基于NIPXI-5105的多通道数据采集系统的设计(英文)

描述了基于LabVIEW软件和NI PXI-5105的多通道数据采集系统。利用LabVIEW和NISCOPE,实现了系统的参数设置、数据采集和存储、波形显示以及数据分析等功能。该系统设置简便,操作简单,界面友好,功能实用。实验结果表明,系统具有良好的可靠性和稳定性,是进行多通道数据采集的有力工具。     

PXI-5154量化仪

日前,美国国家仪器有限公司（National Instruments,简称NI）推出NI PXI-5154量化仪／基于PC的示波器,大大增加了拥有20多个高端、高精度和高通道数的相关产品种类。具备双通道的1GHz PXI-5154量化仪可提供高达2GS／s的实时采样率（对于重复信号,可达20GS／s的等时采样率）,     

PXI-6132在自动测试系统开发中的应用

介绍虚拟仪器技术及虚拟仪器程序设计的LabVIEW图形化集成开发平台、高精度数据采集卡PXI-6132在自动测试系统中用于数据采集程序的开发方法,以及利用PXI-6132数字I/O端口产生数字信号,实现对多路电源选择电路进行控制的实现方法和控制程序流程.实际开发证明,在LabVIEW开发环境下,利用PXI-6132可满足自动测试系统数据采集的需求,实现对多路电源选择电路的有效控制,缩短开发周期,提高开发效率.     

基于LabVIEW的任意波形发生器设计

设计并实现了靶场测试环境中的用于检验光电靶后续设备的任意波形发生器。该系统硬件包括PC机、PXI-1000B机箱、MXI-3外置控制器和PXI-6025E数据采集板卡。该波形发生器在上述硬件的基础上,利用图形化编程软件LabVIEW编制了用户控制软面板。系统主要功能包括:产生各种标准波形,利用鼠标绘制任意波形,波形编辑,任意波形输出等,能满足实际测试的各种需要。     

新型R系列I／O模块

日前,美国国家仪器有限公司（简称NI）推出4种用于PXI平台的新型R系列I／O模块,这些模块都配备了高性能的Xil-inxVirtex@-5现场可编程门阵列（FPGA）芯片。NIPXI-7841R,PXI-7842R,PXI-7851R和PXI-7852R模块具有8个模拟输入、8个模拟输出和96个数字I／O通道,而且模拟输入的速率比以前版本的R系列设备快3．5倍以上。这些新型模块为工程师和科学家们提供了即时可用的硬件;不仅如此,这些硬件还可通过NILabVIEWFPGA软件进行图形化编程,在板卡上进行自定义的功能以满足需要特殊时序和触发条件的应用,如在线数据分析和确定性I／O控制等。     

NI推出最新1GHz带宽的PXI量化仪

美国国家仪器有限公司（National Instruments，简称NI）近日推出NI PXI-5154量化仪／基于PC的示波器，大大增加了拥有20多个高端、高精度和高通道数的相关产品种类。具备双通道的1GHz PXI-5154量化仪可提供高达2GS／s的实时采样率（对于重复信号，可达20GS／s的等时采样率），满足了高速、接近纳秒速率的信号采集。     

NI PXI-2575多路开关模块

NI PXI-2575高密度多路复用开关模块具有196个单线制通道或98个双线制通道，可以向测量设备发送或从被测源接收数百个信号。每一通道均使用继电器，转换能力达100VDC／100VAC或lA。PXI-2575开关的扫描速度高达每秒140圈，是高通道数据记录和自动化测试应用的理想前端设备。这一开关模块与NI PXI-407x系列Flex DMM无缝地集成，可用于高通道电压、电阻、电容和电感的测量。     

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.     

Limits of topographic measurement by the scanning tunnelling and atomic force microscopes

Parameters describing the topographic character of a surface (height, surface wavelength, slope and curvature) can be derived from equivalent sinusoidal profiles. The response of a surface-measuring instrument may be modelled in terms of instrument parameters such as stylus radius, and scanning range and resolution. The performance of the instrument may then be mapped as a zone in amplitude-wavelength (AW) space to show the sinusoidal profiles it is capable of measuring. In a first-order analysis the STM and AFM are considered as equivalent to contact-stylus instruments with a notional stylus radius equal to the tip radius plus the gap. Comparisons between different instruments and types of instrument are readily made by mapping in AW space. The error arising from convolution of the sinusoidal profile with that of the finite tip may be quantified and plotted as contours in AW space.