基于HART协议的点-点智能压力变送器系统

论述了压力变送器的工作原理及HART协议在现场仪表中的应用，研究了基于HART协议的智能变送器及手操器的硬件结构、原理及软件功能描述，压力传感器采用MPX4100A集成硅压力传感器，CPU采用内带8路8位A／D的MC68H08，HART协议调制解调器采用A5191HRT。系统设计了完整的手操器及智能压力变送器的硬件电路及软件编程，实现了点对点的压力数据的采集和传输。     

基于HART协议的微差压智能变送器

在普通微差压变送器的基础上,设计了带有HART通讯协议的智能微差压变送器.介绍了整个智能变送器系统所涉及的硬件,阐述了系统的整体硬件结构以及通讯程序流程和数据采集流程.给出了部分的HART协议智能变送器的电路图,它可以实现HART协议变送器的基本功能.     

基于HART协议的智能温度变送器的软件设计

从HART协议智能温度变送器的功能和协议出发，分析了HART协议智能温度变送器的特点，并进行了软件设计。     

基于HART协议的智能温度变送器的硬件设计

HART协议是由模拟系统向数字系统转变过程中唯一向后兼容的智能仪表解决方案,它在兼顾现场总线好处的同时,保留对现有4～20 mA系统的兼容性.从HART协议智能温度变送器的功能和协议出发,分析了HART协议智能温度变送器的特点,设计了HART协议智能温度变送器实用电路,指出了硬件设计中应考虑到的问题.     

HART协议在分析仪表中的应用

介绍了本单位开发的基于HART协议的智能电导率变送器.文中对HART协议、变送器的硬件与软件设计以及HART协议的应用现状等均作了分析.     

试论带HART功能智能变送器的一般要求

本文讨论了HART协议智能变送器的基本功能和应用,也对常用的几种智能变送器从测量原理到性能进行了比较,并详细介绍了HART通讯的基本语言。     

基于HART协议的智能压力变送器的设计与实现

在传统压力变送器的基础上,研制了一种基于HART协议的两线制智能压力变送器。该压力变送器以低功耗16位嵌入式微处理器MSP430F435为核心,使用硅压阻式压力传感器。传感器输出微小电压信号经放大调理后送入微处理器内部12位A/D的测量,HART协议通信模块由A5191HRT型HART调制解调器与AD421电流环数模转换器构成。整个设计选用低功耗外围扩展器件,最大限度地降低整机功耗。     

用F744校准HART变送器

HART是Highway Addressable Remote Transducer的缩写,它定义了现场智能设备和传统的4～20mA控制系统之间的通讯协议.现已在工业现场广泛使用.采用这种协议,数字信号可以叠加在模拟信号之上进行传输,互不影响.因而,老式模拟变送器和先进的HART智能型变送器可混合在系统中使用.     

基于HART协议高精度智能温度变送器的研制

本文介绍现场总线式仪表HART协议智能温度变送器的功能特点，硬件设计，软件设计。     

HART智能变送器及其转换系统设计

介绍基于HART协议的智能变送器的硬件设计。在保证低功耗的前提下实现HART协议的物理层,并通过HART/RS232转换器与上位机通信,具有电路简单,低功耗的特点。     

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.     

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....     

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。     

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.