有源应答器C1接口硬件电路设计

针对RS-485链路和有源应答器C1接口采用不同的电平,提供一种标准转换方案,采用MAX485与FPGA芯片搭配的方式,在硬件上实现电平标准转换.在对MAX485芯片分析的基础上,设计出相应的外围硬件电路,采用TLP521芯片实现光耦隔离,避免电磁干扰或雷击损坏设备.     

Σ-Δ模数转换器工作原理及应用

∑-△模数转换器具有高分辨率、高集成度、成本低和使用方便的特点，近年来得到广泛的应用．文中从信号的过采样、噪声整形、数字滤波和抽取等方面，阐明∑-△模数转换器的工作原理．并在此基础上，介绍∑-△模数转换器的应用．     

重庆港集装箱码头三维模拟系统设计

以重庆港集装箱码头为实例,利用虚拟现实的方法和技术,混合使用Auto CAD、3D s MAX、Photoshop、Prem iere的技术集成,开发出了集装箱码头的三维可视化仿真系统。介绍了系统的设计方法,系统的构成和工作流程,并对系统中用到的关键技术进行了分析研究,系统虚拟的动画模拟可以为集装箱码头的运营管理提供决策依据。     

一种步进电机驱动器的设计

文中驱动器具有电位器接口,只要用户旋转电位器,就可以准确的调节电机转速;此外驱动器还具有RS-232控制接口,软件开发人员可以很轻松地完成对电机的控制.     

应用单片机实现点对点数据通信

介绍了一个51单片机串行通信应用实例,作为实现点对点数据传输的方法,并给出了实现电路和发送程序.     

Sensitivity analysis to assess the influence of the inertial properties of railway vehicle bodies on the vehicle's dynamic behaviour

A sensitivity analysis has been performed to assess the influence of the inertial properties of railway vehicles on their dynamic behaviour. To do this, 216 dynamic simulations were performed modifying, one at a time, the masses, moments of inertia and heights of the centre of gravity of the carbody, the bogie and the wheelset. Three values were assigned to each parameter, corresponding to the percentiles 10, 50 and 90 of a data set stored in a database of railway vehicles. After processing the results of these simulations, the analysed parameters were sorted by increasing influence. It was also found which of these parameters could be estimated with a lesser degree of accuracy for future simulations without appreciably affecting the simulation results. In general terms, it was concluded that the most sensitive inertial properties are the mass and the vertical moment of inertia, and the least sensitive ones the longitudinal and lateral moments of inertia.     

Influence of the track quality and of the properties of the wheel–rail rolling contact on vehicle dynamics

This work describes an analytical approach to determine what degree of accuracy is required in the definition of the rail vehicle models used for dynamic simulations. This way it would be possible to know in advance how the results of simulations may be altered due to the existence of errors in the creation of rolling stock models, whilst also identifying their critical parameters. This would make it possible to maximise the time available to enhance dynamic analysis and focus efforts on factors that are strictly necessary. In particular, the parameters related both to the track quality and to the rolling contact were considered in this study. With this aim, a sensitivity analysis was performed to assess their influence on the vehicle dynamic behaviour. To do this, 72 dynamic simulations were performed modifying, one at a time, the track quality, the wheel–rail friction coefficient and the equivalent conicity of both new and worn wheels. Three values were assigned to each parameter, and two wear states were considered for each type of wheel, one for new wheels and another one for reprofiled wheels. After processing the results of these simulations, it was concluded that all the parameters considered show very high influence, though the friction coefficient shows the highest influence. Therefore, it is recommended to undertake any future simulation job with measured track geometry and track irregularities, measured wheel profiles and normative values of the wheel–rail friction coefficient.     

路虎揽胜极光HSE DYNAMIC致动版 男友力MAX

“幸福就是,在我需要你的时候,你恰好都在”都说男人爱车如命,但我很负责地告诉大家,我们女人挑选车也是有标准的,在这个浮躁的时代,或许可能找不到24小时体贴又随时待命的好脾气男友,但伴我们每一天出入的爱车,一定要擦亮眼睛选选好,路虎揽胜极光HSE DYNAMIC致动版,绝对不二的男友力MAX选择.一想到夏天,就会联想到冰激凌、冰西瓜、穿短裤、去海边,还有暑期档电影.今年的暑期档电影也是看点颇多:张艺谋的《影》预告片依旧延续了老爷子MV美感的电影画面,     

GPS数据采集及动态显示系统的研究与实现

本文介绍了ROCKWELL公司生产的TU30-D400 OEM板的组成和特点,分析了NEMA 0183标准的数据格式.在Windows操作系统下,基于VB及其MSCOMM控件、结合MAX232实现的电平转换硬件接口电路,设计并实现了GPS信息采集系统.     

基于PLC的船舶航向控制系统的研究及实现

阐述了以SIEMENS S7-200 PLC为硬件平台,使用 CD40-147、SN74LS07和MAX7219集成块进行的先进的信号处理技术,并利用STEP7 Micro/Min V4.0 SP4编程软件的PID Wizard、PID-TUNE等高级指令进行编程实现了船舶航向控制.