Design of multi-channel data acquisition system based on LabVIEW and NI PXI-5105

A data acquisition system based on LabVIEW and NI PXI-5105 is presented for multi-channel data acquisition. It can realize the functions of parameter setting, data acquisition and storage, waveform display and data analysis using LabVIEW and NI-SCOPE device driver. The advantages of the system are that the setting is convenient, the operation is easy, the interface is friendly and the functions are practical. The experiment results show that the system has good stability and high reliability and is a powerful tool for multi-channel data acquisition.

Design and Implementation of a High-Speed Multi-Channel Data Acquisition System

A data acquisition system （DAS） to implement high-speed, real-time and multi-channel data acquisition and store is presented. The control of the system is implemented by the combination of complex programable logic device （CPLD） and digital signal processing （DSP）, the bulk buffer of the system is implemented by the combination of CPLD, DSP, and synchronous dynamic random access memory （SDRAM）, and the data transfer is implemented by the combination of DSP, first in first out （FIFO）, universal serial bus （USB） and USB hub. The system could not only work independently in single-channel mode, but also implement high-speed real-time multi-channel data acquisition system （MCDAS） by the combination of multiple single-channels. The sampling rate and data storage capacity of each channel could reach up to 100 million sampiing per second and 256 MB respectively.

Multi-channel & high-precision data acquisition devi ce for aerospace

This paper describes the detailed desi gn of data acquisition device with multi-channel and high-precision for aerosp ace.Based on detailed analysis of the advantages and disadvantages of tw o common acquisition circuits,the design factors of acquisition device focus o n accuracy,sampling rate,hardware overhead and design space.The me chanical structure of the system is divided into different card layers according to different functions and the structure has the characteristics of high reliability,conveni ence to install and scalability.To ens ure reliable operation mode,the interface uses the optocoupler isolated from th e e xternal circuit.The transmission of signal is decided by the current in the cur rent loop that consists of optocouplers between acquisition device and t est bench.In multi-channel switching circuit,by establ ishing analog multiplexer model,the selection principles of circuit modes are given.

Design and applicability analysis of independent double acquisition circuit of all-fiber optical current transformer

The advantages of the all-fiber optical current transformer include but are not limited to being small in size,having no magnetic saturation,exhibiting high measurement accuracy,and boasting strong electromagnetic interference resistance.However,the high cost of the all-fiber optical transformer limits its promotion and application in engineering.This paper proposes a design scheme of an independent double acquisition loop for the all-fiber optical current transformer based on the single optical path.Firstly,based on the closed-loop control mode and open-loop control mode,the twochannel sampling signal demand for relay protection,and the independent dual-acquisition loop design scheme of the all-fiber optical current transformer are proposed.Secondly,the reliability and economic feasibility of the scheme are demonstrated by an analysis of system failure and cost.The results show that the scheme can actualize the acquisition function of two independent all-fiber optical current transformer products on a single all-fiber current transformer in an integrated manner,which greatly reduces the cost of the all-fiber optical current transformer in engineering applications.

Development of data acquisition and over-current protection systems for a suppressor-grid current with a neutral-beam ion source

Neutral beam injection is one of the effective auxiliary heating methods in magnetic-confinementfusion experiments. In order to acquire the suppressor-grid current signal and avoid the grid being damaged by overheating, a data acquisition and over-current protection system based on the PXI（PCI e Xtensions for Instrumentation） platform has been developed. The system consists of a current sensor, data acquisition module and over-current protection module. In the data acquisition module,the acquired data of one shot will be transferred in isolation and saved in a data-storage server in a txt file. It can also be recalled using NBWave for future analysis. The over-current protection module contains two modes： remote and local. This gives it the function of setting a threshold voltage remotely and locally, and the forbidden time of over-current protection also can be set by a host PC in remote mode. Experimental results demonstrate that the data acquisition and overcurrent protection system has the advantages of setting forbidden time and isolation transmission.

Power Control and Data Acquisition System for High Power Microwave Test Bench

The 6 MW/4.6 GHz lower hybrid current drive （LHCD） system will be set up on the experimental advanced superconducting tokamak （EAST） for achieving a steady-state op- eration. The high power and continuous wave （CW） mode microwave test bench operating at 250 kW/4.6 GHz has already been finished, which can be used to simulate different kinds of high power microwave environments to test microwave components and units for the new LHCD sys- tem. The power control and data acquisition system on the test bench composed of power control, high reflected power protection and data acquisition function is described here in detail. Long- term operation of the test bench showed that the power control and data acquisition system is very stable and reliable.

采用模块化阵列的涡流探伤检测

针对工业领域的金属无损探伤中常常存在一些复杂部位,难以采用常规检测手段进行检测的问题,提出了一种优化探头结构的方法。将模块化理念引入涡流探伤中,设计并开发了一种模块化的涡流探伤系统。该涡流探伤系统将现有的互感式探头结构与电桥式探头结构相结合,结合2种结构各自的优势,以探头线圈上的感应电压值为缺陷检测的特征量,通过单片机将数据传输至以LabVIEW软件搭建的上位机并进行特征显示。测试结果表明,该系统能够检测到缺陷位置产生的感应电压值与无缺陷位置感应电压值的不同,验证了该设计的可行性,能够对金属表面缺陷进行高灵敏度的检测,实现了有效地判断金属材料缺陷位置的目的。

考虑质量比影响的双圆柱涡激振动发电装置数值模拟研究

双圆柱涡激振动发电装置是一种利用海流能发电的新型能源装置。该研究使用Fluent软件模拟了双圆柱涡激振动发电装置的水动力特性。利用用户自定义函数和动网格技术实现了圆柱振子的流固耦合模拟,分析圆柱振子的涡激振动特性。首先,进行网格和时间步长的无关性验证,证明了该数值模拟的准确性;其次,从位移时程曲线、幅值、频率三个方面分析圆柱振子的涡激振动特性;最后,通过对等质量比下串列双圆柱涡激振动发电装置圆柱振子的获能功率及能量转换效率的分析,研究质量比对双圆柱涡激振动发电装置的俘获能特性的影响。研究表明:当质量比m^(*)=3、4、5时,下游圆柱的横流向振幅随约化速度的增加而逐渐大于上游圆柱的横流向振幅;不同质量比下双圆柱振子的横流向无量纲振幅均呈现先随约化速度的增加而增加,然后又减小的趋势;当质量比m^(*)=4时,上、下游圆柱的能量转换效率最高,分别为32.6%、22.8%;当质量比m^(*)=5时,下游圆柱的能量转换效率最高,为30.5%。

基于无线同步通信的变电站漏电流检测系统研究

变电站站用电系统是保障变电站安全稳定运行的关键,电缆中的漏电流可能引发沟道着火等严重事故。固定式监测装置存在造价成本过高、推广难度大等诸多不足。针对站用电系统漏电流的准确检测问题,研发了一套新型的站用电系统漏电流检测系统。该系统由多个无线采集终端构成,具备多通道同步采集、自动数据通信、电流矢量和计算等功能,可实现变电站站用电系统漏电流的精确检测与缺陷的精准定位,从而及时消除事故隐患。为验证所研发系统的有效性与准确性,在变电站现场进行了实际检测,排查发现并处理了多处站用电系统漏电流隐患。结果表明,所研发系统能够快速、有效、准确地检测站用交流系统的运行情况,具有较高的经济性与实用性,有助于保障变电站的安全稳定运行。

多通道脉冲电流自动化检测设备

多通道点火控制装置可控制航天器实现调姿变轨;针对多通道点火控制装置在大批量生产中点火脉冲电流自动化程度低、检测效率差、缺乏数值化表征的问题;提出一种对多通道点火设备脉冲电流采集检测的自动化改进方法,并研制了多通道脉冲电流自动化检测设备;该设备采用模拟数字转换器和基于SDLC(同步数据链路控制)通讯协议的控制系统,建立对于待测产品与检测设备之间集中控制和信息交互,实现对点火信号全周期采集,降低了人为错误风险和偏差;经实验测试,设备对全周期点火电流值的检测最大偏差不大于5%;经部署、工艺验证和长期使用,证明了该设备在提高测试效率、降低成本和改善质量方面取得了显著成果,已应用于某型发动机控制装置的检验测试作业。

基于语料库的汉语习得研究现状及展望

本文基于中国知网全文数据库,采用AntConc3.5.8语料分析软件,对国内基于语料库的汉语习得研究进行了全面统计和分析。考察发现,相关研究可能已步入稳定期,近几年来相关研究持续高产,并以强烈的应用导向为特色。当下研究主要存在研究点分布不均和研究理念相对滞后的问题,究其原因,除了语料库资源的局限外,也与习得研究中的误区有关。未来研究的发展,一方面要求对语料库资源系统进行更新,一方面要求对研究者群体的学术能力予以加强。

面向水泥生产过程的石灰石粒度控制预警

本文介绍了一种对破碎机工作效率进行优化的方法。具体来说,我们在石灰石卸料坑的上方安装了摄像头,用于监控石灰石的粒度情况。当有超规格的石块进入卸料坑时,我们可以通过提前预警的方式通知下游的板喂机,以便其能够提前调整速度和进行预判,从而避免破碎机因为过大的石块而出现卡顿等问题,提高其工作效率。这种方法可以有效地减少生产过程中的停机时间和维护成本,提高生产效率和产品质量。

基于改进EMD阈值的伺服电机驱动控制仿真

伺服电机在运动过程中会产生噪声,影响控制精度,为此提出基于改进EMD阈值的伺服电机驱动控制方法。建立驱控一体的伺服电机数学模型,分析伺服电机驱动性能;通过伺服电机的速度检测和位置检测推导出伺服电机驱动控制的给定三相电流值,通过霍尔电流传感器采集电机实际电流,并通过改进EMD阈值小波滤波方法对采集到的电流实行去噪处理;在伺服电器驱动控制模型内计算给定三相电流值与实际电机电流的差值,在输入线性放大器内实现驱控一体的伺服电机驱动控制。仿真结果表明,所提方法的驱控一体伺服电机驱动控制精度高、抗干扰性强、效果好,更适合于实际应用。

一种高精度单极性交流电有效值测量电路设计

交流电的精确计量是众多用电行业终端设备不可或缺的基本需求。为了实现这一目标,采用单片机、电流互感器、电压互感器和单极性模数转换器设计了一种高精度单极性交流电电流电压测量电路。基于交流电有效值的定义,结合单片机实现了算法矫正,以提高测量精度。用高精度电流电压测量仪进行对比试验,结果显示,该测量电路的误差率成功控制在了千分级。该测量电路可应用于充电桩、逆变器等设备的电流电压检测。

基于STM32F103的电流检测系统设计

在电力系统中,实时检测系统的电流大小非常关键。基于STM32F103芯片设计了一款实时检测电路中电流大小的设备,该设备测得的电流通过LCD显示出来,便于观察,另一方面将这些实时的数据储存在SD卡设备上,对数据进行记录。该设备加入了FreeRTOS实时操作系统,更合理有效地利用CPU的资源,简化应用软件的设计,缩短系统开发时间,更好地保证了系统的实时性和可靠性。

输电线路防误操作装置的设计原理与技术实现

输电线路防误操作装置通过电流采集和无线通讯技术,实现对接地刀闸状态的自动检测,并通过闭锁结构控制测试引线的松开,确保测试人员的安全。系统由防护装置模块、电流测量模块和线路参数测试模块组成,通过各模块之间的通讯和协作,实现了对输电线路防误操作的有效控制和保护。

用于电缆接头故障检测和预警的数据采集终端

电缆接头是煤矿供电系统电缆线路中最薄弱的环节,很容易出现故障。基于成熟的检测技术、先进的物联网通信技术,电缆接头故障检测和预警系统可以快速有效检测电缆接头的工作状态,并及时发现电缆绝缘的缺陷,电缆接头出现异常的短时间内实现快速定位。数据采集终端是电缆接头故障检测和预警系统的基础和核心,为保证煤矿供电系统的稳定性提供了可靠信息支撑。

电源监测电路的优化设计

针对综合测试设备常工作在高温、高压、高冲击等突变恶劣环境中,供电系统的不稳定输出导致了整个测试系统的可靠性和测量精度不够等问题,提出了一种高精度、高稳定性的信号监测电路。该电路首先通过霍尔传感器和分压电路对输入的电源信号进行调理,通过A/D的高精度采集和FPGA的高速数据处理保证采样值的准确性。数据通过FPGA实时传输到上位机进行数值和波形显示以及存储等。经实验验证,该电路可以实现输入电源信号的电流值和电压值的高精度采集,上位机端可以实现采样值的实时显示,实现了综合测试系统的供电电路的实时监测,并且该电路体积较小,便于安装于测试设备内部,数据的实时性良好,有较好的实用价值。

基于工业自适应的多通道数据采集设备分析

此设备由STM32主控、电压处理电路、电流处理电路、外部FLASH电路以及显示模块组成。该设备使用STM32作为主控,可以实现8个通道的12位电压数据采样和4个通道的电流数据采样,ADC采样周期可以达到10μs以内。电压采集范围为-40~40V,电流采集范围为4~20mA。采集的数据准确且稳定,可以通过显示屏幕进行查看,并且此设备为外部FLASH移植了FatFs文件系统,可以很方便地通过电脑查看数据。

基于双电极传感器的腐蚀电流检测系统抗扰技术

目的针对金属电化学腐蚀中腐蚀电流检测,设计一种高精度I-V转换的微电流检测电路,突破宽范围微弱电流高精度检测技术。方法通过分析电路的稳定性,针对100 pA~10 m A的微弱腐蚀电流采集,采用法安级偏置运放实现I-V转换,设计基于ADG708电子开关的8档自动调节电路,并通过24位ADC实现高精度模数转换。针对微弱电流采集中信号易受噪声的影响,设计自适应滤波器用于信号滤波处理。结果通过MATLAB仿真自适应滤波器的有效性,结果表明,在采集i(k)=2sin(2πk)电流时,误差从0.29m A(1σ)降低到0.0039 mA(1σ)。通过电流源校准测试系统精度,在100 pA时误差最大,为4.7%;在10 mA时误差最小,为0.049%。当电流值低于100 nA时,测量误差可以控制在5%以内;100 nA以上时,测量误差可以控制在1%以内。结论在微弱电流采样中引入自适应滤波器后,系统的采样精度显著提高,突破了宽范围的腐蚀电流采集技术,实现了微弱电流检测。可以将腐蚀电流应用在金属腐蚀速率的评价中。