Precision Data Acquisition Research Articles

Application and Research of High Precision Data Acquisition for Laser Gyro

With the wider and wider application of laser gyro in the high precision strapdown inertial navigation system, high precision data acquisition and processing is becoming more and more important. In this paper, the output signal of the laser gyro characteristics are divided, FPGA is used to measure the signal acquisition demodulation, frequency multiplication, counting and other functions of the laser gyro signal acquisition. FIR filtering algorithm is used in DSP to extract the angular velocity signal.

Development of models for forest variable estimation from airborne laser scanning data using an area-based approach at a plot level

Airborne laser scanning (ALS) is increasingly used in the forestry over time, especially in a forest inventory process. A great potential of ALS lies in providing quick high precision data acquisition for purposes such as measurements of stand attributes over large forested areas. Models were developed using an area-based approach to predict forest variables such as wood volume and basal area. The solution was performed through developing an object-oriented script using Python programming language, Python Data Analysis Library (Pandas), which represents a very flexible and powerful data analysis tool in conjunction with interactive computational environment the IPython Notebook. Several regression models for estimation of forest inventory attributes were developed at a plot level.

Multi‐directional response of unreinforced masonry walls: experimental and computational investigations

SummaryThis paper describes the results of an experimental and numerical study that focused on multi‐directional behavior of unreinforced masonry walls and established the requisite of the related proposed design equations. The tests were conducted following several sets of multi‐directional loading combinations imposed on the top plane of the wall along with considering monotonic and cyclic quasi‐static loading protocols. Various boundary conditions, representing possible wall–roof connections, were also considered for different walls to investigate the influence of rotation of the top plane of the wall on the failure modes. The results of the tests were recorded with a host of high precision data acquisition systems, showing three‐dimensional displacements of a grid on the surface of the wall. Finite element models of the walls are developed using the commercial software package ABAQUS/Explicit compiled with a FORTRAN subroutine (VUMAT) written by the authors. The experimental results were then used to validate the finite element models and the developed user‐defined material models. With the utility of validated models, a parametric study was performed on a set of parameters with dominant influence on the behavior of the wall system under in‐plane and out‐of‐plane loading combinations. The experimental and numerical results are finally used to investigate the adequacy of ASCE 41 empirical equations, and some insights and recommendations are made. Copyright © 2016 John Wiley & Sons, Ltd.

Computerized Measurement and Control System of the Universal Testing Machine Based On Virtual Instruments

The measurement and control system of the universal testing machine was carried on the data acquisition and processing and realized the closed-loop control of the actuators. This is a complete automated test platform of computer measurement and control technology. The electronic universal testing machine control system was designed and realized basing on the analysis of the related technologies and requirements. The system solves the determination of mechanical properties of materials such as tensile, elongation, force, deformation and displacement of essentially all metallic and non-metallic materials and it assumes good performance. This study has presented test results of six different materials specimens namely: plastic strip (fiber-reinforced polymer), brick masonry, floor tile, chamois leather bag, polyethylene polymer and polystyrene foam. The system uses a user-friendly dialog, it automatically measures material specimen, it compares the results with the standard national values and it can pass or reject unwanted materials. The measurement and control software for the host computer and electronic drive control system of electronic universal testing machine was realized by LabWindows/CVI software development platform. The user-interface provides features for the complete real-time measurement, control, data processing, output results display, report printing and other functions. Practice has proved that, under normal circumstances the system operation is stable and reliable, real-time data acquisition precision has reached the expected requirements as well as making system maintenance to be convenient and flexible.

Design, Implementation, and Characterization of Precision Timing for Bistatic Acoustic Data Acquisition

One of the challenges presented in using autonomous underwater vehicles (AUVs) for remote data collection is accurate time synchronization. In the case of bistatic acoustics, synchronization is required between AUV and source so that the time in which each ping is sent out is exactly known. There are three key obstacles to achieving this. First, the vehicle is submerged and therefore unable to access common time references directly. Second, the required accuracy in data acquisition far exceeds that possible using a computer clock to trigger data collection. Finally, to achieve accuracy in microseconds, the system must be characterized to eliminate delays introduced by filtering and analog-to-digital conversion. This paper describes the implementation and characterization of an accurate and precise timing and data acquisition system used on an AUV to collect acoustic array data. The timing was achieved using a combination of global positioning system (GPS) pulse-per-second (PPS) for synchronization on the surface and the Microsemi (Aliso Viejo, CA, USA) chip scale atomic clock (CSAC) for timing while submerged, with a PPS triggered data acquisition system. Characterization and calibration procedures were developed to ensure that the system met the experiment requirements, which included less than one percent of a wavelength error in phase, and one tenth of a meter accuracy in range. Analog and digital delays in the system were determined, and a method was demonstrated to further improve accuracy by dynamically estimating digital delays. The steps outlined in this paper for achieving precision data acquisition could be applied to many other remote systems that require similar microsecond accuracy.

High Precision Analog Multiplexers Enable Multi-Channel Data Acquisition in High Temperature Environments

Abstract A growing number of industries are calling for low power electronics that operate reliably at temperatures of 175C and higher. Many of these applications require a precision data acquisition signal chain in order to digitize analog data so that it can be collected and processed. We previously presented a characterized signal chain for a single channel of analog to digital conversion designed around a 600ks ps SAR ADC. However, many systems have a multitude of sensor signals that must be acquired at varying sample rates. In this work we discuss two new analog multiplexers rated for 175°C/210°C that allow multiple analog signals to be connected to the ADC input, enabling the design of a precision multi-channel data acquisition system. One multiplexer is designed on a robust dielectrically isolated process for high performance and low leakage over temperature, and one multiplexer is optimized for low power, low voltage applications. We will examine the architecture of these two integrated circuits, review the characterization over temperature and discuss example application signal chains.

IMAGE BASED EVALUATION FOR THE DETECTION OF CLUSTER PARAMETERS IN GRAPEVINE

Automated image interpretation is a powerful instrument for the acquisition of objective and precise phenotypic data with high throughput. Cluster length, cluster width, berry size and cluster compactness are four important phenotypic traits with impact on cluster morphology, health status and yield. For the image-based evaluation of this grapevine cluster morphology traits, the automated Cluster Analysis Tool (CAT) was developed in Matlab®. The comparison of precise reference measurements with CAT ratings on 100 cluster of ?Riesling? and ?Pinot Noir? showed a significant correlation of r=0.94 (0.97) for cluster width, r=0.90 (0.95) for cluster length and r=0.61 (0.23) for berry size. Variation of compactness could be detected in a crossing population calculating a compactness factor. To assess grapevine cluster morphology traits under laboratory conditions the automated image interpretation tool CAT presents a fast and user-friendly tool. The present study provides an improved and relevant phenotyping method for grapevine breeding. It could also be applied in genetic and ampelographic studies.

A versatile spatial resolution enhancement method for data acquisition

While acquiring specific physical properties within a targeted area, spatial resolution of hardware is usually one of the major limitations that affects the precision of data acquisition. Though measured results with higher spatial resolution are always desired, adequate configuration of hardware setups sometimes implies higher cost or longer acquisition time. In this study, a versatile resolution enhancement method is proposed to improve the sampling resolution. An efficient algorithm is used to convert the lower-resolution data into higher-resolution approximation. Three different engineering applications are used to verify the effectiveness of the proposed method. From the arithmetic results, the spatial sampling resolution can be greatly improved without trading-off the operating time.

Design of Data Acquisition System Based on Ethernet and Virtual Instrument Technology

Ethernet based on TCP/IP is a standard open network, which promotes the development of data acquisition in the direction of network. Data acquisition and processing systems connected by Ethernet make the data acquisition terminals (lower computer) and processing control center (upper computer) from integrated to discrete. Separate data acquisition terminals can realize miniaturization and modularization and increase the flexibility of the application. A new type, low cost, high precision data acquisition terminal based on ARM processor was designed for solving the problem of complicated structure, big volume and high cost of traditional data acquisition system. Combined with the technologies of network communication, a data acquisition PC system based on virtual instrument technology was designed by LabVIEW.

A Low Power Data Acquisition Solution for High Temperature Applications

An increasing number of industries are calling for low power electronics that operate reliably at temperatures of 175°C and higher. Many of these applications require a precision data acquisition signal chain in order to digitize analog data so that it can be collected and processed. We have previously presented a new 600 kSPS SAR ADC that is rated at 210°C to meet these needs. However, the design of the supporting circuitry for a SAR ADC to achieve optimum performance is not trivial, especially over this wide temperature range. In this work we discuss the design of a complete data acquisition circuit building block that will take an analog sensor input, condition it, and digitize it to an SPI serial data stream. We will also discuss some of the practical aspects of fabricating the circuit to survive this harsh environment. This circuit reference design will be published and available off the shelf to designers of harsh environment systems.

Development of Temperature and Magnetic Field Monitoring System of ITER HTS Magnet

The temperature and magnetic field data acquisition system is developed for HTS Magnet of ITER. According to its working environment, the type of probes used for detection and the corresponding supporting equipment are chosen. Based on the requirements of data acquisition precision, the selection of the data acquisition instruments is completed. Optimize the number and configuration of probes and keep key monitoring on its Conduction-cooled structure. A complete set of complete data collection and human-computer interaction system is designed by using LabVIEW.

Design and evaluation of a remote measurement system for the online monitoring of rail vibration signals

The dynamic strain and vibration acceleration are two key parameters in the monitoring of vibrations that can damage track and affect the safety of railway traffic. This paper presents a remote measurement system for the online monitoring of train-induced vibration responses in rail tracks. A precision data acquisition node is designed for the conditioning and monitoring of the vibration signals generated by trains traveling at full speed. The monitored data is remotely acquired using a wireless sensor network. Furthermore, the use of solar power significantly increases the long-term service life of the system. The system is validated using both laboratory tests and a field deployment over a period of several months on an in-service high-speed railway. The obtained results indicate that the remote measurement system can accurately collect dynamic strain and vibration acceleration signals in a rail; these signals can be processed and analyzed to allow timely maintenance actions.

A three-dimensional microdisplacement sensing system based on MEMS bulk-silicon technology.

For the dimensional measurement and characterization of microsized and nanosized components, a three-dimensional microdisplacement sensing system was developed using the piezoresistive effect in silicon. The sensor was fabricated using microelectromechanical system bulk-silicon technology, and it was validated using the finite element method. A precise data acquisition circuit with an accuracy of 20 μV was designed to obtain weak voltage signals. By calibration, the sensing system was shown to have a sensitivity of 17.29 mV/μm and 4.59 mV/μm in the axial and lateral directions, respectively; the nonlinearity in these directions was 0.8% and 1.0% full scale, respectively. A full range of 4.6 μm was achieved in the axial direction. Results of a resolution test indicated that the sensing system had a resolution of 5 nm in the axial direction and 10 nm in the lateral direction.

Design on Measuring System of New Type Electrical Resistivity Imaging Exploring Ground Instrument

Aiming at the deficiencies of single signal of electrical resistivity imaging instrument, poor anti-interference, fixed electrode arrangement and low-sampling accuracy, etc, this paper designs a new type of high-density exploring ground instrument. Based on MCU as controller, the transmitter uses MOSFET tube driving H bridge circuit to transmit any digital code current signal. Based on FPGA as master controller, the receiver uses 24 bit ADC chip to sample the data, designs the key circuit such as reference source, clock and single-ended to differential, accomplishes high precision data acquisition. Distributed intelligent electrode conversion device uses low power relay, so it is very small and low power consumption. We did the noise test and repeated measurement experiments on pure resistance on this instrument. The experimental results show that the transmitting signal is stable, waveform is standard, resistance curve tested by collecting system and actual curve are coherent, the precision is high and the stabilization is good.

PRECISION DATA ACQUISITION (DAQ) MODULE WITH REMOTE REPROGRAMMING

These papers are designed precision data acquisition unit based on a 24- bit ADC type AD7712. It is designed for use in distributed information-measuring systems and networks. Flow data collection allows remote reprogramming - a replacement program of work through the serial interface during operation ( after the identification of the appropriate command ). Flow data collection to automatically perform the following procedures designed to improve the accuracy of the measurement result of : (i) the zero ; (ii) the calibration of exemplary source voltage; (iii ) correction of temperature coefficient of exemplary source voltage; (iv ) correction of quadratic integral non-linearity error of the ADC. Implementation procedures improve the accuracy of measurement error provides acceptable DC voltage ± 0.01% in working conditions and non-linearity of the transformation of not more than ±0.0003%.

English

This paper presents the numerical and experimental investigations of a wavy fin-tube heat exchanger aimed at correctly accounting for all factors influencing the thermal performance of the exchanger. The shape factor for the complex heat conduction path in the wavy fin is determined by using computational analysis and validated experimentally by utilizing electrical analogy to obtain the electric resistance across the fin. This is used to back-calculate the conduction shape factor. In the experimental study, the potential difference, V and current, I, was measured using a high precision data acquisition unit. The results were used to calculate the shape resistance which was compared with that obtained from the numerical model. Grid independence tests were performed on the model and several analytically derived standard shape factor formulae were also used for comparison with the model outputs. The deviation of the numerical results from the analytical formulae for the cases studied was less than +1.2%. The agreement between the experiments and the numerical model was within +3.5%. The results demonstrated the adequacy of the numerical approach to modeling the wavy fintube heat transfer. Effects such as differences in fin shape, fin length and waviness of the fin design on the shape factor were determined and discussed.

Quality and integrity in the production and publication of scientific results: data trimming, manipulation and (self) plagiarism

The publication of scientific manuscripts is an essential part in the research process and in the attempt to produce novel knowledge: only what is published exists. It is the aim of research to produce reproducible and sustainable knowledge. Reproducible knowledge is based on precise observation, the use of modern methodologies and an appropriate statistical analysis. As a consequence, it must be the intention of any scientist to report the truth and nothing but the truth. This principle requires precision and honesty. Deviation from such a behavior may lead to scientific misconduct: It encompasses the use of inappropriate methods and/or statistics, double publication of data, sloppy data presentation and processing, up to data massaging, manipulation, data theft or fabrication. Famous examples can be found throughout the history of research but it appears that such behavior has recently become more common possibly due to excessive competition, the crucial role of grants for scientific productivity and funding as well as promotion. Accordingly, in the training of researchers it seems essential to emphasize the importance of precise data acquisition and analysis to ascertain reproducible data. Similarly, it must be assured that data sets are only published once, that authors have contributed technically and/or intellectually in an important manner and that the work of other scientists is cited appropriately. Editors and reviewers should carefully assess the quality of submitted manuscripts. In fact, it is the aim of the peer review process to assure as much as possible that the quality of submitted manuscripts meets current methodological as well as ethical standards.

Error analysis of spatial interpolation of soil texture under different sampling schemes

为研究土壤质地的合理取样方式, 进而研究其空间变异情况, 为田间施肥及灌溉提供依据, 本试验利用地统计学方法和GIS技术, 在重庆市彭水县重庆烟草试验站, 利用289个表层土样, 研究了16 m间距的栅格取样法(对照, 253个土样, 扣除36个验证样点)、34 m间距的栅格取样法(115个土样)和随机取样法(115个土样)3种取样方式下土壤质地的空间插值精度。3种土壤颗粒指标中粉粒占68.43%, 砂粒含量最少, 占12.68%, 黏粒含量略高于砂粒。砂粒和黏粒具有中等强度的变异性, 粉粒具弱变异性, 且数据符合正态分布。地统计分析显示, 在分析该区域土壤质地时, 采用栅格取样方法应适当增大取样间距, 而采用随机取样方法可适当缩小取样间距。交叉检验显示, 土壤质地成分在3种取样方式下的插值精度均以对照最大, 栅格取样次之, 随机取样最小。综合考虑插值误差、样品采集和分析成本及时效性等因素, 本研究建议在该区域进行土壤质地空间变异规律分析为生产服务时应采用随机取样。

Design of Data Acquisition System in Friction Wear Testing Machine Based on Virtual Instrument LabVIEW

Friction wear testing machine is generally used in researches of various friction wear mechanisms, explorations of influences factors, and property evaluations of friction pair materials. Measurement accuracy and automation level of the friction wear testing machine directly influence the precision of data acquisition and analysis processing, as well as the intuition of data displaying. Based on virtual instrument LabVIEW, a data acquisition system of friction wear testing machine was developed. Hardware of this data acquisition system mainly consists of sensors utilized as acquiring information on rotate speed, normal pressure, friction force and temperature, as well as signal conditioning module and data acquisition card. Utilizing the LabVIEW, data processing and interface displaying software was programmed. Debugging results confirmed that the developed system can accurately acquire the demand information when operating the friction wear testing machine, also intuitively display these obtained information in real-time. Therefore, the developed data acquisition system satisfies the demand of precisely acquiring information related to friction wear testing of experimental materials.

A digital long pulse integrator for EAST Tokamak

A digital integrator has been developed to be compatible with the long pulse plasma discharges on the Experimental Advanced Superconductor Tokamak (EAST), in which the induced signal is modulated by a chopper, and a field programmable gate array (FPGA) in the 16-bit digitizer is used to realize the digital integration in real time. After rectification and integration, the drift is almost linear and stable in controlled temperature, so a period of 50s is used to determine the linear drift rate for drift compensation. The integration data can be directly transferred to the reflective memory (RFM) card, which is installed in the same PCI eXtensions for Instrumentation (PXI) chassis, so the data transmission can be also done in real time. The test results show that the real time data transmission rate is up to 10kHz, the integration drift is typically less than 0.4uVs/s and drift performance is a little worse in real long pulse discharge, which can be reduced further by using more precise data acquisition.