scholarly journals Analysis and application of two-current-source circuit as a signal conditioner for resistive sensors

2017 ◽  
Vol 68 (3) ◽  
pp. 200-205
Author(s):  
Adam Idzkowski ◽  
Jerzy Gołębiowski ◽  
Wojciech Walendziuk
Keyword(s):  
Data Acquisition ◽  
Measurement System ◽  
Measurement Errors ◽  
Current Source ◽  
Laboratory Measurement ◽  
Relative Resistance ◽  
Circuit Realization ◽  
The Difference ◽  
Circuit Output

Abstract The article presents the analysis of metrological properties of a two-current-source supplied circuit. It includes such data as precise and simplified equations for two circuit output voltages in the function of relative resistance increments of sensors. Moreover, graphs showing nonlinearity coefficients of both output voltages for two resistance increments varying widely are presented. Graphs of transfer resistances, depending on relative increments of sensors resistance were also created. The article also contains a description of bridge-based circuit realization with the use of a computer and a data acquisition (DAQ) card. Laboratory measurement of the difference and sum of relative resistance increments of two resistance decade boxes were carried out indirectly with the use of the created measurement system. Measurement errors were calculated and included in the article, as well.

scholarly journals A Smart and Distributed Measurement System to Acquire and Analyze Mechanical Motion Parameters

2013 ◽  
Vol 20 (3) ◽  
pp. 465-478 ◽  
Author(s):  
J.M. Dias Pereira ◽  
Vítor Viegas ◽  
Octavian Postolache ◽  
Pedro Silva Girão
Keyword(s):  
Data Acquisition ◽  
Measurement System ◽  
Measurement Errors ◽  
Supply Voltage ◽  
Low Cost ◽  
Mechanical Motion ◽  
Power Supply Voltage ◽  
Motion Parameters ◽  
Distributed Measurement ◽  
Data Acquisition Unit

Abstract This paper presents a low-cost and smart measurement system to acquire and analyze mechanical motion parameters. The measurement system integrates several measuring nodes that include one or more triaxial accelerometers, a temperature sensor, a data acquisition unit and a wireless communication unit. Particular attention was dedicated to measurement system accuracy and compensation of measurement errors caused by power supply voltage variations, by temperature variations and by accelerometers’ misalignments. Mathematical relationships for error compensation were derived and software routines for measurement system configuration, data acquisition, data processing, and self-testing purposes were developed. The paper includes several simulation and experimental results obtained from an assembled prototype based on a crank-piston mechanism

scholarly journals THE VALUE OF ROBUST STATISTICAL FORECASTS IN THE COVID-19 PANDEMIC

2021 ◽  
Vol 256 ◽  
pp. 19-43
Author(s):  
Jennifer L. Castle ◽  
Jurgen A. Doornik ◽  
David F. Hendry
Keyword(s):  
Structural Change ◽  
Measurement Errors ◽  
Epidemiological Models ◽  
Short Term ◽  
Data Measurement ◽  
Policy Interventions ◽  
Changing Trends ◽  
Technological Advances ◽  
The Difference ◽  
The Uk

The Covid-19 pandemic has put forecasting under the spotlight, pitting epidemiological models against extrapolative time-series devices. We have been producing real-time short-term forecasts of confirmed cases and deaths using robust statistical models since 20 March 2020. The forecasts are adaptive to abrupt structural change, a major feature of the pandemic data due to data measurement errors, definitional and testing changes, policy interventions, technological advances and rapidly changing trends. The pandemic has also led to abrupt structural change in macroeconomic outcomes. Using the same methods, we forecast aggregate UK unemployment over the pandemic. The forecasts rapidly adapt to the employment policies implemented when the UK entered the first lockdown. The difference between our statistical and theory based forecasts provides a measure of the effect of furlough policies on stabilising unemployment, establishing useful scenarios had furlough policies not been implemented.

Design of Measurement System of the Center of Gravity

2013 ◽  
Vol 706-708 ◽  
pp. 733-736
Author(s):  
Fang Li
Keyword(s):  
Measurement System ◽  
Center Of Gravity ◽  
Actual Position ◽  
Ideal Position ◽  
The Future ◽  
The Difference ◽  
New System ◽  
The Ideal

It is very difficult to confirm the position of the center of gravity irregular object.This paper introduces a new system,which can be used in measuring and adjusting of the center of gravity.The irregular object was put on the support parts,then the center of gravity was given.When the actual position was compared with the ideal position,the difference was given. Until actual position and ideal position were coincided,the machining was continuing. Matlab was programmed in this measure system. It will be applied widely in the future.

Total Pressure Correction of a Sub-Miniature Five-Hole Probe in Areas of Pressure Gradients

2012 ◽  
Author(s):  
J. Town ◽  
A. Akturk ◽  
C. Camcı
Keyword(s):  
Pressure Measurement ◽  
Measurement Errors ◽  
Total Pressure ◽  
Pressure Gradients ◽  
Pressure Data ◽  
Flow Conditions ◽  
Complex Flow ◽  
Ducted Fan ◽  
The Difference ◽  
Best Fit

Five-hole probes, being a dependable and accurate aerodynamic tools, are excellent choices for measuring complex flow fields. However, total pressure gradients can induce measurement errors. The combined effect of the different flow conditions on the ports causes the measured total pressure to be prone to a greater error. This paper proposes a way to correct the total pressure measurement. The correction is based on the difference between the measured total pressure data of a Kiel probe and a sub-miniature prism-type five-hole probe. By comparing them in a ducted fan related flow field, a line of best fit was constructed. The line of best fit is dependent on the slope of the line in a total pressure versus span and difference in total pressure between the probes at the same location. A computer program, performs the comparison and creates the correction equation. The equation is subsequently applied to the five-hole probe total pressure measurement, and the other dependent values are adjusted. The validity of the correction is then tested by placing the Kiel probe and the five-hole probe in ducted fans with a variety of different tip clearances.

scholarly journals Integrated Durability of Automobile Alternator Test System Design Based on LabVIEW

2014 ◽  
Vol 8 (1) ◽  
pp. 839-845 ◽  
Author(s):  
Wu Weibin ◽  
Feng Yue ◽  
Du Junyi ◽  
Xu Pengbo ◽  
Feng Yunlin ◽  
...  
Keyword(s):  
Data Acquisition ◽  
Automotive Industry ◽  
Virtual Instrument ◽  
Measurement Errors ◽  
High Speed ◽  
Performance Test ◽  
Test System ◽  
Electrical Performance ◽  
Durability Test ◽  
Limit Test

New standards in the automotive industry highlighted the situation of the actual operation of the alternator and a variety of harsh environment simulation limit test. Using new standards in the automotive industry as a guide, this article presents a virtual instrument based on the durability of automobile generator integrated test system. The design adopt virtual instrument technology in designing the system, Graphic language, LabVIEW is applied in writing measure-control program. The system uses a lot of features on LABVIEW, including Data acquisition, control of serials port, etc. Test implementation uses the host computer via RS232 and RS485 communication port and the data acquisition card, NI PCI- 6221, to control the frequency hybrid motor, temperature control box, electronic loads and other intelligent devices, and to simulate a variety of automotive alternator working conditions and real-time monitoring to monitor the status of generators. Using this system, two separate automobile alternators can be tested in terms of high-speed vehicle impact and high temperature durability test and electrical performance test and other tests at the same time. As a result, the generator speed measurement error is within 1%, the control error is within 2%, voltage and current measurement errors were within 0.5% and 0.4%, which meets the requirements.

Precision Lattice Parameter Measurements with Guinier Camera and Counter Diffractometer: Comparison and Reconciliation of Results

1982 ◽  
Vol 26 ◽  
pp. 11-24 ◽  
Author(s):  
Allan Brown
Keyword(s):  
Measurement Errors ◽  
Systematic Errors ◽  
Lattice Parameter ◽  
Precision Measurements ◽  
Compound A ◽  
X Ray ◽  
Random Measurement ◽  
Precise Characterization ◽  
The Difference

Different procedures used in precision measurements of lattice parameters are, strictly, only valid if they can be shown to give results that are mutually reproducible. For this purpose reproducibility is defined in terms of the parameters a. and standard deviations a. obtained for X-ray specimens of one or more reference materials. The requirement is that all systematic errors should be minimized to a level below that of the random measurement errors. Where these have a Gaussian distribution the significance of the difference, Δa°, between two , measurements can then be Let;Led by evaluating . Thus, if K < 2 the difference, Δa°, cannot be distinguished from the effects of random measurement errors. This condition should be met for specimens of the same sample if reproducibility is good. For K ≥ 3 the value of Δa° is then taken to reflect real differences in the crystalline Jattice of two X-ray specimens of a given compound. A basis is thus created for the study of solid solubility and for the precise characterization of crystalline compounds.

Rolling Weight Deflectometer with Thermal and Vibrational Bending Compensation

1996 ◽  
Vol 1540 (1) ◽  
pp. 77-82 ◽  
Author(s):  
R. F. Johnson ◽  
J. W. Rish
Keyword(s):  
Data Acquisition ◽  
Measurement Errors ◽  
Essential Elements ◽  
Sensor Data ◽  
Falling Weight Deflectometer ◽  
Straight Line ◽  
History Of ◽  
Beam Bending ◽  
Rolling Load ◽  
Falling Weight

A pavement deflectometer has been developed for continuous measurement of airfield pavements under a rolling load wheel. The rolling weight deflectometer (RWD) measures pavement deflection using a new method of laser triangulation. It also compensates for bending of the beam on which the sensors are mounted. This compensation allows accurate measurement of deflection in the presence of motion and thermal effects. The deflection measurement incorporates data from four equally spaced pavement sensors mounted on a beam. The method requires the sensors to remain in a straight line at all times. This method was previously plagued with measurement errors caused by thermal and vibrational effects. The RWD uses a laser beam to monitor the state of bending of the physical beam in real time. The bending data are used with pavement sensor data to produce accurate deflection measurements in the presence of any amount of beam bending. The bending-compensated RWD produces deflection measurements on 0.3-m (1-ft) intervals with an accuracy of 40 microns (0.0015 in.) while moving at 10 km/hr (6 mph). The RWD is composed of a towed trailer, a networked data-acquisition system, and a load platform. Its essential elements consist of a horizontally transported beam, strategically placed pavement sensors, sensors to measure beam bending, an odometer, and a data-acquisition computer. A brief history of pavement deflection methods is presented along with a description of the RWD. Preliminary field results include a comparison between data obtained by a falling weight deflectometer and the RWD.

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