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CONTENTS
| Ryszard Sroka - Data fusion applied to the minimization of estmation uncertainty | 107 |
| Andrzej Bień - Active power measurement with a system based on DSP and analog multiplexer | 123 |
| Ryszard Rybski - Impedance comparison in a circuit with two sinewave generators | 131 |
| Ryszard Rybski, Janusz Kaczmarek, Mariusz Krajewski - Accurate measurement of complex voltage ratio with a sampling voltmeter | 147 |
| Stanisław Trojanowski, Andrzej Gilewski, Jolanta Warchulska - Calculation of sensitivity of the integrating pulse magnetometer with the first order gradiometer | 159 |
| Paweł Swornowski - The influence of the CMMS software on the results of attestation performed with the gauge block and gauge-step | 177 |
| Wojciech Toczek - A prediction of the fault-induced instability of circuit under test as a new approach in categorisation of faults | 191 |
| In memory of the Professor Dr Hab. Jerzy Bolikowski | 203 |
ABSTRACTS
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RYSZARD SROKA
AGH University of Science and Technology,
Faculty of Electrical Engineering, Automatics, Informatics and Electronics
Department of Instrumentation and Measurement, Kraków, Poland
DATA FUSION IN MINIMIZATION OF MEASUREMENT UNCERTAINTY
The paper expounds how, in the Author's opinion, the data fusion process shall be understood and demonstrates that application of fusion in metrology is possible and useful. The process is demonstrated on an example of estimating the expected value of a random variable and its aim was reducing the estimation uncertainty of that statistical parameter. It presents the consecutive stages of data fusion, viz. acquiring and storing information (analysis of estimator properties, assessment of their quality, a priori knowledge), elaboration of data processing methods and process supervision criteria, etc.
Keywords: data fusion, uncertainty minimization, expected value estimation
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ANDRZREJ BIEŃ
AGH University of Science and Technology
Kraków, Poland
ACTIVE POWER MEASUREMENT WITH A SYSTEM BASED ON DSP AND ANALOG MULTIPLEXER
Measurements of the active power in power networks frequently serves for the identification of network parameters as well as those of power consumers. Requirements as to power measurements system have to respect the disturbances of the voltage and current signals and the necessity of their identification. The paper presents the method of the power measurement based on digital processing of the voltage and current signals. The proposed solution bases on the use of a single A/D converter with a analog multiplexer together with digital filters for time delay compensation between the sampled signals. Next the integral based on the Gregori's formula is calculated. Finally, the more correct evaluation of the time interval gives more precise power measurement result. The suggested solutions gives the opportunity for development of a real time measurement system.
In order to determine the correctness of the proposed method, some tests have been performed. The obtained results have confirmed the correctness of the accepted solution and algorithms. The measurement error is less than 0,5% of the measurement range at the sampling frequency of 1kHz for a channel with a 12-bit A/D converter. The measurement time equal to 20ms has been taken with respect to the network basic frequency.
Keywords: active power measurement, real time numerical integration, samples synchronization by digital filters
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RYSZARD RYBSKI
University of Zielona Góra
Institute of Electrical Metrology
IMPEDANCE COMPARISON IN A CIRCUIT WITH TWO DIGITAL SINEWAVE GENERATORS
A circuit for comparing impedances of any character is presented. Impedance comparison is realized automatically by means of a balanced bridge circuit with two sinewave generators. In the presented circuit, the ratio of impedances being compared is determined by measuring the complex ratio of the generators' output voltages. The complex voltage ratio measurement and the balancing algorithm are based on digital signal processing methods. The comparison conditions, uncertainty assessment, as well as the results of the measurements performed by means of the devised circuit are also presented.
Keywords: impedance measurement, ac bridge, ac generators, complex voltage ratio
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R. RYBSKI, J. KACZMAREK, M. KRAJEWSKI
University of Zielona Góra
Institute of Electrical Metrology
ACCURATE MEASUREMENT OF COMPLEX VOLTAGE RATIO WITH A SAMPLING VOLTMETER
In the paper, the idea of complex voltage ratio measurement employing an integrative analog-to-digital converter and computerized evaluation by means of the discrete Fourier transform (DFT) are presented. The effect of main sources of uncertainty in measurement accuracy of the magnitude and argument of complex voltage ratio is analysed. Simulation and experimental results are described.
Keywords: complex voltage ratio, discrete Fourier transform, sampling voltmeter
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S. TROJANOWSKI1, A. GILEWSKI2,3, J. WARCHULSKA2
1Polish Academy of Sciences
Institute of Low Temperature and Structure Research
2International Laboratory of High Magnetic Fields and Low Temperatures
3MAGNET, Wrocław, Poland
CALCULATION OF SENSITIVITY OF THE INTEGRATING PULSE MAGNETOMETER WITH A FIRST ORDER GRADIOMETER
Inductive magnetometers used for measurements in pulsed magnetic fields should have correct frequency characteristics. In the present work we describe the construction of an inductive magnetometer for measurements of the magnetic moment in pulsed magnetic fields, together with the calculation procedures for determination of its sensitivity. We present a method for the determination of the effective coupling coefficient (keff) between the sensing coils set (gradiometer) and cylindrical samples, as well as a method for calculation of the thermal noise (UTN) in the measuring system. The determination of keff permits a straightforward connection of the value of the measured signal with the magnetic moment of the sample and calibration of the gradiometer in absolute units.
Keywords: complex voltage ratio, discrete Fourier transform, sampling voltmeter
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PAWEŁ SWORNOWSKI
Poznan University of Technolog
Institute Mechanical Technology
THE INFLUENCE OF THE CMMS SOFTWARE ON THE RESULTS OF CALIBRATION PERFORMED WITH THE GAUGE BLOCK AND THE GAUGE-STEP
The check of accuracy of the co-ordinate measuring machine (CMM) with the gauge block is performed by measurement of the distance between defined points of the block, and comparison of the result with known value of distance. Several methods of calibration have been worked out, and parameters of accuracy have been defined. The most interesting for user is the standard PN-EN ISO 10360-2 with guide VDI/VDE 2617 and CMMA. Here the gauge block is the check element. The paper presents analysis of the software error, which occurs during calibration.
Keyword: Length measuring, gauge blocks, gauge step, software error
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WOJCIECH TOCZEK
Gdańsk University of Technology
Faculty of Electronics Telecommunication and Informatics
A PREDICTION OF THE FAULT-INDUCED INSTABILITY OF CIRCUIT UNDER TEST AS A NEW APPROACH IN CATEGORISATION OF FAULTS
In the paper a new approach in categorisation of faults is proposed. A prediction of the fault-induced instability of analog electronic circuits under test (CUT) is used as the tool for distinction between soft and hard faults. The linear fractional transformation (LFT) and structured singular value (SSV), the analysis methods from robust control theory, are employed to investigate which parameter could lead to instability of a CUT, and to quantify the deviation in component parameter value that will cause instability. The sixth-order bandpass multiple-loop filter is studied as CUT. The SSV based analysis procedure is applied to a Simulink model, which is realized as LFT representation of faulty circuit. Numerical results are verified by the root locus method.
Keywords: testing of analog circuits, categorisation of faults, fault-induced instability
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