Ivan Župunski, Vladimir Vujicic, Zoran Mitrovic, Slobodan Milovancev, Mile Pesaljevic
The paper presents a stochastic sampling method applied to a measurement of the mean value of the product of two arbitrary signals. This method is especially convenient for measuring electric power, electric energy consumption, as well as root-mean-square of voltage and/or current. The method features a very simple hardware and the possibility of selecting the measurement accuracy by choosing a suitable measurement interval. When measuring electric energy, accuracy better than 0.01 % is achieved. The measurement uncertainty of the stochastic sampling method is analysed and the influence of...
XIX IMEKO World Congress
· TC7
· 2009
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Abraham Mejía-Aguilar, Ramon Pallàs-Areny
Electrical impedance measurements based on pulse excitation are fast and simple to implement, which makes them attractive for low-power measurement systems such as remote water conductivity monitoring based on two-electrode cells. Pulse measurements also allow us to estimate electrode parameters but measurement errors increase when the electrode resistance is very different from that of the electrolyte. We propose a dual pulse excitation technique to minimize errors in estimating electrode parameters: a voltage pulse is followed by a current pulse whose amplitude is set according to the...
XIX IMEKO World Congress
· TC4
· 2009
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Lautaro Ramirez, Luis Omar Becerra, Luis Manuel Peña
The present work exposes the comparison among numerical methods used in the calibration of a set of high accuracy weights by subdivision method. This paper covers the comparison of the mean values, the uncertainties and correlations obtained with the Orthogonal, the Gauss Markov, the Ordinary Least Squares and the Weighted Least Squares (Lagrange Multiplier) methods. These methods are the most commonly used in the realization of the mass scale in the National Metrology Institutes (NMI). Also, the uncertainty evaluated by these methods was compared against the evaluation by a numerical...
XIX IMEKO World Congress
· TC3
· 2009
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Maurizio Caciotta, Sabino Giarnetti, Fabio Leccese, Zbigniew Leonowicz
In electrical energy power networks, disturbances can cause problems in electronic devices so their monitoring is fundamental in Power Quality. In this paper we address the problem of disturbances estimation by using the Hilbert Transform (HT). It is employed as an effective technique for tracking the voltage waveforms in electrical distribution systems. The mathematical simplicity of the proposed technique, compared with the commonly used algorithms from the literature, renders them competitive candidate for the on-line tracking of disturbances. The accurate tracking of the HT facilitates...
XIX IMEKO World Congress
· TC4
· 2009
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Saulius Kausinis, Algimantas Barakauskas Barakauskas, Rimantas Barauskas, Aurimas Jakstas, Albinas Kasparaitis
The paper treats the issue of embedding the traceable length metrology into technological process by performing precise dynamic measurements of line scale in its manufacture line. It addresses the error-related problems specific to line scale calibration in dynamic mode of operation that are caused primarily by dynamic loads. Introducing the dynamic regime of calibration leads to the dynamic calibration error originating due to vibration sources in the structure. This uncertainty contribution should be considered and implicated in the total uncertainty budget. A new 3D finite element model...
XIX IMEKO World Congress
· TC14
· 2009
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Jan Malinsky, Petr Kocourek
This work deals with an educational system for the teaching of standard FlexRay (FR). The FR is a new communication standard intended to be used in cars in the near future. It is primarily intended for communication among so-called x-by-wire systems. Many fundamental and advanced features of FR standard, as well as basic kinds of x-by-wire systems, can be demonstrated by this educational system. The largest benefit is in an illustrative presentation of the FR synchronization mechanism (SM) in operation, as well as of its robustness. The SM is probably the most important FR process, and...
XIX IMEKO World Congress
· TC1
· 2009
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Pablo Luna-Lozano, Ramon Pallàs-Areny
Physiological monitoring outside clinical environments and medical offices can contribute to people's wellness, particularly if that monitoring does not disturb their daily activities, and can also help in life-style improvement. We propose a novel non-conscious method to monitor the heart rate which is based on detecting blood volume changes in the thigh through electrical impedance plethysmography while the subject is seated. Four conductive strip electrodes are concealed underneath seat's upholstery, hence working as capacitive electrodes. A 50 kHz current is injected trough two outer...
XIX IMEKO World Congress
· TC13
· 2009
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Ramon Casanella, Ramon Pallàs-Areny
This work analyzes power consumption in signal conditioning circuits for resistive sensors. We show that, for a given dynamic range for the measurand, simple conditioners based on voltage dividers or Wheatstone bridges directly connected to an analog-to-digital converter (ADC) do not usually have minimal power consumption. We develop analytical guidelines to achieve the optimal power design for signal conditioners and apply them to the actual design of the conditioner for an RTD sensor. We show that by adding a low-power amplifier plus a passive low-pass filter to a voltage divider sensor...
XIX IMEKO World Congress
· TC4
· 2009
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Maria Teresa Todisco
Reported here are some results obtained, from a calculus algorithm application that, based on known equation analytical solutions of water flow profiles, allows the study of steady-state, gradually varied flow in open channel networks. The procedure allows to calculate, in the case of slow water flow into gradually downward slope channels, in the direction of motion, the florates and water levels respectively, in all the nodes and sides of the network. The results have been compared with the solutions proposed by other authors.
XIX IMEKO World Congress
· TC9
· 2009
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Pedro M. Ramos, Fernando M. Janeiro, Tomáš Radil
The comparison of three different algorithms for the estimation of parameters of two sine signals with common frequency is presented. The algorithms are the ellipse fit, the seven parameter sine fit and the spectral sinc fit. The comparison includes signal to noise ratio analysis, amplitude analysis and phase difference analysis.
XIX IMEKO World Congress
· TC4
· 2009
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