IMEKO Event Proceedings

Page 793 of 822 Results 7921 - 7930 of 8218

D.Gallo, C.Landi, N.Rignano
USB-INTERFACED DSP-INSTRUMENT FOR POWER QUALITY ANALYSES

In the paper, the characterization of designed and implemented high-performance real-time power quality measuring instrument is discussed. After a description of the hardware, firmware, power quality analyzer software and USB based data transfer mode, the paper continues with the discussion on a set of preliminary performances tests. In particular a set of test based on dip measurement and Total Harmonic Distortion measurement have been made and will be reported.

Pier Paolo Capra, Flavio Galliana, Milena Astrua, E. Gasparotto
Use of a 100 MΩ step Hamon resistor for calibration of pico-ammeters in dc current in the range 100 pA ÷ 100 nA

This paper describes a measurement circuit for the calibration of pico-ammeters in dc current. The system is based on a 100 MΩ Hamon network developed at INRIM to improve the traceability level of the maintained 1 GΩ standard. Besides the Hamon network, the measurement system, presented in this paper, consists of a precision dc voltage source and an electronic circuit used as voltage guard driver.

Karel Draxler, Renata Styblíková, Michal Ulvr
USE OF A CURRENT SOURCE FOR CALIBRATING AN AUTOMATIC TRANSFORMER TEST SET

This paper describes an innovative procedure for calibrating sets for evaluating instrument current transformer (ICT) errors. The innovation lies in the use of a current source for generating a measured current. There is an adjustable current source at 50 Hz mains frequency with a current transformer on its output. The internal impedance must be sufficiently high to eliminate the methodic error due to calibration. Calibration is carried out by means of a measuring system controlled by a PC through an IEEE 488 bus. Known values of the simulated ratio error and phase displacement are compared with the values measured by the device that is being tested. A software tool determines the simulated and measured error at each calibration point and determines whether the instrument that is being tested fulfils the parameters stated by the manufacturer.

J. Milek, F. Kraus
USE OF ANALYTIC REDUNDANCY IN FAULT-TOLERANT SENSOR SYSTEMS

The paper presents a systematic design of fault-tolerant measurement systems for linear time-invariant processes. The discussed methods utilize analytic redundancy of the underlying process. Two multivariable linear model types (PCA for static and ARX for dynamic modeling) are considered. Both model types can be directly identified from the measured process data. Analysis of the primary and structured residuals enables very sensitive detection, isolation, and identification of single and multiple sensor and actuator faults. The fault diagnosis is conducted via analysis of the identified faults and can be followed by appropriate fault accommodation actions. A faulty sensor variable can be reconstructed using faultfree process variables and appropriate models. Faults which degrade sensor performance in a recoverable way (c.f. bias and gain errors) can be compensated using model-based sensor recalibration. Best data source in groups of doubled sensors can be selected through application of the voting scheme (where the third sensor is the soft sensor), thus enabling optimal sensor reconfiguration.

Z. Svatý
USE OF CLOSE-RANGE PHOTOGRAMMETRY IN FORENSIC SCIENCE

This paper outlines two examples of application of close-range photogrammetry, their preliminary results and observations. The first application is identification and measurement of deformations and displacements of the vehicle chassis after a frontal crash-test. This is done by comparison between the pre- and post-crash models and measurements. The second mentioned application is determination of the road pavement macro-texture, where the photogrammetry can serve as an alternative method.

M. Milfelner, F. Cus
USE OF ERGOMEDICAL DATA FOR CONSTRUCTION

The present paper describes the technological system used to rationalize the production. An important feature in introducing this system into production is the correct arrangement and ergonomics of work station and components. The technological system for analyzing and introducing the ergonomic environment and products contains the ergonomic programme package ANTHROPOS and the digitalizing system GP12. As an example the analysis of the introduction of the work station in the working environment is presented.

Kresimir Malaric, Mirta Tkalec, Juraj Bartolic
USE OF GTEM-CELL IN BIOMEDICAL EXPERIMENTS

Use and application of the GTEM-cell, which is a transmission structure based on a TEM-cell approach, are described. The cell can be used for calibrating small antennas, for immunity and emission testing, and for biomedical experiments. It provides homogenous electromagnetic fields with TEM (transversal electromagnetic mode) distribution, similar to the free space. It has a shield to prevent radiation from the outside, which would interfere with our measurement. Plant Lemna minor has been exposed to the electric field similar to those of the cellular phones and the effect on the growth has been studied. The experiments included exposure to the frequencies of 400 MHz and 900 MHz with strength of electric field being 22 V/m. The time of exposure was 2 and 4 hours. The influence of AM (80%) 1 kHz sine modulation was also tested. Our investigations confirmed that electromagnetic field of frequencies produced by mobile phones or base stations can affect plant growth.

Damir Ilid, Ivan Leniček, Luka Ferkovid
USE OF HIGH-RESOLUTION DIGITAL MULTIMETERS FOR THE CALIBRATION OF TEMPERATURE SENSORS

The calibration of precise negative temperature coefficient resistors (NTCRs), which have resistance RN = 10000 Ω at a temperature of 25 °C and limits of error ±0,2 °C in the range from 0 °C to 70 °C, by means of the reference platinum resistance thermometer Pt-25 (with the resistance of ≈ 25,5 Ω at 0 °C) in the range of (23 ± 4) °C, and the high-resolution digital multimeters (up to 8.5 digits), is described. The influence of the resolution of the digital multimeter is investigated, as well as the influence of the self-heating of NTCRs and the measurement on different ranges and with different currents during the comparison of different type of sensors. The analysis of the resistance-versus-temperature (R - T) dependence is done by using the least-squares method and the two-parameter approximation curve for NTCRs. The results have shown that, in the range of (23 ± 4) °C, which is useful for the laboratory applications, NTCRs can be calibrated by means of Pt-25 thermometer and high-resolution digital multimeters with an uncertainty of a few millikelvin, which is very convenient for their wide application as precise and sensitive temperature sensors.

Riadh Hannachi, Zaccaria Silvestri, Daniel du Colombier, Patrick Pinot
USE OF MIRAGE EFFECT FOR THE DETECTION OF ADSORPTION OF ORGANIC MOLECULES ON THE SURFACE Pt – 10% Ir ALLOY OF MASS STANDARD

One among factors responsible of the instability of mass standard is the adsorption and desorption induced by the cleaning products. An optical non-contact method based on mirage effect is proposed to investigate the adsorption/desorption of cleaning solvents on the surface of mass standards at conditions close to normal temperature and pressure (NTP). A model developed for the mirage effect when physical adsorption occurs on a non-porous sample under NTP conditions is recalled. The experimental results of the mirage deflection obtained, in the case of platinum iridium alloy with ethanol itrogen and ether itrogen mixture, and the relation between the phase of the mirage deflection and the adsorption isotherm allow the measurement of the parameters characterizing the adsorption process, such as the amount of adsorbed matter in the first monolayer.

Anton Scheibelmasser, Udo Traussnigg
USE OF MOBILE FLASH-CARD STORAGES IN MEASUREMENT DEVICES AND SMALL AUTOMATION SYSTEMS

Mobile Flash-Cards in different technologies and formats are well suited to act as an exchangeable non volatile mass storage for data or program code in measurement devices and small automation systems. Due to the use in the fields of digital photography and multimedia applications, flash cards have been introduced into the market and are available in a standardized and compact way. Because of their mobile characteristics, their solid-state design, security features and an easy handling, they are an appropriate storage medium in measurement data acquisition, but furthermore in the field of service and maintenance. This article is supposed to give an overview of the available storage media on the market as well as several ideas for the use in the field of measurement device instrumentation. In addition, the characteristics of the several flash cards are discussed, possible advantages and restrictions are compared.

Page 793 of 822 Results 7921 - 7930 of 8218