Lack of Thermogram Sharpness as Component of Thermographic Temperature Measurement Uncertainty Budget

The number of components of a thermographic temperature measurement uncertainty budget and their ultimate contribution depend on the conditions in which the measurement is performed. The acquired data determine the accuracy with which the uncertainty component is estimated. Unfortunately, when some factors have to be taken into account, it is difficult to determine the value of the uncertainty component caused by the occurrence of this factor. In the case of a thermographic temperature measurement, such a factor is the lack of sharpness of the registered thermogram. This problem intensifies when an additional macro lens must be used. Therefore, it is decided to commence research to prepare an uncertainty budget of thermographic measurement with an additional macro lens based on the B method described in EA-4/02 (European Accreditation publications). As a result, the contribution of factors in the uncertainty budget of thermographic measurement with additional macro lens and the value of expanded uncertainty were obtained.

A practical approach to evaluate the measurement uncertainty budget for calibration of strain gauge based high-precision carrier frequency amplifiers

For high-precision measurements of strain gauge-based transducers, 225 Hz carrier frequency measuring amplifiers are primarily used. The benefits of this carrier frequency method were discussed in previous publications. This publication shows the measurement uncertainty that can be achieved by calibrating an amplifier based on this method. Possibilities for improving the measurement uncertainty and the physical limit from the user's point of view are shown.

Analysis of the measurement uncertainty of a new measurement flexure calibration set-up

A measurement flexure calibration set-up is presented in this paper. The measurement flexures under test are part of a new 5 MN · m standard torque machine measurement system at the PTB. The calibration set-up can create transversal forces up to 200 N and bending moments up to 100 N · m and respectively up to 150 N · m torque moments simultaneously. The measurement uncertainty budget of the set-up is investigated in a theoretical analysis.

MICROPHONE FRONT CAVITY DEPTH MEASUREMENT USING NON-CONTACT METHOD AT NATIONAL MEASUREMENT STANDARDS – NATIONAL STANDARDIZATION AGENCY OF INDONESIA

<p>Front cavity depth of microphone has influence in the determination of laboratory standard microphone sensitivity. Therefore this parameter is included in the measurement uncertainty budget. To determine microphone sensitivity accurately, it is necessary to measure the actual front cavity depth instead of using nominal value. This paper explains the measurement of LS1P and LS2P standard microphone front cavity depth using optical depth measurement facilities at SNSU-BSN and its effect on determining microphone sensitivity. The measurement was obtained from 4 positions distributed over the diaphragm for each microphone. The front cavity depth measurement result for LS1P is 1,94 mm ± 0,01 mm and for LS2P is 0,48 mm ± 0,01 mm These results comply with IEC 61094 Measurement Microphones-Part 2: Primary Method for Pressure Calibration of Laboratory Standard Microphones by Reciprocity Technique as the results are within the permissible range.</p>

Multi-component measuring device - completion, measurement uncertainty budget and signal cross-talk for combined load conditions

<p> </p><p><span style="font-family: Calibri;"><span style="font-size: small;">This paper present the completion and the measurement uncertainty budget of a multi-component measuring facility. The new facility is part of the 1 MN force standard machine [1] of the PTB. It enables the simultaneous generation of a torque in the range from 20 N·m to 2 kN·m in addition to axial forces 20 kN to 1 MN. This allows the characterization of measuring systems which require combined loads of axial forces <em>F</em></span>_{<span style="font-size: xx-small;">z</span>}<span style="font-size: small;"> and torques <em>M</em></span>_{<span style="font-size: xx-small;">z</span>}<span style="font-size: small;"> like friction coefficient sensors. The aim is a measurement uncertainty of (<em>k</em> = 2) for <em>M</em></span>_{<span style="font-size: xx-small;">z</span>}<span style="font-size: small;"> &lt; 0.01 % and <em>F</em></span>_{<span style="font-size: xx-small;">z</span>}<span style="font-size: small;"> &lt; 0.002 %. The physical model yields to extended measurement uncertainties (<em>k</em> = 2) for 20 N·m of 5.9·10</span>^{<span style="font-size: xx-small;">-5</span>}<span style="font-size: small;"> and for the maximum load step <span><em>M</em></span>_{<span>z</span>} = (2000 ± 0.084) N·m.</span></span></p><p> </p>

The influence of source impedance on charge amplifiers

This contribution discusses the influence of the source impedance on the complex sensitivity of a charge amplifier (CA). During calibration of a CA with varying source impedances deviations at higher frequencies were observed, which if not properly taken into account may generate systematic errors beyond the limits of the measurement uncertainty budget. The contribution discusses a model to describe the effect as well as an extension to established CA calibration procedures which allow to quantify and correct the effect.

Line Scale Calibration in Non-Ideal Measurement Situation

The precision line scale calibration in dynamical mode of operation is considered. A new interferometer-controlled comparator with moving microscope has been developed and optimised in order to reduce both the measurement uncertainty and calibration process duration. Modal analysis performed and measurements conducted of the spatial vibrations of comparator structure revealed that dynamically-induced errors can noticeably contribute to the measurement uncertainty budget. They can be prominently reduced, in particular, by proper improvement and optimisation of the carriage structure and elimination of the dry friction in the carriage drive.