Final report on supplementary comparison EURAMET.EM-S32: Comparison of resistance standards at 1 TΩ and 100 TΩ

Abstract

Resistance standards with values in the TΩ range play an important role in electrical instrumentation. The calibration of such standards is, thus, a service offered by many metrology institutes. The techniques used to measure very high resistance values differ quite substantially from the calibration techniques applied in the lower resistance ranges. For this reason, the EURAMET technical committee for electricity and magnetism decided in 2008 to organise for the first time a supplementary comparison of resistance at 1 TΩ and 100 TΩ based on well characterized travelling standards.Eighteen European National Metrology Institutes participated in the comparison. With some exceptions, the results supplied by the participants agree reasonably well with the comparison reference value within the expanded uncertainty.As observed in other resistance comparisons, the characteristics of the standards used as transport artefacts ultimately limit the accuracy of comparisons in this field. The transport behaviour is difficult to model and introduces an undesired bias in the laboratory results. The transport uncertainties are at the level of the uncertainties claimed by some of the participants and, thus, limit the meaningfulness of the comparison results.Another remarkable observation is the big difference in the uncertainty statements made by the participants, even in cases where similar measurement systems were used. The results of the comparison allow the participants to critically review their measurement procedures and uncertainty models.Main text. To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/.The final report has been peer-reviewed and approved for publication by EURAMET, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).

Measurement comparisons: A tool to guarantee the reliability of measurement systems and of high-tech industry

“…Rules to evaluate the results of these ILCs are given by in [4] and applied for example in the comparison [5]. Cox in [4] states that there are two possible estimators for the reference value: the weighted mean or the more robust median to choose alternatively according to the respect of some conditions.…”

“…Fig. 4 reported in [5], shows the results of a 100 TΩ standard resistor at 1000 V in the Supplementary Comparison EURAMET.EM-S32 "Comparison of resistance standards at 1 TΩ and 100 TΩ. The x-axis reports the participant NMIs while the y-axis reports the compatibility index (DoE, i.e degree of equivalence) of each NMI with respect the KRCV.…”

Accurate comparison between INRIM and a secondary calibration laboratory using a top-class multifunction electrical calibrator

“…NMIs and ILCs providers have to provide suitable ILCs to correctly verify the capabilities of secondary laboratories. ILCs concerning the calibration of only fixed electrical standards [1][2][3][4][10][11][12] unfortunately don't cover the wide operating fields of modern secondary electrical calibration laboratories. An instrument covering wide fields and used by INRIM for several years in ILCs with these laboratories is the 8.5-digit high precision DMM.…”

“…Since decades, the measurement capabilities in the field of low frequency electrical quantities (DC and AC Voltage, DC and AC current and DC Resistance) among National Measurements Institutes (NMIs) have been verified by means of inter-laboratory comparisons (ILCs) regarding the calibration of fixed primary electrical standards as in [1][2][3][4]. These Institutes have the competence to correctly disseminate the low-frequency electrical units towards their working standards and instruments and towards secondary laboratories that operated with much higher measurement uncertainties than NMIs.…”

The Strategic Role of Inter-Laboratory Comparison Among International Institutions to Assure Confidence: Report of the INRIM and the European Spatial Agency Comparison on Electrical Quantities

“…To obtain the KCRV the measurements and uncertainties of all the participating Laboratories are considered, formally treating all the participating Laboratories at the same technical level. For this case, the rules to evaluate the results were given by Cox in [4] and applied for example in the comparisons [5][6][7]. Another kind of ILCs involves a NMI and secondary Laboratories of the same country, so belonging to the same MS.…”