Further Interpretation Study on the Term of “Reference” in VIM 3

Abstract

This paper focuses the study on different measuring (or calibration) systems during the process of metrological traceability, due to the different characteristics between the base quantity and derived quantity of the target parameter (or measurand), leading to that representation of the "measurement standard” can not be clearly and consistently made statement. The author will refer to VIM 3 (ISO / IEC Guide 99-2007) for the term of “reference”, using several practical cases of measuring (or calibration) systems related to the measurand of both base quantity and derived quantity, to further interpret and analyze such issue of metrological traceability and calibration hierarchy in terms of measurement standard. In detail, this paper discloses a newly established process for drawing the metrological traceability diagram at National Measurement Laboratory (NML, Chinese Taipei) which includes seven steps, starting from identifying the “measurand” of the expected “measurement result”, then the “reference”, which traditionally would be “measurement standard”, the “measuring system”, the measured “quantity kinds” and “quantity values” of the system, the developed “measurement model (or equation)”, finally the “reference” of the measurement result in each calibration traceable to the “measurand” of the measurement result in the previous calibration of the higher hierarchy. Such new representation of the metrological traceability diagram combines a newly mathematical approach with the conventionally schematic approach to realize the practical interpretation of “metrological traceability” to show how the unbroken calibration chain is functioning seamless and robust on each measurement system in NML.