Weighing cycles and drift readings with high accuracy balances

Abstract

The concept of a weighing cycle required to exclude the drift of the indicated balances from the weighing result is considered, with the drift of the indicated balances considered linear. It is established that the deviation of the actual drift of the indicated balances from linearity can lead to a noticeable methodological error in the measurement results. It is noted that the currently achieved accuracy of measuring the primary masses of standards and their copies, as well as the accuracy of watt-balances, no longer allow us to consider the drift of the indicated balances to be linear. When providing experimental data confirming deviations from the norm, balances are shown from the lines. When calculating the difference in the corresponding masses using linear and nonlinear drift models, the discrepancies can be about 10 μg, which leads to the standard deviation of the measurement results by at least one or two orders of magnitude. You provided formulas for calculating the results of measuring the difference in the mass of the weights being compared, which are valid not only for linear but also for nonlinear drift of the readings. In order to disseminate the concept of weighing cycles in the metrological concept for the case of nonlinear drift, scales are shown, developed weighing cycles of five and six simple weighings of comparable weights, allowing to avoid the consequences of nonlinear drift. These cycles are studied by the method of mathematical modeling and are verified experimentally by the results of weighing on the vacuum comparator SCL1007 from the State Primary Mass Standard – Kilogram SPMS 3-2020. The obtained results will be useful to specialists in scientific research in the field of metrological measurements of mass.