Determination of the calibration and measurment capabilities of the calibration laboratory in the process of its accreditation

Abstract

The aim of the article is to analyze the main features of the formation of the smallest achievable uncertainty of measurement durung accreditation of a calibration laboratory. The purpose of publishing of calibration and measurment capabilities is considered. The form of expression of the smallest achievable uncertainty is analyzed. The coverage factors for the probability of 0.9545 for different distribution laws of the measurand are calculated: arcsine, uniform, triangular, trapezoidal, normal. The table of the Student’s coefficients for a fractional number of effective degrees of freedom is given. When measurand is represented as a range of values, the expression of the smallest achievable uncertainty in the form of a single value in absolute, relative or combined form is considered. The linear interpolation formula is given for the expression of the dependence by two known base points. The variants of preliminary nonlinear transformation of ranges of the input quantity values and the smallest achievable uncertainty are considered. The expression of the smallest achievable uncertainty as a function in an explicit form, depending on the values of the measurand and additional influencing parameters, is shown. The representation of calibration and measurement capabilities in matrix and graphical form is analyzed. The issues of ensuring the completeness and reliability of the representation of calibration and measurement capabilities are considered. The concept of a “best existing” device is analyzed.