The method of expressing the uncertainty of dynamic measurements

Abstract

A spectral method for estimating the dynamic uncertainty of measuring instruments based on a mathematical model of the frequency characteristic of a measuring instrument and a model of the spectral function of an input signal is presented. The model equation for estimating the amplitude value of the dynamic measurement uncertainty is obtained, which is caused by the limited properties of the measuring devices when a measuring signal passes through it in dynamic operation modes. A mathematical simulation of the characteristic of the dynamic uncertainty variation during the passage of a measuring signal through a measuring transducer is performed using the dynamic model of a vibration transducer as an example. Thus, the maximum value of the relative combined uncertainty of the vibration acceleration measurement is 5.33% with an observation time of 300 s and a frequency of 6 kHz. At a monitoring time of 600 s at a frequency of 6 kHz, the combined uncertainty value is 3.98%. At a frequency of 10 kHz at a observation time of 300 s, the combined uncertainty is 3.02% and at a observation time of 600 s at the same frequency of 2.21%. It helps to ensure the uniformity of measurements and enables comparison of the results of dynamic measurements made by different measuring devices and testing by different laboratories of leading countries.