Main metrological characteristics registered during calibration are:
This corresponds to the smallest increment in the indication reading.
This characterises the dispersion of indications along several measurement series for the same load level and performed without changing the position of the transducer on the calibration bench.
This characterises the dispersion of indications along several measurement series for the same load level and performed changing the angular position of the transducer between measurement series.
Reversibility or hysteresis
This characterises the difference in the indications obtained at a given load level by an increasing then decreasing load.
Conformity, interpolation or linearity error
Indications obtained according to applied loads can be modelled by a polynomial allowing the signal released by the dynamometer to be calculated for a given value of force in calibration. Registered variations between average values registered for the indications at each load level and the values given by the polynomial define the conformity or interpolation errors. This error is also called non-linearity errors, if the modelization is a straight line.
This characteristic refers to the fact that the registered indication subjected to a constant load evolves slowly due to the imperfect elastic behaviour of the materials and the detecting elements in the transducer. This generates some hesitation as to which indicator readings should be recorded. To solve this issue, the duration of the constant load should be defined as well as the waiting time after suppression of this load. An evaluation of the importance of this phenomenon can be performed by recording under specific conditions the indication at force zero at the end of each load application series on the transducer. This characteristic is very important as it conditions the quality of calibration to a large extent.
NOTE : Spanish version /en/tecnologia/calibracion/caracteristicas-metrologicas