An Independent Quality Check Of Secondary Platinum Resistance Thermometer Calibrations Above 0 °C

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An Independent Quality Check Of Secondary Platinum Resistance Thermometer Calibrations Above 0 °C (62.28 KB)

Traditionally the use of least squares to evaluate the fit and consistency of a platinum resistance thermometer calibration requires the use of several redundant calibration points each of which adds time and expense to the calibration process. However the behavior of some secondary platinum resistance thermometers is sufficiently close to the ITS-90 reference function to allow a simplification to the deviation function, at least for the purpose of a quality check. By using the first order deviation function the number of degrees of freedom available for a least squares fit is increased and the linear correlation between PRT resistance ratios may be explicitly written in equation form.