Linear regression analysis and the GUM: example of temperature influence on force transfer transducers


  • Dirk Röske Physikalisch Technische Bundesanstalt (PTB) Braunschweig



The deflection of strain-gauge force and torque transducers (the zero-reduced output signal for a given mechanical load) is dependent on the ambient temperature. This is also true of high-precision force transfer transducers used to compare force standard machines. To estimate the extent to which temperature deviations during measurements on different machines affect comparison results and – if necessary – to correct for such deviations, it is important to know the influence of the temperature on the deflection. This effect is usually investigated in special temperature chambers in which the transducer is exposed to various temperatures within a given temperature range while the machine is operated under unchanged laboratory conditions. The regression analysis of the results allows the temperature coefficient to be determined, including an uncertainty analysis. This was done for five force transfer transducers used for a bilateral comparison between NPL (UK) and PTB (Germany).