The influence of the primary voltage ratio standard uncertainty on strain gauge measurements, especially at secondary levels like torque wrench calibration, is discussed. A method is presented to overcome its 1/x behaviour, which affects the uncertainty budget at lower ratios for the usual point-by-point transfer of uncertainty.
Monte Carlo simulations of fitted correction values reduce the relative expanded contribution of the traceability uncertainty to less than 1 · 10^-5 for tared measurements with bridge amplifiers in comparison to five times more for point-by-point traceability.
Considering typical further uncertainty contributions, a tared measurement of voltage ratios is possible with a combined relative expanded uncertainty of less than 1.8 · 10^-5.

The traceability of the torque quantity finds a gap when there is a regime with torque variation rates, once the traditional calibration methods define the references to be of null torque variation (static) or of low torque rate (continuous). This paper presents a method for providing torque traceability to rotating sensors under higher torque variation rates. The principle is presented and then followed by the method description for obtaining the calibration results.

Recent advances in the field of mass metrology allow the use of non artifact-based primary references. This enables the creation of a primary reference that determines mass at the scale of interest without the need for subdivision. In this work, the use of an electromechanical balance allows direct metrology of mass at the milligram to microgram scale using electrical metrology traceable to the International System of Units (SI). The comparison between the electrostatic method and subdivision from the kilogram indicates the mass values produced by these two approaches are in agreement after applying a correction for the surface adsorption of water; only the electrostatic measurements are performed in vacuum. A reduction in uncertainty results from the electrostatic approach at the scale of 10 mg.

This paper investigates the mechanical influences of the shaker armature’s mechanical structure on periodic force calibration, and hence on measurement uncertainty. A finite element model (FEM) was developed in order to perform modal and harmonic analyses of the measurement setup. The verification and validation of the FE model were continuously conducted through a measurement comparison, whereby a scanning vibrometer was used. The results show that the dynamic behaviour of the shaker armature should be taken into consideration before carrying out a periodic force measurement.

The maximum resolution when measuring transduc- ers, which operate on the strain gage principle, is physically limited. The legendary high precision instruments of the DMP series with a high accuracy class of 0.0005 (5 ppm) reach this physical limit. Close to the accuracy class of the DMP series, the “…38”-devices of HBM archive the 0.0025 (25 ppm).
HBM introduces a new amplifier in this “…38” series, the QuantumX MX238B. The MX238B maintains the well-known and proven 225 Hz carrier frequency technology combined with the pa- tented background-calibration function of the high precision ampli- fier DMP41 in a modular and compact data acquisition system.