In order to meet the requirements for a state-of-the-art metrology institute and in an endeavour to build a fully automatic mass laboratory, the Austrian Federal Office of Metrology and Surveying (BEV) has developed and realized in cooperation with Sartorius AG in Goettingen and the Vienna University of Technology three different handling systems for automatic testing weights on high-precision mass comparators. Fully automatic System for alternating weights on mass comparators with different weighing capacity have been realized; one from 1 mg up to 10 g, one from 10 g up to 1 kg an the third...
The Sartorius Robot System CCR10-1000 is designed for fully automatic mass determination in a mass range from 1 kg down to 1 mg. The Robot System includes two Mass Comparators each equipped with a magazine for storage of weights. The portal robot system is a 3-axis system with an additional axis of rotation where a unique weight handler system is installed. The control unit running the control software allows flexible and easy programming of the required measuring sequences. Routine mass calibrations as well as sophisticated weighing series can be performed. A detailed description of the...
In the research a possibility was studied how to reduce a number of repetitions of measurements when performing dissemination of 1 kg mass standard and at the same time maintain the level of confidence of the measurement results. The method considered is designed for weighing schemes where a pair of support plates for weights is required to carry out comparisons of combinations of weights on comparators with automatic weight handler and the same pair of support plates is used for many of the compared weight combinations. The results of analysis indicate to minor relation between the changes...
In this paper we give the results of four methods of calculating uncertainty associated with a mass calibration problem, three based on different implementations – the first and second order law of propagation of uncertainty and the Monte Carlo method – of the generally methodology described by the Guide to the Expression of Uncertainty in Measurement, the fourth based on a Bayesian formulation. Nonlinearities in the model for the calibration problem means that the first order approach can be an unreliable method for evaluating uncertainties, relative to the other three approaches.
The presented study suggests a method that allows estimating the reproducibility error in torque calibrations without the need of performing several measurement series with the torque transducer being mounted in different mounting positions. The aim is to enable uncertainty estimations for simplified calibration procedures, too. The approach is to use statistical data gained from previous calibrations of transducers of the same type. The study shows how to select and classify past calibrations in order to allow prognoses for future calibrations. Furthermore it introduces the method of...
This paper is concerned about the comparison of two important calibration methods for dynamic forces, namely the shock force calibration and the sine force calibration. Example measurements for three different types of force transducers are presented and analyzed by means of a simple mechanical model. The model describes the dynamic behaviour of the considered calibration setup including the transducer’s input-output response and identifies its characteristic parameters.
Force transfer standards allow high-accuracy measurements of forces to be carried out – but they measure only one component of the force vector. The spatial direction of this component is given by the orientation of the transducer. A new force transducer is now designed to measure additionally the direction of the force vector, i.e. all its three components, as well as additional bending moment components and the torque, with high accuracy. For use as a transfer standard, the force vector sensor has to be traced back to standard machines in national metrological institutes. For calibration...
The new weigh-in-motion (WIM) system, presented in this paper, is able to give not only the load, but also an extension of the information supplied by traditional WIM technology, such as dimensions of the tire footprint. It has a smaller cross section in comparison with those of load cells and a better endurance comparing with piezoelectric sensors. The results obtained by Finite Elements Analysis (FEA) have been checked by calibration test, performed on a spring/elastic element made by aluminum alloy.
This paper presents first results of experimental investigations performed with mechanical springs made of single-crystalline silicon (S-Spring) for load cells (LCs) with sputtered-on thin film strain gauges. The investigations are carried out on a specially manufactured S-Spring load cell (S-Spring-LC) with a nominal load of 6 kg and geometry parameters which are optimized by numerical simulations. This paper deals with load depending deformation measurements of the S-Spring to verify the expected low mechanical after effects. For the first time the investigations are carried out with a...
Enormous technological progress in optical fibers for telecommunications has promoted the use of functional grids, mainly in sensor technology. To date, optical sensors with micro-structured Bragg gratings in the core of crystal fibers have been principally used in laboratories, however, there have also been first practical applications. In this paper, HBM’s own practical and theoretical investigations are presented as well as product development based on photonic Bragg sensors. The paper discusses strain and temperature related influences in conjunction with dynamically induced Bragg...