In this research we develop a high speed mass measurement system with conveyor belt (a checkweigher). The objective in this paper is to propose a dynamic model of the measurement system. The checkweigher with electromagnetic force compensation can be approximated by the spring-mass-damper systems as the physical model, and an equation of motion is derived. The model parameters can be obtained from the experimental data. Finally, the validity of the proposed model can be confirmed by comparison of the simulation results with the realistic responses. The dynamic model obtained offers practical and useful information to examine control scheme.

This article describes the design of a measuring facility which can be used to investigate and calibrate so-called "friction coefficient sensors". These measuring facilities are used to measure the prestressing force and the tightening torque, resp. the friction torque of screws. These measurements are aimed at optimizing screw joints. The measuring facility described here is part of a force standard machine (fsm). In addition to the force which this system can realize with a very small measurement uncertainty of 0.002 % (k = 2) (in the measuring range from 20 kN to 1 MN), it can also generate an extremely precise torque (objective: better than 0.005 % at k = 2) in the range from 20 N·m to 2 kN·m.

This paper discusses the traceable determination of mechanical parameters of monolithic binocular shaped dual beam spring elements that are applied as force transducers and load cells in the mass and force metrology. Thereby it mainly deals with the measurement of the specific values creeping, reversibility, reproducibility, zero error and interpolation error which are defined in applicable regulations such as the EN ISO 376 standard or the OIML recommendation R 60. Our determination of those parameters is based on an interferometric deformation measurement of a loaded binocular shaped dual beam spring element which is made of the common aluminum alloy AW 2024. Generally there is no restriction on the spring element material. The parameters mentioned above are derived from the measured interferometer signal according to the EN ISO 376 standard and are thus traceable to the wavelength of light. The used measurement setup is introduced, measurements of the mentioned parameters are presented and their uncertainty is depicted. It is proved that the setup is suitable to classify dual beam spring elements according to the highest accuracy Class 00 of EN ISO 376.

The strain gauge principle is a resistive principle. If a strain is applied only a very small change of resistance occurs. By a Wheatstone bridge the change of resistance can be transferred into a voltage. However this voltage signal on the output of the bridge is still very small. Therefore it must be gained by sophisticated methods. This paper describes the new strain gauge precision instrument DMP41 with highest resolution and highest stability for the use in calibration tasks with e.g. force, torque, pressure transducers or load cells.

An analysis of the dynamic behaviour of the 250 kN primary shock force calibration device at PTB is presented. Two airborne mass bodies with the force transducer under test are brought to collision, and the generated inertial forces are determined by means of laser vibrometers. Measurements with a heavy transducer revealed modal oscillations which were identified by acceleration sensors. The dynamic system behaviour was analysed with a finite element model. It showed that the elastic coupling between the transducer and the reference mass body causes low-frequency oscillations that have to be taken into account for calibration purposes.