9762 papers found
Laboratory of primary mass metrology continue work on dissemination of mass unit using measurements under non ambient conditions using vacuum mass comparator. Method presented in this paper allows determination of mass and volume of weights in range 100 g – 1 kg with separate mass and volume standards.
The paper described principle, construction and main specifications of a 60 MN force transfer system (FTS), which is used to transfer or calibrate large force over 20 MN, and to do inter-comparison of force standards. The paper has raised additional budget of its connecting to uncertainty of the force measured by the FTS, and non-uniformity of force applied on the FTS.
The article discusses basics of procedure for the calibration of automatic gravimetric filling instruments. It deals with the definition of the model function of measurement procedure, determination of the reference mass of test fills and estimation of measurement uncertainty. Depending on whether the calibrated instrument is able or not to record its results and on this basis adjust the filling process, two options for the selection of the calibration model function are addressed. Contributions to the measurement uncertainty are presented with an emphasis on the differences arising from the...
The paper presents results of linearity check of some widely used amplifiers for strain-gauge force, torque and other transducers. The combinatorial method is employed to achieve better uncertainty of the linearity check than using traditional voltage ratio calibrator units. Results for 225 Hz and 4800 Hz carrier frequency amplifiers and a DC amplifier are presented.
Through the analysis of the working principle of the original control system in deadweight force standard machine with independent weight application structure and the stress state of the center boom, we find out the inherent problem in proceeding test, which contains returning process, or in the returning test, which contains proceeding process, due to the weight rearrangement in loading and unloading process. To solve this problem, we propose an innovative technical improvement solution based on classical structured deadweight force standard machine. The standard measurement instrument of...
This paper details a force bilateral comparison between the National Metrology Institute of South Africa (NMISA) and Centro Nacional de Metrologia (CENAM, Mexico). A single 50 kN Force Transducer was used as the artefact. Measurements were conducted in compression mode in the range of 10 kN to 50 kN. The characteristics of the two standard machines used and the procedure of the comparison are briefly discussed. The values of measurements and the associated uncertainties for each laboratory are reported as well as the degree of equivalence between the two national force laboratories.
The build-up force standard machine is widely used in large scale force measurement. The force measurement range of the standard machine depends on a reference force transducer, and it is usually from 10% to 100% rated force in a measurement process. In order to perform continuous calibrations, it should be avoided two measurement processes by changing reference force transducer. This paper describes a new type of wide range standard machine, which is based on exchanging two reference force transducers in operation process. It can measure up to 10 MN, and its range is extended from 3% to...
The paper describes a force comparison at forces steps of 10 MN and 16.5 MN between the FJIM 60 MN force standard machine and the PTB 16.5 MN force standard machine. The comparison was carried out corresponding to the ISO 376. A HBM 20 MN force transducer is used as the transfer standard. The comparison results showed that the relative deviation of the two machines was within ±0.048% up to 16.5 MN with an expanded uncertainty less than 0.115% ( k = 2).
We present the current mathematical procedures at METAS for disseminating the kilogram. We compare the classical method for solving a linear system of equations of mass comparisons to the Lagrange multiplier method. In addition, we have studied the influence of redundancy in mass comparisons and found that the combined standard uncertainty can be reduced when using a redundant design matrix.
The paper described the design of the robotic mass measurement system. The dedicated device was the upgrade of the existing balance, which the measuring range is (1~ 220) g. Measurement process and auxiliary devices for the control were introduced. The electric slider make one-dimensional motions, and the robot arm was constructed by some series electric cylinder module combined in sequence, so robot arm can make a three- dimensional moving. The Programmable Logic Controller (PLC) was programmed to control the Robot Arm and Electric hands to pick, move, and place the weight, one weight at a...