The recording of drinking water consumption and the associated billing of consumption are repeatedly the subject of discussions regarding the accuracy of the water meters used or their operating time. Against this background, data from random sample tests in Germany is used to analyse and compare the measuring behaviour of mechanical and static domestic water meters (ultrasonic, magnetic-inductive). There are significant differences between meter types in terms of flow-depending measurement deviations. Mechanical domestic water meters, and ring piston meters in particular, exceed the traffic error limits up to six times more frequently than static meters. Similarly, mechanical meters are more than 10 times more likely to stick at test flow rates Q(1) and Q(2) than static meters. For all meter types, there is a slight correlation between the frequency with which traffic error limits are exceeded and the volume recorded. The overall picture that emerges is that electronic water meters appear to demonstrate better measurement performance overall. In terms of recorded consumption, simple multi-jet impeller meters tend to show higher values, while ultrasonic meters record smaller total volumes in comparison. The difference between the highest and lowest values is over 20 %. It should be noted that the sample data can only provide an initial insight, as only those meters that are expected to pass the test are included in the test.
We present a highly accurate measurement setup and related methods for the efficient characterization of inductive rotary position sensors. The test bench is designed to measure analog sine/cosine output signals of the device under test (DUT) under nominal conditions as well as deliberate misalignment, such as center offset and tilt tolerances - enabling analysis of DUT performance w.r.t. the angle deviation, the harmonic decomposition, and tolerance sensitivities. We further propose a method to emulate tolerances of a target on the rotary axis, such as on-axis target tilt (skew) or eccentricity (wobble), utilizing only a nominal target by modeling these tolerances as equivalent angle-dependent DUT alignment tolerances. This method is validated with precision reference targets. With laser-guided positioning, the printed circuit board (PCB) of the DUT is automatically positioned relative to the rotary axis (runout +/- 5 mu m) in airgap and radial direction (repeatability 5 mu m, total deviation 30 mu m). The setup is capable of high-speed measurements at a rotation speed of at least 5,000 min-1 which allows precise measurement of the DUT propagation delay (repeatability 14 ns, total deviation similar to 200 ns). The proposed measurement setup enables fast and automated characterization of the DUT angle deviation with excellent accuracy better than 10 '' (0.003 degrees). Dieser Beitrag befasst sich mit der Entwicklung eines hochgenauen Messaufbaus und zugeh & ouml;rigen Methoden zur effizienten Charakterisierung induktiver Drehwinkelsensoren. Der Pr & uuml;fstand ist darauf ausgelegt, analoge Sinus-/Kosinus-Ausgangssignale eines Pr & uuml;flings (DUT) unter nominalen Bedingungen sowie bei bewusster Fehlausrichtung zu messen, wie z. B. Offset- und Neigungstoleranzen, was die Analyse der Winkelabweichung, deren harmonischer Zerlegung, und Toleranzempfindlichkeiten erm & ouml;glicht. Ferner wird eine Methode beschrieben, um Toleranzen eines Targets auf der Drehachse, wie z. B. "Taumeln" oder Exzentrizit & auml;t, unter alleiniger Verwendung eines nominalen Targets zu emulieren, indem diese Toleranzen als winkelabh & auml;ngige Fehlausrichtung des DUT modelliert werden. Dieses Verfahren wird mit pr & auml;zisionsgefertigten Referenztargets validiert. Die Messunsicherheit des vorgeschlagenen Pr & uuml;fstandsaufbaus wird durch eine Wiederholbarkeitsstudie quantifiziert und die systematische Abweichung bestimmt. Mittels lasergef & uuml;hrter Positionierung wird die Leiterplatte (PCB) des DUT automatisch relativ zur Drehachse (Rundlauf +/- 5 mu m) in Luftspalt- und Radialrichtung ausgerichtet (Wiederholbarkeit 5 mu m, Gesamtabweichung 30 mu m). Der Aufbau kann mit einer Rotationsgeschwindigkeit von & uuml;ber 5,000 min-1 betrieben werden. Dies erm & ouml;glicht eine pr & auml;zise Messung der Signallaufzeit des DUT (Wiederholbarkeit 14 ns, Gesamtabweichung ca. 200 ns). Der vorgeschlagene Messaufbau ist flexibel gestaltet, um eine Vielzahl verschiedener Drehwinkelsensoren aufzunehmen und erm & ouml;glicht eine schnelle und automatisierte Charakterisierung der Winkelabweichung des DUT mit hervorragender Genauigkeit von weniger als 10 '' (0,003 degrees).
Abstract Detecting microplastic in the field is the first step to solve the microplastic challenge. To achieve this, innovative sensors must be developed. One alternative to standard laboratory methods is a sensor comprising a flow-through cell with electrodes the frequency-dependent impedance of which depends on the presence and type of particle in the cell. This has already been described in the literature. To speed up the development of such sensors and identify the influence of design details, it is advantageous to have a digital twin of the sensor. So, this work focuses on the design of a digital finite-element (FE) twin for this microplastic sensor, with the aim of predicting the output signal of the sensor derived from changes in the impedance spectrum (magnitude and phase) when a particle passes through the sensor. Ideally, it even suffices to work with features of the spectrum (such as the impedance at 2 MHz) rather than the entire spectrum; such features have to be identified first, and this represents another use of our digital twin. In our investigations, the material parameters from the standard database of the FE tool used (Ansys Electronics) were chosen to incorporate the influence of the electrical conductivity of water into the simulation. It was found that the simulation results corresponded to the measurement results during sensor characterization, i.e., when recording the impedance of the sensor with pure water filling over a frequency range from 20 Hz to 2 MHz. The signals of the sensor obtained from measurements due to a particle in the sensor were confirmed by the simulation. The simulated impedance magnitude described the measured signals both qualitatively and quantitatively. For the impedance phase, this was true only qualitatively. It was found that the particle position and size have a decisive influence on the impedance of the sensor. Effects observed in the measurements (e.g., a negative change in the magnitude of the impedance, when a particle enters the sensor) could be attributed to the particle position or size based on the simulation results. In the future, the digital twin that has been created will allow the effects of changes to the sensor geometry to be analysed digitally first (e.g., a higher sensitivity and/or selectivity on a certain polymer), before the sensor is physically built and measured. While searching the optimal sensor geometry the digital twin reduces the measurement effort and speeds up the development process.
Abstract We propose the MS-CAFNet algorithm, featuring an integrated pipeline that combines per-room geometric registration with a multi-stage convolutional network and symmetry test-time augmentation. This method enables the reduction of 3D point accuracy uncertainty associated with laser scanners (LS) in rooms that are in the shell construction phase with finished interior plastering. Thereby, it facilitates more accurate spatial measurements for geometric modeling and renovation projects. Due to different equipment limitations and environmental factors, high-end and low-end LS have positional errors. Our approach pairs high-accuracy scanners (HAS) as references with corresponding low-accuracy scanners (LAS) of measurements in identical environments to quantify specific error patterns. By establishing a statistical relationship between measurement discrepancies and their spatial distribution, we develop a correction framework that combines traditional geometric processing with targeted neural network refinement. Five-fold room-level cross-validation over 270 rooms shows a peak signal-to-noise ratio (PSNR) improvement of (7.62 ± 0.36 dB) and a mean-square-error reduction of about 68 %. The high-accuracy scanner is used as a high-accuracy working reference : the method harmonises the low-accuracy scanner to this reference by removing its systematic device-specific bias, rather than establishing a metrologically traceable uncertainty against calibrated ground-truth geometry. This approach enables low-end devices to approach the accuracy of high-end devices without hardware modifications.
