Causes of Errors in High-Precision Weighing Instruments and Uncertainty Control Methods

Measurement errors of high-precision weighing instruments are comprehensively affected by multiple factors including sensor nonlinearity, non-uniform mechanical structure and external environmental disturbances, and there are significant interactions among these error sources. Test data show that when the three factors act simultaneously, the peak total system error reaches 0.21% F.S., which is approximately 24% higher than the 0.17% F.S. predicted by linear superposition of single factors. This conclusion is derived from statistical analysis of controlled experimental data under multiple working conditions and repeated measurements, featuring good representativeness and repeatability. The combined uncertainty model established based on the GUM framework realizes unified quantification of each error component. After adopting systematic hierarchical control technology, the expanded uncertainty of measurement results is reduced from 0.116% F.S. to 0.034% F.S., which fully verifies the value of this technology in engineering applications. Future research can focus on the uncertainty propagation mechanism during dynamic weighing.