Analysis of common errors and methods of calibration of ultrasonic level meter A. A. Yusupov, U. K. Sabirov, M. Sh. Begijonov and D. H. Valiyev E3S Web of Conf., 402 (2023) 03051 Published online: 19 July 2023 DOI: 10.1051/e3sconf/202340203051