Electromagnetic type water meter

Abstract

The invention provides an electromagnetic type water meter which at least comprises a conduit, a magnet exciting coil, an electrode, a sensor of a grounding end and a converter comprising an electrode clearing and blank pipe detecting module except for conventional functions. The electrode clearing and blank pipe detecting module is used for clearing voltage on an electrode when a first switch unit and a second switch unit are simultaneously turned on, detecting and calculating the resistance value between the electrode and the grounding end when only the first switch unit is turned on and a voltage exerting unit outputs high-voltage signals and low-voltage signals to the electrode alternatively, and comparing the calculated resistance value with a preset value to determine whether fluid exists in the conduit. The electromagnetic type water meter solves the problem of wrong output caused by the fact that the voltage on the electrode is overlarge and exceeds the range which an instrument amplifier can accept due to various reasons in the prior art.

Description

technical field [0001] The invention relates to an electromagnetic flowmeter, in particular to an electromagnetic water meter with the functions of electrode zeroing and empty pipe detection. Background technique [0002] The electromagnetic water meter applies a magnetic field to the measured fluid through the excitation coil, and the measured fluid moves in the magnetic field to induce an induced electromotive force, and the fluid flow velocity can be obtained by detecting and processing the electromotive force signal, thereby realizing flow measurement. At present, the excitation method is mainly low-frequency square wave excitation, that is, the excitation coil is powered by a constant current source, and the direction of the current in the excitation coil is constantly switched, so that the excitation current changes periodically between positive and negative constant values. During the constant excitation current, the electromagnetic flow sensor outputs a stable flow s...

AI Technical Summary

Problems solved by technology

[0007] In view of the above-mentioned shortcomings of the prior art, the purpose of the present invention is to provide an electromagnetic water meter to solve the problem that when the voltage on the electrode in the prior art (due to various reasons) is too high, it exceeds the acceptable value of the instrument amplifier. range, the problem of electromagnetic water meter output error

[0008] Another object of the present invention is to provide an electromagnetic water meter to solve the problem of inaccurate empty pipe detection of electromagnetic water meters in the prior art

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