Processing method for unstable signals of electromagnetic flowmeter under conditions of high frequency excitation

Abstract

The invention provides a processing method for unstable signals of an electromagnetic flowmeter under conditions of high frequency excitation, which comprises the following steps: an input signal is directly inputted to an analog-to-digital conversion circuit for signal preprocessing; an interference model is constructed, and the characteristic quantity of the dynamic variation of differential interference signals after signal preprocessing is extracted according to the interference model; the differential interference signal is obtained according to the characteristic quantity, and the process of removing the differential interference signal is carried out, and then an output signal of the conducting fluid flow is obtained. The processing method for the unstable signals of the electromagnetic flowmeter under conditions of high frequency excitation has the advantages that the steady speed of currents can be increased and the time for magnetic field excitation can be shortened, therebyreducing current consumption of the device; the using time of battery-powered products can be effectively prolonged; the excitation current in the time for effective signal acquisition can be enhanced, and the signal to noise ratio can be enhanced, thereby solving the problem of the instability of the zero point caused by the introduced interference under conditions of high frequency excitation above 100 Hz.

Description

technical field [0001] The invention relates to the field of computer network technology and communication, in particular to an unsteady-state signal processing method under the condition of high-frequency excitation of an electromagnetic flowmeter. Background technique [0002] The electromagnetic flowmeter uses Faraday's electromagnetic induction principle to generate a magnetic field by supplying current to the coil, and the fluid cutting magnetic field generates a signal related to the flow field for measurement; in order to reduce electrical polarization interference, an alternating magnetic field is usually used for excitation, but due to The coil will bring the inductance effect, so the change of the excitation current will follow the working principle of the inductance. When the current changes suddenly, the inductance will generate a reverse electromotive force to hinder the change of the current, so that the current cannot quickly reach the stable state of loading, ...

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Problems solved by technology

[0002] The electromagnetic flowmeter uses Faraday's electromagnetic induction principle to generate a magnetic field by supplying current to the coil, and the fluid cutting magnetic field generates a signal related to the flow field for measurement; in order to reduce electrical polarization interference, an alternating magnetic field is usually used for excitation, but due to The coil will bring the inductance effect, so the change of the excitation current will follow the working principle of the inductance. When the current changes suddenly, the inductance will generate a reverse electromotive force to hinder the change of the current, so that the current cannot quickly reach the stable state of loading, which will be affected by the loaded voltage. , the resistance and inductance of the coil interact with

[0003] At present, most traditional electromagnetic flowmeters at home and abroad use low-frequency excitation technology to measure in the steady-state region of the excitation current or increase the excitation voltage by improving the excitation circuit when the excitation frequency is increased, forcing the current to increase to a stable state in a short time for measurement; When the excitation current is in the rising state, the magnetic field will change. At this time, the magnetic field is interfered by various external factors, causing the signal to be affected by factors such as temperature, time, grounding, eddy current, dielectric impedance, electrode polarization, and signal crosstalk. Obtain the repeatability and linearity as the excitation current in a steady state, which increases the difficulty of signal processing

[0004] In order to overcome the problem of stable measurement of signals under short-term excitation state, the following two solutions are generally adopted. The first is to increase the excitation current forcibly and quickly by increasing the excitation voltage. However, this method consumes a lot of power and generates a lot of heat, which is not conducive to similar It is used under the condition of battery power supply and low power consumption, and the heat generation will also bring hidden dangers to the long-term use of the instrument. The second is to use other structural sensors such as electromagnets to provide magnetic fields, and to charge the electromagnets in short-term excitation. Finally, the residual magnetism of the electromagnet is used to provide the magnetic field required for the signal. However, due to the high requirements for the sensor, the corresponding material and process cannot be found in China, and its applicable effect needs to be tested by time. Therefore, it is urgently needed. A new technical means, which can solve the problem that the electromagnetic flowmeter cannot enter a stable state due to the excitation current from the high-frequency excitation tape, realize the extraction of the flow field signal and finally obtain a satisfactory measurement accuracy

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