CN204202662U - An Electromagnetic Flowmeter Based on Measurement System - Google Patents

Abstract

The utility model discloses an electromagnetic flowmeter based on measurement system, include: exciting coil, excitation device, electrode, signal processing circuit, AD converter, flow value computing device, flow value output device, the utility model discloses an at least two of excitation device excite the magnetic cycle to exciting coil provides the rectangle excitation current to excitation cycle selectivity conversion to a plurality of excitation, can obtain a plurality of initial flow signal of exciting the frequency, can effectually eliminate because the measuring error that induced noise arouses, and do not incur and stop the fluid flow zero point adjustment and improved measurement accuracy, and the reliability is high.

Description

An Electromagnetic Flowmeter Based on Measurement System

technical field

The utility model relates to an electromagnetic flowmeter based on a measuring system.

Background technique

The weight function of the electromagnetic flowmeter is a fictitious physical quantity. Its physical meaning is: when the electromagnetic flowmeter is working, it measures the contribution of the induced electromotive force generated by each point in the pipe space to the output voltage between the electrodes. Scientists have made a clear definition of the numerical value of the weight function of a certain point in the pipe space measured by the electromagnetic flowmeter, that is, when the unit current flows through two electrodes to form a current loop, the current density of the point. Therefore, there are also many literatures that call the weight function virtual current, and the measurement system of the electromagnetic flowmeter is used to calculate the flow through this current, but the current measurement system is difficult to eliminate the measurement error caused by the induced noise, and the reliability is low .

Contents of the invention

In order to overcome the deficiencies of the prior art, the utility model provides an electromagnetic flowmeter based on a measurement system.

The technical scheme that the utility model solves its technical problem adopts is:

An electromagnetic flowmeter based measurement system comprising:

Exciting coils arranged on the upper and lower sides of the measuring tube, the exciting coils provide a magnetic field to the inside of the measuring tube;

An excitation device, the excitation device is connected to the excitation coil, and provides a rectangular excitation current to the excitation coil with at least two excitation cycles;

An electrode, which is arranged on the left and right sides of the measuring pipe, is used to detect the current generated by cutting the magnetic field line by the flow in the measuring pipe;

a signal processing circuit, the signal processing circuit is connected to the electrodes and is used to process the current signals detected by the electrodes;

an A/D converter connected to a signal processing circuit for converting an analog signal into a digital signal;

flow value calculation means, which is connected to the A/D converter, and is used to generate an electromotive force between the electrodes in each of the excitation periods, based on the electromotive force generated during the excitation period. Pushing the flow signal so as to obtain the flow value signal that will be obtained when the excitation period is infinite;

The flow value output means, the flow value output means and the flow value calculation means are used to output the flow value signal obtained by means of the flow value calculation means by extrapolation.

The flow value calculation device performs extrapolation calculation according to the linear function of the excitation period.

The rectangular excitation current is selectively switched in three excitation cycles, wherein the flow value calculation device obtains flow value signals from the flow signals of the three excitation cycles.

The signal processing circuit includes an amplifier circuit and a filter circuit, and the signal is output after passing through the amplifier circuit and the filter circuit in sequence.

The flow value calculation device is a microprocessor.

The flow value output device is a display.

The beneficial effects of the utility model are: the excitation device of the utility model provides rectangular excitation currents to the excitation coils in at least two excitation cycles, and selectively converts multiple excitation cycles to obtain initial flows of multiple excitation frequencies The signal can effectively eliminate the measurement error caused by the induction noise, without zero point adjustment that causes the fluid flow to stop, and improves the measurement accuracy with high reliability.

Description of drawings

Below in conjunction with accompanying drawing and embodiment the utility model is further described.

Fig. 1 is the structure schematic diagram of the utility model.

detailed description

With reference to Fig. 1, Fig. 1 is the structural schematic diagram of a specific embodiment of the present invention, as shown in the figure, a kind of electromagnetic flowmeter based on measuring system, comprises:

The excitation coil 2 arranged on the upper and lower sides of the measuring tube, the exciting coil 2 provides a magnetic field to the inside of the measuring tube;

An excitation device, the excitation device is connected to the excitation coil, and provides a rectangular excitation current to the excitation coil with at least two excitation cycles;

Electrode 1, the electrode 1 is arranged on the left and right sides of the measuring pipe fitting, and is used to detect the current generated by cutting the magnetic force line of the flow in the measuring pipe fitting;

A signal processing circuit, the signal processing circuit is connected to the electrode 1, and is used to process the current signal detected by the electrode 1;

an A/D converter connected to a signal processing circuit for converting an analog signal into a digital signal;

flow value calculation means, which is connected to the A/D converter, and is used to generate an electromotive force between the electrodes in each of the excitation periods, based on the electromotive force generated during the excitation period. Pushing the flow signal so as to obtain the flow value signal that will be obtained when the excitation period is infinite;

The flow value output means, the flow value output means and the flow value calculation means are used to output the flow value signal obtained by means of the flow value calculation means by extrapolation.

Preferably, the rectangular excitation current is selectively switched in three excitation cycles, wherein the flow value calculation device obtains the flow value signal from the flow signals of the three excitation cycles, and the flow value calculation device obtains the flow value signal according to the excitation cycle The linear function of the linear function is extrapolated. Since the initial flow signals of the three excitation frequencies can be obtained, the measurement error caused by the induction noise can be effectively eliminated, and the zero point adjustment that causes the stop of the fluid flow is not performed, and the measurement accuracy is improved, and it is reliable. high sex.

Further, the signal processing circuit includes an amplifier circuit and a filter circuit, and the signal is output after passing through the amplifier circuit and the filter circuit in sequence, that is, the filter circuit filters the output of the signal amplifier circuit to reduce the influence of interference noise and obtain the fundamental wave of the flow velocity signal, And make the power of various interference noises decrease as the bandwidth decreases, improve the signal-to-noise ratio, and improve the measurement accuracy of the electromagnetic flowmeter.

Preferably, the flow value calculation device is a microprocessor, and the flow value output device is a display, and the microprocessor is preferably an MSP430 single-chip microcomputer of Hong Kong TI Company or an 80C552 single-chip microcomputer of Netherlands PHILIPS company.

The preferred implementation of the present utility model has been specifically described above. Of course, the present utility model can also adopt forms different from the above-mentioned embodiments, and those skilled in the art can make equivalent transformations or modifications without violating the spirit of the present invention. Corresponding changes should all belong to the protection scope of the present utility model.

Claims (1)

1. An electromagnetic flowmeter based on a measurement system, characterized in that: comprising: Exciting coils (2) arranged on the upper and lower sides of the measuring tube, the exciting coils (2) provide a magnetic field to the inside of the measuring tube; An excitation device, the excitation device is connected to the excitation coil, and provides a rectangular excitation current to the excitation coil with at least two excitation cycles; An electrode (1), the electrode (1) is arranged on the left and right sides of the measuring pipe fitting, and is used to detect the current generated by cutting the magnetic field line by the flow in the measuring pipe fitting; A signal processing circuit, the signal processing circuit is connected to the electrode (1), and is used to process the current signal detected by the electrode (1); an A/D converter connected to a signal processing circuit for converting an analog signal into a digital signal; flow value calculation means, which is connected to the A/D converter, and is used to generate an electromotive force between the electrodes in each of the excitation periods, based on the electromotive force generated during the excitation period. Pushing the flow signal so as to obtain the flow value signal that will be obtained when the excitation period is infinite; The flow value output means, the flow value output means and the flow value calculation means are used to output the flow value signal obtained by means of the flow value calculation means by extrapolation.