CN100357710C - Signal amplification treatment method of electromagnetic flow meter - Google Patents

Abstract

The present invention relates to a signal amplifying and processing method of an electromagnetic flow meter. Baseline feedback regulation in a zero-excitation process of a sensor is adopted, and effective undistorted amplification, acquisition and processing are carried out to signals in a sequent excitation time period of positive and negative rectangular waves. Thus, not only the interference of signal zero drift is dynamically eliminated, but accurate measurement within a wide flow range is realized, and the capabilities of analyzing and processing signals are enhanced.

Description

Signal amplification treatment method of electromagnetic flow meter

Technical field

The present invention relates to a kind of signal amplification treatment method of electromagnetic flow meter.

Technical background

Modern Electromagnetic Flow is to adopt positive and negative square wave modulation system excitation to make sensor produce the corresponding flow induced potential, and the flow signal of sensor output can be eliminated polarization phenomena like this provides the steady state flow signal again.In the reality, also there are interference problems such as the low and big zero point drift of signal to noise ratio (S/N ratio) in the flow signal of sensor output.Patent ZL99113868.6 provides a kind of effective ways that can dynamically eliminate zero point drift interference and accurate amplifying signal to the signal Processing under the positive and negative square wave modulation.But it is to adopt under forward modulation or negative sense modulating time section signal is carried out the reaction type processing and amplifying, for the electromagnetic flowmeter signal processing and amplifying, it does not utilize the zero excitation process of electromagnetic flowmeter to carry out the elimination of zero point drift, is unfavorable for providing more time that signal is amplified, gathers and handles at positive and negative rectangle excitation time.

Summary of the invention

The purpose of this invention is to provide a kind of signal amplification treatment method of electromagnetic flow meter, it is in the zero excitation process of the positive and negative square wave excitation of sensor signal to be carried out the baseline feedback adjusting, allows at thereafter positive and negative square wave excitation time Duan Zhongke signal be carried out stable amplification, collection and processing.So both dynamically the zero point drift of erasure signal was disturbed, and provided time enough for signal amplification, collection and the processing of high excitation under the cycle again.Help further improving measuring accuracy to flow signal.Enhancing is to the analyzing and processing ability of signal.

For achieving the above object, the present invention by the following technical solutions:

A kind of signal amplification treatment method of electromagnetic flow meter, T0～T10 beat sequential the T of sensor, excitation controller and impedance transducer controller generation chronologically, make magnetic field B=0 of sensor in T0～T3 period, the magnetic field B that makes sensor in T3～T6 period is for just, make magnetic field B=0 of sensor in T6～T7 period, the magnetic field B that makes sensor in T7～T10 period is for negative; Otherwise, making magnetic field B=0 of sensor (1) in T0～T3 period, the magnetic field B that makes sensor (1) in T3～T6 period is for negative, makes magnetic field B=0 of sensor (1) in T6～T7 period, and the magnetic field B that makes sensor (1) in T7～T10 period is for just; Sensor output signal S0 is to impedance transducer, output at impedance transducer has signal S1, it is characterized in that feedback arrangement that difference amplifier and baseline adjuster form chronologically T signal S1 is carried out the processing and amplifying of baseline under adjusting in T1～T2 period, difference amplifier carries out difference amplification back output signal S2 to the output F of signal S1 and baseline adjuster, in T1～T2 period, the baseline adjuster is that benchmark carries out feedback adjusting to difference amplifier with signal S2 with the X0 value, baseline adjuster output F=F1 makes the output signal S2 of difference amplifier be adjusted to X0 value place, T2 is after the moment, the baseline adjuster keeps output F=F1 (T2), make difference amplifier in the output signal S2 translation X0 value of T3 after the moment, flow rate calculation device T chronologically collects X1 and X2 at T4～T5 and two periods of T8～T9 to signal S2, and the flow rate calculation device can be calculated present flow rate value Q according to the difference of X1 and X2; The T1 of above-mentioned sequential T～T2 period, the output F=F1=K3 of baseline adjuster * (S2-X0), select K3 should make the output signal S2 of difference amplifier be dynamically adapted to X0 value place has

$\mathrm{<figure-callout\; id="2"\; label="S"\; filenames="C20051002847400061.png"\; state="\{\{state\}\}">S</figure-callout>}2=\frac{X0+\mathrm{<figure-callout\; id="1"\; label="S"\; filenames="C20051002847400061.png,C20051002847400071.png"\; state="\{\{state\}\}">S</figure-callout>}1/\mathrm{<figure-callout\; id="3"\; label="K"\; filenames="C20051002847400061.png,C20051002847400071.png"\; state="\{\{state\}\}">K</figure-callout>}3}{1+1/(\mathrm{<figure-callout\; id="2"\; label="K"\; filenames="C20051002847400061.png"\; state="\{\{state\}\}">K</figure-callout>}2\&times;K3)},\mathrm{<figure-callout\; id="1"\; label="K"\; filenames="C20051002847400061.png,C20051002847400071.png"\; state="\{\{state\}\}">K</figure-callout>}1>1,\mathrm{<figure-callout\; id="2"\; label="S"\; filenames="C20051002847400061.png"\; state="\{\{state\}\}">S</figure-callout>}2\&ap;X0,$

Wherein K1 is the conversion coefficient of impedance transducer; K2 and K3 are amplification coefficient.

The above-mentioned signal S1 and the output F of baseline adjuster draw output S2=K2 * (S1-F) behind difference amplifier;

Above-mentioned flow rate calculation device according to the formula that X1 and X2 calculate the present flow rate value is: Q=K4 * (X1-X2), the symbol correspondence of Q the direction of rate of flow of fluid V.

The T4 that above-mentioned flow rate calculation device is gathered signal S2～T5 period and T8～T9 period equal in length, the length of T5～T9 is the integral multiple of power frequency period simultaneously, the present flow rate value Q of Ji Suaning has eliminated the interference of power frequency like this.

The present invention compared with prior art, have following conspicuous outstanding substantive distinguishing features and remarkable advantage: the present invention adopts under one zero excitation process of sensor and carries out the baseline feedback adjusting, both dynamically having eliminated the zero point drift of signal disturbs, provide time enough for signal amplification, collection and processing in positive and negative square wave excitation time section thereafter again, help further improving measuring accuracy, strengthened analyzing and processing ability signal to flow signal.

Description of drawings

Fig. 1 is one embodiment of the present of invention structural principle block diagram.Fig. 2 and Fig. 3 are two kinds of signal sequence graphs of a relation.

Embodiment

A preferred embodiment of the present invention such as following: referring to Fig. 1, Fig. 2 and Fig. 3.

A kind of signal amplification treatment method of electromagnetic flow meter, sensor 1, T0～T10 beat sequential the T of excitation controller 2 and impedance transducer 3 controller 7 generations chronologically, make magnetic field B=0 of sensor 1 in T0～T3 period, making the magnetic field B of sensor 1 in T3～T6 period is plus or minus, make magnetic field B=0 of sensor 1 in T6～T7 period, making the magnetic field B of sensor 1 in T7～T10 period is negative or positive, sensor 1 output signal S0 is to impedance transducer 3, at impedance transducer 3 output signal S1, it is characterized in that feedback arrangement that difference amplifier 4 and baseline adjuster 6 form chronologically T signal S1 is carried out the processing and amplifying of baseline under adjusting in T1～T2 period, the output F of 4 couples of signal S1 of difference amplifier and baseline adjuster 6 carries out difference and amplifies back output signal S2, T1 back baseline adjuster 6 constantly is that benchmark carries out feedback adjusting to difference amplifier 4 with signal S2 with the X0 value, baseline adjuster 6 output F=F1 make the output signal S2 of difference amplifier 4 be adjusted to X0 value place, T2 is after the moment, baseline adjuster 6 keeps output F=F1 (T2), make difference amplifier 4 in the output signal S2 translation X0 value of T3 after the moment, flow rate calculation device 5 T chronologically collects X1 and X2 at T4～T5 and two periods of T8～T9 to signal S2, and flow rate calculation device 5 can be calculated present flow rate value Q according to the difference of X1 and X2; The T1 of above-mentioned sequential T～T2 period, the output F=F1=K3 of baseline adjuster 6 * (S2-X0), select K3 should make the output signal S2 of difference amplifier 4 be dynamically adapted to X0 value place has

$\mathrm{<figure-callout\; id="2"\; label="S"\; filenames="C20051002847400061.png"\; state="\{\{state\}\}">S</figure-callout>}2=\frac{X0+\mathrm{<figure-callout\; id="1"\; label="S"\; filenames="C20051002847400061.png,C20051002847400071.png"\; state="\{\{state\}\}">S</figure-callout>}1/\mathrm{<figure-callout\; id="3"\; label="K"\; filenames="C20051002847400061.png,C20051002847400071.png"\; state="\{\{state\}\}">K</figure-callout>}3}{1+1/(\mathrm{<figure-callout\; id="2"\; label="K"\; filenames="C20051002847400061.png"\; state="\{\{state\}\}">K</figure-callout>}2\&times;K3)},\mathrm{<figure-callout\; id="1"\; label="K"\; filenames="C20051002847400061.png,C20051002847400071.png"\; state="\{\{state\}\}">K</figure-callout>}1>1,\mathrm{<figure-callout\; id="2"\; label="S"\; filenames="C20051002847400061.png"\; state="\{\{state\}\}">S</figure-callout>}2\&ap;X0.$

Wherein K1 is the conversion coefficient of impedance transducer; K2 and K3 are amplification coefficient.

The above-mentioned signal S1 and the output F of baseline adjuster 6 draw output S2=K2 * (S1-F) behind difference amplifier 4.

Above-mentioned flow rate calculation device 5 according to the formula that X1 and X2 calculate the present flow rate value is: Q=K4 * (X1-X2), the symbol correspondence of Q the direction of rate of flow of fluid V.

T4～T5 period that 5 couples of signal S2 of above-mentioned flow rate calculation device gather and T8～T9 period equal in length, the length of T5～T9 is the integral multiple of power frequency period simultaneously, the present flow rate value Q of Ji Suaning has eliminated the interference of power frequency like this.

Claims (4)

1. signal amplification treatment method of electromagnetic flow meter, T0～T10 beat sequential the T of sensor (1), excitation controller (2) and impedance transducer (3) controller (7) generation chronologically, make magnetic field B=0 of sensor (1) in T0～T3 period, the magnetic field B that makes sensor (1) in T3～T6 period is for just, make magnetic field B=0 of sensor (1) in T6～T7 period, the magnetic field B that makes sensor (1) in T7～T10 period is for negative; Otherwise, making magnetic field B=0 of sensor (1) in T0～T3 period, the magnetic field B that makes sensor (1) in T3～T6 period is for negative, makes magnetic field B=0 of sensor (1) in T6～T7 period, and the magnetic field B that makes sensor (1) in T7～T10 period is for just; Sensor (1) output signal S0 is to impedance transducer (3), output at impedance transducer (3) has signal S1, it is characterized in that feedback arrangement that difference amplifier (4) and baseline adjuster (6) form chronologically T signal S1 is carried out the processing and amplifying of baseline under adjusting in T1～T2 period, difference amplifier (4) carries out difference amplification back output signal S2 to the output F of signal S1 and baseline adjuster (6), in T1～T2 period, baseline adjuster (6) is that benchmark carries out feedback adjusting to difference amplifier (4) with signal S2 with the X0 value, baseline adjuster (6) output F=F1 makes the output signal S2 of difference amplifier (4) be adjusted to X0 value place, T2 is after the moment, baseline adjuster (6) keeps output F=F1 (T2), make difference amplifier (4) in the output signal S2 translation X0 value of T3 after the moment, flow rate calculation device (5) T chronologically collects X1 and X2 at T4～T5 and two periods of T8～T9 to signal S2, and flow rate calculation device (5) can be calculated present flow rate value Q according to the difference of X1 and X2; The T1 of described sequential T～T2 period, the output F=F1=K3 of baseline adjuster (6) * (S2-X0), select K3 should make the output signal S2 of difference amplifier (4) be dynamically adapted to X0 value place has

$S2=\frac{X0+S1/K3}{1+1/(K2\&times;K3)},$ K1＞1，S2≈X0

Wherein K1 is the conversion coefficient of impedance transducer; K2 and K3 are amplification coefficient.

2. signal amplification treatment method of electromagnetic flow meter according to claim 1, the output F that it is characterized in that signal S1 and baseline adjuster (6) draw output S2=K2 * (S1-F) behind difference amplifier (4).

3. signal amplification treatment method of electromagnetic flow meter according to claim 1, it is characterized in that described flow rate calculation device (5) according to the formula that X1 and X2 calculate the present flow rate value is: Q=K4 * (X1-X2), the symbol correspondence of Q the direction of rate of flow of fluid V.

4. signal amplification treatment method of electromagnetic flow meter according to claim 1, it is characterized in that T4～T5 period and T8～T9 period equal in length that described flow rate calculation device (5) is gathered signal S2, the length of T5～T9 is the integral multiple of power frequency period simultaneously, and the present flow rate value Q of Ji Suaning has eliminated the interference of power frequency like this.

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