JP2016090524A - Calibration method and calibration system of electromagnetic flowmeter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To realize calibration of a detector of an electromagnetic flowmeter without making water flow into the electromagnetic flowmeter at a low cost.SOLUTION: A calibration method of an electromagnetic flowmeter includes: a measurement step (S1) for measuring a cross-section area of a measurement tube and a distance between electrodes; a measurement step (S2) for measuring density of a magnetic flux at a center of the measurement tube and density of a magnetic flux in the vicinity of the electrodes; a parabolic distribution function calculation step (S3, S4) for multiplying the density of a magnetic flux by a weight function indicating contribution to electromotive force generation, of a flow rate of fluid flowing in the measurement tube, and determining a parabolic distribution function showing a relation between a position where the density of a magnetic flux is measured and the calculated multiplication value; a parameter calculation step (S5) for integrating a formula of the parabolic distribution function from a position of one electrode to a position of the other electrode so as to calculate an electromotive force parameter which is proportional to electromotive force generated by the fluid flowing on a straight line connecting the electrodes; and a correction coefficient calculation step (S6) for calculating a correction coefficient on the basis of the electromotive force parameter and the cross-section area of the measurement tube.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a calibration method and a calibration system for calibrating a detector of an electromagnetic flow meter.

  The cause of the variation in the performance of the electromagnetic flowmeter is mechanical variation, specifically (A) variation in the diameter of the measuring tube, (B) variation in the position and shape of the electrode, and (C) variation in the magnetic field distribution. and so on.

  The variation of the electronic circuit of the electromagnetic flow meter can be calibrated by applying an accurate signal voltage to the transducer of the electromagnetic flow meter, but the effect of the mechanical variation of the electromagnetic flow meter detector on the flow rate is unknown. Actual flow rate calibration is actually performed to adjust the flow rate by actually flowing water through the electromagnetic flow meter (see Patent Document 1 and Patent Document 2).

No. 4-50500 Japanese Utility Model Publication No. 5-36174

However, the conventional actual flow rate calibration has a problem in that a large-scale calibration facility and cost are required.
Patent Documents 1 and 2 disclose dry calibration techniques that calibrate an electromagnetic flowmeter without flowing water. However, the technique disclosed in Patent Document 1 adjusts the gain of the signal processing circuit by applying a dry calibration voltage to the signal processing circuit, and calibrating the variation in the electronic circuit of the electromagnetic flow meter is not possible. Even if it is possible, the mechanical variation cannot be calibrated.

On the other hand, in the technique disclosed in Patent Document 2, calibration is performed by vibrating a measurement tube of an electromagnetic flowmeter in the tube axis direction. When the flow velocity of the fluid flowing through the measurement pipe of the electromagnetic flowmeter is V, the inner diameter of the measurement pipe is D, and the magnetic flux density of the magnetic field applied perpendicularly to the measurement pipe is B, the electromotive force E obtained from the detector of the electromagnetic flowmeter the _a, electromotive force after amplified by a signal processing circuit E _a 'is expressed by the following equation.
E _A '∝kBDV (1)

Here, k is a coefficient related to the magnetic field distribution and the measurement tube. On the other hand, if the angular velocity corresponding to the excitation frequency when the measuring tube is vibrated in the tube axis direction is ω _B , and the vibration amplitude is Xo, the electromotive force E _B associated with the vibration of the measuring tube is expressed as a signal. The electromotive force E _B ′ after amplification by the processing circuit is as follows.
E _B '∝kBDω _B Xo (2)

In the technique disclosed in Patent Document 2, a flow rate V is obtained by calculating a ratio R of E _A '/ E _B ' and multiplying the ratio R by a known constant ω _B Xo.
V = Rω _B Xo (3)

  The technique disclosed in Patent Document 2 requires that the magnetic flux density distribution be uniform within a range in which the measurement tube vibrates in the tube axis direction. If there is a bias in the magnetic flux density distribution, an error occurs in the calculation of Equation (3). In order to make the magnetic flux density distribution uniform within the range in which the measuring tube vibrates in the direction of the tube axis, it is necessary to make the magnetic flux density distribution uniform over a wider range than a normal electromagnetic flowmeter. Since a vibrating device that vibrates is necessary, the product cost of the electromagnetic flowmeter increases.

  The present invention has been made in order to solve the above-described problems, and a calibration method and calibration of an electromagnetic flow meter capable of realizing calibration of a detector of the electromagnetic flow meter at low cost without flowing water through the electromagnetic flow meter. The purpose is to provide a system.

  The electromagnetic flow meter calibration method of the present invention includes a first measurement step of measuring a cross-sectional area of a measurement tube of an electromagnetic flow meter to be calibrated and a distance between two electrodes provided on the measurement tube; Measures the magnetic flux density at the center of the measuring tube and the magnetic flux density in the vicinity of the two electrodes on a straight line connecting the two electrodes while a magnetic field is applied to the measuring tube from the excitation coil of the flow meter. A value obtained by multiplying the second measurement step, the value of the magnetic flux density measured in the second measurement step, and a predetermined weight function indicating the contribution to the electromotive force generation of the flow velocity of the fluid flowing through the measurement tube For each position where the magnetic flux density is measured, and a parabolic distribution function calculating step for determining an expression of a parabolic distribution function indicating a relationship between the position where the magnetic flux density is measured and the calculated multiplication value, Determined in the parabolic distribution function calculation step A parameter for calculating an electromotive force parameter proportional to an electromotive force generated by a fluid flowing on a straight line connecting the two electrodes by integrating the expression of the parabolic distribution function from the position of one electrode to the position of the other electrode. Based on the calculation step, the electromotive force parameter calculated in the parameter calculation step, and the cross-sectional area measured in the first measurement step, a correction coefficient for correcting the flow rate or flow velocity of the fluid flowing through the measurement pipe is calculated. And a correction coefficient calculating step.

  Further, in one configuration example of the electromagnetic flow meter calibration method of the present invention, the correction coefficient calculating step includes a correction coefficient of a reference electromagnetic flow meter, a cross-sectional area of a measurement tube of the electromagnetic flow meter, and an electromotive force parameter. Based on the step acquired from the storage means, the acquired value, the electromotive force parameter calculated in the parameter calculation step, and the cross-sectional area measured in the first measurement step, the measuring tube of the electromagnetic flow meter to be calibrated And a step of calculating a correction coefficient for correcting the flow rate or flow velocity of the fluid flowing through the fluid.

  The calibration system for an electromagnetic flowmeter of the present invention includes an optical sensor for measuring a cross-sectional area of a measurement tube of an electromagnetic flowmeter to be calibrated and a distance between two electrodes provided on the measurement tube, and the electromagnetic flow rate. The magnetic flux density at the center of the measuring tube and the magnetic flux density in the vicinity of the two electrodes are measured on a straight line connecting the two electrodes while a magnetic field is applied to the measuring tube from the exciting coil of the meter. A position where the magnetic flux density is measured by multiplying a gauss meter by a value obtained by multiplying the value of the magnetic flux density measured by the gauss meter and a predetermined weight function indicating the contribution to the electromotive force generation of the flow velocity of the fluid flowing through the measuring tube. A parabolic distribution function calculating means for determining a parabolic distribution function formula indicating the relationship between the position where the magnetic flux density is measured and the calculated multiplication value, and the parabolic distribution function calculating means Parabolic distribution function formula Parameter calculating means for calculating an electromotive force parameter proportional to an electromotive force generated by a fluid flowing on a straight line connecting the two electrodes by integrating from the position of one electrode to the position of the other electrode; Correction coefficient calculation means for calculating a correction coefficient for correcting the flow rate or flow velocity of the fluid flowing through the measurement tube based on the electromotive force parameter calculated by the means and the cross-sectional area measured by the optical sensor. It is a feature.

  According to the present invention, since the correction coefficient can be obtained without flowing water through the electromagnetic flow meter, the cost and man-hours required for the calibration of the detector can be reduced. In the present invention, when the electromagnetic flow meter to be calibrated is set on the calibration device, the calibration work can be automated by carrying the measurement and carrying the electromagnetic flow meter on the device. Further, in the present invention, it is possible to specify whether the flow error of the electromagnetic flowmeter is caused by the measuring tube, the electrode position, or the magnetic flux density distribution, and therefore a complaint has been generated from the electromagnetic flowmeter user. When investigation and countermeasures become easier. Further, in the present invention, unlike the method of vibrating the measurement tube, it is not necessary to make the magnetic flux density distribution uniform over a wider range than a normal electromagnetic flow meter, and there is also a need for a vibration device that vibrates the measurement tube. Therefore, it is not necessary to use an electromagnetic flow meter with a special specification, and calibration can be performed on a normal electromagnetic flow meter.

It is a block diagram which shows the structure of the calibration system of the electromagnetic flowmeter which concerns on embodiment of this invention. It is a block diagram which shows an example of a structure of the correction coefficient calculation part of the calibration system of the electromagnetic flowmeter which concerns on embodiment of this invention. It is a flowchart explaining operation | movement of the calibration system of the electromagnetic flowmeter which concerns on embodiment of this invention. It is sectional drawing explaining the measuring method of the magnetic flux density by a gauss meter. It is a figure which shows the contribution to the electromotive force generation | occurrence | production of the flow velocity of the fluid which flows through a measurement pipe | tube. It is a figure which shows one example of the change of the value which multiplied the distribution of magnetic flux density, and the weight function.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram showing a configuration of an electromagnetic flowmeter calibration system according to an embodiment of the present invention. The calibration system according to the present embodiment connects an optical sensor 2 that measures a cross-sectional area of a measurement tube of an electromagnetic flow meter to be calibrated and a distance between two electrodes provided on the measurement tube, and the two electrodes. A Gauss meter 3 that measures the magnetic flux density at the center of the measurement tube and the magnetic flux density near the two electrodes on a straight line, and a correction coefficient calculation unit that calculates a correction coefficient for correcting the flow rate or flow velocity of the fluid flowing through the measurement tube. 4 is provided.

The detector 1 of the electromagnetic flow meter includes an excitation coil 10a, 10b that generates a magnetic field, a measurement tube 11 that is disposed in the magnetic field generated from the excitation coil 10a, 10b, and a pair of electrodes 12a that are provided on the measurement tube 11. , 12b.
The optical sensor 2 includes sensor heads 20 a and 20 b and a sensor controller 21.

  FIG. 2 is a block diagram showing an example of the configuration of the correction coefficient calculation unit 4. The correction coefficient calculation unit 4 includes a parabolic distribution function calculation means 40, a parameter calculation means 41, a correction coefficient calculation means 42, a storage means 43, and a correction coefficient setting means 44.

  Hereinafter, the operation of the calibration system of the present embodiment will be described with reference to the flowchart of FIG. During calibration of the electromagnetic flow meter, the sensor controller 21 of the optical sensor 2 irradiates laser parallel light from the sensor head 20a toward one opening of the measurement tube 11 of the electromagnetic flow meter to be calibrated, and passes through the measurement tube 11. The laser parallel light emitted from the other opening is received by the sensor head 20b to detect the position of the edge on the inner wall side of the measuring tube 11 and exposed to the cross-sectional area S of the measuring tube 11 and the inner wall of the measuring tube 11. The distance d between the electrodes 12a and 12b is calculated (step S1 in FIG. 3). Regarding the cross-sectional area S, the inner diameter D of the measuring tube 11 may be obtained based on the position of the edge on the inner wall side of the measuring tube 11, and the cross-sectional area S may be calculated from the inner diameter D, or the light passing through the measuring tube 11 may be calculated. The cross-sectional area S may be calculated by integrating the areas. Since the positions of the electrodes 12a and 12b are known, the distance d between the electrodes 12a and 12b can be obtained by detecting the edge position with respect to the known position of the inner wall of the measuring tube 11. As an optical sensor as described above, for example, there is an edge sensor manufactured by Azbil Corporation.

Next, an excitation current is supplied from a converter (not shown) paired with the detector 1 to the excitation coils 10a and 10b of the electromagnetic flow meter to be calibrated. Thereby, a magnetic field is applied perpendicularly to the measuring tube 11.
After completion of the measurement by the optical sensor 2, the electrode 12a as shown in FIG. 4, of a position on the straight line L connecting the 12b, the position x ₁ and the electrode 12a near the central position x ₂ and the electrode 12b near the measuring tube the position x ₃ of which is arranged the probe of the gauss meter 3. The gauss meter 3 detects the magnetic field with the probe, and the magnetic flux density B (x ₂ ) at the center position x ₂ of the measuring tube 11, the magnetic flux density B (x ₁ ) at the position x ₁ near the electrode 12b, and the vicinity of the electrode 12a. The magnetic flux density B (x ₃ ) at the position x ₃ is measured (step S2 in FIG. 3). The measurement tube 11 is placed on the stage, and the magnetic flux density B (x ₁ ), B (x ₂ ), B (x ₃ ) is set so that the probe attached on the stage is placed inside the measurement tube 11. Therefore, the coordinates (x ₁ , x ₂ , x ₃ ) on the straight line L can be accurately determined from the positional relationship between the stage and the measuring tube 11 and the positional relationship between the stage and the probe.

The electromotive force E generated between the electrodes 12a and 12b of the electromagnetic flowmeter is determined from the inner diameter D, the magnetic flux density B, and the flow velocity V of the fluid flowing through the measurement tube 11, as shown in the following equation. If the cross-sectional area S and the distance d between the electrodes 12a and 12b and the magnetic flux density B can be measured, the correction coefficient DF of the flow rate (flow velocity) can be determined (k in equation (4) is a coefficient).
E = kBDV (4)
The flow rate Q is obtained by the following equation.
^{Q = (πD 2/4)} × V ··· (5)

The cross-sectional area S of the measuring tube 11 and the distance d between the electrodes 12a and 12b can be accurately measured by the optical sensor 2 as described above, but the magnetic flux density B is not uniform, It is necessary to measure the distribution of the magnetic flux density B. However, the flow rate of the fluid has a different contribution (weight) to the generation of electromotive force depending on the location, and the electromotive force E due to the fluid is substantially determined by the speed of the fluid flowing on the straight line L connecting the electrodes 12a and 12b. Therefore, magnetic flux densities B (x ₁ ), B (x ₂ ), B (x ₃ ) at three points, that is, the central position of the measuring tube 11 that greatly contributes to the generation of electromotive force, the position in the vicinity of the electrode 12b, and the position in the vicinity of the electrode 12a. Is measured, a parameter proportional to the electromotive force E is obtained from the magnetic flux densities B (x ₁ ), B (x ₂ ), B (x ₃ ) and the weight function, and the flow rate is compared with a reference detector. A correction coefficient DF of (flow velocity) is obtained.

5A and 5B are diagrams showing the contribution (weight) of the flow velocity of the fluid flowing through the measurement tube 11 to the generation of electromotive force, and FIG. 5A is a cross-section of the measurement tube 11 ( FIG. 5B shows the weight when viewed in the tube axis direction (z direction) of the measurement tube 11.
The weighting function U is expressed by an expression (6) in the orthogonal coordinates (x, y).
U = (1+ (x ² −y ² )) / (1 + 2 (x ² −y ² ) + (x ² + y ² ) ² ) (6)

The weighting function U is a polar coordinate (r, θ) that represents a point on the cross section of the measuring tube 11 by a distance r from the origin (position of the electrode 12a or 12b) and a deviation angle θ from the starting line (x axis). Then, it becomes like Formula (7).
U = (1 + r ² cos (2θ)) / (1 + 2r ² cos (2θ) + r ⁴ ) (7)

  Note that, in the cross section of the measurement tube 11, the expressions (6) and (7) are obtained from the center of the measurement tube 11 with the position of the electrode 12 a as the origin for the semicircular region on the electrode 12 a side from the center of the measurement tube 11. For the semicircular region on the electrode 12b side, the position of the electrode 12b is the origin.

For example, as apparent from equation (7), since r ⁴ is included in the denominator of the equation of the weight function U, the electromotive force in the vicinity of the electrodes 12a and 12b is higher than that in the vicinity of the center of the measuring tube 11. The contribution to generation is very large. The above weight function is described in the literature “Akira Endo,“ Basic Theory of Electromagnetic Flowmeters: Japanese Translation of Induktive Stromungsmessung Abschn.1, 2 ”, Power Reactor and Nuclear Fuel Development Corporation, 1985”. It is disclosed.

The parabolic distribution function calculating means 40 of the correction coefficient calculating unit 4 is a magnetic flux density B (x ₁ ) measured by the gauss meter 3 at three points (x ₁ , x ₂ , x ₃ ) on the straight line L connecting the electrodes 12a, 12b. ), B (x ₂ ), B (x ₃ ), the weight function U (x of the coordinates (x ₁ , x ₂ , x ₃ ) on the straight line L obtained from the equation (6) or (7) ₁ ), U (x ₂ ), and U (x ₃ ) multiplied by values B (x ₁ ) U (x ₁ ), B (x ₂ ) U (x ₂ ), B (x ₃ ) U (x ₃ ) ) Is calculated (step S3 in FIG. 3). The multiplication values B (x ₁ ) U (x ₁ ), B (x ₂ ) U (x ₂ ), and B (x ₃ ) U (x ₃ ) correspond to the coordinates x on the straight line L as shown in FIG. It changes into a parabola. The origin O (x = 0) in FIG. 6 corresponds to the center position of the measuring tube 11.

Then, the parabolic distribution function calculating means 40 includes (x ₁ , B (x ₁ ) U (x ₁ )), (x ₂ , B (x ₂ ) U (x ₂ )), (x ₃ , B (x ₃ ) Coefficients a, b, and c of a parabolic distribution function (quadratic function) such as the following equation passing through three points U (x ₃ )) are determined (step S4 in FIG. 3).
BU = ax ² + bx + c (8)

The parameter calculation unit 41 of the correction coefficient calculation unit 4 changes the formula (8) determined by the parabolic distribution function calculation unit 40 from the position of the electrode 12b (x = −d / 2) to the position of the electrode 12a (x = d / 2). ), The electromotive force parameter M proportional to the electromotive force E generated by the fluid flowing on the straight line L connecting the electrodes 12a and 12b is calculated (step S5 in FIG. 3). The indefinite integral of BU is F (x) = 2 / 3ax ³ + 1 / 2bx ² + cx + D (D is a constant and disappears with a definite integral), so M = F (d / 2) −F (−d / 2). Needless to say, the distance d between the electrodes 12a and 12b obtained in step S1 is used to determine the positions of the electrodes 12a and 12b (x = −d / 2, d / 2).

The correction coefficient calculation means 42 of the correction coefficient calculation unit 4 includes a correction coefficient DF0 of an electromagnetic flow meter that is the same type as the electromagnetic flow meter to be calibrated, a cross-sectional area S0 of the measurement tube of the electromagnetic flow meter, and an electromotive force parameter M0. Is obtained from the storage means 43, and the correction coefficient DF is calculated from these values and the electromotive force parameter M calculated by the parameter calculation means 41 by the following equation (step S6 in FIG. 3).
DF = DF0 × M / M0 × S / S0 (9)

  The cross-sectional area S0 and electromotive force parameter M0 of the measurement pipe of the reference electromagnetic flowmeter may be obtained in the same manner as described above, and the correction coefficient DF0 of the reference electromagnetic flowmeter is actually applied to the electromagnetic flowmeter. What is necessary is just to obtain | require beforehand by the actual flow volume calibration which flows water into.

The correction coefficient setting unit 44 of the correction coefficient calculation unit 4 sets the correction coefficient DF calculated by the correction coefficient calculation unit 42 to the converter (not shown) of the electromagnetic flow meter to be calibrated (step S7 in FIG. 3).
In this way, the correction coefficient DF of the detector 1 of the electromagnetic flow meter to be calibrated can be obtained. As described above, the correction coefficient DF is set in a converter that converts the electromotive force E output from the detector 1 into a flow rate value or a flow velocity value. The converter corrects the flow rate value or the flow velocity value by multiplying the flow rate value or the flow velocity value calculated from the electromotive force E by the correction coefficient DF.

  As described above, in the present embodiment, since the correction coefficient DF can be obtained without flowing water through the electromagnetic flow meter, the cost and man-hours required for calibration of the detector 1 can be reduced. In this embodiment, when the electromagnetic flow meter to be calibrated is set on the calibration device, the calibration work can be automated by carrying the electromagnetic flow meter on the device and performing the measurement in steps S1 and S2. . Further, in the present embodiment, it is possible to specify whether the flow error of the electromagnetic flow meter is caused by the measurement tube, the electrode position, or the magnetic flux density distribution. It becomes easier to investigate and take measures when it occurs.

  In the present embodiment, there is no need to make the magnetic flux density distribution uniform over a wider range than a normal electromagnetic flowmeter as in Patent Document 2, and there is no need for a vibration device that vibrates the measurement tube. It is not necessary to use a special specification electromagnetic flow meter, and calibration can be performed on a normal electromagnetic flow meter.

  The correction coefficient calculation unit 4 described in the present embodiment can be realized by a computer having a CPU (Central Processing Unit), a storage device, and an interface, and a program for controlling these hardware resources. The CPU executes the processing described in the present embodiment in accordance with a program stored in the storage device.

  The present invention can be applied to a technique for calibrating a detector of an electromagnetic flow meter.

  DESCRIPTION OF SYMBOLS 1 ... Detector, 2 ... Optical sensor, 3 ... Gauss meter, 4 ... Correction coefficient calculation part, 10a, 10b ... Excitation coil, 11 ... Measuring tube, 12a, 12b ... Electrode, 20a, 20b ... Sensor head, 21 ... Sensor controller , 40 ... Parabolic distribution function calculating means, 41 ... Parameter calculating means, 42 ... Correction coefficient calculating means, 43 ... Storage means, 44 ... Correction coefficient setting means.

Claims (4)

A first measurement step for measuring a cross-sectional area of a measurement tube of an electromagnetic flow meter to be calibrated and a distance between two electrodes provided on the measurement tube;
In a state where a magnetic field is applied from the exciting coil of the electromagnetic flow meter to the measurement tube, a magnetic flux density at the center of the measurement tube and a magnetic flux density near the two electrodes on a straight line connecting the two electrodes. A second measuring step for measuring
The magnetic flux density was measured by multiplying the value of the magnetic flux density measured in the second measurement step by a predetermined weight function indicating the contribution to the electromotive force generation of the flow velocity of the fluid flowing through the measuring tube. A parabolic distribution function calculating step for calculating a parabolic distribution function for each position and determining a formula of a parabolic distribution function indicating a relationship between the position where the magnetic flux density is measured and the calculated multiplication value;
An electromotive force generated by a fluid flowing on a straight line connecting the two electrodes by integrating the parabolic distribution function determined in the parabolic distribution function calculating step from the position of one electrode to the position of the other electrode. A parameter calculating step for calculating an electromotive force parameter proportional to
Correction coefficient calculation for calculating a correction coefficient for correcting the flow rate or flow velocity of the fluid flowing through the measurement pipe based on the electromotive force parameter calculated in the parameter calculation step and the cross-sectional area measured in the first measurement step. And a calibration method for an electromagnetic flowmeter. The electromagnetic flowmeter calibration method according to claim 1,
The correction coefficient calculating step includes:
Obtaining a correction coefficient of a reference electromagnetic flow meter, a cross-sectional area of the measurement pipe of the electromagnetic flow meter, and an electromotive force parameter from the storage means;
Based on the acquired value, the electromotive force parameter calculated in the parameter calculation step, and the cross-sectional area measured in the first measurement step, the flow rate or flow velocity of the fluid flowing through the measurement pipe of the electromagnetic flow meter to be calibrated is calculated. And a step of calculating a correction coefficient for correcting the electromagnetic flowmeter. An optical sensor for measuring a cross-sectional area of a measurement tube of an electromagnetic flow meter to be calibrated and a distance between two electrodes provided on the measurement tube;
In a state where a magnetic field is applied from the exciting coil of the electromagnetic flow meter to the measurement tube, a magnetic flux density at the center of the measurement tube and a magnetic flux density near the two electrodes on a straight line connecting the two electrodes. Gauss meter to measure
A value obtained by multiplying the value of the magnetic flux density measured by the gauss meter and a predetermined weight function indicating the contribution to the electromotive force generation of the flow velocity of the fluid flowing through the measuring tube is calculated for each position where the magnetic flux density is measured. A parabolic distribution function calculating means for determining an expression of a parabolic distribution function indicating a relationship between the position where the magnetic flux density is measured and the calculated multiplication value;
The electromotive force generated by the fluid flowing on the straight line connecting the two electrodes by integrating the parabolic distribution function formula determined by the parabolic distribution function calculating means from the position of one electrode to the position of the other electrode. Parameter calculating means for calculating an electromotive force parameter proportional to
Correction coefficient calculation means for calculating a correction coefficient for correcting the flow rate or flow velocity of the fluid flowing through the measurement pipe based on the electromotive force parameter calculated by the parameter calculation means and the cross-sectional area measured by the optical sensor; A calibration system for an electromagnetic flowmeter, comprising: The electromagnetic flowmeter calibration system according to claim 3,
Furthermore, a storage means for storing in advance the correction coefficient of the electromagnetic flow meter serving as a reference, the cross-sectional area of the measurement pipe of the electromagnetic flow meter, and the electromotive force parameter,
The correction coefficient calculation means is configured to measure a calibration target electromagnetic flowmeter based on a value stored in the storage means, an electromotive force parameter calculated by the parameter calculation means, and a cross-sectional area measured by the optical sensor. A calibration system for an electromagnetic flowmeter, wherein a correction coefficient for correcting a flow rate or a flow velocity of a fluid flowing through a pipe is calculated.

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