KR102162312B1 - Method of performing calibration of mass flow and apparatus therefor - Google Patents

Abstract

Disclosed are a flow calibration method and an apparatus thereof, the method which comprises the following steps of: acquiring flow rate-related data from a product for which a flow rate is to be measured; extracting a preset flow rate setting value from the obtained flow rate-related data; measuring an actual flow rate value in the product for which the flow rate is to be measured using at least one sensor; receiving a flow rate setting value input from a user through a predetermined interface; calculating an estimated flow rate setting value based on the preset flow rate setting value, the measured actual flow rate value, and the input flow rate setting value; and calibrating the flow rate value input as a correction factor for the calculated estimated flow rate setting value. According to the present invention, a set flow rate value can be automatically calibrated so that a set flow rate and an actual flow rate match.

Description

Method of performing calibration of mass flow and apparatus therefor

The present invention relates to a flow rate calibration method and device thereof, and more particularly, to a flow rate calibration method and an apparatus for automatically calibrating a set flow rate so that a set flow rate and an actual flow rate match through a correction factor.

After creating a vacuum in the semiconductor chamber during a semiconductor process or manufacturing process, argon gas is injected to cause discharge. At this time, when setting the required gas flow rate, it is very important that a gas having a flow rate that matches the set gas flow rate flows. In fact, there are many cases in which the gas with a flow rate that matches the set flow rate does not flow due to aging of the pipe or equipment abnormality or gas or various environmental factors.

In this case, in order to accurately measure the amount of injected gas, a measuring device and a controller for controlling it are required. In charge of this is the Mass Flow Controller (MFC), which is a major component of semiconductor manufacturing equipment. MFC plays an important role to the extent that it affects the quality of the semiconductor itself.

Even through MFC, it is not possible to match the automatically set flow rate with the flowing flow rate, and the corresponding technician manually adjusts it through many experiments. In addition, in the case of MFC, the country of origin is mostly overseas, and the use of the calibration program is limited because it is not distributed to users, so there is a problem that it is expensive and requires a lot of time for calibration.

A problem to be solved by the present invention is to provide a flow rate calibration method and an apparatus for automatically calibrating a set flow rate value so that the set flow rate and the actual flow rate match by allowing the user to directly change the output value of the MFC.

According to an embodiment of the present invention for solving the above technical problem, a flow rate calibration method includes: obtaining, by a flow rate calibration device, flow rate-related data from a product to measure the flow rate; Extracting, by the flow rate calibration device, a preset flow rate setting value from the obtained flow rate-related data; Measuring, by the flow rate calibration device, an actual flow rate value in the product for which the flow rate is to be measured using at least one sensor; Receiving, by the flow rate calibration device, a flow rate setting value input from a user through a predetermined interface; Calculating, by the flow rate calibration device, an estimated flow rate setting value based on the preset flow rate setting value, the measured actual flow rate value, and the input flow rate setting value; And calibrating, by the flow rate calibration device, the input flow rate value with a correction factor for the calculated estimated flow rate setting value.

The flow rate calibration method includes: calculating, by the flow rate calibration device, a first estimated flow rate setting value based on a first flow rate setting value, a first measured flow rate value for the first flow rate setting value, and an input flow rate setting value; Obtaining, by the flow rate calibration device, a second measured flow rate value for the first estimated flow rate set value; Checking, by the flow rate calibration device, whether the second measured flow rate value matches the input flow rate set value; If they do not match, the flow calibration device estimates N+1 based on the Nth (N is an integer that increases sequentially from 1) estimated flow rate set value, the N+1 measured flow rate value, and the input flow rate set value. Calculating a flow rate setting value; Obtaining, by the flow rate calibration device, an N+2th measured flow rate value for the N+1th estimated flow rate set value; Checking, by the flow rate calibration device, whether the N+2th measured flow rate value matches the input set value; When the N+2 measured flow rate value matches the input flow rate set value, determining, by the flow rate calibration device, the N+1 estimated flow rate set value as a final estimated flow rate set value; And storing, by the flow rate calibration device, as data by linking the first estimated flow rate setting value and the determined final estimated flow rate setting value, wherein the correction factor comprises the input flow rate value and the final estimated flow rate setting value. It can be a difference value.

The flow rate calibration method comprises the steps of: re-measurement of an actual flow rate value for the calibrated input flow rate setting value by the flow rate calibration device; If the remeasured flow rate value and the input flow rate value do not match within a predetermined range, re-estimation based on the calibrated input flow rate setting value, the remeasured flow rate value, and the input flow rate setting value Calculating a flow rate setting value; Obtaining a final estimated flow rate set value according to the re-estimated flow rate set value; And obtaining a final estimated flow rate set value according to the reestimated flow rate set value and a correction factor for the inputted flow rate set value, and re-calibrating the inputted flow rate set value according to the obtained correction factor. can do.

According to another embodiment of the present invention for solving the technical problem, the flow rate calibration device obtains flow rate-related data from a product to measure flow rate, and extracts a preset flow rate setting value from the obtained flow rate-related data Acquisition unit; A flow rate measurement unit that measures an actual flow rate value of the product to measure the flow rate using at least one sensor; An interface unit for receiving a flow rate setting value input from a user; A flow rate calculator configured to calculate an estimated flow rate setting value based on the preset flow rate set value, the measured actual flow rate value, and the inputted flow rate set value; And a calibration unit for calibrating the input flow rate value with a correction factor for the calculated estimated flow rate setting value.

According to the present invention, there is an advantage that a user does not manually control an output value, and a calibration operation is automatically performed in response to a change in the output value.

Further, according to the present invention, as the calibration is performed automatically, the maintenance cost of the semiconductor equipment is reduced, and the calibration period is drastically shortened compared to the manual.

1 is a view showing a flow chart of a flow rate calibration method according to an embodiment of the present invention.
2 is a diagram showing an example of flow rate-related data according to an embodiment of the present invention.
3 is a flowchart illustrating a method of obtaining a correction factor according to an embodiment of the present invention.
4 is a diagram showing a calibration curve according to an embodiment of the present invention.
5 is a diagram showing a block diagram of a flow rate calibration apparatus according to an embodiment of the present invention.

Advantages and features of the present invention, and a method of achieving them will become apparent with reference to the embodiments described below in detail together with the accompanying drawings. However, the present invention is not limited to the embodiments described herein and may be embodied in other forms. Rather, the embodiments introduced herein are provided so that the disclosed content may be thorough and complete, and the spirit of the present invention may be sufficiently conveyed to those skilled in the art.

The terms used in the present application are only used to describe specific embodiments, and are not intended to limit the present invention. Singular expressions include plural expressions unless the context clearly indicates otherwise. In the present application, terms such as "comprise" or "have" are intended to designate the presence of features, numbers, steps, actions, components, parts, or combinations thereof described in the specification, but one or more other features. It is to be understood that the presence or addition of elements or numbers, steps, actions, components, parts, or combinations thereof, does not preclude in advance the possibility of being added.

Unless otherwise defined, all terms including technical or scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the present invention belongs. Terms such as those defined in a commonly used dictionary should be interpreted as having a meaning consistent with the meaning of the related technology, and should not be interpreted as an ideal or excessively formal meaning unless explicitly defined in this application. Does not.

A preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings.

1 is a view showing a flow chart of a flow rate calibration method according to an embodiment of the present invention.

Referring to FIG. 1, in step 110, an apparatus for performing a flow rate calibration method acquires flow rate-related data from a product to measure a flow rate. In the present specification, an apparatus for performing a flow calibration method will be referred to as a flow calibration apparatus or a mass flow meter.

The mass flow controller is a device that measures and controls the flow of gas, and functions to keep the amount of gas used during the semiconductor process constant. Mass flow meters are also referred to as mass flow controllers or MFCs.

Mass flow meters typically contain sensors, bypasses, flow control valves and special circuitry. The gas is input at the inlet joint and is divided to flow into both the flow sensor and bypass, the sensor measures the mass flow rate of the gas, and the flow control valve makes the difference between the measured flow rate and the flow rate received from the external flow setting signal zero. Correct the flow rate as possible.

2 is a diagram showing an example of flow rate-related data according to an embodiment of the present invention.

In step 120, the mass flow meter extracts a preset flow rate setting value from the obtained flow rate-related data.

The acquired flow-related data contains various information, and includes the flow rate set value preset in the product. The mass flow meter extracts a preset flow rate setting value by filtering the acquired flow-related data by address.

In step 130, the mass flow meter measures the actual flow rate value of the product to measure the flow rate using the provided sensors.

In step 140, the mass flow meter receives a flow rate setting value from a user through a predetermined interface.

In step 150, the mass flow meter calculates an estimated flow rate setting value based on a preset flow rate setting value, a measured flow rate value, and an input flow rate setting value.

Equation 1 below is an equation for the estimated flow rate setting value.

The preset flow rate setting value and the measured flow rate value should be the same, but they are not the same due to many variables. Therefore, there have been many problems because the flow rate cannot flow according to the preset flow rate setting value. Here, the estimated flow rate setting value is a flow rate setting value to be changed for actually flowing the input flow rate value based on the ratio of the preset flow rate setting value and the measured flow rate value.

In step 160, the mass flow meter calibrates the input flow rate value as a correction factor for the calculated estimated flow rate set value. When the calibrated flow rate value is set as the flow rate value set in the product, the flow rate that matches the input flow rate value flows.

3 is a flowchart illustrating a method of obtaining a correction factor according to an embodiment of the present invention.

The correction factor is obtained through an experiment, and is obtained through an acquired flow rate setting value, an actual measured flow rate measurement value, and a flow rate setting value to be set.

Referring to FIG. 3, in step 310, the mass flow meter calculates a first estimated flow rate setting value based on a first flow rate set value, a first measured flow rate value, and an input flow rate set value from the product to be measured.

The first flow rate setting value means a flow rate setting value extracted from the flow rate-related data of the product in the same manner as steps 110 and 120 of FIG. 1. The first measured flow rate value means the actual measured flow rate value, and the input flow rate setting value means the flow rate value input by the user.

Even if the flow rate is set as the input flow rate set value, the flow rate that matches the input flow rate set value does not flow due to an error. Therefore, it is necessary to correct the flow rate setting value assuming the input flow rate setting value as the actual flow rate. At this time, the first corrected flow rate value is referred to as a first estimated flow rate set value.

Table 1 below is a diagram showing a first flow rate set value, a first measured flow rate value, an error flow rate, and an error rate.

Set%FS 1st flow setting value 1st measured flow value Error flow Error rate (%) 100 300 300.1 0.100 0.033 75 225 224.09 -0.910 -0.404

The first estimated flow rate setting value is shown in Equation 2 below.

In step 320, the mass flow meter obtains a second measured flow rate value by setting the flow rate setting value as the first estimated flow rate setting value.

In step 330, it is checked whether the second measured flow rate value matches the input flow rate set value.

If they do not match, in step 340, the mass flow meter calculates a second estimated flow rate set value based on the first estimated flow rate set value, the second measured flow rate value, and the input flow rate set value from the product. Due to the characteristics of the product pipe and various variables, the second measured flow rate value according to the first estimated flow rate setting value does not mostly coincide with the input flow rate setting value. Therefore, when the estimated flow rate setting value is obtained again from the first estimated flow rate setting value and the second measured flow rate value, the input flow rate setting value and the actual measured flow rate value become even slightly closer.

The second estimated flow rate setting value is shown in Equation 3 below.

If they match, the process moves to step 370, and the first estimated flow rate set value becomes the final estimated flow rate set value.

In step 350, the mass flow meter obtains a third measured flow rate value by setting the flow rate setting value as the second estimated flow rate setting value.

In step 360, it is checked whether the third measured flow rate value matches the input flow rate set value.

If the third measured flow rate value does not match the input flow rate set value, the process moves to step 340 again, and repeats continuously until the measured flow rate value matches the input flow rate set value.

Thereafter, if the measured flow rate value matches the input flow rate setting value, in step 370, the flow rate setting value is determined as the final estimated flow rate setting value. When the flow rate setting value is set as the final estimated flow rate setting value, the flow rate value set by the user becomes the actual flow rate value. The final estimated flow rate setting value is a flow rate setting value corrected according to the characteristics of the product based on the actual measured flow rate value to the flow rate value extracted as data.

In step 380, the mass flow meter associates the first estimated flow rate setting value with the final estimated flow rate setting value and stores it as data. At this time, the difference between the input flow rate set value and the final estimated flow rate set value becomes a correction factor. The final estimated flow rate set value is obtained based on the first estimated flow rate set value, and the first estimated flow rate set value is obtained based on the input flow rate set value.

In an embodiment of the present invention, the mass flow meter generates and stores a calibration curve based on the stored data. Alternatively, in another embodiment of the present invention, the mass flow meter may also store stored data in a table format.

4 is a diagram showing a calibration curve according to an embodiment of the present invention.

4, the x-axis represents the first estimated flow rate set value, and the y-axis represents the final estimated flow rate set value. The calibration curve has nonlinear characteristics that are not linear.

1 and 4, reference numeral 410 denotes a calibration curve, the final estimated flow rate set value for the first estimated flow rate set value x1 is y1, and the input flow rate set value 420 is y2 and the final The value 430 of y2-y1, which is a difference from y1, which is the estimated flow rate set value, becomes a correction factor.

Although not shown in the drawing, after step 160 of FIG. 1, the mass flow meter may re-measure the actual flow rate value for the calibrated input flow rate value. If the remeasured actual flow rate value does not match the input flow rate value within a predetermined range, as shown in Equation 4, the calibrated flow rate set value, the remeasured flow rate value for the calibrated flow rate set value, and the input flow rate setting Calculate the reestimated flow rate setting value based on the value.

Thereafter, when the reestimated flow rate set value is calculated, the final estimated flow rate set value according to the reestimated flow rate set value is obtained according to the calibration curve of FIG. 4 to obtain a correction factor, and the input flow rate set value according to the obtained correction factor Can be re-calibrated. In some cases, steps after step 160 may be repeated by determining a depth.

The correction factor can only be accurate if there is a lot of data through many experiments. If a large number of estimated flow rate setpoints are obtained and the product characteristics and environmental data are combined, the data on the correction factor can become big data. When an artificial intelligence engine is used through data labeling or weighting for big data, an AI execution method for calibrating a flow rate setting value may be performed.

5 is a diagram showing a block diagram of a flow rate calibration apparatus according to an embodiment of the present invention.

Referring to FIG. 5, the flow calibration apparatus 500 includes a data acquisition unit 510, a flow rate measurement unit 520, an interface unit 530, a flow rate calculation unit 540, and a calibration unit 550. In the present invention, the flow calibration device 500 may be provided as a separate device in the mass flow meter (MFC), and the flow calibration device 500 may be the same device as the mass flow meter.

The data acquisition unit 510 acquires flow rate-related data from a product to measure the flow rate.

Thereafter, the data acquisition unit 510 extracts a preset flow rate setting value from the obtained flow rate-related data. The acquired flow-related data contains various information, and includes the flow rate set value preset in the product. The data acquisition unit 510 extracts a preset flow rate setting value by filtering by address.

The flow rate measurement unit 520 measures the actual flow rate value of the product using the provided sensors.

The interface unit 530 receives a flow rate value set by a user through a predetermined interface.

The flow rate calculation unit 540 calculates an estimated flow rate setting value based on a preset flow rate setting value, a measured flow rate value, and an input flow rate setting value. The estimated flow rate setting value is calculated by Equation 1 above.

The preset flow rate setting value and the measured flow rate value should be the same, but they are not the same due to many variables. Therefore, there have been many problems because the flow rate cannot flow according to the preset flow rate setting value. Here, the estimated flow rate setting value is a flow rate setting value to be changed for actually flowing the input flow rate value based on the ratio of the preset flow rate setting value and the measured flow rate value.

The calibration unit 550 calibrates the input flow rate value as a correction factor for the calculated estimated flow rate setting value. When the calibrated flow rate value is set as the flow rate value set in the product, the flow rate that matches the input flow rate value flows.

The correction factor is obtained through an experiment, and is obtained through an acquired flow rate setting value, an actual measured flow rate measurement value, and a flow rate setting value to be set.

Hereinafter, the acquisition of the correction factor will be described.

The flow rate calculation unit 540 is based on the first flow rate set value from the product to be measured flow rate, the first measured flow rate value measured by the flow rate measurement unit 520 and the input flow rate set value received by the interface unit 530. Calculate the first estimated flow rate set value.

The first flow rate set value means the flow rate set value extracted from the product flow-related data. The first measured flow rate value means the actual measured flow rate value, and the input flow rate setting value means the flow rate value input by the user. Even if the flow rate is set as the input flow rate set value, the flow rate that matches the input flow rate set value does not flow due to an error. Therefore, it is necessary to correct the flow rate setting value assuming the input flow rate setting value as the actual flow rate. At this time, the first corrected flow rate value is referred to as a first estimated flow rate set value. The first estimated flow rate setting value is calculated by Equation 2 above.

The flow rate calculation unit 540 obtains a second measured flow rate value by the flow rate measurement unit 520 by using the flow rate set value as the first estimated flow rate set value.

After that, the flow rate calculation unit 540 checks whether the second measured flow rate value matches the input flow rate set value.

If not, the flow rate calculation unit 540 calculates a second estimated flow rate setting value based on the first estimated flow rate set value, the second measured flow rate value, and the input flow rate set value from the product. Due to the characteristics of the product pipe and various variables, the second measured flow rate value according to the first estimated flow rate setting value does not mostly coincide with the input flow rate setting value. Therefore, when the estimated flow rate setting value is obtained again from the first estimated flow rate setting value and the second measured flow rate value, the input flow rate setting value and the actual measured flow rate value become even slightly closer. The second estimated flow rate setting value is calculated by Equation 3 above.

The flow rate calculation unit 540 obtains a third measured flow rate value by the flow rate measurement unit 520 by using the flow rate set value as the second estimated flow rate set value.

The flow rate calculation unit 540 checks whether the third measured flow rate value matches the input flow rate set value, and if the third measured flow rate value does not match the input flow rate set value, the measured flow rate value is determined by the above equations. Repeat repeatedly until it matches the input flow rate setting value.

Thereafter, when the measured flow rate value matches the input flow rate set value, the flow rate calculation unit 540 determines the flow rate set value as the final estimated flow rate set value. When the flow rate setting value is set as the final estimated flow rate setting value, the flow rate value set by the user becomes the actual flow rate value. The final estimated flow rate setting value is a flow rate setting value corrected according to the characteristics of the product based on the actual measured flow rate value to the flow rate value extracted as data.

The calibration unit 550 stores the first estimated flow rate setting value and the final estimated flow rate setting value as data in a storage unit (not shown). At this time, the difference between the input flow rate set value and the final estimated flow rate set value becomes a correction factor. The final estimated flow rate set value is obtained based on the first estimated flow rate set value, and the first estimated flow rate set value is obtained based on the input flow rate set value. Thereafter, the calibration unit 550 generates and stores a calibration curve based on the stored data. In another embodiment, the calibration unit 550 may also store stored data in a table format.

Returning to the top again, the flow measurement unit 520 may re-measure the actual flow rate value for the calibrated input flow rate value. When the actual flow rate value does not coincide with the input flow rate value within a predetermined range, the flow rate calculation unit 540 re-measures flow rate for the calibrated flow rate set value and the calibrated flow rate set value, as shown in Equation 4 above. Based on the value and the entered flow rate setting value, the reestimated flow rate setting value is calculated.

Thereafter, when the reestimated flow rate setting value is calculated, the calibration unit 550 obtains a final estimated flow rate setting value according to the reestimated flow rate setting value according to the calibration curve, obtains a correction factor, and inputs it according to the obtained correction factor You can recalibrate the flow rate setting. In some cases, the calibration unit 550 may repeat by determining a depth.

The correction factor can only be accurate if there is a lot of data through many experiments. If a large number of estimated flow rate setpoints are obtained and the product characteristics and environmental data are combined, the data on the correction factor can become big data. When an artificial intelligence engine is used through data labeling or weighting for big data, an AI execution method for calibrating a flow rate setting value may be performed.

The flow calibration method as described above can also be implemented as computer-readable codes on a computer-readable recording medium. The computer-readable recording medium includes all types of recording media storing data that can be read by a computer system. Examples of computer-readable recording media include ROM, RAM, CD-ROM, magnetic tapes, floppy disks, and optical data storage devices. In addition, the computer-readable recording medium is distributed over a computer system connected through a network, so that computer-readable codes can be stored and executed in a distributed manner. In addition, functional programs, codes, and code segments for implementing the disk management method can be easily inferred by programmers in the technical field to which the present invention belongs.

So far, the present invention has been looked at around its preferred embodiments. Those of ordinary skill in the art to which the present invention pertains will be able to understand that the present invention can be implemented in a modified form without departing from the essential characteristics of the present invention. Therefore, the disclosed embodiments should be considered from an illustrative point of view rather than a limiting point of view. The scope of the present invention is shown in the claims rather than the foregoing description, and all differences within the scope equivalent thereto should be construed as being included in the present invention.

Claims (6)

Obtaining, by a flow rate calibration device, flow-related data from a product for which the flow rate is to be measured;
Extracting, by the flow rate calibration device, a preset flow rate setting value from the obtained flow rate-related data;
Measuring, by the flow rate calibration device, an actual flow rate value in the product to be measured by using at least one sensor;
Receiving, by the flow rate calibration device, a flow rate setting value input from a user through a predetermined interface;
Calculating, by the flow rate calibration device, an estimated flow rate setting value based on the preset flow rate setting value, the measured actual flow rate value, and the input flow rate setting value; And
Comprising, by the flow rate calibration device, calibrating the input flow rate value with a correction factor for the calculated estimated flow rate setting value,
Calculating, by the flow rate calibration device, a first estimated flow rate set value based on a first flow rate set value, a first measured flow rate value for the first flow rate set value, and an input flow rate set value;
Obtaining, by the flow rate calibration device, a second measured flow rate value for the first estimated flow rate set value;
Checking, by the flow rate calibration device, whether the second measured flow rate value matches the input flow rate set value;
If it does not match, the flow calibration device is based on the Nth (N is an integer sequentially increasing from 1) estimated flow rate set value, N+1th measured flow rate value, and the input flow rate set value, based on the N+1th estimated flow rate. Calculating a set value;
Obtaining, by the flow rate calibration device, an N+2th measured flow rate value for the N+1th estimated flow rate set value;
Checking, by the flow rate calibration device, whether the N+2th measured flow rate value matches the input set value;
When the N+2 measured flow rate value matches the input flow rate set value, determining, by the flow rate calibration device, the N+1 estimated flow rate set value as a final estimated flow rate set value; And
The flow rate calibration device further comprises the step of storing as data by linking the first estimated flow rate setting value and the determined final estimated flow rate setting value,
The correction factor is a difference value between the input flow rate value and the final estimated flow rate set value,
Re-measuring, by the flow rate calibration device, an actual flow rate value for the calibrated input flow rate setting value;
If the remeasured flow rate value and the input flow rate value do not match within a predetermined range, re-estimation based on the calibrated input flow rate setting value, the remeasured flow rate value, and the input flow rate setting value Calculating a flow rate setting value;
Obtaining a final estimated flow rate set value according to the re-estimated flow rate set value; And
Obtaining a final estimated flow rate set value according to the reestimated flow rate set value and a correction factor for the inputted flow rate set value, and recalibrating the inputted flow rate set value according to the obtained correction factor. Flow calibration method, characterized in that. delete delete In the flow calibration device,
A data acquisition unit for acquiring flow rate-related data from a product to measure flow rate, and extracting a preset flow rate setting value from the obtained flow rate-related data;
A flow rate measurement unit that measures an actual flow rate value of the product to measure the flow rate using at least one sensor;
An interface unit for receiving a flow rate setting value input from a user;
A flow rate calculator configured to calculate an estimated flow rate setting value based on the preset flow rate set value, the measured actual flow rate value, and the inputted flow rate set value; And
And a calibration unit for calibrating the input flow rate value with a correction factor for the calculated estimated flow rate setting value,
The flow rate calculation unit calculates a first estimated flow rate set value based on a first flow rate set value, a first measured flow rate value for the first flow rate set value, and an input flow rate set value, and calculates the first estimated flow rate set value. Acquire a second measured flow rate value, check whether the second measured flow rate value matches the input flow rate set value, and if not, the flow rate calibration device is Nth (N is an integer sequentially increasing from 1) Based on the estimated flow rate set value, the N+1th measured flow rate value, and the input flow rate set value, the N+1th estimated flow rate set value is calculated, and the flow rate calibration device calculates the N+1th estimated flow rate set value. Obtaining the N+2 measured flow rate value, and the flow calibration device checks whether the N+2th measured flow rate value matches the input set value, and the N+2 measured flow rate value matches the input flow rate set value. In case, the N+1 estimated flow rate set value is determined as the final estimated flow rate set value,
The calibration unit stores the first estimated flow rate set value and the determined final estimated flow rate set value as data,
The correction factor is a difference value between the input flow rate value and the final estimated flow rate set value,
When the flow rate calculation unit re-measures an actual flow rate value for the calibrated input flow rate set value by the flow rate calibration device, and the re-measured flow rate value and the input flow rate value do not match within a predetermined range, Calculate a reestimated flow rate set value based on the calibrated input flow rate set value, the remeasured flow rate value, and the inputted flow rate set value, and obtain a final estimated flow rate set value according to the re-estimated flow rate set value,
The calibration unit obtains a final estimated flow rate set value according to the reestimated flow rate set value and a correction factor for the inputted flow rate set value, and recalibrates the inputted flow rate set value according to the obtained correction factor. Flow calibration device.
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