Dissolved oxygen sensor calibration method

Abstract

The invention discloses a dissolved oxygen sensor calibration method, which comprises the following steps: at each set temperature, detecting through a to-be-calibrated dissolved oxygen sensor to obtain a sampling temperature value, and detecting through a standard temperature sensor to obtain a standard temperature value; performing linear regression fitting by using the recorded sampling temperature value and the standard temperature value, establishing a temperature correction function of the to-be-calibrated dissolved oxygen sensor, and obtaining a corrected temperature value; adjusting the saturation degree of dissolved oxygen in the water body at each set temperature, and recording phase values detected by the uncalibrated dissolved oxygen sensor and dissolved oxygen content values obtained by the calibrated dissolved oxygen sensor under different saturation degrees; performing linear regression fitting by using the phase value and the dissolved oxygen content value, establishing a linear fitting function of the dissolved oxygen content value and the phase value, and screening data records according to a fitting index R2; and carrying out dissolved oxygen sensor calibration function curved surface fitting by utilizing the reserved data record to generate a calibration formula so as to realize calibration of the dissolved oxygen sensor.

Description

Technical Field

[0001] This invention belongs to the field of water quality monitoring technology and relates to a sensor for measuring dissolved oxygen content in seawater, specifically, a calibration method for a dissolved oxygen sensor. Background Technology

[0002] In the process of measuring dissolved oxygen in the ocean, the temperature and phase values ​​of seawater are collected in real time using a dissolved oxygen sensor. Then, the dissolved oxygen content in the seawater can be obtained using a pre-calibrated calculation formula. The quality of seawater and the degree of pollution of seawater can be measured based on the calculated dissolved oxygen content.

[0003] However, due to the complex and ever-changing marine monitoring environment with numerous interfering factors, the hardware of the dissolved oxygen sensor is affected by the complex marine environment during actual use. After a period of use, the temperature and / or phase values ​​detected by the sensor may deviate from the actual situation to some extent. Consequently, the dissolved oxygen content value calculated using the calibration formula provided by the manufacturer is no longer accurate. In other words, the calibration formula provided by the manufacturer can no longer accurately reflect the true relationship between the dissolved oxygen content value and the temperature and phase values ​​detected by the dissolved oxygen sensor. Therefore, it is necessary to recalibrate the dissolved oxygen sensor after problems are discovered during use to ensure the normal operation of seawater dissolved oxygen monitoring. Summary of the Invention

[0004] To address at least one of the aforementioned technical problems in the prior art, this invention proposes a dissolved oxygen sensor calibration method. When deviations occur in the temperature and / or phase values ​​detected by the dissolved oxygen sensor, the method can refit and generate a true relationship between the dissolved oxygen content value and the actual detected temperature and phase values, thereby achieving accurate monitoring of seawater dissolved oxygen content.

[0005] To solve the above-mentioned technical problems, the present invention adopts the following technical solution: A method for calibrating a dissolved oxygen sensor, comprising: Place the dissolved oxygen sensor to be calibrated and the standard temperature sensor into a constant temperature water bath, and adjust the temperature of the water bath to stabilize at [temperature values ​​missing]. n A set temperature; At each set temperature, the sampling temperature value is obtained by detecting the dissolved oxygen sensor to be calibrated, and the standard temperature value is obtained by detecting the standard temperature sensor. Using records n Each sampling temperature value and n A linear regression fit was performed on the standard temperature values ​​to establish a temperature correction function for the dissolved oxygen sensor to be calibrated, and the corrected temperature values ​​were obtained. Place the calibrated dissolved oxygen sensor and the dissolved oxygen sensor to be calibrated into a constant temperature water bath, and adjust the dissolved oxygen saturation of the water in the constant temperature water bath to stabilize at m set points at each set temperature. The phase values ​​detected by the uncalibrated dissolved oxygen sensor and the dissolved oxygen content values ​​obtained by the calibrated dissolved oxygen sensor are recorded at each set temperature and each saturation set point, respectively. Using the data recorded at each set temperature m Each phase value and m A linear regression was performed on the dissolved oxygen content values ​​to establish a linear fitting function between the dissolved oxygen content values ​​and the phase values, and the R-squared regression model fit index of the linear fitting function was calculated. R 2 ,reserve R 2 Data records that are greater than or equal to the set threshold; By using the retained data records, a surface fit is performed on the dissolved oxygen sensor calibration function to generate the final dissolved oxygen sensor calibration formula.

[0006] In some embodiments of this application, the following steps may be specifically designed during the process of establishing the temperature correction function for the dissolved oxygen sensor to be calibrated: Using records n Each sampling temperature value and n Linear regression fitting was performed on the standard temperature values ​​to obtain the initial coefficients. k , b : ; ; in, x i For the dissolved oxygen sensor to be calibrated in the first i The sampled temperature value is obtained by detecting a set temperature. y i For standard temperature sensors in the first i A standard temperature value is obtained by detecting a set temperature. for n The average of the sampled temperature values; for n The average of a number of standard temperature values; Using initial coefficients k , b Establish the temperature correction function for the dissolved oxygen sensor to be calibrated: X = kx + b ; in, xThe sampling temperature value is obtained by detecting the dissolved oxygen sensor to be calibrated; X This is the corrected temperature value. When the temperature value detected by the dissolved oxygen sensor deviates, a temperature correction function is used to correct the detected temperature, thus obtaining a more accurate actual temperature value. Substituting the corrected temperature value into the calibration formula improves the accuracy of dissolved oxygen content calculation.

[0007] In some embodiments of this application, the sampling temperature value x It can be the average value of multiple temperature measurements taken by the dissolved oxygen sensor to be calibrated at a certain set temperature in the constant temperature water bath.

[0008] In some embodiments of this application, the following steps can be specifically designed in the process of establishing a linear fitting function between dissolved oxygen content and phase value: Using the data recorded at each set temperature m Each phase value and m A linear regression was performed on the dissolved oxygen content values ​​to establish a quartic linear fitting function: Z = k 4Y 4 + k 3Y 3 + k 2Y 2 + k 1Y+ k 0; Where Y is the phase value detected by the dissolved oxygen sensor to be calibrated; Z The dissolved oxygen content value is calculated by the calibrated dissolved oxygen sensor based on the temperature and phase values ​​it detects. k 0、 k 1. k 2. k 3. k 4 is the fitting coefficient. Because m Each phase value was obtained by sampling at the same temperature and different dissolved oxygen saturations. Therefore, using a quartic linear fitting function can speed up the calculation and improve the calibration efficiency while meeting the error judgment requirements.

[0009] In some embodiments of this application, the R-squared regression model fit index of the quartic linear fitting function at each set temperature is calculated. R 2 : ; in, Y i For the dissolved oxygen sensor to be calibrated in the first i Phase values ​​acquired at each saturation setpoint; Zi For the calibrated dissolved oxygen sensor in the first i Dissolved oxygen content values ​​obtained at each saturation setpoint; for m The average value of each of the dissolved oxygen content values; If the fitting index is calculated at a certain set temperature R 2 If the temperature is below a set threshold, all data recorded at that set temperature will be discarded, and only data recorded at that temperature will be retained. R 2 Data records greater than or equal to a set threshold are used to fit the calibration function.

[0010] In some embodiments of this application, the set threshold can be set to 0.9999 to ensure measurement accuracy.

[0011] In some embodiments of this application, the configuration can be adjusted according to the actual changes in seawater dissolved oxygen content. m Each setpoint is selected within a saturation range of 20% to 120%. m Preferably, the number of saturation setpoints should be greater than or equal to 13, that is, at least 13 saturation setpoints should be configured to improve the fit.

[0012] In some embodiments of this application, the dissolved oxygen saturation in the constant temperature water bath can be adjusted by introducing oxygen or nitrogen into the constant temperature water bath, so that the dissolved oxygen saturation in the water can vary within the range of 20% to 120%.

[0013] In some embodiments of this application, the following steps may be specifically designed in the process of generating the dissolved oxygen sensor calibration formula: Establish the calibration function for the dissolved oxygen sensor: ; in, X The temperature value is the corrected value after the temperature detected by the dissolved oxygen sensor to be calibrated is adjusted. Y The phase value detected by the dissolved oxygen sensor to be calibrated; O This refers to the dissolved oxygen content value. A, B, C, D, E, F, G For calibration parameters; By performing surface fitting on the dissolved oxygen sensor calibration function using all retained data records, the calibration parameters can be obtained. A, B, C, D, E, F, G The value of is used to generate the final dissolved oxygen sensor calibration formula.

[0014] In some embodiments of this application, after the dissolved oxygen sensor to be calibrated is completed and put into use, the temperature value detected by the dissolved oxygen sensor first needs to be corrected by the temperature correction function to generate the corrected temperature value. XThen, the phase value detected by the dissolved oxygen sensor is compared with that of the dissolved oxygen sensor. Y Substitute these values ​​into the dissolved oxygen sensor calibration formula to calculate the final dissolved oxygen content value.

[0015] Compared with the prior art, the advantages and positive effects of the present invention are mainly reflected in: 1. The dissolved oxygen sensor calibration method of the present invention designs a temperature correction function to correct the temperature value detected by the dissolved oxygen sensor. It uses the deviation between the phase sampling value and the actual dissolved oxygen content value at the same temperature and their fitted function curve to determine whether the phase value detected by the dissolved oxygen sensor is abnormal. The corrected temperature value and the selected normal phase value are used to participate in the surface fitting of the dissolved oxygen sensor calibration function. Thus, a calibration formula that reflects the true relationship between the dissolved oxygen content value and the actual detected temperature and phase values ​​can be obtained. In actual use, the true value of seawater dissolved oxygen content can be calculated to ensure the normal operation of seawater dissolved oxygen monitoring.

[0016] 2. The dissolved oxygen sensor calibration method of the present invention is simple to operate and easy to implement, and can improve the stability of dissolved oxygen measurement and the accuracy of measurement in a variable marine environment.

[0017] Other features and advantages of the present invention will become clearer after reading the detailed description of the embodiments of the present invention in conjunction with the accompanying drawings. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly described below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without any creative effort.

[0019] Figure 1 A flowchart illustrating one embodiment of the dissolved oxygen sensor calibration method proposed in this invention; Figure 2 A quartic linear fitting function curve of phase value and dissolved oxygen content value in one embodiment; Figure 3 This is a surface fitting diagram of one embodiment of temperature value, phase value, and dissolved oxygen content value. Detailed Implementation

[0020] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0021] In the description of this invention, the consecutive numbers of the method steps are for ease of review and understanding. Considering the overall technical solution of this invention and the logical relationship between each step, adjusting the implementation order of the steps will not affect the technical effect achieved by the technical solution of this invention.

[0022] This embodiment addresses the problem that after a period of use, dissolved oxygen sensors are easily affected by external environmental factors, leading to deviations between the detected temperature or phase values ​​and the actual values. This results in inaccurate dissolved oxygen content values ​​calculated using existing calibration formulas. To address this issue, a dissolved oxygen sensor calibration method is proposed. The method refits and generates a calibration formula based on the actual temperature and phase values ​​detected by the dissolved oxygen sensor, enabling the dissolved oxygen sensor to continue to be used and achieve accurate online monitoring of seawater dissolved oxygen content.

[0023] The following is combined Figure 1 The specific execution process of the dissolved oxygen sensor calibration method in this embodiment will be described in detail.

[0024] S101. Place the dissolved oxygen sensor to be calibrated and the standard temperature sensor into the constant temperature water bath, and adjust the temperature of the constant temperature water bath to stabilize at [temperature values ​​missing]. n A set temperature.

[0025] In this embodiment, the standard temperature sensor specifically refers to a sensor capable of accurately detecting water temperature. The dissolved oxygen sensor to be calibrated is placed together with the standard temperature sensor in a constant-temperature water bath, and the water temperature in the bath is simultaneously detected. This is used to determine whether the temperature value detected by the dissolved oxygen sensor is normal, and to correct the detected temperature value when there is a deviation between the detected temperature value and the actual value.

[0026] In some embodiments, the water temperature in the thermostatic bath can be adjusted and stabilized at 35℃, 30℃, 25℃, 20℃, 15℃, 10℃, 5℃, and 2℃ respectively, that is, eight set temperatures can be provided. n =8, so that the fitting accuracy can be improved when the temperature correction function is subsequently fitted.

[0027] S102. At each set temperature, the sampling temperature value is obtained by detecting the dissolved oxygen sensor to be calibrated, and the standard temperature value is obtained by detecting the standard temperature sensor.

[0028] In this embodiment, when the water temperature in the constant temperature bath is stabilized at a certain set temperature, the dissolved oxygen sensor to be calibrated performs multiple temperature acquisitions. The average value of the multiple acquired temperature values ​​is taken as the sampled temperature value detected by the dissolved oxygen sensor to be calibrated. xThe temperature value collected by the standard temperature sensor is used as the standard temperature value. y .

[0029] In some embodiments, the dissolved oxygen sensor to be calibrated can be configured to collect temperature values ​​twice at each set temperature, and the average of the two collected temperature values ​​can be calculated as the sampling temperature value at that set temperature. x .

[0030] For example, given set temperatures of 35℃, 30℃, 25℃, 20℃, 15℃, 10℃, 5℃, and 2℃, the data includes the temperature values ​​collected twice by the dissolved oxygen sensor to be calibrated, the average of the two collected temperatures, and the standard temperature value detected by the standard temperature sensor. y As shown in the table below.

[0031] Table 1

[0032] S103. Using the recorded sampled temperature value and the standard temperature value, perform linear regression fitting to establish the temperature correction function of the dissolved oxygen sensor to be calibrated, and obtain the corrected temperature value.

[0033] In this embodiment, it can be based on the detected n Each sampling temperature value and n By performing linear regression fitting on a set of standard temperature values, the initial coefficients of the temperature correction function are first obtained. k , b ,in: ; ; In the formula, x i This indicates that the dissolved oxygen sensor to be calibrated is in the first... i The sampled temperature value is obtained by detecting a set temperature. y i Indicates the standard temperature sensor at the first i A standard temperature value is obtained by detecting a set temperature. express n The average of the sampled temperature values; express n The average of several standard temperature values.

[0034] Substituting the data from Table 1 into the above formula yields: k =1.005; b =1.8157.

[0035] Then, using the obtained initial coefficients k , bEstablish the temperature correction function for the dissolved oxygen sensor to be calibrated: X = kx + b (1); In equation (1), x This indicates the sampling temperature value obtained by detecting the dissolved oxygen sensor to be calibrated, i.e., the average value of multiple actual sampling temperatures; X This indicates the corrected temperature value.

[0036] When the temperature value detected by the dissolved oxygen sensor deviates, the temperature correction function (1) can be used to correct the detected temperature, thereby obtaining a basically true actual temperature value. After the dissolved oxygen sensor is calibrated and put back into use, the temperature value detected by the dissolved oxygen sensor (which can be the directly collected temperature value or the average value of multiple collected temperatures) also needs to be corrected by the temperature correction function (1) first. Then, the corrected temperature value is substituted into the calibration formula to calculate the dissolved oxygen content value, thereby improving the accuracy of dissolved oxygen monitoring.

[0037] S104. Place the dissolved oxygen sensor to be calibrated and the calibrated dissolved oxygen sensor into a constant temperature water bath, and adjust the dissolved oxygen saturation of the water in the constant temperature water bath to stabilize at m set points at each set temperature.

[0038] In this embodiment, the calibrated dissolved oxygen sensor specifically refers to a sensor capable of accurately obtaining dissolved oxygen content values. The dissolved oxygen sensor to be calibrated and the calibrated dissolved oxygen sensor are placed together in a constant-temperature water bath. While the constant-temperature water bath is stable at each set temperature, the dissolved oxygen saturation of the water in the constant-temperature water bath is adjusted to stabilize at each of the m set points.

[0039] In some embodiments, the dissolved oxygen saturation of the water in the constant-temperature water bath can be adjusted by introducing oxygen or nitrogen into the bath, respectively. For example, introducing oxygen will increase the dissolved oxygen saturation of the water in the constant-temperature water bath; introducing nitrogen will decrease the dissolved oxygen saturation of the water in the constant-temperature water bath. After adjusting the dissolved oxygen saturation of the water in the constant-temperature water bath to a certain set point, it is left to stand for half an hour, and then data is collected synchronously.

[0040] In some embodiments, the configuration can be tailored to the actual changes in seawater dissolved oxygen content. m A set point can be selected, for example, within the saturation range of 20% to 120%. m A set point, the m Ideally, the number of saturation setpoints should be greater than or equal to 13, that is, at least 13 saturation setpoints should be configured to obtain a more accurate linear fitting function between dissolved oxygen content and phase value.

[0041] As a specific embodiment, 13 saturation setpoints can be configured for each set temperature, that is, m =13. The 13 saturation set points can be set near 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%, 95%, 100%, 105%, 110%, and 120%, respectively.

[0042] S105. Record the phase value detected by the uncalibrated dissolved oxygen sensor and the dissolved oxygen content value obtained by the calibrated dissolved oxygen sensor at each set temperature and each saturation set point.

[0043] In this embodiment, the temperature of the constant temperature water bath can first be stabilized at a certain set temperature, such as 30°C. Then, oxygen or nitrogen is introduced into the constant temperature water bath to adjust the dissolved oxygen saturation of the water, thereby stabilizing the dissolved oxygen saturation at a certain level. m A set point. After adjusting the dissolved oxygen saturation of the water in the constant temperature water bath to a certain set point, for example, when the saturation reaches about 20%, let the water in the constant temperature water bath stand still for half an hour or more. Then, use an uncalibrated dissolved oxygen sensor to detect the phase value Y and temperature value of the water in the constant temperature water bath, and use the temperature correction function (1) to correct the detected temperature value and calculate the corrected temperature value X. At the same time, use a calibrated dissolved oxygen sensor to detect the temperature value and phase value of the water in the constant temperature water bath, and use the calibration formula of the calibrated dissolved oxygen sensor to calculate the dissolved oxygen content Z of the water in the constant temperature water bath. After the detection is completed, continue to introduce oxygen or nitrogen into the constant temperature water bath to adjust the dissolved oxygen saturation of the water in the constant temperature water bath to the next set point, for example, when the saturation reaches about 30%, let the water in the constant temperature water bath stand still for half an hour or more, and record the phase value Y and the corrected temperature value X detected by the uncalibrated dissolved oxygen sensor, as well as the dissolved oxygen content Z obtained by the calibrated dissolved oxygen sensor. And so on, until... m After all set points have been detected and recorded, the temperature at that set point can be obtained. m Each phase value and m Dissolved oxygen content value.

[0044] Table 2 shows the phase value Y and the corrected temperature value X detected by the uncalibrated dissolved oxygen sensor at 13 saturation setpoints at a set temperature of 30℃, as well as the dissolved oxygen content value Z obtained by the calibrated dissolved oxygen sensor.

[0045] Table 2

[0046] Adjust the temperature of the thermostatic water bath to stabilize at the next set temperature, for example, 25°C. Repeat the dissolved oxygen saturation adjustment process described above to obtain the dissolved oxygen saturation at the set temperature of 25°C. m The phase value, corrected temperature value, and dissolved oxygen content value corresponding to each saturation setpoint.

[0047] And so on, record n The phase value, corrected temperature value, and dissolved oxygen content value corresponding to each saturation setpoint at a given temperature are used to form... n × m Group data records.

[0048] S106. Utilize the data recorded at each set temperature. m Each phase value and m Linear regression fitting was performed on the dissolved oxygen content values ​​to establish a linear fitting function between the dissolved oxygen content values ​​and the phase values.

[0049] In this embodiment, to obtain the error range of the relationship between the phase value and the dissolved oxygen content value, a fourth-order linear fitting function can be established: Z = k 4Y 4 + k 3Y 3 + k 2Y 2 + k 1Y+ k 0 (2); Where Y is the phase value detected by the dissolved oxygen sensor to be calibrated; Z The dissolved oxygen content value is calculated by the calibrated dissolved oxygen sensor based on the temperature and phase values ​​it detects. k 0、 k 1. k 2. k 3. k 4 represents the fitting coefficient.

[0050] because m Each phase value was obtained by sampling at the same temperature and different dissolved oxygen saturations. Therefore, using a quartic linear fitting function can speed up the calculation and improve the calibration efficiency while meeting the error judgment requirements.

[0051] Figure 2 The fitted curve is obtained by performing a fourth-order linear fit between the phase values ​​and dissolved oxygen content values ​​in Table 2. k 4 =0.0004; k 3 =-0.0761; k 2 =4.9277;k 1 =-147.95; k 0 =1820.6.

[0052] S107. Calculate the R-squared regression model fitting index of the linear fitting function between the dissolved oxygen content value and the phase value at each set temperature. R 2 .

[0053] R squared (R 2 The variance index (VRI) is a commonly used indicator to measure the goodness of fit of a regression model. It represents the proportion of the variance of the dependent variable explained by the model, and its value ranges from 0% to 100%. The closer the value is to 100%, the better the model fits the data.

[0054] In this embodiment, the R-squared regression model fitting index corresponding to the above-mentioned fourth-order linear fitting function (2) is... R 2 The formula is: ; in, Y i For the dissolved oxygen sensor to be calibrated in the first i Phase values ​​acquired at each saturation setpoint; Z i For the calibrated dissolved oxygen sensor in the first i Dissolved oxygen content values ​​obtained at each saturation setpoint; for m The average value of the dissolved oxygen content values.

[0055] Calculate the fitting index of the linear fitting function between the dissolved oxygen content value and the phase value at each set temperature. R 2 Thus obtain n Each fitting index R 2 .

[0056] S108, Fitting Indices R 2 The data records are filtered by comparing them with a set threshold.

[0057] The fitting index calculated at each set temperature R 2 Compared with a set threshold, if R 2 If the set threshold is not met, all data recorded at that set temperature will be discarded; if... R 2 If the value is greater than or equal to the set threshold, all data recorded at that set temperature will be retained for use in fitting subsequent calibration functions.

[0058] In some embodiments, the set threshold can be set to 0.9999 to ensure measurement accuracy.

[0059] Figure 2 The fitting index of the quartic linear fitting function in R 2 =1, which is greater than the set threshold of 0.9999. Therefore, all data records at the set temperature of 30℃ are retained, such as 13 phase values, 13 corrected temperature values, and 13 dissolved oxygen content values, for subsequent calibration function fitting process.

[0060] S109. Using the retained data records, perform surface fitting of the dissolved oxygen sensor calibration function to generate the final dissolved oxygen sensor calibration formula.

[0061] In this embodiment, the calibration function for the dissolved oxygen sensor can be established as follows: (3); in, X The corrected temperature value corresponding to the temperature value detected by the dissolved oxygen sensor to be calibrated; Y The phase value detected by the dissolved oxygen sensor to be calibrated; O This refers to the dissolved oxygen content value. A, B, C, D, E, F, G These are calibration parameters.

[0062] This embodiment utilizes all the retained data records after screening to perform surface fitting on temperature values, phase values, and dissolved oxygen content values ​​to obtain calibration parameters. A, B, C, D, E, F, G The value of is substituted into the calibration function (3) to obtain the final calibration formula of the dissolved oxygen sensor, thus completing the calibration process of the dissolved oxygen sensor.

[0063] Figure 3 The graph shows the surface fitting of the calibration function for the dissolved oxygen sensor, where A = -0.02515; B = 28.88; C = 0.5938; D = -3.731; and E = 1.38 × 10⁻⁶. -06 F=0.0001332; G=0.003104; its fit index R 2 It can reach 0.9996.

[0064] Once the dissolved oxygen sensor to be calibrated is completed, it can be put back into use. In actual use, the temperature value detected by the dissolved oxygen sensor should first be corrected by the temperature correction function (1) to generate the corrected temperature value. X Then, the phase value was detected by the dissolved oxygen sensor. Y Substitute them into the dissolved oxygen sensor calibration formula (3) to calculate the final dissolved oxygen content value.

[0065] Of course, the above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments, or make equivalent substitutions for some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions claimed by the present invention.

Claims

1. A method for calibrating a dissolved oxygen sensor, characterized in that, include: Place the dissolved oxygen sensor to be calibrated and the standard temperature sensor into a constant temperature water bath, and adjust the temperature of the water bath to stabilize at [temperature values ​​missing]. n A set temperature; At each set temperature, the sampling temperature value is obtained by detecting the dissolved oxygen sensor to be calibrated, and the standard temperature value is obtained by detecting the standard temperature sensor. Using records n Each sampling temperature value and n A linear regression fit was performed on the standard temperature values ​​to establish a temperature correction function for the dissolved oxygen sensor to be calibrated, and the corrected temperature values ​​were obtained. Place the calibrated dissolved oxygen sensor and the dissolved oxygen sensor to be calibrated into a constant temperature water bath, and adjust the dissolved oxygen saturation of the water in the constant temperature water bath to stabilize at m set points at each set temperature. The phase values ​​detected by the uncalibrated dissolved oxygen sensor and the dissolved oxygen content values ​​obtained by the calibrated dissolved oxygen sensor are recorded at each set temperature and each saturation set point, respectively. Using the data recorded at each set temperature m Each phase value and m A linear regression was performed on the dissolved oxygen content values ​​to establish a linear fitting function between the dissolved oxygen content values ​​and the phase values, and the R-squared regression model fit index of the linear fitting function was calculated. R 2 ,reserve R 2 Data records that are greater than or equal to the set threshold; By using the retained data records, a surface fit is performed on the dissolved oxygen sensor calibration function to generate the final dissolved oxygen sensor calibration formula.

2. The dissolved oxygen sensor calibration method according to claim 1, characterized in that, The process of establishing the temperature correction function for the dissolved oxygen sensor to be calibrated includes: Using records n Each sampling temperature value and n Linear regression fitting was performed on the standard temperature values ​​to obtain the initial coefficients. k , b : ； ； in, x i For the dissolved oxygen sensor to be calibrated in the first i The sampled temperature value is obtained by detecting a set temperature. y i For standard temperature sensors in the first i A standard temperature value is obtained by detecting a set temperature. for n The average of the sampled temperature values; for n The average of a number of standard temperature values; Using initial coefficients k , b Establish the temperature correction function for the dissolved oxygen sensor to be calibrated: X = kx + b ； in, x The sampling temperature value is obtained by detecting the dissolved oxygen sensor to be calibrated; X This is the corrected temperature value.

3. The dissolved oxygen sensor calibration method according to claim 2, characterized in that, The sampling temperature value x The average value of multiple temperature measurements of the water in the constant temperature water bath at a certain set temperature by the dissolved oxygen sensor to be calibrated.

4. The dissolved oxygen sensor calibration method according to claim 1, characterized in that, The process of establishing a linear fitting function between dissolved oxygen content and phase value includes: Using the data recorded at each set temperature m Each phase value and m A linear regression was performed on the dissolved oxygen content values ​​to establish a quartic linear fitting function: Z = k 4Y 4 + k 3Y 3 + k 2Y 2 + k 1Y+ k 0; Where Y is the phase value detected by the dissolved oxygen sensor to be calibrated; Z The dissolved oxygen content value is calculated by the calibrated dissolved oxygen sensor based on the temperature and phase values ​​it detects. k 0、 k 1. k 2. k 3. k 4 represents the fitting coefficient.

5. The dissolved oxygen sensor calibration method according to claim 4, characterized in that, Calculate the R-squared regression model fit index of the quartic linear fitting function at each set temperature. R 2 : ； in, Y i For the dissolved oxygen sensor to be calibrated in the first i Phase values ​​acquired at each saturation setpoint; Z i For the calibrated dissolved oxygen sensor in the first i Dissolved oxygen content values ​​obtained at each saturation setpoint; for m The average value of each of the dissolved oxygen content values; If the fitting index is calculated at a certain set temperature R 2 If the data is below a set threshold, all data recorded at that set temperature will be discarded, and only data recorded at that temperature will be retained. R 2 Data records that are greater than or equal to the set threshold.

6. The dissolved oxygen sensor calibration method according to claim 5, characterized in that, The set threshold is 0.9999.

7. The dissolved oxygen sensor calibration method according to claim 1, characterized in that, The m Each setpoint is selected within a saturation range of 20% to 120%. m ≥13.

8. The dissolved oxygen sensor calibration method according to claim 1, characterized in that, The dissolved oxygen saturation of the water in the constant temperature water bath is adjusted by introducing oxygen or nitrogen into the constant temperature water bath.

9. The dissolved oxygen sensor calibration method according to any one of claims 1 to 8, characterized in that, The process of generating the dissolved oxygen sensor calibration formula includes: Establish the calibration function for the dissolved oxygen sensor: ； in, X The temperature value is the corrected value after the temperature detected by the dissolved oxygen sensor to be calibrated is adjusted. Y The phase value detected by the dissolved oxygen sensor to be calibrated; O This refers to the dissolved oxygen content value. A, B, C, D, E, F, G For calibration parameters; By performing surface fitting on the dissolved oxygen sensor calibration function using all retained data records, the calibration parameters can be obtained. A, B, C, D, E, F, G The value of is used to generate the final dissolved oxygen sensor calibration formula.

10. The dissolved oxygen sensor calibration method according to claim 9, characterized in that, After the dissolved oxygen sensor to be calibrated is completed and put into use, the temperature value detected by the dissolved oxygen sensor is first corrected by the temperature correction function to generate the corrected temperature value. X Then, the phase value detected by the dissolved oxygen sensor is compared with that of the dissolved oxygen sensor. Y Substitute these values ​​into the dissolved oxygen sensor calibration formula to calculate the dissolved oxygen content value.

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