Sensor-based liquid conductivity measurement method and system

Abstract

The application relates to the technical field of conductivity measurement, in particular to a liquid conductivity measurement method and system based on a sensor, which comprises the following steps: in the process of measuring the conductivity of a liquid, the conductivity and temperature of a to-be-measured solution at different moments are acquired in real time, the first trend degree and the second trend degree of the to-be-measured solution are calculated, and the first evaluation value of the to-be-measured liquid is determined; the moment of growth mutation is acquired; the reverse trend amount of the to-be-measured liquid is calculated, the second evaluation value of the to-be-measured liquid is determined; the smoothing coefficient corresponding to the EMA algorithm of the to-be-measured liquid is obtained, the conductivity in the effective measurement period is smoothed by using the EMA algorithm, and the liquid conductivity is measured based on the smoothed conductivity corresponding to the last moment in the effective measurement period. The smoothing coefficient of the EMA algorithm is adjusted, the influence of the complex nonlinear change of the conductivity with the increase of the temperature is reduced, and the measurement accuracy of the liquid conductivity is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of conductivity measurement, in particular to a sensor-based liquid conductivity measurement method and system. BACKGROUND

[0002] Conductivity refers to the ability of a liquid to conduct current, which is directly related to the ion concentration, type and temperature in the solution. With the development of sensor technology, liquid conductivity has gradually become an important concern in the industrial field, environmental pollution monitoring field and new technology field.

[0003] In the process of measuring the conductivity of a liquid using an inductive sensor, an induced magnetic field is generated by an alternating current, and the eddy current effect generated by the electromagnetic induction of the solution is measured to indirectly determine the conductivity. However, the induced magnetic field generates heat, causing a change in the temperature of the liquid. The change in temperature affects the ionization degree, solubility and ion mobility of electrolytes in the solution, and also causes interactions between ions in the solution, resulting in ion association and steric hindrance effects, which reduce the effective carrier concentration. As a result, the conductivity changes with temperature in a highly complex nonlinear manner, affecting the accuracy of the measurement of the conductivity of the liquid. SUMMARY

[0004] To solve the above technical problems, a sensor-based liquid conductivity measurement method and system are provided to solve the existing problems.

[0005] The technical problem of the present application is solved by providing a sensor-based liquid conductivity measurement method and system, comprising the following steps:

[0006] In a first aspect, the present application provides a sensor-based liquid conductivity measurement method, which comprises the following steps:

[0007] In the process of measuring the conductivity of a liquid, the conductivity and temperature of the solution to be measured at different times are obtained in real time. Based on the continuous change in conductivity, the effective measurement period is obtained.

[0008] The difference in temperature between adjacent time points and the linear change in temperature at all time points in the effective measurement period are analyzed, and the first trend degree of the solution to be measured is calculated. Based on the difference in conductivity between adjacent time points and the nonlinear change in conductivity in the effective measurement period, the second trend degree of the solution to be measured is calculated. The first evaluation value of the liquid to be measured is determined based on the first trend degree.

[0009] According to the mutation of abnormal growth of the conductivity in the effective determination period, the growth mutation time is obtained; by the change rate and trend change of the conductivity at different growth mutation times in the effective determination period, the reverse trend amount of the liquid to be measured is calculated, and the discrete situation of the conductivity at all times between the adjacent two growth mutation times is combined to determine the second evaluation value of the liquid to be measured;

[0010] Based on the first evaluation value and the second evaluation value, the smoothing coefficient of the EMA algorithm corresponding to the liquid to be measured is obtained, the conductivity in the effective determination period is smoothed by using the EMA algorithm, and the liquid conductivity is determined based on the smoothed conductivity corresponding to the last time in the effective determination period.

[0011] Preferably, the acquisition process of the effective determination period is: the first time is recorded as the starting time, the minimum time when the conductivities of multiple continuous times are equal is recorded as the ending time, and the time period between the starting time and the ending time is recorded as the effective determination period.

[0012] Preferably, the calculation of the first trend degree of the liquid to be measured comprises:

[0013] The temperatures at all times in the effective determination period are linearly fitted, and the fitting error is calculated;

[0014] The mean value of the temperature difference between all adjacent two times in the effective determination period is calculated, and is recorded as the relative temperature difference;

[0015] The first trend degree is the result of positive mapping of the ratio of the relative temperature difference to the fitting error.

[0016] Preferably, the calculation of the second trend degree of the liquid to be measured comprises:

[0017] The conductivities at all times in the effective determination period are curve-fitted to obtain a fitting curve, and the distance between the conductivities at all times in the effective determination period and the predicted values on the fitting curve at all times is calculated;

[0018] The mean value of the conductivity difference between all adjacent two times in the effective determination period is calculated, and is recorded as the relative difference;

[0019] The second trend degree is the result of positive mapping of the ratio between the relative difference and the distance.

[0020] Preferably, the first evaluation value is the product of the first trend degree and the second trend degree.

[0021] Preferably, the growth mutation time point acquisition process is: detecting mutations of conductivities at all time points in an effective measurement period to obtain abnormal time points; if a difference between the conductivity at each abnormal time point and the conductivity at a previous time point of the abnormal time point is greater than 0, the abnormal time point is recorded as a growth mutation time point.

[0022] Preferably, the reverse trend amount of the liquid to be measured is calculated by:

[0023] trend decomposition is performed on conductivities corresponding to all growth mutation time points in the effective measurement period to calculate a trend intensity;

[0024] a sum value of relative change rates of the conductivities between all adjacent growth mutation time points in the effective measurement period is calculated, and a ratio of a positive mapping result of the sum value to the trend intensity is taken as the reverse trend amount of the liquid to be measured.

[0025] Preferably, the second evaluation value of the liquid to be measured is determined by:

[0026] a dispersion degree of the conductivities at all time points between adjacent growth mutation time points in the effective measurement period is calculated, an accumulated sum of the dispersion degrees corresponding to all adjacent growth mutation time points in the effective measurement period is calculated, and a negative mapping is performed on the accumulated sum;

[0027] the second evaluation value is a product of a negative mapping result and the reverse trend amount.

[0028] Preferably, the smoothing coefficient is a normalized result of a ratio of the second evaluation value to the first evaluation value.

[0029] In a second aspect, the embodiments of the present application further provide a liquid conductivity measurement system based on a sensor, which comprises a memory, a processor, and a computer program stored in the memory and running on the processor, and the processor implements steps of the liquid conductivity measurement method based on the sensor.

[0030] The present application has at least the following beneficial effects:

[0031] The application calculates the first trend degree of the to-be-tested solution by the linear change of the temperature in the to-be-tested solution, and has the beneficial effect of considering the case that the temperature change conforms to the linear change trend, and the significance of the temperature growth trend, reflecting the linear trend of the temperature growth; secondly, the second trend degree of the to-be-tested solution is calculated by the nonlinear change of the conductivity, and has the beneficial effect of considering the case that the conductivity change conforms to the nonlinear change trend, and the significant case of the conductivity growth trend, reflecting the nonlinear trend of the conductivity growth; the first evaluation value of the to-be-tested liquid is determined, and has the beneficial effect of reflecting that the more significant the nonlinear trend presented by the conductivity measurement result due to the temperature change, the more significant the influence of the temperature change on the conductivity; the growth mutation moment is obtained, and has the beneficial effect of considering the mutation point of the abnormal growth of the conductivity; the reverse trend amount of the to-be-tested liquid is calculated, and has the beneficial effect of reflecting the case that the conductivity growth is weak or the reverse step phenomenon appears due to the interaction between ions; the second evaluation value of the to-be-tested liquid is determined, and has the beneficial effect of evaluating the significance of the influence of the interaction between ions in the liquid and the serious case of the reverse step phenomenon of the conductivity; the smoothing coefficient corresponding to the EMA algorithm of the to-be-tested liquid is obtained, the conductivity in the effective measurement period is smoothed by using the EMA algorithm, and the liquid conductivity is measured based on the smoothed conductivity corresponding to the last moment in the effective measurement period, and has the beneficial effect that by evaluating the influence of the temperature rise on the ion migration speed and the interaction between ions in the solution, the smoothing coefficient of the EMA algorithm is adjusted, when the ionization degree of the ions in the solution is strong and the ion association caused by the interaction between ions is weak, a smaller smoothing coefficient is used to reduce the lag of the rapid rising trend and improve the sensitivity to the historical data; when the ion association caused by the interaction between ions in the solution is strong, a larger smoothing coefficient is used to respond to the significant change of the conductivity in time and improve the measurement accuracy of the liquid conductivity. BRIEF DESCRIPTION OF DRAWINGS

[0032] The sensor-based liquid conductivity measurement method of the application will be further described in detail below with reference to the accompanying drawings.

[0033] Figure 1 The step flow chart of the sensor-based liquid conductivity measurement method provided by the embodiment of the application is shown in the figure.

[0034] Figure 2 The step flow chart of the smoothing coefficient acquisition method provided by the embodiment of the application is shown in the figure. DETAILED DESCRIPTION

[0035] In order to make the purpose, technical scheme and advantages of the present application clearer, the sensor-based liquid conductivity measurement method and system proposed by the present application are further described in detail below in combination with the drawings and examples. It should be understood that the specific examples described herein are only used to explain the present application and do not limit the present application.

[0036] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the present application belongs.

[0037] Please refer to Figure 1 which shows the step flow chart of the sensor-based liquid conductivity measurement method provided by an embodiment of the present application, which comprises the following steps:

[0038] Step 1, during the measurement of the conductivity of the liquid, the conductivity and temperature of the solution to be measured at different times are acquired in real time.

[0039] Liquid conductivity, as an important parameter of the electrical properties of liquid, is the potential difference per unit length of current passing through a given volume of liquid, which is an important electrical indicator reflecting the physical and chemical properties of the ion properties, ionization ability and charge transfer performance of the substance. Conductivity can evaluate the concentration and conductivity of ions in electrolyte solution and is commonly used in water quality monitoring, industrial production, agriculture and other fields. Temperature has a great influence on the measurement of conductivity, as it directly affects the ionization degree, solubility, ion migration speed, viscosity, and expansion of the solution, thereby affecting the conductivity of the solution.

[0040] Inductive sensor is a non-contact conductivity measurement technology, whose principle is based on the law of electromagnetic induction to measure the conductivity of the solution. In an inductive conductivity sensor, the sensor contains a primary coil and a secondary coil inside. The primary coil passes through an alternating current to generate an alternating electromagnetic field, and the alternating magnetic field induces an eddy current in the liquid. The strength of the eddy current is proportional to the conductivity of the liquid, i.e. the higher the concentration of ions in the liquid, the stronger the induced eddy current, and the secondary coil detects the current to determine the conductivity of the liquid. However, the eddy current generates heat when flowing in the liquid, and this heat is transferred to the liquid through heat conduction, causing the temperature of the liquid to rise, thereby causing deviation in the measurement of conductivity.

[0041] Based on the above analysis, the conductivity and temperature of the solution to be measured at different times are collected by the inductive sensor and the temperature sensor, and the missing values of the collected data are filled in;

[0042] In the embodiment, the time interval of data collection is 0.02 s, and as other embodiments, the implementer can set it according to the actual situation; secondly, the linear interpolation filling method is used for missing value filling, wherein the linear interpolation filling method is a known technology, and will not be described here.

[0043] The first time is recorded as the starting time, and the minimum time when the conductivity is equal at a plurality of continuous times is recorded as the end time.

[0044] In the embodiment, the minimum time when the conductivity is equal at 10 continuous times is recorded as the end time; for the convenience of understanding, it is scaled to the minimum time when the conductivity is equal at 3 continuous times, and recorded as the end time. Assuming that the conductivities of 7 times are 2, 3, 2, 5, 4, 4, and 4, the conductivity of the first time is 2, the first time is recorded as the starting time, and the conductivity is 4 at the continuous 3 times. The time when the conductivity first appears 4 is recorded as the end time.

[0045] The period between the starting time and the end time is recorded as the effective measurement period, and the conductivities and temperatures of the solution to be measured at each time in the effective measurement period are obtained.

[0046] It should be noted that the effective measurement period includes the starting time and the end time.

[0047] Thus, the conductivities and temperatures of the solution to be measured at each time in the effective measurement period are obtained.

[0048] Step 2, analyze the temperature difference between adjacent times in the effective measurement period and the linear change of the temperature at all times, calculate the first trend degree of the solution to be measured; based on the difference between the conductivities of adjacent times in the effective measurement period and the nonlinear change of the conductivity, calculate the second trend degree of the solution to be measured, and combine the first trend degree to determine the first evaluation value of the liquid to be measured.

[0049] Further, the temperature rise will reduce the viscosity of the solution and increase the dissociation degree of the weak electrolyte solution. The reduction of the solution viscosity will reduce the movement resistance of the solute ions, accelerate the ion migration speed, make the charge passing through the interface in unit time more, and increase the conductivity. The increase of the dissociation degree of the weak electrolyte will increase the number of ions that can be migrated in unit volume of the liquid to be measured, and further increase the conductivity of the liquid.

[0050] Secondly, the more obvious the linear growth trend of the temperature of the liquid to be measured, the faster the increase rate of the conductivity caused by the temperature rise and the increase of the migration speed of the solute ions, and the more obvious the nonlinear growth phenomenon of the conductivity caused by the gradual increase of the dissociation degree of the weak electrolyte solution.

[0051] Firstly, the temperature change trend of the solution to be measured is analyzed, and a first trend degree is calculated, specifically as follows:

[0052] The temperature at all times in the effective determination period is linearly fitted, and a fitting error is calculated;

[0053] In this embodiment, the least squares method is used for linear fitting, wherein the least squares method is a known technology and will not be described here; secondly, the fitting error is measured by calculating the mean absolute error, wherein the calculation formula of the mean absolute error is a known technology, and the specific calculation formula is: , wherein represents the mean absolute error, represents the actual temperature, represents the predicted value on the fitting straight line, and n represents the number of all times in the effective determination period.

[0054] The mean value of the temperature difference between all adjacent two times in the effective determination period is calculated, denoted as a relative temperature difference, and the ratio of the relative temperature difference to the fitting error is positively mapped as the first trend degree of the solution to be measured;

[0055] In this embodiment, the mean value of the temperature difference between each time and its previous time in the effective determination period is calculated, denoted as a relative temperature difference; secondly, the specific process of positive mapping is as follows: the ratio of the relative temperature difference to the fitting error is denoted as , then the result of is taken as the result of positive mapping, wherein is an exponential function with a natural constant as the base number, and the process of positive mapping makes the result of positive mapping greater than 0, avoiding the occurrence of negative values.

[0056] It should be noted that the smaller the fitting error is, the more the temperature change conforms to the linear change trend, the larger the relative temperature difference is, the more significant the temperature growth trend is, and the larger the obtained first trend degree is, indicating that the linear trend of the temperature growth of the solution to be measured in the effective determination period is more obvious.

[0057] Secondly, the change trend of the conductivity of the solution to be measured is analyzed, and a second trend degree is calculated, specifically as follows:

[0058] The conductivities at all times in the effective determination period are curve-fitted to obtain a fitting curve;

[0059] In this embodiment, the least squares method is used for curve fitting, wherein the least squares method is a known technology and will not be described here.

[0060] The distance between the conductivities at all times in the effective determination period and the predicted values at all times on the fitting curve is calculated;

[0061] In the embodiment, the distance is calculated by DTW distance between the conductivity at all time points in the effective measurement period and the predicted value at all time points on the fitting curve, wherein the calculation of the DTW distance is a known technology and will not be described here.

[0062] The mean value of the difference between the conductivities at all adjacent time points in the effective measurement period is calculated, denoted as the relative difference.

[0063] In the embodiment, the mean value of the difference between the conductivities at each time point and the previous time point in the effective measurement period is calculated, denoted as the relative difference.

[0064] The ratio between the relative difference and the distance is positively mapped as the second trend degree of the to-be-measured solution.

[0065] In the embodiment, the specific process of positive mapping is: positively mapping by an exponential function, assuming that the slope of the fitting straight line is denoted as , then The result of is taken as the result of positive mapping, wherein is an exponential function with a natural constant as the base number, and the process of positive mapping makes the result of positive mapping greater than 0.

[0066] It should be noted that the greater the relative difference, the more significant the growth trend of the conductivity, the smaller the distance, the more the change of the conductivity conforms to the nonlinear change trend, and the greater the obtained second trend degree, indicating that the nonlinear trend of the conductivity growth of the to-be-measured solution in the effective measurement period is more obvious.

[0067] Further, based on the first trend degree and the second trend degree, a first evaluation value is determined, specifically:

[0068] The product of the first trend degree and the second trend degree is taken as the first evaluation value of the to-be-measured solution.

[0069] It should be noted that the greater the first evaluation value, the more significant the nonlinear change of the measurement result of the conductivity presented by the temperature change.

[0070] Thus, the first evaluation value of the to-be-measured solution is obtained.

[0071] Step 3, according to the sudden change of abnormal growth of the conductivity in the effective measurement period, the growth mutation time point is obtained; by the change rate and trend change of the conductivity at different growth mutation time points in the effective measurement period, the reverse trend amount of the to-be-measured solution is calculated, and the second evaluation value of the to-be-measured solution is determined by combining the dispersion of the conductivity at all time points between adjacent two growth mutation time points.

[0072] Furthermore, in high-concentration solutions, increased temperature promotes inter-ion interactions, increasing the probability of collisions and potentially leading to ion association and steric hindrance. These associated molecules migrate slowly, resulting in a decrease in effective carrier concentration. The more severe the impact of inter-ion interactions caused by increased temperature in high-concentration solutions, the more significant the slowdown or plateauing of conductivity growth. Simultaneously, the degree of abrupt changes in conductivity growth due to increased temperature is lower, and even reverse abrupt changes occur, exhibiting a clear unstable correlation.

[0073] Based on the above analysis, the reverse trend quantity is determined by observing the abrupt changes in the conductivity of the test solution at different times within the effective measurement period. Specifically:

[0074] Abnormal moments are detected by detecting sudden changes in conductivity at all times within the effective measurement period.

[0075] In this embodiment, the BG (Bernaola Galvan) segmentation algorithm is used for mutation detection. The BG segmentation algorithm is a well-known technology and will not be described in detail here.

[0076] If the difference between the conductivity at each abnormal moment and the conductivity at the previous moment is greater than 0, the abnormal moment is recorded as the moment of sudden growth.

[0077] Trend decomposition was performed on the conductivity corresponding to all abrupt increases within the effective measurement period to calculate the trend intensity.

[0078] In this embodiment, the STL (Seasonal-Trend decomposition using Loess) decomposition algorithm is used for trend decomposition. Both the STL decomposition algorithm and the calculation of trend strength are well-known techniques.

[0079] Calculate the sum of the relative rates of change of conductivity between all two adjacent moments of abrupt change in conductivity within the effective measurement period, and use the ratio of the positive mapping result of the sum to the trend intensity as the reverse trend quantity of the liquid under test.

[0080] In this embodiment, the relative rate of change of conductivity between each abrupt change in growth and the next abrupt change in growth within the effective measurement period is calculated. The calculation of the relative rate of change is a known technique, and the specific formula is as follows: ,in, The relative rate of change For the first Conductivity at each abrupt change in growth. For the first The conductivity at each abrupt change in growth; secondly, the positive mapping process is as follows: positive mapping is performed through an exponential function, assuming the sum is denoted as... , then the result of the positive mapping is taken as the result of the positive mapping, wherein, is an exponential function with a natural constant as the base number, and the result of the positive mapping is made greater than 0 through the positive mapping process.

[0081] It should be noted that the greater the sum value, the more significant the relative change in conductivity, and the more obvious the reverse step phenomenon of conductivity, the smaller the trend strength, the more serious the reverse drift condition of the step attenuation degree of conductivity, the greater the reverse trend amount, and the more significant the reverse step phenomenon of conductivity, that is, the more obvious the reverse change of conductivity after the growth mutation, and the more significant the interaction between ions in the liquid.

[0082] Further, a second evaluation value is determined by combining the reverse trend amount and the fluctuation of conductivity between the two adjacent growth mutation moments, specifically:

[0083] The dispersion degree of conductivity at all times between the two adjacent growth mutation moments in the effective measurement period is calculated, the cumulative sum of the dispersion degrees corresponding to the two adjacent growth mutation moments in the effective measurement period is calculated, and the cumulative sum is negatively mapped;

[0084] In this embodiment, the dispersion degree is measured by calculating the coefficient of variation of conductivity at all times between the two adjacent growth mutation moments, wherein the calculation of the coefficient of variation is a known technology and will not be described here. Secondly, the process of negative mapping is to take the reciprocal of the cumulative sum as the result of negative mapping.

[0085] The product of the result of negative mapping and the reverse trend amount is taken as the second evaluation value of the liquid to be measured.

[0086] It should be noted that the greater the negative mapping, the more significant the fluctuation of conductivity between the two growth mutation moments, and the more significant the interaction between ions in the liquid; the greater the second evaluation value, the more serious the reverse step phenomenon of conductivity, and the more significant the interaction between ions in the liquid.

[0087] Thus, the second evaluation value of the liquid to be measured is obtained.

[0088] Step 4, based on the first evaluation value and the second evaluation value, the smoothing coefficient of the EMA algorithm corresponding to the liquid to be measured is obtained, the conductivity in the effective measurement period is smoothed by using the EMA algorithm, and the conductivity of the liquid is measured based on the smoothed conductivity corresponding to the last moment in the effective measurement period.

[0089] Further, when the conductivity is smoothed by using an exponential moving average algorithm (EMA), the more serious the dissociation of the weak electrolyte in the liquid and the faster the ion migration speed caused by the temperature rise of the liquid, i.e., the greater the first evaluation value, the smaller the smoothing coefficient of the EMA algorithm should be set to improve the sensitivity to the historical data; and the more serious the reverse step phenomenon of the conductivity caused by the interaction between ions, i.e., the greater the second evaluation value, the greater the smoothing coefficient of the EMA algorithm should be set to respond to these significant change trends more quickly, avoid the reverse step feature caused by the interaction between ions from being blurred, and at the same time, retain the real change trend of the conductivity of the liquid to be measured.

[0090] Based on the above analysis, based on the first evaluation value and the second evaluation value, a smoothing coefficient is determined, specifically:

[0091] The normalized result of the ratio of the second evaluation value to the first evaluation value is taken as the smoothing coefficient corresponding to the liquid to be measured.

[0092] In this embodiment, the sigmoid function is used for normalization processing, wherein the sigmoid function is a known technology and will not be described here again, and wherein the step flowchart of the method for obtaining the smoothing coefficient provided in the embodiments of the present application is shown in Figure 2 .

[0093] Based on the smoothing coefficient, the conductivities at all times within the effective measurement period are smoothed by using the EMA algorithm, and the smoothed conductivity at the end time within the effective measurement period is taken as the conductivity of the solution to be measured.

[0094] It should be noted that the EMA algorithm is a known technology and will not be described here again.

[0095] Based on the same inventive concept as the above method, the embodiments of the present application also provide a liquid conductivity measuring system based on a sensor, which comprises a memory, a processor, and a computer program stored in the memory and running on the processor, and the processor implements the steps of any one of the methods in the above liquid conductivity measuring method based on a sensor when executing the computer program.

[0096] It should be understood that, although Figure 1 the steps in the flowchart are displayed in sequence according to the arrows, these steps are not necessarily executed in sequence according to the arrows. Unless otherwise specified herein, the execution of these steps has no strict sequence limitation, and these steps can be executed in other sequences. Moreover, Figure 1At least one of the steps in the above embodiments can include a plurality of sub-steps or a plurality of stages, which are not necessarily executed at the same time, but can be executed at different times, and the order of execution of the sub-steps or stages is not necessarily sequential, but can be executed in rotation or alternation with other steps or at least a part of the sub-steps or stages of other steps.

[0097] The technical features of the above embodiments can be combined in any manner. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described, but it should be understood that any combination of the technical features is within the scope of the present disclosure as long as there is no contradiction.

[0098] The above embodiments only express several implementation manners of the present application, and the description is relatively specific and detailed, but it should not be understood as a limitation on the present application. It should be noted that, for those skilled in the art, several modifications and improvements can be made without departing from the concept of the present application, and therefore, any simple modification, equivalent change and modification made to the above embodiments according to the technical essence of the present application, as long as it does not depart from the technical solution of the present application, is within the protection scope of the technical solution of the present application.

Claims

1. A sensor-based method of liquid conductivity measurement, characterized in that, The method comprises the following steps: During the conductivity measurement of the liquid, the conductivity and temperature of the solution to be measured at different time points are acquired in real time, a first time point is recorded as a starting time point, a minimum time point at which the conductivity of a plurality of continuous time points is equal is recorded as an ending time point, and a time period between the starting time point and the ending time point is recorded as an effective measurement time period; The temperatures at all time points in the effective measurement time period are linearly fitted, and a fitting error is calculated; the average of the temperature difference between any two adjacent time points in the effective measurement time period is calculated and recorded as a relative temperature difference; a positive mapping result of the ratio of the relative temperature difference to the fitting error is taken as a first trend degree; the conductivities at all time points in the effective measurement time period are curve-fitted to obtain a fitting curve, and a positive mapping result of the ratio of the average of the conductivity difference between any two adjacent time points in the effective measurement time period to the distance between the conductivity at each time point in the effective measurement time period and the predicted value at each time point on the fitting curve is taken as a second trend degree; the product of the first trend degree and the second trend degree is taken as a first evaluation value of the liquid to be measured; The conductivities at all time points in the effective measurement time period are detected for abrupt change to obtain abnormal time points; if the difference between the conductivity at each abnormal time point and the conductivity at the previous time point is greater than 0, the abnormal time point is recorded as a growth abrupt change time point; the conductivities corresponding to all growth abrupt change time points in the effective measurement time period are decomposed for trend to calculate a trend intensity, the sum of the relative change rates of the conductivities between any two adjacent growth abrupt change time points in the effective measurement time period is calculated, and a ratio of a positive mapping result of the sum to the trend intensity is taken as a reverse trend amount of the liquid to be measured; the dispersion degree of the conductivities at all time points between any two adjacent growth abrupt change time points in the effective measurement time period is calculated, the cumulative sum of the dispersion degrees corresponding to all adjacent growth abrupt change time points in the effective measurement time period is calculated, and a negative mapping result of the cumulative sum is obtained; the product of the negative mapping result and the reverse trend amount is taken as a second evaluation value. The ratio of the first evaluation value to the second evaluation value is normalized to obtain a smoothing coefficient of the EMA algorithm corresponding to the liquid to be measured, the conductivities in the effective measurement time period are smoothed by using the EMA algorithm, and the liquid conductivity is measured based on the smoothed conductivity corresponding to the last time point in the effective measurement time period.

2. A sensor-based liquid conductivity measurement system comprising a memory, a processor and a computer program stored in the memory and running on the processor, characterized in that The processor executes the computer program to realize the steps of the liquid conductivity measurement method based on a sensor according to any one of claims 1.

Images