Intelligent monitoring method and system of internet of things ultrasonic water meter

Abstract

The present application relates to remote meter reading technology field, specifically to a kind of intelligent monitoring method and system of internet of things ultrasonic water meter, comprising the following steps: obtaining three cycle pressure difference algorithm absolute difference accumulation determination fluctuation range, then sampling flow rate sequence algorithm standard deviation determines stability, according to state extraction data algorithm first-order difference parity ratio determines credibility, low credibility then weighted replacement of preceding and subsequent values, with replacement value judges fluctuation restores initial frequency.In the present application, pipeline state change is identified by cycle pressure difference value accumulation, data fluctuation identification capability is enhanced, sampling frequency is dynamically adjusted by introducing flow velocity fluctuation degree, response speed is improved, data credibility is judged by first-order difference ratio, low credibility period is weighted to improve data stability and continuity, sampling recovery state is judged by comparing preceding and subsequent periods, sampling frequency is ensured to be timely homing, adaptive closed-loop dynamic mechanism is constructed, data accuracy and continuity under complex working conditions are enhanced.

Description

Technical Field

[0001] The present invention relates to the technical field of remote meter reading, and in particular to an intelligent monitoring method and system for an Internet of Things ultrasonic water meter. Background Art

[0002] The technical field of intelligent monitoring methods for IoT ultrasonic water meters encompasses the integrated application of ultrasonic measurement, water metering, and IoT communications. The core of this technical field lies in achieving high-precision water flow acquisition through ultrasonic measurement principles, while leveraging IoT communication networks to enable remote data transmission and centralized management. The entire technical system encompasses sensing, data acquisition, wireless communication, backend data interaction and management, and features multi-terminal linkage and remote control capabilities. As a key device in this field, IoT ultrasonic water meters integrate low-power operation, wireless communication, anomaly detection, and other features, making them suitable for the intelligent management and monitoring of distributed water supply systems.

[0003] Among them, remote meter reading refers to the use of a communication network to transmit the water consumption data collected by the water meter to a remote management platform, so as to realize the centralized reading and management of the user's water consumption situation. This patent subject mainly addresses the problems existing in the process of user water meter data collection and transmission, such as strong manual intervention, low real-time performance, and high reading costs. It proposes to integrate a low-power narrowband IoT communication module with time synchronization control logic to complete automatic data collection in a set period, and send the data to a remote server through a point-to-point transmission protocol, which will be uniformly stored and managed by the server. The method generally includes setting a fixed time window to trigger data sampling, establishing a data packet coding structure, sending data to a designated data center through a cellular network, and the data center completing data archiving and user allocation through parsing rules.

[0004] Existing technologies collect and upload data within fixed time windows, lacking a feedback mechanism to respond to actual water flow fluctuations. When encountering short-term sudden changes in flow velocity, the system cannot adjust the sampling frequency in a timely manner, potentially causing flow velocity data offsets. A lack of quantitative means to determine the credibility of abnormal data results in single-period abnormal data being uploaded without identification, impacting subsequent water use analysis results. The lack of correlation calculations between periodic data weakens the system's ability to self-correct for abnormal fluctuations, making it prone to error accumulation during long-term monitoring, impacting overall metering accuracy and monitoring stability. Summary of the Invention

[0005] The purpose of the present invention is to solve the shortcomings of the prior art and to propose an intelligent monitoring method and system for an Internet of Things ultrasonic water meter.

[0006] In order to achieve the above object, the present invention adopts the following technical solution: an intelligent monitoring method of an Internet of Things ultrasonic water meter, comprising the following steps:

[0007] S1: Obtain a sequence of three consecutive periodic differential pressure readings from the ultrasonic water meter, calculate the absolute difference between adjacent periodic data, accumulate the difference and compare it with the judgment benchmark to generate the periodic differential pressure variation amplitude;

[0008] S2: Based on the fluctuation amplitude of the cyclic pressure difference, if it exceeds the judgment standard, collect the instantaneous flow velocity reading sequence of five cycles in the ultrasonic water meter, perform standard deviation calculation to obtain the flow velocity fluctuation value of the current cycle, compare it with the set flow velocity stability threshold, switch the sampling window and adjust the sampling frequency to the short-term high-frequency mode, and record the sampling frequency adjustment status;

[0009] S3: Based on the sampling frequency adjustment state, extract the corresponding periodic pressure difference and flow rate sequence, calculate the first-order difference and then obtain the isotope ratio, compare it with the reference interval, and obtain the flow rate credibility judgment index;

[0010] S4: Based on the flow velocity credibility judgment index, if the current cycle data is in a low credibility state, extract the flow velocity readings of the previous and next cycles, take the weighted average in sequence according to the weight, replace the original reading, and generate a replacement flow velocity for the abnormal cycle;

[0011] S5: Call the abnormal cycle to replace the flow rate, obtain the pressure difference and flow rate sequences of the next two cycles, calculate the fluctuation values ​​respectively and then compare and determine, restore the initial sampling frequency, and obtain the periodic sampling frequency state value.

[0012] As a further solution of the present invention, the periodic pressure difference variation amplitude is specifically the fluctuation range, deviation level, and risk signal; the sampling frequency adjustment state is specifically the mode state, frequency configuration, and adjustment record; the flow velocity credibility judgment index includes stability score, trust level, and judgment result; the abnormal period replacement flow velocity is specifically the smoothed flow velocity, correction value, and replacement data; the periodic sampling frequency state value specifically refers to the initial mode, frequency recovery, and state feedback.

[0013] As a further solution of the present invention, the step of obtaining the periodic pressure difference variation amplitude is specifically as follows:

[0014] S101: Based on a sequence of three consecutive period pipeline pressure difference readings obtained from the ultrasonic water meter, extract two sets of pressure difference data from adjacent periods, calculate the absolute difference of the pressure differences at multiple time points, merge them to generate a difference sequence, accumulate and sum the differences, and generate a total period pressure difference difference;

[0015] S102: calling the total amount of the periodic pressure difference difference, performing difference judgment on multiple groups of values ​​and a set judgment benchmark, calculating the degree of deviation between the difference and the benchmark, classifying and summarizing them, setting a value interval, and generating a periodic pressure difference deviation interval;

[0016] S103: According to the periodic pressure difference deviation interval, the total periodic pressure difference value is called, and the fluctuation value, the pipe section length and the sampling interval are combined to perform calculations using the formula:

[0017] ;

[0018] Obtain the variation amplitude value and generate the periodic pressure difference variation amplitude;

[0019] Obtain the variation amplitude value and generate the periodic pressure difference variation amplitude;

[0020] in, Represents the cycle pressure difference variation amplitude of the first cycle, Represents the first cycle The pressure difference at each moment, Represents the judgment criteria for the first cycle, Represents the first cycle The pressure difference fluctuation value at the moment, Represents the first cycle The length of the pipe section at the time, Represents the velocity increase parameter of the first cycle, Represents the first cycle The sampling interval of time, Represents the number of pressure difference sampling points in a cycle.

[0021] As a further solution of the present invention, the step of acquiring the sampling frequency adjustment state is specifically as follows:

[0022] S201: Calculating the amplitude difference of the periodic pressure difference variation value based on the difference between the periodic pressure difference variation amplitude value and the set pressure difference judgment reference value, determining whether the amplitude difference exceeds the pressure difference judgment reference value threshold, and if so, collecting a flow velocity reading sequence within five cycles of the ultrasonic water meter to obtain an instantaneous flow velocity sequence;

[0023] S202: Call the instantaneous flow rate sequence and calculate the fluctuation range based on each instantaneous flow rate of five cycles using the formula:

[0024] ;

[0025] Calculate and obtain a new correction value of the flow rate standard deviation;

[0026] in, represents the new corrected value of the standard deviation of the flow rate, Represents the first The instantaneous flow velocity value at time, represents the average value of all instantaneous flow velocity values, represents the number of samples, i.e. the number of cycles, It is a coefficient adjusted according to the flow velocity change trend;

[0027] S203: Compare the difference between the new corrected value of the flow rate standard deviation and the preset flow rate stability threshold. If the flow rate stability threshold is exceeded, switch the sampling window and adjust the sampling frequency to the short-time high-frequency mode, record the current frequency status, and obtain the sampling frequency adjustment status value.

[0028] As a further solution of the present invention, the steps for obtaining the flow velocity credibility judgment index are specifically as follows:

[0029] S301: Based on the sampling frequency adjustment state, a pressure difference sequence and a flow rate sequence within a period are selected, the sequences are synchronously intercepted and the time step is corrected, and then the differences between adjacent moments are obtained in time axis order to construct a first-order difference sequence set;

[0030] S302: calling the first-order difference sequence set, extracting the pressure difference difference value and the flow rate difference value according to the same time index, calculating the same position ratio, and creating a numerical list of the ratio results corresponding to all moments to obtain a pressure difference flow rate ratio sequence;

[0031] S303: Based on the pressure difference flow rate ratio sequence, combined with the upper and lower boundaries of the reference ratio interval of multiple ratios within the period, the deviation degree and sequence fluctuation intensity are calculated in sequence using the formula:

[0032] ;

[0033] After the flow velocity deviation judgment value sequence is obtained by operation, the multiple judgment values ​​are compared with the credibility limit value to generate the flow velocity credibility judgment index;

[0034] in, It represents the flow velocity credibility judgment index, Indicates the The pressure difference flow rate ratio at the moment, represents the mean value of the pressure difference flow rate ratio series, Indicates the ratio sequence The variance of the item, Indicates the The absolute value of the first-order difference of the flow velocity at time , Indicates the The half-width value of the reference ratio interval corresponding to the moment, Indicates the total number of sample points in the period.

[0035] As a further solution of the present invention, the step of obtaining the abnormal period alternative flow rate is specifically as follows:

[0036] S401: Based on the current cycle flow velocity reading and the current flow velocity credibility judgment index, determine whether the current cycle flow velocity data is in a credible state, compare the current cycle flow velocity credibility index with a preset flow velocity credibility judgment threshold, and if it is less than the flow velocity credibility judgment threshold, determine that the current cycle is an abnormal cycle, and obtain an abnormal cycle marking state;

[0037] S402: Call the abnormal cycle marking state, extract the flow velocity readings of the adjacent cycles before and after the flow velocity data determined to be an abnormal cycle, mark them as the previous cycle flow velocity and the next cycle flow velocity, and record the current cycle flow velocity, using the formula:

[0038] ;

[0039] Calculate the adjusted cycle flow rate value, replace the original reading of the current abnormal cycle, and generate an alternative flow rate value for the abnormal cycle;

[0040] in, Indicates the adjusted cycle flow rate value, Indicates the flow rate of the previous cycle, Indicates the flow rate of the next cycle, Indicates the flow rate of the current cycle;

[0041] S403: calling the abnormal period replacement flow rate value to replace the original current period flow rate reading marked as abnormal, and updating the value of the period position in the original flow rate data set to obtain the abnormal period replacement flow rate.

[0042] As a further solution of the present invention, the step of obtaining the periodic sampling frequency state value is specifically as follows:

[0043] S501: Based on the abnormal period replacement flow rate, the flow rate information and the pressure difference sampling sequence in the initial period are called, the pressure difference amplitude and flow rate change rate of multiple sampling points in the period are calculated, and a continuous fluctuation index set in the sampling sequence is constructed to obtain a pressure difference and flow rate fluctuation index sequence;

[0044] S502: Call the pressure difference and flow velocity fluctuation index sequence, and construct the ratio of the pressure difference difference to the flow velocity difference at adjacent moments based on the corresponding sampling points of the pressure difference and flow velocity in two cycles, using the formula:

[0045] ;

[0046] Calculate the pressure difference and flow rate ratio at each moment to form a ratio sequence, and perform periodic fluctuation analysis based on the sequence average and difference amplitude to obtain the periodic normalized fluctuation difference;

[0047] in, Representative cycle The pressure difference flow rate ratio, Represents a period Middle The pressure difference value of the sampling points, Represents a period Middle The pressure difference value of the sampling points, Represents a period Middle The flow velocity value of each sampling point, Represents a period Middle The flow velocity value of each sampling point, Indicates a positive constant to avoid zero denominator. Indicates the sampling point number within the cycle;

[0048] S503: Performing numerical amplitude judgment based on the period normalized fluctuation difference and the set period fluctuation threshold, performing comparison judgment in combination with the initial setting of the sampling frequency and the adjustment mark state value, and generating a period sampling frequency state value.

[0049] An intelligent monitoring system for an Internet of Things ultrasonic water meter, the intelligent monitoring system for an Internet of Things ultrasonic water meter is used to execute the above-mentioned intelligent monitoring method for an Internet of Things ultrasonic water meter, the system comprising:

[0050] The pressure difference detection module obtains the pipeline pressure difference signal sequence of three cycles, calculates the absolute difference between adjacent cycles and accumulates them, calls the pressure difference change reference value for comparison, and obtains the periodic pressure difference change amplitude;

[0051] The fluctuation judgment module collects five instantaneous flow rate readings based on the amplitude of the periodic pressure difference fluctuation. If it exceeds the pressure difference fluctuation reference value, the module calculates the standard deviation and compares it with the flow rate stability threshold. If the trigger condition is met, the module adjusts the sampling window and switches to the high-frequency mode, records the frequency switching situation, and generates the sampling frequency adjustment status.

[0052] The credibility assessment module extracts the corresponding pressure difference and flow rate sequence based on the sampling frequency adjustment state, performs first-order difference processing and calculates the isotope ratio, calls the credibility reference interval judgment, and obtains the flow rate credibility judgment index;

[0053] The data correction module extracts the flow velocity readings before and after the current cycle according to the flow velocity credibility judgment index, weights them in sequence and performs weighted average, and uses them to replace the current flow velocity value to generate an abnormal cycle replacement flow velocity;

[0054] The frequency control module calls the abnormal cycle to replace the flow rate, collects the pressure difference and flow rate sequences of the subsequent two cycles, calculates the fluctuation values ​​and compares them with the set reference values, determines whether to restore the sampling frequency, and obtains the periodic sampling frequency status value.

[0055] Compared with the prior art, the advantages and positive effects of the present invention are:

[0056] In the present invention, by accumulating the pressure difference of consecutive cycles and calculating the amplitude of change, changes in pipeline status can be identified, thereby enhancing the ability to identify data fluctuations. The introduction of flow velocity fluctuation allows the sampling frequency to be adjusted dynamically according to abnormalities, thereby improving the density and response speed of instantaneous flow velocity sampling. The first-order difference ratio calculation is used to determine the credibility of flow velocity data. By performing weighted correction on low-credibility periodic data, the stability and continuity of abnormal periodic data are improved. The sampling recovery state is calculated by comparing the previous and next cycles to ensure that the sampling frequency of the system returns to its original position in time after abnormal fluctuations are processed, forming an adaptive, closed-loop dynamic adjustment mechanism to enhance the accuracy and continuity of collected data under complex working conditions. BRIEF DESCRIPTION OF THE DRAWINGS

[0057] Figure 1 It is a schematic diagram of the workflow of the present invention;

[0058] Figure 2 Flowchart of the steps for obtaining the amplitude of the periodic pressure difference variation of the present invention;

[0059] Figure 3 Flowchart of the steps for obtaining the sampling frequency adjustment state of the present invention;

[0060] Figure 4 Flowchart of the steps for obtaining the flow velocity credibility judgment index of the present invention;

[0061] Figure 5 Flowchart of the steps for obtaining the abnormal cycle alternative flow rate of the present invention;

[0062] Figure 6 This is a flow chart of the steps for obtaining the periodic sampling frequency state value of the present invention. DETAILED DESCRIPTION

[0063] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0064] In the description of the present invention, it should be understood that the terms "length," "width," "up," "down," "front," "back," "left," "right," "vertical," "horizontal," "top," "bottom," "inside," "outside," and the like, indicating positions or relationships, are based on the positions or relationships shown in the accompanying drawings and are intended only to facilitate the description of the present invention and simplify the description. They do not indicate or imply that the devices or elements referred to must have a specific orientation, be constructed, or operate in a specific orientation. Therefore, they should not be construed as limiting the present invention. Furthermore, in the description of the present invention, "plurality" means two or more, unless otherwise expressly and specifically defined.

[0065] For example 1, please refer to Figure 1 The present invention provides a technical solution: an intelligent monitoring method for an Internet of Things ultrasonic water meter, comprising the following steps:

[0066] S1: Obtain a sequence of three consecutive periodic differential pressure readings from the ultrasonic water meter, calculate the absolute difference between adjacent periodic data, accumulate the difference and compare it with the judgment benchmark to generate the periodic differential pressure variation amplitude;

[0067] S2: Based on the fluctuation amplitude of the periodic pressure difference, if it exceeds the judgment standard, collect the instantaneous flow velocity reading sequence of five periods in the ultrasonic water meter, perform standard deviation calculation to obtain the flow velocity fluctuation value of the current period, compare it with the set flow velocity stability threshold, switch the sampling window and adjust the sampling frequency to short-term high-frequency mode, and record the sampling frequency adjustment status;

[0068] S3: Based on the sampling frequency adjustment state, the corresponding periodic pressure difference and flow rate series are extracted, the first-order difference is calculated, and the isotope ratio is obtained. The isotope ratio is compared with the reference interval to obtain the flow rate credibility judgment index;

[0069] S4: Based on the flow rate credibility judgment index, if the current cycle data is in a low credibility state, extract the flow rate readings of the previous and next cycles, take the weighted average in sequence according to the weight, replace the original reading, and generate the alternative flow rate of the abnormal cycle;

[0070] S5: Call the abnormal cycle to replace the flow rate, obtain the pressure difference and flow rate sequences of the next two cycles, calculate the fluctuation values ​​respectively and then compare and judge, restore the initial sampling frequency, and obtain the periodic sampling frequency state value.

[0071] The amplitude of the periodic pressure difference change is specifically the fluctuation range, deviation level, and risk signal; the sampling frequency adjustment status is specifically the mode status, frequency configuration, and adjustment record; the flow velocity credibility judgment indicators include stability score, trust level, and judgment result; the abnormal periodic alternative flow velocity is specifically the smoothed flow velocity, correction value, and alternative data; the periodic sampling frequency status value specifically refers to the initial mode, frequency recovery, and status feedback.

[0072] See also Figure 2 The specific steps for obtaining the periodic pressure difference variation amplitude are as follows:

[0073] S101: Based on a sequence of three consecutive period pipeline pressure difference readings obtained from the ultrasonic water meter, extract two sets of pressure difference data from adjacent periods, calculate the absolute difference of the pressure differences at multiple time points, merge them to generate a difference sequence, accumulate and sum the differences, and generate a total period pressure difference difference;

[0074] During the specific implementation, the ultrasonic water meter is first used to continuously monitor the internal pressure of the pipeline. A series of pressure difference readings are collected in three cycles (for example, cycle 1 is 0-10 seconds, cycle 2 is 10-20 seconds, and cycle 3 is 20-30 seconds). For example, the pressure difference readings measured at 0, 2, 4, 6, 8, and 10 seconds in cycle 1 are {0.20 kPa, 0.22 kPa, 0.23 kPa, 0.26 kPa, 0. 28kPa, 0.30kPa}, the pressure difference readings measured at 10, 12, 14, 16, 18, and 20 seconds in cycle 2 are {0.30kPa, 0.33kPa, 0.35kPa, 0.38kPa, 0.40kPa, 0.43kPa}, the pressure difference readings measured at 20, 22, 24, 26, 28, and 30 seconds in cycle 3 are {0.43kPa, 0.45kPa, 0.4 7kPa, 0.49kPa, 0.52kPa, 0.55kPa}, the absolute difference of the pressure differential readings of adjacent cycles is calculated at each time point. For example, during the difference calculation process of corresponding time points in cycle 1 and cycle 2, the calculations are as follows: 0.30kPa-0.20kPa=0.10kPa, 0.33kPa-0.22kPa=0.11kPa, and so on until all corresponding points are calculated. The differences are merged to generate a new difference sequence {0.10kPa, 0.11kPa, 0.12kPa, 0.12kPa, 0.12kPa, 0.13kPa}, and the cumulative summation is further performed to sum all elements of the difference sequence, specifically 0.10+0.11+0.12+0.12+0.12+0.13=0.70kPa, and the total periodic pressure differential difference is 0.70kPa.

[0075] S102: call the total amount of cycle pressure difference difference, judge the difference between multiple groups of values ​​and the set judgment benchmark, calculate the degree of deviation between the difference and the benchmark, classify and summarize and set the value interval to generate the cycle pressure difference deviation interval; call the total amount of cycle pressure difference difference 0.70kPa and compare it with the set judgment benchmark (determined by the water department based on pipe type, pipe diameter, water flow characteristics and empirical data), take the standard water supply pipe in the city (pipe diameter DN100, material PE, judgment benchmark value 0.50kPa) as an example, and perform the difference judgment process as follows: specifically, call the total amount of cycle pressure difference difference 0.70kPa and compare it with the set judgment benchmark The absolute difference between the value of 0.70kPa and the judgment standard of 0.50kPa is calculated as 0.70kPa-0.50kPa=0.20kPa, and the degree of deviation is clearly obtained as 0.20kPa; the obtained degree of deviation is divided into a numerical range, and according to the preset interval division standard, 0-0.05kPa is a slight deviation range, 0.05-0.15kPa is a medium deviation range, and 0.15kPa and above are significant deviation ranges. Therefore, the degree of deviation of 0.20kPa is classified as a significant deviation range; the final periodic pressure difference deviation range is obtained as a "significant deviation range".

[0076] S103: Based on the periodic pressure difference deviation interval, the total periodic pressure difference value is called, and the calculation is performed in combination with the fluctuation value, the pipe section length and the sampling interval, using the formula:

[0077] ;

[0078] Obtain the variation amplitude value and generate the periodic pressure difference variation amplitude;

[0079] in, Represents the cycle pressure difference variation amplitude of the first cycle, Represents the first cycle The pressure difference at each moment, Represents the judgment criteria for the first cycle, Represents the first cycle The pressure difference fluctuation value at the moment, Represents the first cycle The length of the pipe section at the time, Represents the velocity increase parameter of the first cycle, Represents the first cycle The sampling interval of time, Represents the number of pressure difference sampling points in a cycle.

[0080] The total pressure difference of the call cycle is 0.70kPa, and the subsequent calculation is performed based on the fluctuation value, pipe length, and sampling interval. Obtained through monitoring equipment, for example, the pressure difference fluctuation values ​​at 6 moments are {0.03kPa, 0.02kPa, 0.03kPa, 0.02kPa, 0.03kPa, 0.03kPa}, and each moment corresponds to the length of the pipe section. Obtained through actual measurement, specific data see Table 1:

[0081] Table 1 Pipe section length measurement data

[0082] ,

[0083] As shown in Table 1, the pipe length data are all 10 meters, and the sampling intervals are For 2 seconds, the flow rate increase parameter The setting refers to the urban water supply pipeline velocity change specification, usually 0.05, the judgment basis is 0.50kPa. Based on the above data, the formula is calculated:

[0084] ;

[0085] Bring in actual data calculation:

[0086] ;

[0087] The further calculation process is as follows:

[0088] First calculate the values ​​in brackets separately:

[0089] Item 1: (0.03 + 0.5) / 2 = 0.265, multiplied by 0.10 = 0.0265;

[0090] Item 2: (0.02 + 0.5) / 2 = 0.260, multiplied by 0.11 = 0.0286;

[0091] Item 3: (0.03 + 0.5) / 2 = 0.265, multiplied by 0.12 = 0.0318;

[0092] Item 4: (0.02 + 0.5) / 2 = 0.260, multiplied by 0.12 = 0.0312;

[0093] Item 5: (0.03 + 0.5) / 2 = 0.265, multiplied by 0.12 = 0.0318;

[0094] Item 6: (0.03 + 0.5) / 2 = 0.265, multiplied by 0.13 = 0.03445;

[0095] Then sum: 0.0265+0.0286+0.0318+0.0312+0.0318+0.03445=0.18435;

[0096] The final square root is:

[0097] ;

[0098] The result 0.4294kPa represents the amplitude of the cycle pressure difference change, and further uses this value to represent the degree of change of the cycle pressure difference. Combined with the cycle pressure difference deviation interval (significant deviation interval), the change of pipeline status within the cycle is quantitatively described. The formula is beneficial in that the parameter and The deviation is multiplied by the standardized index combining the pipe length and the pressure difference fluctuation to achieve a quantitative expression that is more sensitive to the pressure difference fluctuation amplitude.

[0099] See also Figure 3 , the steps for obtaining the sampling frequency adjustment status are as follows:

[0100] S201: Calculating the amplitude difference of the periodic pressure difference variation value based on the difference between the periodic pressure difference variation amplitude value and the set pressure difference judgment reference value, determining whether the amplitude difference exceeds the pressure difference judgment reference value threshold, and if so, collecting a flow velocity reading sequence within five cycles of the ultrasonic water meter to obtain an instantaneous flow velocity sequence;

[0101] First, the periodic pressure difference variation amplitude value is used as the starting data source for executing the action. The specific acquisition of the periodic pressure difference variation amplitude value is to obtain the pressure difference sequence of the two measuring points before and after the pipeline through the ultrasonic water meter within a certain measurement period (for example, 5 consecutive measurement cycles, each cycle is 10 seconds). For example, the actual measured value of the pressure difference sequence is kPa, and the difference calculation method is used to obtain the variation range between adjacent measured values. For example, the variation between the first and second weeks is , the second and third cycles are , and so on, the pressure difference variation amplitude sequence between each cycle is obtained as kPa, and then select the maximum absolute value in this sequence (for example, 1.6 kPa in this example) as the periodic pressure differential fluctuation amplitude. This periodic pressure differential fluctuation amplitude is then compared with the pressure differential judgment reference value. The specific value of the pressure differential judgment reference value is determined by referring to the usual allowable pressure differential fluctuation range in the water flow network. Typical settings are shown in Table 2.

[0102] Table 2 Pressure difference judgment reference value setting table

[0103] ,

[0104] Refer to Table 2. This example uses a DN50 pipe, and the pressure difference judgment reference value is set to 1.0kPa, and its corresponding reference value threshold is 0.5kPa. The specific execution action is to use the difference operation to determine the amplitude difference between the periodic pressure difference fluctuation amplitude value and the pressure difference judgment reference value. The specific operation is:

[0105] ,

[0106] The difference result of 0.6kPa exceeds the reference value threshold of 0.5kPa, and is therefore determined to be out of the allowable range. The next step is to collect a sequence of instantaneous flow velocity readings within 5 consecutive cycles from the ultrasonic water meter to obtain an instantaneous flow velocity sequence for the next calculation.

[0107] S202: Call the instantaneous flow rate sequence and calculate the fluctuation range based on each instantaneous flow rate of the five cycles using the formula:

[0108] ;

[0109] Calculate and obtain a new correction value of the flow rate standard deviation;

[0110] in, represents the new corrected value of the standard deviation of the flow rate, Represents the first The instantaneous flow velocity value at time, represents the average value of all instantaneous flow velocity values, represents the number of samples, i.e. the number of cycles, It is a coefficient adjusted according to the flow velocity change trend;

[0111] Extract the instantaneous flow velocity reading sequence within five consecutive cycles obtained in the previous step, and calculate the standard deviation fluctuation range based on this. Taking the actual measurement as an example, the instantaneous flow velocity value read by the ultrasonic water meter within five cycles is m / s. Then, the difference between each velocity value and the sequence average velocity is calculated in turn. The sequence average velocity is calculated as follows:

[0112] ;

[0113] Next, the square of the difference between each instantaneous velocity value and the sequence average is calculated. The specific calculation process is: the square of the difference between the first velocity point is calculated as , the second one is , and so on, complete the calculation of the square of the difference between all five flow rate values ​​and the average value, and get the square of difference sequence The sum of the above sequence is divided by the number of cycles minus 1, which is 4. The specific execution is:

[0114] ;

[0115] Taking the square root of the result, the standard deviation is Then adjust the coefficient based on the flow rate change trend Adjust the standard deviation. The value of this coefficient is determined by referring to the actual water meter flow rate fluctuation characteristics. It is usually set in the range of 1.0 to 1.5. In this example, it is set to 1.2. The adjusted standard deviation is In addition, the difference operation is performed to determine the maximum velocity difference, that is, the difference between the maximum value of 0.56m / s and the minimum value of 0.48m / s in the sequence is 0.08m / s. This difference is then weighted by the natural logarithm of the number of cycles. The specific execution is as follows: Finally, the two values ​​are summed, that is, 0.0385m / s+0.0497m / s=0.0882m / s, and the new corrected value of the velocity standard deviation is obtained. .

[0116] S203: Compare the difference between the new corrected value of the flow rate standard deviation and the preset flow rate stability threshold. If the flow rate stability threshold is exceeded, switch the sampling window and adjust the sampling frequency to the short-time high-frequency mode, record the current frequency status, and obtain the sampling frequency adjustment status value.

[0117] The specific implementation is to first obtain the new correction value of the flow velocity standard deviation from the previous step. For example, the instantaneous flow velocity sequence measured by the ultrasonic water meter within five cycles is (unit: m / s): , according to the formula provided in the previous step:

[0118] ;

[0119] Further explanation of the parameters in the formula: Indicates the The instantaneous flow rate in a measurement cycle, for example, the flow rate values ​​above correspond to , , and so on; represents the average of five instantaneous flow rates and is calculated as:

[0120] ;

[0121] That is, the number of cycles is 5. The flow rate trend adjustment coefficient is set according to the water flow conditions. The value range is usually between 1.0 and 1.5. Here we take 1.2 as an example. The maximum flow rate difference 0.56 (maximum) minus 0.48 (minimum) equals 0.08 m / s.

[0122] Substitute the numerical value into the calculation:

[0123] ;

[0124] The step-by-step calculation is:

[0125] First calculate the variance part:

[0126] ;

[0127]

[0128] ;

[0129] ;;

[0130] ;

[0131] The new corrected value of the standard deviation of the obtained flow rate The specific operation of the subsequent comparative analysis of this new correction value is to calculate the difference between this value and the preset flow rate stability threshold. This threshold is usually set based on the flow rate fluctuation range of the actual water meter's stable operation, as shown in Table 3.

[0132] Table 3 Flow rate stability threshold setting table

[0133] ,

[0134] Refer to Table 3. The corresponding flow velocity in this example is 0.526 m / s, which belongs to the medium flow range. The selected flow velocity stability threshold is 0.050 m / s. Then the calculated 0.0882 m / s is compared with 0.050 m / s. The specific execution process is as follows:

[0135] ;

[0136] This difference exceeds the preset threshold, which means that the fluctuation amplitude of the current water meter measured flow rate has exceeded the set allowable range. The frequency adjustment action is performed: the ultrasonic water meter sampling window is switched to a shorter period, for example, the original 10 seconds is adjusted to 2 seconds, and the sampling frequency is adjusted from once per minute to once every 10 seconds. This adjustment process is achieved by modifying the cycle parameters in the program sampling instruction in the ultrasonic water meter. The specific instruction is to send a sampling parameter adjustment command to the water meter through the communication interface. The parameters are the sampling period "2s" and the frequency "6 times / min". After sending the command, the water meter immediately enters the short-term high-frequency mode and stores the frequency status mark in the device memory to mark the current device working in high-frequency sampling mode, that is, the acquisition of the sampling frequency adjustment status value is completed.

[0137] See also Figure 4 ,The specific steps for obtaining the flow velocity credibility judgment index are:

[0138] S301: Based on the sampling frequency adjustment state, the pressure difference sequence and flow rate sequence within the period are selected, the sequences are synchronously intercepted and the time step is corrected, and the differences between adjacent moments are obtained in the time axis order to construct a first-order difference sequence set;

[0139] First, set the fluid measurement cycle. For example, if it is determined that in an actual scenario, the pressure and flow rate of an oil pipeline are measured in a 5-second cycle and data is collected once per second, then a total of 5 sets of pressure difference information and flow rate data are obtained within the cycle, which are recorded as pressure difference sequences. With flow rate sequence , the above two sequences are cut into the same time length according to the time mark and unified into 5 data points, and then the time axis is corrected according to the set unified time step (here one step per second) to ensure that the pressure difference and flow rate data are strictly corresponding at each moment, and then the difference operation is performed on the pressure difference and flow rate sequences respectively, that is, the difference between the adjacent time data is calculated to obtain the first-order difference sequence set. Specifically, the pressure difference first-order difference sequence is calculated as , and the first-order difference sequence of flow velocity is obtained as , the data volume of both sequences is 4 points, and the result constitutes the first-order difference sequence set based on subsequent operations.

[0140] S302: Call the first-order difference sequence set, extract the pressure difference difference value and the flow rate difference value according to the same time index, calculate the same position ratio, and create a numerical list of the ratio results corresponding to all moments to obtain the pressure difference flow rate ratio sequence;

[0141] In the process of calling the first-order difference sequence set obtained above, the pressure difference value and the flow rate difference value are extracted one by one, that is, in practice, each data pair is called in turn. For example, the data pair at time 2 is the pressure difference value and velocity difference , and then through the operation Calculate the isotope ratio and store it in the value list. Repeat this operation to get 4 ratios to form a pressure difference flow rate ratio sequence. For example, the sequence may be , the actual calculation is, for example, the pressure difference value at a given moment MPa, velocity differential value m / s, then the calculated isotope ratio is , and so on.

[0142] S303: Based on the pressure difference flow rate ratio sequence, combined with the upper and lower boundaries of the reference ratio interval of multiple ratios within the period, the deviation degree and sequence fluctuation intensity are calculated in sequence using the formula:

[0143] ;

[0144] After the flow velocity deviation judgment value sequence is obtained by operation, the multiple judgment values ​​are compared with the credibility limit value to generate the flow velocity credibility judgment index;

[0145] in, It represents the flow velocity credibility judgment index, Indicates the The pressure difference flow rate ratio at the moment, represents the mean value of the pressure difference flow rate ratio series, Indicates the first The variance of the item, Indicates the The absolute value of the first-order difference of the flow velocity at time , Indicates the The half-width value of the reference ratio interval corresponding to the moment, Indicates the total number of sample points in the period.

[0146] First, determine the reference ratio range, which is obtained by long-term data statistics of pressure difference and flow rate ratio measured on site. For example, referring to the past 100 sets of measurement data, the reference ratio range is determined to be , then the half-width value The interval half-width is uniformly taken as 0.4, and the ratios in the sequence and the mean of the ratio sequence are further calculated. The degree of deviation, such as assuming that the ratio sequence in this period is , then first calculate the sequence mean , and further calculate the deviation such as the deviation value at time 1 , continue to calculate the deviation of each point one by one to obtain the complete deviation degree sequence; at the same time, calculate the variance value of each item in the ratio sequence , for example, the variance corresponding to time 1 is , similarly calculate the complete variance sequence; further call the velocity difference absolute value sequence For example, if the absolute value of velocity difference at time 1 is 0.05 m / s, then the respective values ​​of Then open the square, such as ;

[0147] Then divide the above deviation values ​​by the square root result one by one, and then divide by the corresponding reference ratio half-width value Finally, the results of all moments are accumulated to complete the credibility judgment index The calculation process, such as:

[0148] ;

[0149] The actual measurement data is shown in the following table:

[0150] Table 4 Pressure difference and flow rate measurement data within a cycle

[0151] ,

[0152] As shown in Table 4, the data at each moment are obtained based on real-time monitoring of the on-site fluid delivery pipeline. The data are measured by standard instruments, where the pressure difference and flow rate are measured using a pressure difference sensor and a flow meter, respectively.

[0153] The credibility judgment index value Compared with the preset credibility limit value (the benchmark value obtained through historical data statistics), for example, in the actual scenario, the credibility benchmark is set to 3.5. If 4.5 exceeds the benchmark value 3.5, it means that the credibility of the flow rate in this cycle is reduced. This result indicates that there are abnormal flow rate fluctuations within the cycle. This numerical result is an important basis for generating the flow rate credibility judgment index.

[0154] The innovation of the formula lies in that by introducing a comprehensive fluctuation quantity composed of the pressure difference flow rate ratio sequence, variance and absolute value of flow rate difference, the amplitude of data fluctuation and abnormal deviation are accurately expressed in the calculation, thereby enhancing the sensitivity and accuracy of the credibility index to the actual flow rate fluctuation anomaly.

[0155] See also Figure 5 , the specific steps for obtaining the abnormal period alternative flow rate are:

[0156] S401: Based on the current cycle flow velocity reading and the current flow velocity credibility judgment index, determine whether the current cycle flow velocity data is in a credible state, compare the current cycle flow velocity credibility index with a preset flow velocity credibility judgment threshold, and if it is less than the flow velocity credibility judgment threshold, determine that the current cycle is an abnormal cycle, and obtain an abnormal cycle marking state;

[0157] The specific implementation is as follows: First, obtain the flow velocity value measured in the current monitoring period. For example, the flow velocity reading of the current period measured at a hydrological station is , and call the velocity credibility judgment index value corresponding to the current cycle at the same time, such as the credibility judgment index is ; Then, by obtaining the pre-set velocity credibility threshold, the setting process of this threshold is generally based on the credibility statistical analysis results of historical velocity monitoring data. By statistically analyzing the historical data of a certain measuring station, for example, selecting 100 historical cycle data, it is found through analysis that the normal distribution range of the velocity credibility index is 0.85~0.95, and the credibility judgment threshold is set to the lower limit of the range, that is, the threshold is 0.85; then the value of the credibility judgment index of the current cycle is Compare the value with the credibility threshold and perform the value comparison action, specifically directly Compared with the credibility threshold of 0.85, since 0.78 is less than 0.85, it is determined that the data of this cycle is in an abnormal state, so the flow rate reading of the current cycle is Mark it as abnormal cycle state and record the state mark.

[0158] S402: Call the abnormal cycle marking state, extract the flow velocity readings of the adjacent cycles before and after the flow velocity data determined to be an abnormal cycle, mark them as the previous cycle flow velocity and the next cycle flow velocity, and record the current cycle flow velocity, using the formula:

[0159] ;

[0160] Calculate the adjusted cycle flow rate value, replace the original reading of the current abnormal cycle, and generate an alternative flow rate value for the abnormal cycle;

[0161] in, Indicates the adjusted cycle flow rate value, Indicates the flow rate of the previous cycle, Indicates the flow rate of the next cycle, Indicates the flow rate of the current cycle;

[0162] The execution steps include: first call the stored flow rate reading of the previous cycle and the flow rate reading of the next cycle For example, if the current cycle is the 10th cycle, the flow rate reading is measured in the 9th cycle. , the flow rate reading measured in the 11th cycle ; and call the current cycle raw flow rate reading , and then use the formula:

[0163] ;

[0164] Calculate the adjusted abnormal period alternative flow rate value, where the detailed explanation of each parameter is as follows:

[0165] : Indicates the calculated new flow rate value that replaces the abnormal flow rate of the current cycle;

[0166] : Indicates the actual monitored flow velocity value of the normal cycle before the current abnormal cycle. In this embodiment, it is the flow velocity value of the 9th cycle, which is 3.2 m / s;

[0167] : Indicates the actual monitored flow velocity value of a normal cycle after the current abnormal cycle. In this embodiment, it is the flow velocity value of the 11th cycle, which is 3.6 m / s;

[0168] : represents the original monitored flow velocity value of the current cycle, which is 3.4m / s; then substitute the above value into the formula for calculation:

[0169] First, calculate the sum of squares:

[0170] ;

[0171] Then perform the square root operation:

[0172] ;

[0173] Then compare it with the current cycle flow rate value Perform product calculation:

[0174] ;

[0175] Then calculate the absolute value of the difference in flow rate between the previous and next cycles:

[0176] ;

[0177] Then sum it with the constant 1:

[0178] ;

[0179] Finally, a division operation is performed to obtain the alternative flow rate:

[0180] ;

[0181] The final calculated abnormal period alternative velocity value is 11.6974m / s.

[0182] S403: calling the abnormal period replacement flow rate value to replace the original current period flow rate reading marked as abnormal, and updating the value of the period position in the original flow rate data set to obtain the abnormal period replacement flow rate.

[0183] Call the abnormal cycle to replace the flow rate value, that is, , perform specific replacement actions: through data storage instructions, directly update the position of the abnormal state period in the original flow rate data set, and replace the original flow rate value of the original abnormal period with the original value of the original flow rate value. Replace the value and update it to the currently calculated replacement value , and is stored back in the original location in the velocity data set. At this time, the velocity data of the 10th cycle in the original data set is updated to the newly calculated abnormal cycle replacement velocity value of 11.6974m / s.

[0184] See also Figure 6 , the specific steps for obtaining the periodic sampling frequency status value are:

[0185] S501: Based on the abnormal period replacing the flow rate, the flow rate information and the pressure difference sampling sequence in the initial period are called, the pressure difference amplitude and flow rate change rate of multiple sampling points in the period are calculated, and a continuous fluctuation index set in the sampling sequence is constructed to obtain a pressure difference and flow rate fluctuation index sequence;

[0186] First, the flow rate information and corresponding pressure difference information obtained at each sampling point in the initial cycle are called. The process of obtaining this information is through multiple flow rate sensors and pressure difference sensors arranged at fixed positions in the pipeline. Assuming that 5 points are sampled in an initial cycle (for example, within 5 seconds), the flow rate sequence data are collected respectively. And the corresponding pressure difference series data , call these data to perform point-by-point calculations. For two adjacent sampling points, such as point 1 (flow rate 3.5m / s, pressure difference 20kPa) and point 2 (flow rate 3.6m / s, pressure difference 22kPa), calculate the pressure difference change and flow rate change rate respectively, that is, the pressure difference amplitude is The flow rate change rate is (Assuming the sampling interval is 0.2 seconds), then call the next adjacent sampling point to perform similar calculations, repeat the above actions in sequence to obtain the fluctuation index of all sampling points, and form a complete pressure difference flow rate fluctuation index sequence, that is, in the sequence of 5 points, gradually obtain the pressure difference amplitude sequence and flow rate change series , and then the above sequence is formed into a set of continuous fluctuation indicators within the period, and finally a complete pressure difference and flow rate fluctuation indicator sequence is obtained as the final result of this section.

[0187] S502: Call the pressure difference and flow rate fluctuation index sequence, and construct the ratio of the pressure difference difference to the flow rate difference at adjacent moments based on the corresponding sampling points of the pressure difference and flow rate in two cycles, using the formula:

[0188] ;

[0189] Calculate the pressure difference and flow rate ratio at each moment to form a ratio sequence, and perform periodic fluctuation analysis based on the sequence average and difference amplitude to obtain the periodic normalized fluctuation difference;

[0190] in, Representative cycle The pressure difference flow rate ratio, Represents a period Middle The pressure difference value of the sampling points, Represents a period Middle The pressure difference value of the sampling points, Represents a period Middle The flow velocity value of each sampling point, Represents a period Middle The flow velocity value of each sampling point, Indicates a positive constant to avoid zero denominator. Indicates the sampling point number within the cycle;

[0191] Call the pressure difference flow rate fluctuation index sequence, take the sampling point data corresponding to the pressure difference and flow rate of adjacent periods (period a and period b, for example, two adjacent 5-second sampling periods), for example, the sampling data of period a is the pressure difference sequence , flow rate sequence , the data of period b is the pressure difference sequence , flow rate sequence , call the above data into the formula one by one:

[0192] ;

[0193] in, and Represent the pressure difference value of the j-th sampling point in period a and period b respectively, and Represent the flow velocity values ​​of the jth sampling point in period a and period b respectively, To avoid small positive values ​​with zero denominator (such as );

[0194] Specific operation examples:

[0195] Substituting the first sampling point into the formula, the calculation is:

[0196] ;

[0197] Calculate the 2nd to 5th sampling points in sequence to obtain the sequence:

[0198] , call the above ratio sequence, perform numerical average operation and compare the difference amplitude of each value in the sequence, that is, calculate the sequence mean respectively , then call each point to calculate the deviation from the sequence mean, and then obtain the volatility difference of each point. Finally, normalize all volatility differences, that is, divide each volatility difference by the mean, and obtain the periodic normalized volatility difference sequence as the final result.

[0199] S503: Perform numerical amplitude judgment based on the period normalized fluctuation difference and the set period fluctuation threshold, compare and judge based on the initial setting of the sampling frequency and the adjustment mark status value, and generate a period sampling frequency status value.

[0200] The period-normalized fluctuation difference is obtained by the above calculation, for example , then the initially set periodic fluctuation threshold is called for each value, for example, the threshold is set to 0.02. The specific execution process of the numerical amplitude judgment is as follows: each element of the normalized fluctuation difference is directly compared with the threshold. Assuming that when the periodic normalized fluctuation difference is 0.01 and is less than the threshold 0.02, the state value is judged to be "stable". When the normalized fluctuation difference is 0.02 and equals the threshold, the state value is judged to be "critically stable". When the normalized fluctuation difference is greater than 0.02, the state value is "unstable". The initial sampling frequency setting (for example, the initial sampling frequency is 5Hz) is further called to compare with the sampling frequency adjustment flag state value. Specifically, if the above state value is "unstable", the frequency adjustment flag state value update action is executed, and the state value is marked as "frequency needs to be increased". If the state is "stable" or "critically stable", the state value is marked as "maintain frequency unchanged". The sampling frequency state value obtained by the above comparison is: when any fluctuation difference within the period is judged to be "unstable", the overall periodic sampling frequency state value is marked as "frequency increase"; otherwise, the state value remains "frequency unchanged".

[0201] Table 5 Periodic sampling parameters

[0202] ,

[0203] As shown in Table 5, each parameter is obtained through the measured data of cycles a and b. The pressure difference flow rate ratio of each sampling point is calculated to be 9.90 kPa·s / m. The sampling frequency adjustment flag status value is determined by comparing the period normalized fluctuation difference with the preset threshold value of 0.02.

[0204] The benefit of the formula is that, by calculating the ratio between the pressure difference and the specific flow velocity sampling points, the stability of the flow within the cycle can be accurately determined in real time, and further determine whether the cycle sampling frequency state needs to be adjusted.

[0205] An intelligent monitoring system for an Internet of Things ultrasonic water meter is provided. The intelligent monitoring system for an Internet of Things ultrasonic water meter is used to implement the intelligent monitoring method for an Internet of Things ultrasonic water meter. The system includes:

[0206] The pressure difference detection module obtains the pipeline pressure difference signal sequence of three cycles, calculates the absolute difference between adjacent cycles and accumulates them, calls the pressure difference change reference value for comparison, and obtains the periodic pressure difference change amplitude;

[0207] The fluctuation judgment module collects five instantaneous flow rate readings based on the amplitude of the periodic pressure difference fluctuation. If it exceeds the pressure difference fluctuation reference value, it calculates its standard deviation and compares it with the flow rate stability threshold. If the trigger condition is met, it adjusts the sampling window and switches to high-frequency mode, records the frequency switching situation, and generates the sampling frequency adjustment status;

[0208] The credibility assessment module extracts the corresponding pressure difference and flow rate series based on the sampling frequency adjustment state, performs first-order difference processing and calculates the isotope ratio, calls the credibility reference interval judgment, and obtains the flow rate credibility judgment index;

[0209] The data correction module extracts the flow velocity readings before and after the current cycle based on the flow velocity credibility judgment index, assigns weights in sequence and performs weighted average, and uses them to replace the current flow velocity value to generate the abnormal cycle replacement flow velocity;

[0210] The frequency control module calls the abnormal cycle to replace the flow rate, collects the pressure difference and flow rate sequences of the subsequent two cycles, calculates the fluctuation values ​​and compares them with the set reference values, determines whether to restore the sampling frequency, and obtains the periodic sampling frequency status value.

[0211] The above are merely preferred embodiments of the present invention and do not limit the present invention in any other form. Any technician familiar with the profession may use the technical content disclosed above to change or modify it into an equivalent embodiment with equivalent changes and apply it to other fields. However, any simple modification, equivalent change and modification made to the above embodiment based on the technical essence of the present invention without departing from the content of the technical solution of the present invention shall still fall within the scope of protection of the technical solution of the present invention.

Claims

1. An intelligent monitoring method for an Internet of Things ultrasonic water meter, characterized in that: The following steps are involved: S1: Obtain a sequence of three consecutive periodic differential pressure readings from the ultrasonic water meter, calculate the absolute difference between adjacent periodic data, accumulate the difference and compare it with the judgment benchmark to generate the periodic differential pressure variation amplitude; S2: Based on the fluctuation amplitude of the cyclic pressure difference, if it exceeds the judgment standard, collect the instantaneous flow velocity reading sequence of five cycles in the ultrasonic water meter, perform standard deviation calculation to obtain the flow velocity fluctuation value of the current cycle, compare it with the set flow velocity stability threshold, switch the sampling window and adjust the sampling frequency to the short-term high-frequency mode, and record the sampling frequency adjustment status; S3: Based on the sampling frequency adjustment state, extract the corresponding periodic pressure difference and flow rate sequence, calculate the first-order difference and then obtain the isotope ratio, compare it with the reference interval, and obtain the flow rate credibility judgment index; S4: Based on the flow velocity credibility judgment index, if the current cycle data is in a low credibility state, extract the flow velocity readings of the previous and next cycles, take the weighted average in sequence according to the weight, replace the original reading, and generate a replacement flow velocity for the abnormal cycle; S5: Call the abnormal cycle to replace the flow rate, obtain the pressure difference and flow rate sequence of the next two cycles, calculate the fluctuation values ​​respectively and then compare and determine, restore the initial sampling frequency, and obtain the periodic sampling frequency state value; The periodic pressure difference fluctuation amplitude specifically includes the fluctuation range, deviation level, and risk signal; the sampling frequency adjustment state specifically includes the mode state, frequency configuration, and adjustment record; the flow velocity credibility judgment index includes the stability score, trust level, and judgment result; the abnormal period replacement flow velocity specifically includes the smoothed flow velocity, correction value, and replacement data; and the periodic sampling frequency state value specifically includes the initial mode, frequency recovery, and state feedback; The steps for obtaining the periodic pressure difference variation amplitude are specifically as follows: S101: Based on a sequence of three consecutive period pipeline pressure difference readings obtained from the ultrasonic water meter, extract two sets of pressure difference data from adjacent periods, calculate the absolute difference of the pressure differences at multiple time points, merge them to generate a difference sequence, accumulate and sum the differences, and generate a total period pressure difference difference; S102: calling the total amount of the periodic pressure difference difference, performing difference judgment on multiple groups of values ​​and a set judgment benchmark, calculating the degree of deviation between the difference and the benchmark, classifying and summarizing them, setting a value interval, and generating a periodic pressure difference deviation interval; S103: According to the periodic pressure difference deviation interval, the total periodic pressure difference value is called, and the fluctuation value, the pipe section length and the sampling interval are combined to perform calculations using the formula: ； Obtain the variation amplitude value and generate the periodic pressure difference variation amplitude; in, Represents the cycle pressure difference variation amplitude of the first cycle, Represents the first cycle The pressure difference at each moment, Represents the judgment criteria for the first cycle, Represents the first cycle The pressure difference fluctuation value at the moment, Represents the first cycle The length of the pipe section at the time, Represents the velocity increase parameter of the first cycle, Represents the first cycle The sampling interval of time, Represents the number of pressure difference sampling points in a cycle.

2. The intelligent monitoring method of the Internet of Things ultrasonic water meter according to claim 1 is characterized in that: The steps for obtaining the sampling frequency adjustment status are specifically as follows: S201: Calculating the amplitude difference of the periodic pressure difference variation value based on the difference between the periodic pressure difference variation amplitude value and the set pressure difference judgment reference value, determining whether the amplitude difference exceeds the pressure difference judgment reference value threshold, and if so, collecting a flow velocity reading sequence within five cycles of the ultrasonic water meter to obtain an instantaneous flow velocity sequence; S202: Call the instantaneous flow rate sequence and calculate the fluctuation range based on each instantaneous flow rate of five cycles using the formula: ； Calculate and obtain a new correction value of the flow rate standard deviation; in, represents the new corrected value of the standard deviation of the flow rate, Represents the first The instantaneous flow velocity value at time, represents the average value of all instantaneous flow velocity values, represents the number of samples, i.e. the number of cycles, It is a coefficient adjusted according to the flow velocity change trend; S203: Compare the difference between the new corrected value of the flow rate standard deviation and the preset flow rate stability threshold. If the flow rate stability threshold is exceeded, switch the sampling window and adjust the sampling frequency to the short-time high-frequency mode, record the current frequency status, and obtain the sampling frequency adjustment status value.

3. The intelligent monitoring method of the Internet of Things ultrasonic water meter according to claim 2 is characterized in that: The steps for obtaining the flow velocity credibility judgment index are specifically as follows: S301: Based on the sampling frequency adjustment state, a pressure difference sequence and a flow rate sequence within a period are selected, the sequences are synchronously intercepted and the time step is corrected, and then the differences between adjacent moments are obtained in time axis order to construct a first-order difference sequence set; S302: calling the first-order difference sequence set, extracting the pressure difference difference value and the flow rate difference value according to the same time index, calculating the same position ratio, and creating a numerical list of the ratio results corresponding to all moments to obtain a pressure difference flow rate ratio sequence; S303: Based on the pressure difference flow rate ratio sequence, combined with the upper and lower boundaries of the reference ratio interval of multiple ratios within the period, the deviation degree and sequence fluctuation intensity are calculated in sequence using the formula: ； After the flow velocity deviation judgment value sequence is obtained by operation, the multiple judgment values ​​are compared with the credibility limit value to generate the flow velocity credibility judgment index; in, It represents the flow velocity credibility judgment index, Indicates the The pressure difference flow rate ratio at the moment, represents the mean value of the pressure difference flow rate ratio series, Indicates the ratio sequence The variance of the item, Indicates the The absolute value of the first-order difference of the flow velocity at time , Indicates the The half-width value of the reference ratio interval corresponding to the moment, Indicates the total number of sample points in the period.

4. The intelligent monitoring method of the Internet of Things ultrasonic water meter according to claim 3 is characterized in that: The specific steps for obtaining the abnormal period alternative flow rate are: S401: Based on the current cycle flow velocity reading and the current flow velocity credibility judgment index, determine whether the current cycle flow velocity data is in a credible state, compare the current cycle flow velocity credibility index with a preset flow velocity credibility judgment threshold, and if it is less than the flow velocity credibility judgment threshold, determine that the current cycle is an abnormal cycle, and obtain an abnormal cycle marking state; S402: Call the abnormal cycle marking state, extract the flow velocity readings of the adjacent cycles before and after the flow velocity data determined to be an abnormal cycle, mark them as the previous cycle flow velocity and the next cycle flow velocity, and record the current cycle flow velocity, using the formula: ； Calculate the adjusted cycle flow rate value, replace the original reading of the current abnormal cycle, and generate an alternative flow rate value for the abnormal cycle; in, Indicates the adjusted cycle flow rate value, Indicates the flow rate of the previous cycle, Indicates the flow rate of the next cycle, Indicates the flow rate of the current cycle; S403: calling the abnormal period replacement flow rate value to replace the original current period flow rate reading marked as abnormal, and updating the value of the period position in the original flow rate data set to obtain the abnormal period replacement flow rate.

5. The intelligent monitoring method of the Internet of Things ultrasonic water meter according to claim 4 is characterized in that: The steps for obtaining the periodic sampling frequency state value are specifically as follows: S501: Based on the abnormal period replacement flow rate, the flow rate information and the pressure difference sampling sequence in the initial period are called, the pressure difference amplitude and flow rate change rate of multiple sampling points in the period are calculated, and a continuous fluctuation index set in the sampling sequence is constructed to obtain a pressure difference and flow rate fluctuation index sequence; S502: Call the pressure difference and flow velocity fluctuation index sequence, and construct the ratio of the pressure difference difference to the flow velocity difference at adjacent moments based on the corresponding sampling points of the pressure difference and flow velocity in two cycles, using the formula: ； Calculate the pressure difference and flow rate ratio at each moment to form a ratio sequence, and perform periodic fluctuation analysis based on the sequence average and difference amplitude to obtain the periodic normalized fluctuation difference; in, Representative cycle The pressure difference flow rate ratio, Represents a period Middle The pressure difference value of the sampling points, Represents a period Middle The pressure difference value of the sampling points, Represents a period Middle The flow velocity value of each sampling point, Represents a period Middle The flow velocity value of each sampling point, Indicates a positive constant to avoid zero denominator. Indicates the sampling point number within the cycle; S503: Performing numerical amplitude judgment based on the period normalized fluctuation difference and the set period fluctuation threshold, performing comparison judgment in combination with the initial setting of the sampling frequency and the adjustment mark state value, and generating a period sampling frequency state value.

6. An intelligent monitoring system for ultrasonic water meters of the Internet of Things, characterized in that: The intelligent monitoring method of an Internet of Things ultrasonic water meter according to any one of claims 1 to 5, wherein the system comprises: The pressure difference detection module obtains the pipeline pressure difference signal sequence of three cycles, calculates the absolute difference between adjacent cycles and accumulates them, calls the pressure difference change reference value for comparison, and obtains the periodic pressure difference change amplitude; The fluctuation judgment module collects five instantaneous flow rate readings based on the amplitude of the periodic pressure difference fluctuation. If it exceeds the pressure difference fluctuation reference value, the module calculates the standard deviation and compares it with the flow rate stability threshold. If the trigger condition is met, the module adjusts the sampling window and switches to the high-frequency mode, records the frequency switching situation, and generates the sampling frequency adjustment status. The credibility assessment module extracts the corresponding pressure difference and flow rate sequence based on the sampling frequency adjustment state, performs first-order difference processing and calculates the isotope ratio, calls the credibility reference interval judgment, and obtains the flow rate credibility judgment index; The data correction module extracts the flow velocity readings before and after the current cycle according to the flow velocity credibility judgment index, weights them in sequence and performs weighted average, and uses them to replace the current flow velocity value to generate an abnormal cycle replacement flow velocity; The frequency control module calls the abnormal cycle to replace the flow rate, collects the pressure difference and flow rate sequences of the subsequent two cycles, calculates the fluctuation values ​​and compares them with the set reference values, determines whether to restore the sampling frequency, and obtains the periodic sampling frequency status value.

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