Metering data monitoring method and device for water meter

Abstract

The invention discloses a metering data monitoring method and device for a water meter, and relates to the technical field of water flow measurement. Obtaining first transmission time according to the trigger threshold value and determining a first effective point location; determining an oscillation starting reference point location through feature classification; judging whether the first transmission time is valid or not according to the oscillation starting reference point location and the first valid point location; obtaining a target downstream transmission time and a target countercurrent transmission time according to the plurality of effective first transmission times; and the water flow in the measurement period is calculated according to the water flow data, and the water flow data is sent to the cloud server. By calculating the oscillation starting reference point location and the first effective point location, whether a wave hopping phenomenon occurs or not during measurement of the transmission time can be detected, and the influence degree of environmental noise on measurement of the ultrasonic transmission time is represented, so that the effectiveness of the ultrasonic transmission time can be judged; the water flow is calculated according to the effective transmission time, so that the credibility of the calculated data is improved, and the accuracy of the metering data of the water meter is ensured.

Description

Technical Field

[0001] The present invention relates to the technical field of water flow measurement, and in particular to a method and device for monitoring metering data of a water meter. Background Art

[0002] As a new type of water meter, ultrasonic water meter has the advantages of wide range ratio, small pressure loss, high measurement accuracy, no moving parts, and low maintenance cost compared with traditional mechanical water meters. Recently, it has been widely used in water volume measurement to achieve accurate and fair trade measurement. Ultrasonic water meters can be divided into correlation method, beam deviation method, Doppler method, noise method and time difference method according to different measurement principles. Because the time difference method has the advantages of low power consumption, high sensitivity, simple algorithm and small data processing volume under the premise of ensuring high measurement accuracy, it is widely used in ultrasonic flow measurement. The time difference method calculates the flow velocity or flow of the measured medium by detecting the downstream propagation time value and the upstream propagation time value of the ultrasonic signal. Therefore, accurately detecting the upstream and downstream propagation time values ​​of the ultrasonic signal is the key to the time difference method measurement.

[0003] In the time difference method, the threshold method is usually used to detect the propagation time value of the ultrasonic signal in the measured medium. However, it is easily interfered by noise, and the detection performance is affected by the change of the waveform. When the amplitude of the ultrasonic signal changes, it is easy for the threshold to be triggered at different rising edges of the ultrasonic signal, rather than always at the same rising edge, resulting in errors in the measured ultrasonic signal propagation time value, which in turn leads to inaccurate metering data of the water meter. Summary of the invention

[0004] The purpose of the present invention is to solve the problem of inaccurate metering data of the water meter mentioned in the above background technology, and to propose a metering data monitoring method for the water meter.

[0005] A first aspect of the present invention provides a method for monitoring metering data of a water meter, the method comprising:

[0006] In each ultrasonic transmission and reception cycle, a timer is started and a target ultrasonic wave is transmitted in a preset direction;

[0007] Receiving the acoustic voltage signal after the target ultrasonic wave crosses the water flow, obtaining a first transmission time according to a trigger threshold and determining a first effective point; the first transmission time includes a downstream transmission time and an upstream transmission time;

[0008] Dividing the acoustic wave voltage signal into a plurality of sub-signal segments, and classifying the plurality of sub-signal segments to obtain a starting reference point;

[0009] Determining whether the first transmission time is valid according to the oscillation reference point and the first valid point;

[0010] In each measurement cycle, a target downstream transmission time and a target upstream transmission time are obtained according to a plurality of valid first transmission times; each measurement cycle includes a plurality of ultrasonic transmission and reception cycles;

[0011] The water flow rate within the measurement period is calculated according to the target downstream transmission time and the target upstream transmission time, and the water flow rate data is sent to the cloud server.

[0012] Optionally, obtaining the first transmission time according to the trigger threshold and determining the first valid point position includes:

[0013] When the amplitude of the acoustic wave voltage signal exceeds the trigger threshold for the first time, the timer is triggered, and this moment is recorded as the trigger moment;

[0014] When the amplitude of the acoustic wave voltage signal after the triggering moment is equal to the zero-crossing threshold, the timing of the timer is stopped to obtain a first transmission time; the triggering threshold is greater than the zero-crossing threshold;

[0015] The first peak of the acoustic wave voltage signal after the triggering moment is taken as the first effective point.

[0016] Optionally, judging whether the first transmission time is valid according to the oscillation reference point and the first valid point includes:

[0017] Starting from the first effective point, jump forward by a preset number of waves to obtain the measured peak of the first wave;

[0018] If the measured peak of the head wave is the first peak after the oscillation reference point, the first transmission time is determined to be valid; otherwise, the first transmission time is determined to be invalid.

[0019] Optionally, dividing the acoustic wave voltage signal into a plurality of sub-signal segments and classifying the plurality of sub-signal segments to obtain the oscillation reference point position includes:

[0020] According to the positive zero-crossing point, the acoustic wave voltage signal is divided into a plurality of sub-signal segments; the positive zero-crossing point refers to the point where the amplitude of the acoustic wave voltage signal changes from negative to positive;

[0021] For each sub-signal segment, extract the energy characteristic value and the frequency characteristic value of the sub-signal segment, and normalize the energy characteristic value and the frequency characteristic value respectively to obtain the target energy characteristic value and the target frequency characteristic value;

[0022] According to the target energy characteristic value and the target frequency characteristic value, the probability that the sub-signal segment belongs to the ultrasonic wave is calculated, and the sub-signal segment with a probability greater than a preset threshold is determined as an ultrasonic wave signal segment;

[0023] The first sampling point of the first ultrasonic signal segment is used as the starting reference point.

[0024] Optionally, each sub-signal segment includes multiple sampling points; the energy characteristic value of each sub-signal segment is the root mean square value of the amplitude of the sampling points of the sub-signal segment; and the frequency characteristic value of each sub-signal segment is the number of sampling points of the sub-signal segment.

[0025] A second aspect of the present invention provides a metering data monitoring device for a water meter, the device comprising:

[0026] The ultrasonic wave transmitting module is used to start the timer and transmit the target ultrasonic wave in a preset direction in each ultrasonic wave transmitting and receiving cycle;

[0027] A primary receiving module is used to receive the acoustic voltage signal of the target ultrasonic wave after it crosses the water flow, obtain a first transmission time according to a trigger threshold, and determine a first effective point; the first transmission time includes a downstream transmission time and an upstream transmission time;

[0028] A reference point determination module, used for dividing the acoustic wave voltage signal into a plurality of sub-signal segments, and classifying the plurality of sub-signal segments to obtain a starting reference point position;

[0029] An information validity judgment module, used for judging whether the first transmission time is valid according to the oscillation reference point and the first valid point;

[0030] A transmission time determination module is used to obtain a target downstream transmission time and a target upstream transmission time according to a plurality of valid first transmission times in each measurement cycle; each measurement cycle includes a plurality of ultrasonic transmission and reception cycles;

[0031] The flow calculation module is used to calculate the water flow within the measurement period according to the target downstream transmission time and the target upstream transmission time, and send the water flow data to the cloud server.

[0032] Optionally, the primary receiving module includes:

[0033] A trigger determination module, used to trigger the timer when the amplitude of the acoustic wave voltage signal exceeds the trigger threshold for the first time, and record this moment as the trigger moment;

[0034] A first transmission time determination module, configured to stop the timing of the timer and obtain a first transmission time when the amplitude of the acoustic wave voltage signal after the triggering moment is equal to a zero-crossing threshold; the triggering threshold is greater than the zero-crossing threshold;

[0035] The first effective point determination module is used to take the first peak of the acoustic wave voltage signal after the triggering moment as the first effective point.

[0036] Optionally, the transmission time determination module includes:

[0037] A head wave calculation module is used to jump forward a preset number of waves from the first effective point to obtain a head wave measured peak;

[0038] The time validity judgment module is used to determine that the first transmission time is valid if the measured peak of the head wave is the first peak after the oscillation reference point; otherwise, determine that the first transmission time is invalid.

[0039] Optionally, the reference point determination module includes:

[0040] A signal division module, used for dividing the acoustic wave voltage signal into a plurality of sub-signal segments according to a positive zero-crossing point; the positive zero-crossing point refers to a point where the amplitude of the acoustic wave voltage signal changes from negative to positive;

[0041] A feature extraction module, used for extracting the energy feature value and the frequency feature value of each sub-signal segment;

[0042] A normalization module, used to normalize the energy characteristic value and the frequency characteristic value of the sub-signal segment respectively to obtain a target energy characteristic value and a target frequency characteristic value;

[0043] An ultrasonic probability calculation module, used to calculate the probability that the sub-signal segment belongs to an ultrasonic wave according to the target energy and the target frequency;

[0044] The vibration starting reference point determination module is used to take the first sampling point of the sub-signal segment whose probability of belonging to the ultrasonic wave jumps to above a preset threshold as the vibration starting reference point.

[0045] Optionally, each sub-signal segment includes multiple sampling points; each sub-signal segment includes multiple sampling points; the energy characteristic value of each sub-signal segment is the root mean square value of the amplitude of the sampling points of the sub-signal segment; and the frequency characteristic value of each sub-signal segment is the number of sampling points of the sub-signal segment.

[0046] Beneficial effects of the present invention:

[0047] The present invention proposes a metering data monitoring method for a water meter, the method comprising: in each ultrasonic transmission and reception cycle, starting a timer and transmitting a target ultrasonic wave along a preset direction; receiving an acoustic wave voltage signal after the target ultrasonic wave crosses the water flow, obtaining a first transmission time and determining a first valid point according to a trigger threshold; the first transmission time includes a downstream transmission time and a downstream transmission time; dividing the acoustic wave voltage signal into a plurality of sub-signal segments, and classifying the plurality of sub-signal segments to obtain an oscillation reference point; judging whether the first transmission time is valid according to the oscillation reference point and the first valid point; in each measurement cycle, obtaining a target downstream transmission time and a target upstream transmission time according to a plurality of valid first transmission times; each measurement cycle includes a plurality of ultrasonic transmission and reception cycles; calculating the water flow rate within the measurement cycle according to the target downstream transmission time and upstream transmission time, and sending the water flow rate data to a cloud server.

[0048] By calculating the starting reference point and the first effective point, it is possible to detect whether a wave jump occurs when measuring the transmission time, characterizing the degree of influence of environmental noise on the measurement of ultrasonic transmission time, and thus determining the effectiveness of the ultrasonic transmission time; the water flow is calculated based on the effective transmission time, which improves the credibility of the calculated data and ensures the accuracy of the water meter's metering data. BRIEF DESCRIPTION OF THE DRAWINGS

[0049] The present invention will be further described below in conjunction with the accompanying drawings.

[0050] Figure 1 A flow chart of a method for monitoring metering data of a water meter is provided for an embodiment of the present invention;

[0051] Figure 2 An architectural diagram of a metering data monitoring device for a water meter is provided for an embodiment of the present invention. DETAILED DESCRIPTION

[0052] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0053] The embodiment of the present invention provides a method for monitoring metering data of a water meter. Figure 1 , Figure 1 A flow chart of a method for monitoring metering data of a water meter provided in an embodiment of the present invention. The method comprises the following steps:

[0054] S101, in each ultrasonic transmission and reception cycle, start the timer and transmit the target ultrasonic wave along a preset direction.

[0055] S102, receiving the sound wave voltage signal after the target ultrasonic wave crosses the water flow, obtaining the first transmission time according to the trigger threshold and determining the first effective point.

[0056] S103, dividing the acoustic wave voltage signal into a plurality of sub-signal segments, and classifying the plurality of sub-signal segments to obtain a starting oscillation reference point.

[0057] S104: judging whether the first transmission time is valid according to the oscillation reference point and the first valid point.

[0058] S105 , in each measurement cycle, obtaining a target downstream transmission time and a target upstream transmission time according to a plurality of valid first transmission times.

[0059] S106, calculating the water flow rate within the measurement period according to the target downstream transmission time and the target upstream transmission time, and sending the water flow rate data to the cloud server.

[0060] The first transmission time includes a downstream transmission time and a upstream transmission time; and each measurement cycle includes a plurality of ultrasonic transmission and reception cycles.

[0061] Based on a metering data monitoring method for a water meter provided by an embodiment of the present invention, by calculating the starting reference point and the first effective point, it can be detected whether a wave jumping phenomenon occurs when measuring the transmission time, and the influence of environmental noise on the ultrasonic transmission time measurement is characterized, so that the effectiveness of the ultrasonic transmission time can be judged; the water flow rate is calculated according to the effective transmission time, which improves the credibility of the calculated data and ensures the accuracy of the metering data of the water meter.

[0062] In one implementation, the smart water meter may include a measuring pipe and multiple ultrasonic transducers. Taking two ultrasonic transducers A and B as an example, in one transmission and reception cycle, transducer A can be used as an ultrasonic generator and transducer B can be used as an ultrasonic receiver; in another transmission and reception cycle, transducer B can be used as an ultrasonic generator and transducer A can be used as an ultrasonic receiver; in different ultrasonic transmission and reception cycles within the measurement cycle, the roles of ultrasonic transducers A and B are interchanged, and the downstream transmission time and upstream transmission time can be obtained.

[0063] In one measurement cycle, there are multiple ultrasonic transmission and reception cycles. In each transmission and reception cycle, a downstream transmission time or a reverse transmission time can be obtained. The mean of the effective downstream transmission time and the effective reverse transmission time in one measurement cycle is calculated to obtain the mean downstream transmission time T d and the mean countercurrent transmission time T c, Substitute the two means into the following formula to obtain the water flow velocity:

[0064]

[0065] Among them, V water is the required water flow velocity; L is the straight-line distance between the two ultrasonic transducers; θ is the angle between the connecting line of the two transducers and the water flow direction (less than 90°).

[0066] According to the water flow velocity, the water flow rate during the test cycle can be obtained by the following formula:

[0067]

[0068] Among them, Q is the required water flow; D is the diameter of the measurement pipe; T is the duration of the measurement cycle.

[0069] Through this method, the influence of the propagation speed of ultrasonic waves in water on the results can be ignored, and the amount of water flowing through the measuring pipe can be accurately calculated.

[0070] In one implementation, the trigger threshold is a voltage value that is significantly greater than the noise signal and within the amplitude range of the ultrasonic signal. The trigger threshold can be used to determine whether the ultrasonic signal is received. In addition, when not interfered by noise, the relative position of the first peak (called the characteristic peak) where the trigger threshold is located and the head wave is fixed, that is, there are a fixed number of peaks between the characteristic peak and the head wave.

[0071] In one implementation, water flow data over a period of time can be stored locally and sent to a cloud server periodically, which can reduce energy consumption.

[0072] In one implementation, the smart water meter can receive water consumption limit information sent by the cloud server and cut off the water flow when the water consumption reaches the limit, thus realizing smart metering and billing.

[0073] In one embodiment, step S102 includes:

[0074] Step 1: When the amplitude of the acoustic wave voltage signal exceeds the trigger threshold for the first time, the timer is triggered and this moment is recorded as the trigger moment.

[0075] Step 2: When the amplitude of the acoustic wave voltage signal after the triggering moment is equal to the zero-crossing threshold, the timer is stopped to obtain the first transmission time.

[0076] Step three: taking the first peak of the acoustic wave voltage signal after the triggering moment as the first effective point.

[0077] Among them, the trigger threshold is greater than the zero-crossing threshold.

[0078] In one implementation, the threshold determination method is relatively simple to implement and can be implemented through programming or hardware circuits at a low cost.

[0079] In one implementation, the zero-crossing threshold may be a zero value. The zero-crossing threshold may also be obtained by obtaining an environmental signal after starting the timer when no ultrasonic signal is received, and calculated by the following formula:

[0080]

[0081] Where ZCT is the zero-crossing threshold; n is the number of samples; ES i is the amplitude of the i-th sampling point. By calculating the zero-crossing threshold by this method, the influence of noise, interference or other non-ideal factors on time estimation can be reduced, making the calculation of transmission time more accurate.

[0082] In one embodiment, step S103 includes:

[0083] Step 1: divide the acoustic wave voltage signal into multiple sub-signal segments according to the positive zero-crossing point.

[0084] Step 2: For each sub-signal segment, extract the energy eigenvalue and frequency eigenvalue of the sub-signal segment, and normalize the energy eigenvalue and the frequency eigenvalue to obtain the target energy eigenvalue and the target frequency eigenvalue.

[0085] Step three, according to the target energy characteristic value and the target frequency characteristic value, the probability that the sub-signal segment belongs to the ultrasonic wave is calculated, and the sub-signal segment with a probability greater than a preset threshold is determined as an ultrasonic wave signal segment.

[0086] Step 4: Use the first sampling point of the first ultrasonic signal segment as the oscillation reference point.

[0087] The positive zero crossing point refers to the point where the amplitude of the acoustic wave voltage signal changes from negative to positive.

[0088] In one implementation, the ultrasonic signal is composed of a series of sinusoidal signals, which are different from the noise signal in terms of frequency and energy. The ultrasonic signal and the noise signal can be distinguished by energy and frequency.

[0089] In one implementation, the normalized calculation results of the frequency eigenvalue and energy eigenvalue of the ultrasonic signal tend to 1, and the normalized calculation results of the frequency eigenvalue and energy eigenvalue of the noise signal are far away from 1. The product of the normalized target energy eigenvalue and the target frequency eigenvalue can be used as the probability value. In this way, the probability calculation result of the ultrasonic signal segment tends to 1, and the probability calculation result of the noise signal is far away from 1. The lower limit value of the ultrasonic signal and the upper limit value of the noise signal can be determined through experimental data, and the average of the lower limit value and the upper limit value can be used as the preset threshold. The starting reference point can be found through the preset threshold.

[0090] In one embodiment, step S104 includes:

[0091] Step 1: Starting from the first valid point, jump forward the preset number of waves to obtain the actual measured peak of the first wave.

[0092] Step 2: If the measured peak of the head wave is the first peak after the oscillation reference point, the first transmission time is determined to be valid; otherwise, the first transmission time is determined to be invalid.

[0093] In one implementation, by jumping forward a preset number of waves to find the measured peak of the head wave and comparing it with the reference point of the start of oscillation, it can be ensured that the calculation of the transmission time is based on the correct starting point of the ultrasonic signal. This strategy can eliminate misjudgments caused by noise or other interference signals, thereby improving the accuracy of transmission time judgment.

[0094] In one implementation, if the proportion of effective time is lower than a preset ratio, the water meter is judged to be faulty and an alarm message is sent to the management platform, which helps to detect water meter abnormalities in a timely manner.

[0095] In one embodiment, each sub-signal segment includes multiple sampling points; the energy characteristic value of each sub-signal segment is the root mean square value of the amplitude of the sampling points of the sub-signal segment; and the frequency characteristic value of each sub-signal segment is the number of sampling points of the sub-signal segment.

[0096] In one implementation, the higher the frequency of a signal segment, the fewer the number of sampling points in the segment; the greater the energy of the signal segment, the higher the amplitude of the sampling points. Reflecting the characteristics of the signal segment based on the number and amplitude of the sampling points can improve calculation efficiency.

[0097] The embodiment of the present invention provides a metering data monitoring device for a water meter. Figure 2 , Figure 2 The present invention provides an architecture diagram of a metering data monitoring device for a water meter. The device includes:

[0098] The ultrasonic transmitting module is used to start the timer and transmit the target ultrasonic wave along the preset direction in each ultrasonic transmitting and receiving cycle.

[0099] The primary receiving module is used to receive the sound wave voltage signal after the target ultrasonic wave crosses the water flow, obtain the first transmission time according to the trigger threshold and determine the first effective point.

[0100] The reference point determination module is used to divide the acoustic wave voltage signal into multiple sub-signal segments, and classify the multiple sub-signal segments to obtain the oscillation reference point position.

[0101] The information validity judgment module is used to judge whether the first transmission time is valid according to the oscillation reference point and the first valid point.

[0102] The transmission time determination module is used to obtain a target downstream transmission time and a target upstream transmission time according to a plurality of valid first transmission times in each measurement cycle.

[0103] The flow calculation module is used to calculate the water flow within the measurement period according to the target downstream transmission time and the target upstream transmission time, and send the water flow data to the cloud server.

[0104] The first transmission time includes a downstream transmission time and a upstream transmission time; and each measurement cycle includes a plurality of ultrasonic transmission and reception cycles.

[0105] A metering data monitoring device for a water meter provided by an embodiment of the present invention can detect whether a wave jumping phenomenon occurs when measuring the transmission time by calculating the starting reference point and the first effective point, thereby characterizing the degree of influence of environmental noise on the measurement of ultrasonic transmission time, and thus the effectiveness of the ultrasonic transmission time can be judged; the water flow rate is calculated according to the effective transmission time, which improves the credibility of the calculated data and ensures the accuracy of the metering data of the water meter.

[0106] In one embodiment, the primary receiving module includes:

[0107] The trigger determination module is used to trigger the timer when the amplitude of the acoustic wave voltage signal exceeds the trigger threshold for the first time, and record this moment as the trigger moment.

[0108] The first transmission time determination module is used to stop the timer when the amplitude of the acoustic wave voltage signal after the triggering moment is equal to the zero-crossing threshold, and obtain the first transmission time; the triggering threshold is greater than the zero-crossing threshold.

[0109] The first effective point determination module is used to take the first peak of the acoustic wave voltage signal after the triggering moment as the first effective point.

[0110] In one embodiment, the reference point determination module includes:

[0111] The signal division module is used to divide the acoustic wave voltage signal into multiple sub-signal segments according to the positive zero-crossing point.

[0112] The feature extraction module is used to extract the energy feature value and frequency feature value of each sub-signal segment.

[0113] The normalization module is used to normalize the energy characteristic value and the frequency characteristic value of the sub-signal segment respectively to obtain a target energy characteristic value and a target frequency characteristic value.

[0114] The ultrasonic probability calculation module is used to calculate the probability that the sub-signal segment belongs to the ultrasonic wave according to the target energy and the target frequency.

[0115] The vibration starting reference point determination module is used to take the first sampling point of the sub-signal segment whose probability of belonging to the ultrasonic wave jumps to above a preset threshold as the vibration starting reference point.

[0116] The positive zero crossing point refers to the point where the amplitude of the acoustic wave voltage signal changes from negative to positive.

[0117] In one embodiment, the transmission time determination module includes:

[0118] The head wave calculation module is used to jump forward a preset number of waves from the first effective point to obtain the actual measured peak of the head wave.

[0119] The time validity judgment module is used to judge that the first transmission time is valid if the measured peak of the head wave is the first peak after the oscillation reference point; otherwise, the first transmission time is invalid.

[0120] In one embodiment, each sub-signal segment includes multiple sampling points; each sub-signal segment includes multiple sampling points; the energy characteristic value of each sub-signal segment is the root mean square value of the amplitude of the sampling points of the sub-signal segment; and the frequency characteristic value of each sub-signal segment is the number of sampling points of the sub-signal segment.

[0121] The above is a detailed description of an embodiment of the present invention, but the content is only a preferred embodiment of the present invention and cannot be considered to limit the scope of implementation of the present invention. All equivalent changes and improvements made within the scope of the present invention should still fall within the scope of the patent coverage of the present invention.

Claims

1. A method for monitoring metering data of a water meter, characterized in that: The method comprises: In each ultrasonic transmission and reception cycle, a timer is started and a target ultrasonic wave is transmitted in a preset direction; Receiving the acoustic voltage signal after the target ultrasonic wave crosses the water flow, obtaining a first transmission time according to a trigger threshold and determining a first effective point; the first transmission time includes a downstream transmission time and an upstream transmission time; Dividing the acoustic wave voltage signal into a plurality of sub-signal segments, and classifying the plurality of sub-signal segments to obtain a starting reference point; Determining whether the first transmission time is valid according to the oscillation reference point and the first valid point; In each measurement cycle, a target downstream transmission time and a target upstream transmission time are obtained according to a plurality of valid first transmission times; each measurement cycle includes a plurality of ultrasonic transmission and reception cycles; The water flow rate within the measurement period is calculated according to the target downstream transmission time and the target upstream transmission time, and the water flow rate data is sent to the cloud server.

2. A method for monitoring metering data of a water meter according to claim 1, characterized in that: The obtaining of the first transmission time according to the trigger threshold and determining the first valid point position comprises: When the amplitude of the acoustic wave voltage signal exceeds the trigger threshold for the first time, the timer is triggered, and this moment is recorded as the trigger moment; When the amplitude of the acoustic wave voltage signal after the triggering moment is equal to the zero-crossing threshold, the timing of the timer is stopped to obtain a first transmission time; the triggering threshold is greater than the zero-crossing threshold; The first peak of the acoustic wave voltage signal after the triggering moment is taken as the first effective point.

3. A method for monitoring metering data of a water meter according to claim 2, characterized in that: The determining whether the first transmission time is valid according to the oscillation reference point and the first valid point includes: Starting from the first effective point, jump forward by a preset number of waves to obtain the measured peak of the first wave; If the measured peak of the head wave is the first peak after the oscillation reference point, the first transmission time is determined to be valid; otherwise, the first transmission time is determined to be invalid.

4. A method for monitoring metering data of a water meter according to claim 1, characterized in that: The step of dividing the acoustic wave voltage signal into a plurality of sub-signal segments and classifying the plurality of sub-signal segments to obtain the oscillation reference point comprises: According to the positive zero-crossing point, the acoustic wave voltage signal is divided into a plurality of sub-signal segments; the positive zero-crossing point refers to the point where the amplitude of the acoustic wave voltage signal changes from negative to positive; For each sub-signal segment, extract the energy characteristic value and the frequency characteristic value of the sub-signal segment, and normalize the energy characteristic value and the frequency characteristic value respectively to obtain the target energy characteristic value and the target frequency characteristic value; According to the target energy characteristic value and the target frequency characteristic value, the probability that the sub-signal segment belongs to the ultrasonic wave is calculated, and the sub-signal segment with a probability greater than a preset threshold is determined as an ultrasonic wave signal segment; The first sampling point of the first ultrasonic signal segment is used as the starting reference point.

5. A method for monitoring metering data of a water meter according to claim 4, characterized in that: Each sub-signal segment includes multiple sampling points; the energy characteristic value of each sub-signal segment is the root mean square value of the amplitude of the sampling points of the sub-signal segment; and the frequency characteristic value of each sub-signal segment is the number of sampling points of the sub-signal segment.

6. A metering data monitoring device for a water meter, characterized in that: The device comprises: The ultrasonic wave transmitting module is used to start the timer and transmit the target ultrasonic wave in a preset direction in each ultrasonic wave transmitting and receiving cycle; A primary receiving module is used to receive the acoustic voltage signal of the target ultrasonic wave after it crosses the water flow, obtain a first transmission time according to a trigger threshold, and determine a first effective point; the first transmission time includes a downstream transmission time and an upstream transmission time; A reference point determination module, used for dividing the acoustic wave voltage signal into a plurality of sub-signal segments, and classifying the plurality of sub-signal segments to obtain a starting reference point position; An information validity judgment module, used for judging whether the first transmission time is valid according to the oscillation reference point and the first valid point; A transmission time determination module, used to obtain a target downstream transmission time and a target upstream transmission time according to a plurality of valid first transmission times in each measurement cycle; each measurement cycle includes a plurality of ultrasonic transmission and reception cycles; The flow calculation module is used to calculate the water flow within the measurement period according to the target downstream transmission time and the target upstream transmission time, and send the water flow data to the cloud server.

7. A metering data monitoring device for a water meter according to claim 6, characterized in that: The primary receiving module comprises: A trigger determination module, configured to trigger the timer when the amplitude of the acoustic wave voltage signal exceeds the trigger threshold for the first time, and record this moment as the trigger moment; A first transmission time determination module, configured to stop the timing of the timer and obtain a first transmission time when the amplitude of the acoustic wave voltage signal after the triggering moment is equal to a zero-crossing threshold; the triggering threshold is greater than the zero-crossing threshold; The first effective point determination module is used to take the first peak of the acoustic wave voltage signal after the triggering moment as the first effective point.

8. A metering data monitoring device for a water meter according to claim 7, characterized in that: The transmission time determination module comprises: A head wave calculation module is used to jump forward a preset number of waves from the first effective point to obtain a head wave measured peak; The time validity judgment module is used to determine that the first transmission time is valid if the measured peak of the head wave is the first peak after the oscillation reference point; otherwise, determine that the first transmission time is invalid.

9. A metering data monitoring device for a water meter according to claim 6, characterized in that: The reference point determination module comprises: A signal division module, used for dividing the acoustic wave voltage signal into a plurality of sub-signal segments according to a positive zero-crossing point; the positive zero-crossing point refers to a point where the amplitude of the acoustic wave voltage signal changes from negative to positive; A feature extraction module, used for extracting the energy feature value and the frequency feature value of each sub-signal segment; A normalization module, used to normalize the energy characteristic value and the frequency characteristic value of the sub-signal segment respectively to obtain a target energy characteristic value and a target frequency characteristic value; An ultrasonic probability calculation module, used to calculate the probability that the sub-signal segment belongs to an ultrasonic wave according to the target energy and the target frequency; The vibration starting reference point determination module is used to take the first sampling point of the sub-signal segment whose probability of belonging to the ultrasonic wave jumps to above a preset threshold as the vibration starting reference point.

10. A metering data monitoring device for a water meter according to claim 9, characterized in that: Each sub-signal segment includes multiple sampling points; each sub-signal segment includes multiple sampling points; the energy characteristic value of each sub-signal segment is the root mean square value of the amplitude of the sampling points of the sub-signal segment; the frequency characteristic value of each sub-signal segment is the number of sampling points of the sub-signal segment.

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