Ultrasonic gas meter and anomaly detection method thereof

Abstract

The invention provides an anomaly detection method of an ultrasonic gas meter and the ultrasonic gas meter, and relates to the technical field of flow monitoring. The invention provides a more accurate and timely anomaly detection method aiming at the problem that an existing detection method for judging whether an instrument is abnormal or not only by judging flight time of an ultrasonic gas meter is not timely and accurate enough in anomaly response. The method comprises the following steps: exciting a first transducer according to a preset frequency to enable the first transducer to emit an ultrasonic signal; the second transducer receives the ultrasonic signal transmitted by the first transducer and generates an echo signal waveform; and waveform features are extracted from the echo signal waveforms, and if the waveform features do not conform to a preset rule, it is judged that detection of the ultrasonic gas meter is abnormal. In addition, according to different identification results, different processing modes are adopted, the anti-interference capability of the instrument is improved, and the abnormal detection of the instrument is more accurate.

Description

Technical Field

[0001] This application relates to the technical field of flow monitoring, and particularly to an ultrasonic gas meter and an abnormal detection method thereof. Background Art

[0002] Ultrasonic gas meters usually calculate the flow rate using the time difference method. A pair of transducers receive the ultrasonic signals emitted by each other and record the received time, which is called the time of flight (TOF). When there is fluid flowing through the flow channel, the reception times required for the downstream and upstream flows are different. Using this time difference and combining with the flow channel structure parameters, the current instantaneous flow rate can be calculated.

[0003] Since the actual environment where the ultrasonic gas meter is located is relatively complex, it is very likely to be interfered by other devices during use, or the pipeline is not clean, and pollutants or water may enter the gas meter. In this regard, in related technologies, generally, the internal environment of the current meter is judged by identifying the time of flight. If the time of flight exceeds the preset range, the meter is regarded as abnormal.

[0004] However, in actual applications, the composition of natural gas is complex, the sound velocities in different gases vary greatly, and the sound velocity is also affected by temperature and pressure. Therefore, using the time of flight as the judgment standard for meter abnormalities is relatively rough, and the response to abnormalities is not timely enough. Summary of the Invention

[0005] The purpose of this application is to provide an abnormal detection method for an ultrasonic gas meter to solve the problems in related technologies that the detection means for abnormalities of ultrasonic gas meters are rough and the response to abnormalities is not timely enough.

[0006] An abnormal detection method for an ultrasonic gas meter, the ultrasonic gas meter includes a first transducer and a second transducer, and is characterized in that the method includes the following steps:

[0007] Excite the first transducer according to a preset frequency so that the first transducer emits an ultrasonic signal;

[0008] The second transducer receives the ultrasonic signal emitted by the first transducer and generates an echo signal waveform;

[0009] Extract waveform features from the echo signal waveform. If the waveform features do not conform to the preset rules, it is judged that the ultrasonic gas meter detects an abnormality.

[0010] Further, the waveform features include a slope feature and the pulse width of the echo signal. In response to judging that the slope feature is abnormal and the pulse width is abnormal, it is judged that the ultrasonic gas meter detects an abnormality;

[0011] Judging whether the slope feature is abnormal includes the following steps:

[0012] Take the amplitude point of the echo signal as a feature point;

[0013] Set at least one feature level, take the intersection point where each feature level first intersects with the echo signal as a feature point, and take the intersection point where the feature level last intersects with the echo signal as a feature point;

[0014] Connect adjacent feature points to obtain feature line segments;

[0015] Calculate the slope of each feature line segment. If the slope of any feature line segment exceeds the preset slope range, it is determined that the slope feature is abnormal;

[0016] Judging whether the pulse width is abnormal includes the following steps: Extract the pulse widths of the echo signals for a preset number of times from the echo signal waveform. If the pulse width exceeds the preset width range, it is determined that the pulse width detection is abnormal.

[0017] The number of set feature levels is one. Take the amplitude point of the echo signal as the first feature point, take the intersection point where the feature level first intersects with the echo signal as the second feature point, and take the intersection point where the feature level last intersects with the echo signal as the third feature point;

[0018] The method further includes calculating the absolute value of the slope of the first feature line segment to obtain the first absolute slope value, and calculating the absolute value of the slope of the second feature line segment to obtain the second absolute slope value;

[0019] Calculate the difference between the first absolute slope value and the second absolute slope value. If the difference exceeds the preset difference range, it is determined that the slope feature is abnormal.

[0020] Further, in response to determining that the slope feature is abnormal and the pulse width is within the preset width range, determine whether the change in the flight time of the ultrasonic signal exceeds the preset time range. If so, it is determined that the ultrasonic gas meter detection is abnormal.

[0021] Further, the method further includes: In response to determining that the change in the flight time of the ultrasonic signal does not exceed the preset time range, mark the ultrasonic gas meter and re - perform the abnormality detection. If the number of marks of the ultrasonic gas meter within the preset time is greater than the preset mark threshold, it is determined that the ultrasonic gas meter detection is abnormal.

[0022] Further, in response to determining that the slope feature is normal and the pulse width is abnormal, perform filtering processing on the echo signal.

[0023] Further, the method includes extracting the amplitude features of the echo signals with a preset quantity from the echo signal waveform, judging the oscillation condition of the echo signal based on the amplitude features. If the oscillation condition of the echo signal exceeds the preset range, perform abnormality detection on the ultrasonic gas meter.

[0024] An ultrasonic gas meter is applied to gas flow monitoring and includes a metering module. The metering module is arranged in a pipeline to be measured. The metering module includes a first transducer and a second transducer. The first transducer and the second transducer are arranged along the axial direction of the pipeline to be measured and send ultrasonic waves to each other.

[0025] Further, the ultrasonic gas meter further includes a control module and a processing module. The control module excites the first transducer according to a preset frequency to make the first transducer emit an ultrasonic signal. The second transducer receives the ultrasonic signal emitted by the first transducer and generates an echo signal waveform. The processing module extracts waveform features from the echo signal waveform and determines whether the waveform features conform to a preset rule. If the waveform features do not conform to the preset rule, it is determined that the detection of the ultrasonic gas meter is abnormal.

[0026] Further, the waveform features include a slope feature and the pulse width of the echo signal. The processing module determines that the detection of the ultrasonic gas meter is abnormal in response to determining that the slope feature is abnormal and the pulse width is abnormal.

[0027] Determining whether the slope feature is abnormal includes the following steps:

[0028] Taking the amplitude points of the echo signal as feature points;

[0029] Setting at least one feature level, taking the intersection point of each feature level and the echo signal for the first time as a feature point, and taking the intersection point of the feature level and the echo signal for the last time as a feature point;

[0030] Connecting adjacent feature points to obtain feature line segments;

[0031] Calculating the slope of each feature line segment. If the slope of any feature line segment exceeds the preset slope range, it is determined that the slope feature is abnormal;

[0032] Determining whether the pulse width is abnormal includes the following steps: Extracting the pulse width of the echo signal from the echo signal waveform. If the pulse width exceeds the preset width range, it is determined that the detection of the pulse width is abnormal.

[0033] Further, the processing module determines whether the change in the flight time of the ultrasonic signal exceeds the preset time range in response to determining that the slope feature is abnormal and the pulse width is within the preset width range. If so, it is determined that the detection of the ultrasonic gas meter is abnormal.

[0034] The ultrasonic gas meter anomaly detection method provided by this application excites the first transducer at a preset frequency to make the first transducer emit ultrasonic signals; the second transducer receives the ultrasonic signals emitted by the first transducer and generates an echo signal waveform; waveform features are extracted from the echo signal waveform. If the waveform features do not conform to the preset rules, it is determined that the ultrasonic gas meter detection is abnormal. This method adopts different processing methods according to different recognition results, improves the anti-interference ability of the instrument, and makes the instrument anomaly detection more accurate. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 It is a flowchart of the anomaly detection method for the ultrasonic gas meter provided by an embodiment of this application.

[0036] Figure 2 It is a detailed sub-flowchart of the anomaly detection method for the ultrasonic gas meter provided by an embodiment of this application.

[0037] Figure 3 It is a flowchart for detecting anomalies in the slope characteristics of the echo signal waveform of the ultrasonic gas meter provided by an embodiment of this application.

[0038] Figure 4 It is a waveform diagram of the wave signal when setting a characteristic level during the slope detection of the ultrasonic gas meter provided by an embodiment of this application.

[0039] Figure 5 It is a waveform diagram of the wave signal when setting two characteristic levels during the slope detection of the ultrasonic gas meter provided by an embodiment of this application.

[0040] Figure 6 It is a flowchart for detecting anomalies in the pulse width characteristics of the echo signal of the ultrasonic gas meter provided by an embodiment of this application.

[0041] Figure 7 It is a schematic structural diagram of the ultrasonic gas meter provided by an embodiment of this application. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0042] The following will describe this application in detail in conjunction with the specific embodiments shown in the drawings, but these embodiments do not limit this application. Structural, method, or functional transformations made by those of ordinary skill in the art based on these embodiments are all included within the protection scope of this application.

[0043] An anomaly detection method for an ultrasonic gas meter, the ultrasonic gas meter includes a first transducer and a second transducer, as Figure 1 、 Figure 2 shown, the anomaly detection method for the ultrasonic gas meter includes the following steps:

[0044] Step S1, obtain an echo signal and generate an echo signal waveform.

[0045] Step S2: Extract the waveform features of the echo signal and perform anomaly detection on the waveform features of the echo signal.

[0046] Step S3: Determine whether the waveform features conform to the preset rules and judge whether the ultrasonic gas meter is abnormal.

[0047] In step S2, the anomaly detection of the waveform features of the echo signal includes the slope feature anomaly detection S21 and the pulse width feature anomaly detection S22.

[0048] Step S21: Perform anomaly detection on the slope features of the echo signal.

[0049] Step S22: Perform anomaly detection on the pulse width features of the echo signal.

[0050] Based on the judgment results of the slope feature anomaly detection in step S21 and the pulse width feature anomaly detection in step S22, perform meter anomaly judgment and step jump.

[0051] If it is judged that the slope feature is normal and the pulse width is abnormal, it means that the echo signal may be interfered, and jump to step S31 to perform filtering processing;

[0052] If it is judged that the slope feature is abnormal and the pulse width is normal, further detection is required, and jump to step S32 to perform anomaly detection on the flight time of the echo signal.

[0053] If the slope feature is abnormal and the pulse width is abnormal, it means that the meter is abnormal, and jump to step S36 to feedback the anomaly.

[0054] If the slope feature is normal and the pulse width is normal, it means that the meter is normal, and jump to step S37.

[0055] In step S3, the following steps are included:

[0056] Step S31: Perform filtering processing, and the meter anomaly detection ends.

[0057] Step S32: Perform anomaly detection on the flight time of the echo signal.

[0058] For the detection result of step S32: If the flight time is abnormal, judge that the meter is abnormal and jump to step S36. If the flight time is normal, continue the detection and execute step S33.

[0059] Step S33: Mark the number of times and mark the number of times of the above situation.

[0060] Step S34: Judge whether the number of times recorded within the preset time is greater than the preset number threshold.

[0061] For the judgment result of step S34, if it is greater, it means the instrument has an abnormality, and jump to step S36. If it is less, jump to step S35 to reset the marking times.

[0062] In step S35, when the marking times are reset, it means the instrument has no abnormality, and jump to step S37.

[0063] In step S36, feedback that the instrument detects an abnormality, and the instrument abnormality detection ends.

[0064] In step S37, feedback that the instrument detects no abnormality, and the instrument abnormality detection ends.

[0065] First, execute step S1 to obtain an echo signal and generate an echo signal waveform.

[0066] For the convenience of description, in the embodiments of the present application, the first transducer is defined as the one that transmits ultrasonic signals, and the second transducer is defined as the one that receives ultrasonic signals. The first transducer is excited at a preset frequency so that the first transducer emits ultrasonic signals, and the second transducer receives the ultrasonic signals emitted by the first transducer to generate an echo signal waveform.

[0067] After obtaining the echo signal waveform, execute step S2 to extract waveform features from the echo signal waveform and perform abnormality detection on the waveform features of the echo signal.

[0068] Specifically, the preset rule refers to the change rule of the waveform features of the echo signal when ultrasonic waves normally propagate in the metering medium in the pipeline to be measured. The propagation of ultrasonic waves will be affected by the environment, such as when there are high-power electrical appliances used around the instrument or the instrument gets contaminated. When the propagation of ultrasonic waves is affected, the waveform features of the generated echo signal will also change accordingly. At this time, the changed waveform features of the echo signal can be analyzed, and the analysis result is compared with the waveform features of the ultrasonic waves when they normally propagate in the metering medium. If it does not conform to the waveform features under normal conditions, that is, it does not conform to the preset rule, it can be determined that the instrument detection is abnormal.

[0069] After that, execute step S3 to determine whether the waveform features conform to the preset rule and determine whether the ultrasonic gas meter is abnormal.

[0070] As an optional implementation manner, in step S2, the waveform feature abnormality detection includes slope feature abnormality detection S21 and pulse width feature abnormality detection S22.

[0071] As Figure 3 shown, the slope feature abnormality detection S21 includes the following steps:

[0072] In step S211, take the amplitude points of the echo signal as a feature point.

[0073] Step S212: Set at least one characteristic level, take the intersection point where each characteristic level first intersects with the echo signal as a characteristic point, and take the intersection point where each characteristic level last intersects with the echo signal as another characteristic point.

[0074] Step S213: Connect adjacent characteristic points to obtain characteristic line segments;

[0075] Step S214: Calculate the slope of each characteristic line segment. If the slope of any characteristic line segment exceeds the preset slope range, it indicates that the slope characteristic is abnormal.

[0076] In step S212, the characteristic level can be set according to the actual situation. The value of the characteristic level is greater than zero and less than the amplitude. Generally, the characteristic level can be a value near the symmetry axis of the echo signal. When the echo signal first intersects with this level, it can be regarded that the second transducer receives the echo signal.

[0077] In step S213, adjacent characteristic points refer to two adjacent characteristic points along the time axis direction.

[0078] In step S214, the preset slope range includes the preset slope range of the rising waveform and the preset slope range of the falling waveform, which can be specifically set according to the actual situation. For example, it can be set according to the slope fluctuation range of the characteristic line segment of the rising waveform and the slope fluctuation range of the characteristic line segment of the falling waveform of the echo signal when ultrasonic waves propagate normally in the metering medium in the pipeline to be measured. When the instrument is in the normal working state, the slopes of the rising waveform and the falling waveform of the echo signal change and fluctuate within a certain range. When the slope of the characteristic line segment of the rising waveform or the slope of the characteristic line segment of the falling waveform of the acquired echo signal exceeds the corresponding preset slope range respectively, it can be regarded that the slope characteristic is abnormal.

[0079] In the slope characteristic anomaly detection step S214, if the difference between the absolute value of the rising waveform characteristic line segment and the absolute value of the falling waveform characteristic line segment exceeds the preset difference range, it can also indicate that the slope characteristic is abnormal.

[0080] Specifically, the preset difference range is set to be between zero and the maximum deviation between the absolute value of the slope of the rising waveform of the characteristic line segment of the echo signal and the absolute value of the slope of the falling waveform when ultrasonic waves propagate normally in the metering medium in the pipeline to be measured.

[0081] For the slope characteristic anomaly detection, as an optional implementation manner, the number of set characteristic levels is one. Take the amplitude point of the echo signal as the first characteristic point, take the intersection point where the characteristic level first intersects with the echo signal as the second characteristic point, and take the intersection point where the characteristic level last intersects with the echo signal as the third characteristic point.

[0082] The first feature point is connected to the second feature point to obtain a first feature line segment, and the first feature point is connected to the third feature point to obtain a second feature line segment.

[0083] Calculate the absolute value of the slope of the first feature line segment to obtain a first absolute slope value, calculate the absolute value of the slope of the second feature line segment to obtain a second absolute slope value. Calculate the difference between the first absolute slope value and the second absolute slope value.

[0084] Specifically, as Figure 4 shown, in a received ultrasonic echo signal graph, the amplitude point B of the echo signal is the first feature point, the characteristic level is Vstart, the first intersection point A of the characteristic level and the echo signal is the second feature point, and the last intersection point C is the third feature point. Connect AB and BC respectively to obtain a first feature line segment AB and a second feature line segment BC. The first feature line segment AB represents the rising waveform, and the second feature line segment BC represents the falling waveform. At this time, the slope K of the first feature line segment AB can be obtained AB , and the slope K of the second feature line segment BC BC . Then substitute into the following formula:

[0085] k 上升min ≤|k AB |≤k 上升max

[0086] k 下降min ≤|k BC |≤k 下降max

[0087] 0≤||k AB |-|k BC ||≤Δk max

[0088] In the above three formulas, k 上升min to k 上升max represent the preset slope range of the rising waveform, k 下降min to k 下降max represent the preset slope range of the falling waveform, and Δk max represents the maximum deviation between the slope of the rising waveform and the slope of the falling waveform.

[0089] If one of the above three formulas is not satisfied, it is considered that the slope feature of this echo signal is abnormal. Otherwise, it is judged that the slope feature of the echo signal is normal.

[0090] For the slope feature anomaly detection, as another alternative implementation, set more than one characteristic level, such as Figure 5, two characteristic levels are set, and the amplitude points of the echo signal, the intersection points where each characteristic level first intersects with the echo signal, and the intersection points where each characteristic level last intersects with the echo signal are used as characteristic points. Adjacent characteristic points are connected in sequence along the time axis direction to obtain characteristic line segments. Calculate the slope of each characteristic line segment and substitute it into the formula to obtain the inequality:

[0091] k 上升min ≤|k AB |≤k 上升max

[0092] k 下降min ≤|k DE |≤k 下降max

[0093] 0≤||k AB |-|k DE ||≤Δk max

[0094] k 上升min ≤|k BC |≤k 上升max

[0095] k 下降min ≤|k CD |≤k 下降max

[0096] 0≤||k BC |-|k CD ||≤Δk max

[0097] If any one of the inequalities does not hold, it is considered that the slope characteristic of this echo signal is abnormal. Otherwise, it is judged that the slope characteristic of the echo signal is normal.

[0098] As Figure 6 shown, the pulse width anomaly detection S22 includes the following steps:

[0099] Step S221: Extract the pulse widths of the echo signals for a preset number of times in the echo signal waveform.

[0100] Step S222: Judge whether the pulse width exceeds the preset width range. If any one of the pulse widths exceeds the preset pulse width range, it means that the pulse width detection is abnormal.

[0101] In step S221, the preset number of times is set according to the actual situation. If higher measurement accuracy is required, the preset number of times can be increased; if faster processing speed is required, the preset number of times can be reduced.

[0102] In step S222, the preset width range of the pulse width can be set according to the actual situation. For example, it can be set according to the pulse width change fluctuation range of the echo signal generated when the ultrasonic wave propagates normally in the measurement medium in the pipeline to be measured. When the instrument is in the normal working state, since the transducer is triggered at a fixed frequency, the pulse width period of the echo signal should also be within a certain range. If the pulse width of the acquired echo signal exceeds this range, it can be regarded as an abnormality in the pulse width of the waveform feature. Otherwise, it indicates that the pulse width of the echo signal is normal.

[0103] As an optional implementation manner, if the judgment results of steps S21 and S22 are that the slope feature is abnormal and the pulse width is abnormal, it can be judged that the ultrasonic gas meter detection is abnormal, and jump to step S36.

[0104] As an optional implementation manner, if the judgment results of steps S21 and S22 are that the slope feature is normal and the pulse width is abnormal, it indicates that the echo signal is interfered, and jump to step S31 to perform filtering processing on the echo signal.

[0105] Specifically, when the slope feature is normal and the pulse width is abnormal, it indicates that there is noise or interference in the transmission process of the echo signal, and filtering processing is required to reduce the impact on the instrument measurement. The filtering measures include but are not limited to methods such as median filtering and eliminating overly abnormal data. Through the filtering processing operation, the fluctuation of the signal can be smoothed, the influence of noise and interference can be reduced, and the stability and accuracy of the echo signal can be improved.

[0106] As an optional implementation manner, if the judgment results of steps S21 and S22 are that the slope feature is abnormal but the pulse width is normal, then jump to step S32 to judge whether the flight time of the ultrasonic signal is abnormal.

[0107] Specifically, in step S32, judging whether the flight time of the ultrasonic signal is abnormal means judging whether the flight time of the ultrasonic signal exceeds the preset time range. The preset time range is set according to the actual situation. For example, it can be set according to the flight time when the flow rate of the measurement medium in the pipeline to be measured is the fastest and the flight time when the flow rate is the slowest. Judge whether the acquired flight time of the ultrasonic wave is within this preset time range. If so, it indicates that the flight time is normal, otherwise, it indicates that the flight time is abnormal.

[0108] As an optional implementation manner, if step S32 judges that the flight time is abnormal, it means that the medium flow in the pipeline is abnormal, and the propagation speed of the ultrasonic wave in the pipeline has changed greatly. At this time, it can be judged that the instrument detection is abnormal, and execute step S36.

[0109] As an alternative implementation, if it is determined in step S32 that the flight time is normal, step S5 is executed to mark the meter. Then step S34 is executed to determine whether the number of marks of the ultrasonic gas meter within the preset time is greater than the preset mark threshold. If so, it can be determined that the ultrasonic gas meter is detected abnormally, and the process jumps to step S36; if not, step S35 is executed to reset the number of marks and wait for the next detection.

[0110] Specifically, marking the meter means recording the number of times when the slope feature is abnormal, the pulse width is normal, but the change in flight time does not exceed the preset time range. The preset time and the preset mark threshold can be set according to actual needs. When the recorded number exceeds the preset mark threshold within the preset time, even if the change in flight time does not exceed the preset time range, it can be determined that the flow measurement detection of the meter is abnormal. In this way, it is possible to solve the abnormal situation where in the actual situation, the flight time and pulse width characteristics of the echo signal have no obvious difference from those when the meter is working normally, but the slope characteristics are significantly different. For example, this situation may occur when foreign objects adhere to the flow channel of the meter. At this time, by marking and monitoring the meter, the abnormalities existing in the meter can be detected in time to ensure the accuracy and reliability of the meter.

[0111] As an alternative implementation, before performing abnormal detection on the waveform characteristics of the echo signal, abnormal detection on the amplitude characteristics of the echo signal can also be performed first. The abnormal detection of the amplitude characteristics includes the following steps: extracting the amplitude characteristics of a preset number of echo signals from the echo signal waveform, judging the oscillation situation of the echo signal based on the amplitude characteristics, and if the oscillation situation of the echo signal exceeds the preset range, performing abnormal detection on the meter.

[0112] Specifically, extract the amplitudes of a preset number of echo signals from the echo signal waveform. The preset number is set according to actual needs, aiming to ensure that sufficient and effective information is obtained to meet specific detection requirements. Perform statistical analysis based on the extracted amplitudes, such as calculating the amplitude standard deviation or range, to obtain the amplitude characteristics of the echo signal, and quantitatively evaluate the stability of the signal with the amplitude characteristics to judge the oscillation situation of the echo signal. The preset range is set according to the actual situation. For example, it can be set based on the minimum and maximum values of the signal amplitude of the echo signal when ultrasonic waves propagate normally in the measurement medium in the pipeline to be measured. When the meter is affected, the signal amplitude of the echo signal oscillates greatly. The oscillation situation of the echo signal can be judged through the amplitude characteristics of the echo signal. If the oscillation situation of the echo signal exceeds the preset range, it means that the meter may be abnormal at this time, and the next abnormal detection operation can be continued; otherwise, wait for the next amplitude detection.

[0113] By adding an abnormal detection step for amplitude characteristics before detecting abnormalities in the waveform characteristics of the echo signal, echo signals that may be abnormal are screened out, so as to specifically detect waveform characteristic abnormalities, avoid unnecessary detection of normal signals, and reduce the power consumption of the instrument.

[0114] The abnormal detection method provided by the embodiments of the present application analyzes the waveform characteristics of the echo signal, where the waveform characteristics include slope characteristics and pulse width characteristics, and together with the abnormal detection of the flight time of the echo signal and the amplitude characteristic detection, it can more accurately determine whether the current instrument is abnormal, and can provide different processing methods according to different results, improving the anti-interference ability of the instrument.

[0115] As Figure 7 shown, a schematic structural diagram of an ultrasonic gas meter applying the above abnormal detection method, the ultrasonic gas meter includes: a metering module 11, a control module 12, and a processing module 13. The metering module 11 is arranged in the pipeline to be measured, and includes a first transducer 121 and a second transducer 122. The first transducer 121 and the second transducer 122 are arranged along the axial direction of the pipeline to be measured and send ultrasonic waves to each other.

[0116] The control module 12 excites the first transducer 121 according to a preset frequency, so that the first transducer 121 emits an ultrasonic wave signal, and the second transducer 122 receives the ultrasonic wave signal emitted by the first transducer 121 to generate an echo signal waveform;

[0117] The processing module 13 extracts waveform characteristics from the echo signal waveform and determines whether the waveform characteristics conform to a preset rule. If the waveform characteristics do not conform to the preset rule, it indicates that the ultrasonic gas meter detects an abnormality.

[0118] Specifically, the preset rule refers to the waveform characteristics when ultrasonic waves propagate normally in the gas in the measurement pipeline. The ultrasonic gas meter will be affected by the use environment, such as when there are high-power electrical appliances used around the instrument or foreign objects enter the instrument. When the above situations occur, the propagation of ultrasonic waves and the sending and receiving of ultrasonic waves by the metering module 11 will be affected, and the waveform characteristics of the echo signal obtained by the processing module 13 will also change. At this time, the waveform characteristics of the changed echo signal can be analyzed and compared with the waveform characteristics when ultrasonic waves propagate normally in the gas in the pipeline. If they do not conform, it can be determined that the ultrasonic gas meter is abnormal.

[0119] According to the above description, the ultrasonic gas meter provided by the embodiment of the present application controls the first transducer 121 and the second transducer 122 in the metering module 11 to receive and transmit ultrasonic signals through the control module 12. The processing module 13 collects the echo signals generated by the metering module and analyzes the waveform characteristics of the echo signals, and compares the analysis results with the waveform characteristics of the normal propagation of ultrasonic waves in the gas in the measurement pipeline, so as to judge whether the instrument is abnormal.

[0120] As an optional implementation manner, the waveform characteristics include slope characteristics and echo signal pulse width characteristics.

[0121] Judging whether the slope characteristics are abnormal includes the following steps:

[0122] Step S211: Take the amplitude points of the echo signal as a feature point.

[0123] Step S212: Set at least one feature level, and take the intersection point where each feature level first intersects with the echo signal as a feature point, and take the intersection point where each feature level last intersects with the echo signal as another feature point.

[0124] Step S213: Connect adjacent feature points to obtain feature line segments;

[0125] Step S214: Calculate the slope of each feature line segment. If the slope of any feature line segment exceeds the preset slope range, it means that the slope characteristics are abnormal.

[0126] In step S212, the feature level can be set according to the actual situation. The value of the feature level is greater than zero and less than the amplitude. Generally, the feature level can be a value near the axis of symmetry of the echo signal. When the echo signal first intersects with this level, it can be regarded as the metering module 11 receiving the echo signal.

[0127] In step S213, adjacent feature points refer to two feature points that are next to each other along the time axis direction.

[0128] In step S214, the preset slope range includes the preset slope range of the rising waveform and the preset slope range of the falling waveform, which can be specifically set according to the actual situation. For example, it can be set according to the slope fluctuation range of the rising waveform feature line segment and the slope fluctuation range of the falling waveform feature line segment of the echo signal when the ultrasonic wave normally propagates in the gas in the pipeline to be measured. When the instrument is in the normal working state, the slope of the rising waveform and the slope of the falling waveform of the echo signal change within a certain range. When the slope of the rising waveform feature line segment or the slope of the falling waveform feature line segment of the obtained echo signal respectively exceeds the corresponding preset slope range, it can be regarded as the slope characteristics being abnormal, otherwise, it can be regarded as the slope characteristics of the echo signal being normal.

[0129] Determining whether the pulse width is abnormal includes the following steps:

[0130] Step S221: Extract the pulse widths of the echo signals for a preset number of times in the waveform of the echo signal.

[0131] Step S222: Determine whether the pulse width exceeds the preset width range. If any one of the pulse widths exceeds the preset pulse width range, it indicates that the pulse width detection is abnormal.

[0132] In step S221, the preset number of times is set according to the actual situation. If higher measurement accuracy is required, the preset number of times can be increased; if faster processing speed is required, the preset number of times can be reduced.

[0133] In step S222, the preset width range of the pulse width can be set according to the actual situation. For example, it can be set according to the variation range of the pulse width of the echo signal generated when the ultrasonic wave propagates normally in the gas in the pipeline to be measured. When the instrument is in the normal working state, since the transducer is triggered at a fixed frequency, the pulse width period of the echo signal should also be within a certain range. If the pulse width of the acquired echo signal exceeds this range, it can be regarded as an abnormality in the pulse width in the waveform characteristics; otherwise, it indicates that the pulse width of the echo signal is normal.

[0134] As an optional implementation manner, when the processing module 13 determines that the slope feature is abnormal and the pulse width is abnormal, it can indicate that the signal feature of the echo signal is abnormal, and it can be determined that the ultrasonic gas meter detection is abnormal;

[0135] As an optional implementation manner, when the processing module 13 determines that the slope feature is abnormal and the pulse width is normal, the processing module 13 determines whether the change in the flight time of the ultrasonic signal exceeds the preset time range. If so, it is determined that the ultrasonic gas meter detection is abnormal.

[0136] Specifically, the preset time range is specifically set according to the actual situation. The preset time range is set according to the actual situation. For example, it can be set according to the flight time when the flow rate of the measurement medium in the pipeline to be measured is the fastest and the flight time when the flow rate is the slowest. Determine whether the acquired flight time of the ultrasonic wave is within this preset time range. If so, it indicates that the flight time is normal; otherwise, it indicates that the flight time is abnormal.

[0137] Specifically, when the processing module 13 determines that the slope feature is abnormal but the pulse width is normal, it further determines whether the change in the flight time of the ultrasonic signal is abnormal. If so, it represents that the medium flow in the pipeline is abnormal and the propagation speed of the ultrasonic wave in the pipeline has changed greatly, and it is determined that the ultrasonic gas meter detection is abnormal.

[0138] As an alternative embodiment, when the processing module 13 determines that the slope feature is abnormal, but the pulse width is normal and the time of flight is normal, the meter is marked, and then it is determined whether the number of marks of the ultrasonic gas meter within the preset time is greater than the preset marking threshold. If so, it can be determined that the ultrasonic gas meter is detected abnormally. If not, the number of marks is reset and waiting for the next detection.

[0139] The ultrasonic gas meter provided by the embodiment of the present application cooperates with each other through the metering module, the control module and the processing module. The control module controls the metering module to receive and send ultrasonic waves, and the processing module obtains and analyzes the waveform characteristics of the echo signal. The waveform characteristics include slope characteristics and pulse width characteristics. Coupled with the abnormal detection of the time of flight of the echo signal, it can more accurately and timely determine whether the current ultrasonic gas meter is abnormal.

[0140] The above-disclosed are only the preferred embodiments of the present application, but they are not intended to limit the scope of the rights of the present application. Those of ordinary skill in the art can understand that: within the spirit and scope of the present application and the appended claims, changes, modifications, substitutions, combinations, and simplifications should all be equivalent replacement methods and still fall within the scope covered by the invention.

Claims

1. An abnormal detection method for an ultrasonic gas meter, the ultrasonic gas meter including a first transducer and a second transducer, characterized in that, The method includes the following steps: Excite the first transducer at a preset frequency so that the first transducer emits an ultrasonic signal; The second transducer receives the ultrasonic signal emitted by the first transducer and generates an echo signal waveform; Extract waveform features from the echo signal waveform. If the waveform features do not conform to the preset rules, it is determined that the ultrasonic gas meter detects an abnormality.

2. The abnormality detection method of the ultrasonic gas meter according to claim 1, wherein The waveform features include a slope feature and an echo signal pulse width. In response to determining that the slope feature is abnormal and the pulse width is abnormal, it is determined that the ultrasonic gas meter detects an abnormality; Determining whether the slope feature is abnormal includes the following steps: Taking the amplitude point of the echo signal as a feature point; Setting at least one feature level, taking the intersection point where each feature level first intersects with the echo signal as a feature point, and taking the intersection point where the feature level last intersects with the echo signal as a feature point; Connect adjacent feature points to obtain a feature line segment; Calculate the slope of each feature line segment. If the slope of any feature line segment exceeds the preset slope range, it is determined that the slope feature is abnormal; Determining whether the pulse width is abnormal includes the following steps: Extract the pulse width of the echo signal from the echo signal waveform. If the pulse width exceeds the preset width range, it is determined that the pulse width detection is abnormal.

3. The abnormality detection method of the ultrasonic gas meter according to claim 2, wherein The number of feature levels set is one. Taking the amplitude point of the echo signal as the first feature point, taking the intersection point where the feature level first intersects with the echo signal as the second feature point, and taking the intersection point where the feature level last intersects with the echo signal as the third feature point; The method further includes calculating the absolute value of the slope of the first feature line segment to obtain a first absolute slope value, and calculating the absolute value of the slope of the second feature line segment to obtain a second absolute slope value; Calculate the difference between the first absolute slope value and the second absolute slope value. If the difference exceeds the preset difference range, it is determined that the slope feature is abnormal.

4. The abnormal detection method of the ultrasonic gas meter according to claim 3, characterized in that The method further includes: In response to determining that the slope feature is abnormal and the pulse width is within the preset width range, determine whether the change in the flight time of the ultrasonic signal exceeds the preset time range. If so, it is determined that the ultrasonic gas meter detects an abnormality.

5. The abnormality detection method of the ultrasonic gas meter according to claim 4, wherein The method further includes: In response to determining that the change in the flight time of the ultrasonic signal does not exceed the preset time range, mark the ultrasonic gas meter and re-perform the abnormality detection. If the number of marks of the ultrasonic gas meter within the preset time is greater than the preset mark threshold, it is determined that the ultrasonic gas meter detects an abnormality.

6. The ultrasonic gas meter according to claim 3, wherein In response to determining that the slope feature is normal and the pulse width is abnormal, filter the echo signal.

7. The abnormal detection method of the ultrasonic gas meter according to claim 2, characterized in that the method includes extracting the amplitude characteristics of a preset number of echo signals from the echo signal waveform, judging the oscillation condition of the echo signal based on the amplitude characteristics, and if the oscillation condition of the echo signal exceeds a preset range, performing abnormal detection on the ultrasonic gas meter.

8. An ultrasonic gas meter, applied to gas flow monitoring, includes a metering module, the metering module is arranged in a pipeline to be measured, the metering module includes a first transducer and a second transducer, the first transducer and the second transducer are arranged along the axial direction of the pipeline to be measured and send ultrasonic waves to each other; Characterized in that, the ultrasonic gas meter further includes: a control module, the control module excites the first transducer according to a preset frequency so that the first transducer emits an ultrasonic signal, and the second transducer receives the ultrasonic signal emitted by the first transducer to generate an echo signal waveform; a processing module, the processing module extracts waveform characteristics from the echo signal waveform and judges whether the waveform characteristics conform to a preset rule, and if the waveform characteristics do not conform to the preset rule, it is judged that the ultrasonic gas meter detects abnormally.

9. The ultrasonic gas meter according to claim 8, characterized in that the waveform characteristics include a slope characteristic and an echo signal pulse width, and the processing module judges that the ultrasonic gas meter detects abnormally in response to judging that the slope characteristic is abnormal and the pulse width is abnormal; judging whether the slope characteristic is abnormal includes the following steps: taking the amplitude points of the echo signal as a feature point; setting at least one characteristic level, taking the intersection point where each characteristic level first intersects with the echo signal as a feature point, and taking the intersection point where the characteristic level last intersects with the echo signal as a feature point; connecting adjacent feature points to obtain a feature line segment; calculating the slope of each feature line segment, and if the slope of any feature line segment exceeds a preset slope range, judging that the slope characteristic is abnormal; judging whether the pulse width is abnormal includes the following steps: extracting the pulse width of the echo signal from the echo signal waveform, and if the pulse width exceeds a preset width range, judging that the pulse width detection is abnormal.

10. The ultrasonic gas meter according to claim 9, characterized in that the processing module judges whether the change in the flight time of the ultrasonic signal exceeds a preset time range in response to judging that the slope characteristic is abnormal and the pulse width is within the preset width range, and if so, judges that the ultrasonic gas meter detects abnormally.

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