A valve control system for a gas meter and a gas meter

Abstract

The application relates to the technical field of valve control and discloses a valve control system for a gas meter and the gas meter, which comprises the following steps: collecting a metering pulse sequence of the gas meter, calculating interval time of two adjacent metering pulses, dividing the metering pulse sequence into an even-numbered sequence group and an odd-numbered sequence group according to the interval time, further generating an odd-even half-cycle phase offset, extracting a direction track of the odd-even half-cycle phase offset in a preset sliding window, determining the longest run length of the direction track, calculating a phase locking degree, judging whether the odd-even half-cycle phase offset and the phase locking degree satisfy a characteristic judgment condition, in response to the characteristic judgment condition being satisfied, pairing and merging the adjacent even-numbered sequence group and the adjacent odd-numbered sequence group, calculating a paired flow, further determining a flow continuity discrimination value, and when the flow continuity discrimination value is greater than zero, issuing a valve closing instruction to the gas meter.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of valve control, more particularly, it relates to a valve control system for a gas meter and the gas meter. BACKGROUND

[0002] The diaphragm gas meter is a typical positive displacement meter, which includes a metering cavity composed of two flexible diaphragms. The gas pushes the diaphragms reciprocatingly, and then drives the distribution valve to reverse through the crank connecting rod, thereby completing the cumulative measurement of volume. This mechanical alternating motion inevitably produces periodic flow rate changes. Under large flow conditions, the pulsation is averaged, which does not significantly interfere with the total calculation. However, when approaching the minimum flow, the periodic pulsation is amplified in the time dimension, resulting in that the pulse output interval of the gas meter is not uniform, but presents obvious alternating length. In the domestic gas system, the gas meter is often configured with a low-pressure regulator. When the user-end gas valve is closed, the low-pressure regulator is in a locked state. However, the valve seat material, spring and sealing structure of the regulator may have slight creep or penetration after a long period of static state, which presents intermittent release of extremely small flow. Although the release is extremely small, it may cause abnormal continuation of the meter-end flow signal when no one uses gas at night.

[0003] The current commonly used gas leakage monitoring and valve closing logic is to determine whether there is a continuous low flow signal within a time window to determine whether there is a gas leakage. When the inherent periodic fluctuation of the diaphragm meter is superimposed with the micro-leakage of the regulator, the data shows a regular low flow sequence, which is extremely easy to be determined as a gas leakage. At this time, the valve is automatically closed at night when no one uses gas, and the user needs to perform a reset operation when using gas the next day. This condition not only increases the maintenance cost, but also may cause safety management problems. Specifically, the traditional method ignores the periodic characteristics of the metering mechanism and the micro-release effect of the pipeline regulator, which makes it difficult for the system to distinguish between real gas leakage and false micro-flow. SUMMARY

[0004] The present application provides a valve control system for a gas meter and the gas meter, which solves the technical problems proposed in the background art.

[0005] In a first aspect, a valve control system for a gas meter, comprising:

[0006] A data acquisition module is configured to acquire a metering pulse sequence of the gas meter, calculate interval time of two adjacent metering pulses, and divide the metering pulse sequence into an even-numbered group and an odd-numbered group according to the interval time, and further generate an odd-even half-cycle phase offset.

[0007] A data processing module is configured to extract a direction trajectory of the odd-even half-cycle phase offset within a preset sliding window, determine a longest run length of the direction trajectory, and calculate a phase locking degree.

[0008] a joint determination module configured to determine whether the odd-even half-cycle phase offset and the phase lock degree satisfy a characteristic determination condition;

[0009] a persistence determination module configured to, in response to the characteristic determination condition being satisfied, combine the adjacent even-numbered group and the adjacent odd-numbered group in pairs, calculate a pair flow, and further determine a flow persistence determination value;

[0010] a valve closing module configured to, when the flow persistence determination value is greater than zero, send a valve closing instruction to the gas meter.

[0011] Further, a metering pulse sequence of the gas meter is collected, an interval time between two adjacent metering pulses is calculated, and the metering pulse sequence is divided into an even-numbered group and an odd-numbered group according to the interval time, including:

[0012] The metering pulse sequence is collected, and a timestamp of each metering pulse is determined;

[0013] Each metering pulse is incrementally numbered with 1 as a starting point according to the chronological order of the timestamps;

[0014] The metering pulse sequence is divided into the even-numbered group and the odd-numbered group according to the parity of the metering pulse numbers.

[0015] Further, the odd-even half-cycle phase offset is generated, including: taking a ratio of a median of the even-numbered group to a median of the odd-numbered group as an odd-even half-cycle phase offset amount.

[0016] Further, within a preset sliding window, a direction trajectory of tracking the odd-even half-cycle phase offset is extracted, a longest run length of the direction trajectory is determined, and a phase lock degree is calculated, including:

[0017] The metering pulse sequence is extracted by sliding with the preset sliding window, and the odd-even half-cycle phase offset corresponding to each metering pulse sequence is determined;

[0018] The odd-even half-cycle phase offset corresponding to each metering pulse sequence is subtracted by one to form the direction trajectory;

[0019] The time length of the longest segment of continuous same values in the direction trajectory is determined as the longest run length L;

[0020] The phase lock degree 2 is calculated based on the longest run length -L .

[0021] Further, it is determined whether the odd-even half-cycle phase offset and the phase lock degree satisfy a characteristic determination condition, including:

[0022] In the observed preset sliding window set, the parity half-cycle phase bias of each preset sliding window is determined, and the median and the median absolute deviation of the parity half-cycle phase bias are obtained;

[0023] The bias significance is obtained based on the median and the median absolute deviation;

[0024] The longest run length of the direction trajectory is mapped as the phase locking degree, and the number of windows of the observed preset sliding window set is taken as the reference amount; when the bias significance is greater than 1 and the phase locking degree is less than the reference amount, it is determined that the feature determination condition is met.

[0025] Further, in response to meeting the feature determination condition, the adjacent even order number group and the adjacent odd order number group are paired and merged, and the paired flow is calculated, including:

[0026] The preset sliding window with the current time as the end point is taken as the current sliding window;

[0027] The 2nth measurement pulse and the 2n-1th measurement pulse in the measurement pulse sequence of the current sliding window are paired and merged to obtain a paired and merged set;

[0028] The time stamps corresponding to the paired and merged measurement pulse pairs are added to obtain the corresponding paired time p n ;

[0029] The paired flow q n =2v p / p n ; wherein, v p represents a single pulse volume constant.

[0030] Further, a flow persistence discriminant value is determined, including:

[0031] Based on the paired and merged set, a paired flow sequence in ascending order is obtained;

[0032] The median absolute deviation of the paired flow sequence is adaptively determined by a monotone stopping criterion;

[0033] The paired flow sequence is divided into equal-length front and back sections according to the number;

[0034] The median of the front section and the median of the back section, and the median absolute deviation of the paired flow sequence are determined;

[0035] The difference between the median of the front section and the median of the back section and the ratio of the median absolute deviation are taken as the flow persistence discriminant value.

[0036] Further, when the flow persistence discriminant value is greater than zero, a valve closing instruction is issued to the gas meter, including:

[0037] When the flow persistence discriminant value is greater than zero, the maximum pair order number in the latter section is taken as the latest completed pair order number; the valve closing execution time is obtained by extending the time stamp corresponding to the latest completed pair order number backward by 3 pairing times; the valve closing instruction is issued to the gas meter at the valve closing execution time.

[0038] Second aspect. A gas meter comprising a terminal configured to implement any one of the valve control systems for a gas meter.

[0039] The beneficial effects of the present application are that: by establishing a complete judgment logic of the odd-even half-cycle phase offset, the phase locking degree and the flow persistence discriminant value, the real gas leakage and the false micro-flow can be effectively distinguished when the inherent periodic fluctuations of the metering pulse and the micro-leakage effect of the pressure regulator are superimposed, and the probability of the traditional valve control logic mistakenly closing the valve at midnight is significantly reduced. The present application not only improves the accuracy and robustness of gas leakage monitoring, reduces unnecessary reset operations and maintenance costs at the user end, but also establishes a dynamic balance between system safety and use convenience, thereby ensuring gas safety while improving the intelligence and reliability of the gas meter. BRIEF DESCRIPTION OF DRAWINGS

[0040] Figure 1 is a module diagram of a valve control system for a gas meter of the present application. DETAILED DESCRIPTION

[0041] The subject matter described herein will now be discussed with reference to example implementations. It should be understood that the discussion of these implementations is merely meant to provide a better understanding of the subject matter described herein and can be changed in function and arrangement without departing from the scope of the present description. Various processes or components can be omitted, substituted, or added according to desired implementations. Additionally, features described with respect to some examples can be combined in other examples.

[0042] Example One

[0043] As shown in Figure 1 A valve control system for a gas meter, comprising:

[0044] A data acquisition module for acquiring a metering pulse sequence of the gas meter, calculating an interval time of two adjacent metering pulses, and dividing the metering pulse sequence into an even order number group and an odd order number group according to the interval time, and further generating an odd-even half-cycle phase offset;

[0045] A data processing module for extracting a directional trajectory of the odd-even half-cycle phase offset within a preset sliding window, determining a longest run length of the directional trajectory, and calculating a phase locking degree;

[0046] A joint determination module is configured to determine whether the odd-even half-cycle phase offset and the phase lock degree meet a feature determination condition.

[0047] A persistence determination module is configured to, in response to the feature determination condition being met, combine the adjacent even-numbered group and the adjacent odd-numbered group in pairs, calculate the paired flow, and further determine a flow persistence determination value.

[0048] A valve closing module is configured to, when the flow persistence determination value is greater than zero, send a valve closing instruction to the gas meter.

[0049] In an embodiment of the present application, a metering pulse sequence of a gas meter is collected, interval times of two adjacent metering pulses are calculated, and the metering pulse sequence is divided into an even-numbered group and an odd-numbered group according to the interval times, comprising:

[0050] The metering pulse sequence is collected, and a time stamp of each metering pulse is determined;

[0051] Each metering pulse is numbered in ascending order with 1 as the starting point according to the order of the time stamp;

[0052] The metering pulse sequence is divided into the even-numbered group and the odd-numbered group according to the parity of the metering pulse number.

[0053] It should be noted that the metering pulse sequence is a set of continuous pulse signals generated by the internal mechanical structure of the gas meter when the gas meter measures the volume of gas, and each pulse corresponds to a fixed gas volume, i.e., a single-pulse volume constant.

[0054] It should be noted that the parity of the number refers to the attribute of the number in the pulse number, and the attribute of the number being odd (such as 1, 3, 5,...) is odd, and the attribute of the number being even (such as 2, 4, 6,...) is even; the division into the even-numbered group and the odd-numbered group refers to splitting the sorted metering pulse sequence into two independent sub-sets according to the parity of the number; the odd-numbered group contains all pulses numbered as odd, and the even-numbered group contains all pulses numbered as even, thereby separating the pulse signals corresponding to the odd half-cycle and the even half-cycle of the gas meter.

[0055] In an embodiment of the present application, the odd-even half-cycle phase offset is generated, comprising: taking the ratio of the median of the even-numbered group to the median of the odd-numbered group as the odd-even half-cycle phase offset.

[0056] It should be noted that, based on the inherent characteristics of the two diaphragm chambers of the gas meter working alternately, i.e., the two diaphragm chambers correspond to the odd half-cycle and the even half-cycle of the measurement respectively, the difference in the working rhythm will be directly reflected in the pulse interval time. By calculating the ratio of the median of the pulse interval time of the even-numbered group to the median of the pulse interval time of the odd-numbered group, the odd-even half-cycle phase offset can be obtained to quantify the rhythm difference.

[0057] It should be noted that the median is selected as the calculation reference because the diaphragm gas meter may have accidental fluctuations in the pulse interval time under low flow conditions (such as individual abnormal intervals caused by transient micro leakage of the pressure regulator), and the median as a robust statistical quantity can effectively exclude such abnormal value interference and ensure that the calculation result truly reflects the inherent rhythm difference of two half cycles.

[0058] In an embodiment of the present application, within a preset sliding window, the direction trajectory of the tracking odd-even half cycle phase offset is extracted, the longest run length of the direction trajectory is determined, and the phase locking degree is calculated, comprising:

[0059] The metering pulse sequence is extracted by sliding the preset sliding window, and the odd-even half cycle phase offset corresponding to each metering pulse sequence is determined;

[0060] The direction trajectory is formed by subtracting one from the odd-even half cycle phase offset corresponding to each metering pulse sequence;

[0061] The time length of the longest segment of continuous same value in the direction trajectory is determined as the longest run length L;

[0062] The phase locking degree 2 is calculated based on the longest run length -L .

[0063] It should be noted that the phase offset of the gas meter is not fixed and can randomly fluctuate due to micro leakage of the downstream pressure regulator, or can be stable and unchanged (i.e., phase locking) due to long-term unipolar leakage. By dynamically intercepting pulse data of different time periods through a preset sliding window, the discrete phase offset is converted into a direction trajectory, and the stable segment of the direction is captured through the longest run length, and finally the stability is quantified by the phase locking degree. The smaller the locking degree, the more stable the offset direction, and the more significant the phase locking.

[0064] It should be noted that the preset sliding window refers to an analysis unit containing a fixed number of metering pulses, which will slide along the time axis in sequence, and a new pulse sequence will be intercepted after each movement, forming multiple continuous window pulse sequences. The odd-even half cycle phase offset corresponding to each window pulse sequence is determined. That is, through the sliding window, the static single offset can be converted into a dynamic continuous offset sequence, realizing the tracking of the phase offset change trend.

[0065] It should be noted that the bias is subtracted by one so as to convert the bias size into the bias direction. That is, when the bias is greater than one, it indicates that the interval time of the even order number group is longer (the even half-week rhythm is slow), and the bias is biased to the even half-week; when the bias is less than one, it indicates that the interval time of the odd order number group is longer (the odd half-week rhythm is slow), and the bias is biased to the odd half-week; when the bias is equal to one, it indicates that the two half-week rhythms are consistent, and there is no bias. Through the subtraction operation, the continuous bias value can be converted into three discrete direction identifiers of positive, zero and negative, and these identifiers are arranged in the window order, that is, a direction track is formed to reflect the change trend of the bias direction.

[0066] In detail, the direction conversion rule is: subtract one from the bias value of the phase bias of each window:

[0067] If the calculation result is greater than zero: the direction identifier is positive, representing that the bias is biased to the even half-week;

[0068] If the calculation result is equal to zero: the direction identifier is zero, representing that the bias has no bias;

[0069] If the calculation result is less than zero: the direction identifier is negative, representing that the bias is biased to the odd half-week;

[0070] Arrange the direction identifiers of all windows in the window sliding order to form a continuous direction sequence, that is, a direction track.

[0071] It should be noted that the segment with continuous same value refers to the part in the direction track where the direction identifiers of continuous multiple windows are completely consistent (such as continuous positive, continuous zero, and continuous negative), which is called a run; the time length refers to the total time corresponding to all windows in the run (the time of each window is determined by the time stamp difference between the last pulse and the first pulse in the window); and the longest run length L is the total time corresponding to the run with the largest time length among all runs. That is, the longest run length directly reflects the stable duration of the bias direction, and the longer the duration, the more stable the phase bias direction, and the closer to the phase locking state.

[0072] In detail, the phase locking state refers to a continuous state in which the phase bias (i.e., the asymmetry of the measurement rhythm of the two half-weeks) between the odd and even half-weeks in the measurement process of the diaphragm gas meter based on the alternation of the even and odd half-weeks keeps stable and does not randomly reverse for a long time. The gas meter realizes gas measurement through the alternate action of the two diaphragm chambers. Under normal low flow conditions, the measurement rhythm of the two half-weeks will be slightly asymmetric. During the unintentional micro-air supplement process of the downstream pressure regulator, such as locking, pressure climbing, and micro-permeation, a unipolar biasing effect will be continuously applied to one group of half-weeks (even or odd half-weeks). For example, continuously supplementing air to the gas path corresponding to the even half-week.

[0073] When the unipolar bias of the voltage regulator is superimposed on the inherent rhythm of the half-cycle alternation in the table, the relative relationship between the even half-cycle pulse interval and the odd half-cycle pulse interval (i.e. the direction of phase bias) is stabilized for a long time. Either the even half-cycle interval is always longer, or the odd half-cycle interval is always longer, and the bias direction does not change randomly, at which time the phase-locked state is formed.

[0074] It should be noted that the phase locking degree is a quantification of the degree of continuous stability of the phase bias direction, and the calculation method is the negative power of the longest run length of 2.

[0075] In detail, the larger L is (the longer the bias direction is stable), the smaller the value of 2 -L , indicating that the phase locking degree is higher; the smaller L is (the bias direction changes frequently), the larger the value of 2 -L , indicating that the phase locking degree is lower. For example: if L=3, the phase locking degree is 0.125; if L=5, the phase locking degree is 0.03125.

[0076] In an embodiment of the present application, determining whether the odd-even half-cycle phase bias and the phase locking degree satisfy the characteristic determination condition comprises:

[0077] In the observed preset sliding window set, the odd-even half-cycle phase bias of each preset sliding window is determined, and the median and the median absolute deviation of the odd-even half-cycle phase bias are obtained;

[0078] The bias significance is obtained based on the median and the median absolute deviation;

[0079] The longest run length of the direction trajectory is mapped to the phase locking degree, and the number of windows of the observed preset sliding window set is taken as a reference quantity; when the bias significance is greater than 1 and the phase locking degree is less than the reference quantity, it is determined that the characteristic determination condition is satisfied.

[0080] It should be noted that the observed preset sliding window set refers to the window set corresponding to the metering pulse sequence that has been intercepted and processed by the sliding window before the current time. For each window in the set, the odd-even half-cycle phase bias of each window needs to be calculated first; then, based on the odd-even half-cycle phase bias of all windows, two statistical quantities are calculated:

[0081] Median: the value located in the middle position after sorting all bias values by size, reflecting the central tendency of the bias values;

[0082] Median absolute deviation (MAD): first calculate the absolute difference between each bias value and the median, and then take the median of these absolute differences, reflecting the dispersion degree of the bias values.

[0083] It should be noted that the bias significance is the ratio of the median and the median absolute deviation, which is used to measure whether the odd-even half cycle phase bias has statistical significance (i.e. whether the bias is significantly deviated from the unbiased state, rather than random fluctuation). If the ratio is large, it means that the bias is systematic and non-random; if the ratio is small, it means that the bias may be random noise.

[0084] It should be noted that the bias significance is the ratio of the median and the median absolute deviation, which is used to measure whether the odd-even half cycle phase bias has statistical significance (i.e. whether the bias is significantly deviated from the unbiased state, rather than random fluctuation). If the ratio is large, it means that the bias is systematic and non-random; if the ratio is small, it means that the bias may be random noise.

[0085] In an embodiment of the present application, in response to satisfying the feature judgment condition, the adjacent even order number group and the adjacent odd order number group are paired and merged, and the paired flow is calculated, including:

[0086] The preset sliding window with the current time as the end point is taken as the current sliding window;

[0087] The 2n-th and 2n-1-th measurement pulses in the pulse sequence of the current sliding window are paired and merged to obtain a paired and merged set;

[0088] The time stamps corresponding to the paired and merged measurement pulses are added to obtain the corresponding paired time p n ;

[0089] The paired flow q n =2v p / p n is calculated; wherein v p represents a single pulse volume constant.

[0090] It should be noted that in the pulse sequence of the current sliding window, adjacent pulses are paired according to the parity of the number. That is, the first (odd number) and the second (even number) are merged into the first pair, the third (odd number) and the fourth (even number) are merged into the second pair, and so on, to form a paired and merged set. Thus, the pulses of the odd half cycle and the even half cycle are combined to offset the phase bias of the single half cycle.

[0091] It should be noted that each pair of pulses has its own time stamp (i.e. the exact time of pulse generation). Adding the values of the two time stamps gives the paired time of the pair of pulses, which reflects the total time span covered by the pair of pulses.

[0092] It should be noted that the single pulse volume constant of the gas meter is an inherent parameter. Each pair of pulses contains 2 pulses, so the total gas volume is 2v p . The total gas volume divided by the pair time is the pair flow q n corresponding to the pair of pulses. Thus, based on a pair of pulses, the phase bias of a single half cycle can be neutralized, and the gas passing rate can be more truly reflected.

[0093] It should be noted that by pair merging, the pulses of odd half cycles and even half cycles are combined, the interference of single half cycle phase bias on flow judgment is eliminated, and false microflows are avoided from being misjudged as real gas leakage due to phase bias.

[0094] In an embodiment of the present application, the flow persistence discrimination value is determined, comprising:

[0095] Based on the pair merging set, a pair flow sequence in ascending order of pair number is obtained;

[0096] The median absolute deviation of the pair flow sequence is adaptively determined by a monotone stopping criterion;

[0097] The pair flow sequence is divided into equal-length front and rear sections according to the pair number;

[0098] The median of the front section and the median of the rear section, and the median absolute deviation of the pair flow sequence are determined;

[0099] The ratio of the difference between the median of the front section and the median of the rear section to the median absolute deviation is taken as the flow persistence discrimination value.

[0100] It should be noted that the median absolute deviation (MAD) is a robust statistic that measures the degree of dispersion of data. The monotone stopping criterion means that as the number of pulse pairs selected (i.e. the number of flow samples analyzed) increases, the MAD of the pair flow corresponding to these numbers is calculated; when the MAD no longer decreases significantly (tends to be stable) with the increase of the number, the number at this time is the adaptively determined number. Thus, the number of samples selected can reflect the stable characteristics of the flow.

[0101] For example: sequence [0.02, 0.022, 0.025]:

[0102] Taking 1 pair, there is only 1 flow value, and the MAD is 0;

[0103] Taking 2 pairs, the flow is 0.02, 0.022, the median is 0.021, the absolute difference of each value from the median is 0.001, 0.001, and the MAD is 0.001;

[0104] When taking 3 pairs, the flow rates are 0.02, 0.022, and 0.025, the median is 0.022, the absolute differences between each value and the median are 0.002, 0, and 0.003, and the MAD is 0.002.

[0105] If we continue to increase the logarithm (e.g., take 4 pairs, add a fourth pair of traffic of 0.028, calculate MAD and find that MAD increases from 0.002 to 0.003, and MAD does not decrease significantly when the logarithm is increased again, then we adaptively determine the logarithm to be 4).

[0106] It should be noted that an adaptively determined logarithm is used to divide the paired flow sequences into two equal segments (the first segment and the second segment). This allows for a comparison of the central trends of the earlier and later flows to determine whether there is a continuous change in the flow.

[0107] For example, if the adaptive determination of the logarithm is 4 and the paired flow sequence is [0.02, 0.022, 0.025, 0.028], then the first segment consists of the first two pairs with a flow of [0.02, 0.022]; the second segment consists of the last two pairs with a flow of [0.025, 0.028].

[0108] It should be noted that the change in flow rate is obtained by subtracting the median of the first segment from the median of the second segment, and then divided by the MAD of the entire sequence (standardization to eliminate the influence of dimensions and dispersion) to obtain the flow continuity discrimination value. If the value is positive and large, it indicates that the flow rate in the later segment is significantly higher than that in the earlier segment, and there is a continuous increase in flow rate (indicating a real leak); if it is close to 0 or negative, it indicates that there is no continuous increase in flow rate (indicating an EOPI pseudo-microflow).

[0109] In one embodiment of the present invention, when the flow continuity discrimination value is greater than zero, a valve closing command is issued to the gas meter, including:

[0110] When the flow continuity judgment value is greater than zero, the largest pair number in the latter segment is taken as the most recently completed pair number; the valve closing execution time is obtained by extending the timestamp corresponding to the most recently completed pair number by 3 pairs of time; and a valve closing command is issued to the gas meter at the valve closing execution time.

[0111] It should be noted that a flow continuity discrimination value greater than zero indicates that the median level of the paired flow in the later stage (the median of the later stage) is significantly higher than that in the earlier stage, suggesting a continuous upward trend in gas flow, which is highly likely to be a genuine gas leak (not an EOPI spurious microflow). In this case, it is necessary to first identify the most recently completed metering unit, i.e., the largest pair number in the later stage. The pair number is the number of each pair of pulses in the paired merge set (incrementing from 1 according to time sequence); the largest pair number is the pair of pulses with the highest number in the later stage, and because it is the last pulse pair to complete metering in the later stage, it is called the most recently completed pair number. This anchors the calculation benchmark for the valve closing time to the latest complete metering node, avoiding time deviations caused by using an incomplete half-cycle of metering as the benchmark.

[0112] It should be noted that the adaptive determination of the logarithm is 4, and the paired flow sequence is divided into two segments according to the pair sequence number 1 to 4: the front segment is the pair sequence number 1, 2 (the two earlier pairs of pulses), and the rear segment is the pair sequence number 3, 4 (the two newer pairs of pulses). The maximum value of the pair sequence number in the rear segment is 4, so the most recently completed pair sequence number is 4.

[0113] It should be noted that the timestamp corresponding to the most recently completed pair sequence number is the timestamp of the last pulse in the pair of pulses. Since each pair of pulses is composed of an odd half-cycle pulse and an even half-cycle pulse (for example, the pair sequence number 4 corresponds to the odd half-cycle pulse numbered 7 and the even half-cycle pulse numbered 8), the completion of the pair of pulses is marked by the generation of the even half-cycle pulse, so the corresponding timestamp is the timestamp of the even half-cycle pulse (that is, the timestamp of the pulse with the larger number in the pair of pulses). The 3 paired times are sequentially extended backward, that is, the complete time from the beginning of the odd half-cycle to the end of the even half-cycle. The 3 paired times are sequentially extended, so as to ensure that the valve closing time falls after 3 complete measurement periods, avoiding the current incomplete half-cycle, and leaving a stable execution preparation time for the system, at the same time, synchronizing with the half-cycle rotation rhythm of the gas meter, avoiding statistical deviation caused by the valve closing action interrupting the measurement period.

[0114] Embodiment Two

[0115] A gas meter, comprising a terminal, configured to implement any one of the valve control systems for the gas meter.

[0116] The above describes the embodiments of the present embodiment, but the present embodiment is not limited to the specific embodiments described above, and the specific embodiments described above are only illustrative and not limiting. Those skilled in the art can make many forms under the inspiration of the present embodiment, which are all within the protection scope of the present embodiment.

Claims

1. A valve control system for a gas meter, characterized in that, include: The data acquisition module is used to acquire the metering pulse sequence and determine the timestamp of each metering pulse; Each metering pulse is numbered sequentially, starting from 1, based on the order of its timestamps. Based on the parity of the metering pulse number, the metering pulse sequence is divided into an even number group and an odd number group. The ratio of the median pulse interval time of the even number group to the median pulse interval time of the odd number group is used as the odd-even half-cycle phase offset. The data processing module is used to extract the direction trajectory of the tracking odd and even half-cycle phase offset within a preset sliding window, determine the longest run length L of the direction trajectory, and calculate the phase lock degree 2 based on the longest run length. -L ; The joint determination module is used to determine the odd and even half-cycle phase offset of each preset sliding window within the observed preset sliding window set, and obtain the median and median absolute deviation of the odd and even half-cycle phase offset; obtain the offset significance based on the ratio of the median and the median absolute deviation; map the longest run length of the direction trajectory to the phase lock degree, and use the number of windows in the observed preset sliding window set as a reference. When the bias significance is greater than 1 and the phase lock degree is less than the reference value, it is determined that the feature determination condition is met. The persistence discrimination module is used to merge adjacent even-order groups and adjacent odd-order groups in pairs in response to the satisfaction of feature judgment conditions, calculate the paired flow, and obtain the paired flow sequence in ascending order of pair numbers based on the paired merged set. The logarithm is adaptively determined based on the absolute deviation of the median of paired flow sequences using the monotonically stopping criterion; the paired flow sequences are divided into equal-length first and second segments according to the logarithm; the median of the first segment and the median of the second segment, as well as the absolute deviation of the median of the paired flow sequences, are determined; the ratio of the difference between the median of the first segment and the median of the second segment to the absolute deviation of the median is used as the flow persistence discrimination value. The valve closing module is used to send a valve closing command to the gas meter when the flow continuity judgment value is greater than zero.

2. A valve control system for a gas meter according to claim 1, characterized in that, Within a preset sliding window, extract the directional trajectory tracking the phase offset of the odd and even half-cycles, and determine the longest run length of the directional trajectory, including: The metering pulse sequence is extracted by sliding a preset sliding window, and the odd and even half-cycle phase offsets corresponding to each metering pulse sequence are determined. The direction trajectory is formed by subtracting one from the odd and even half-cycle phase offset corresponding to each metering pulse sequence; The longest segment of time with the same continuous value in the directional trajectory is determined as the longest run length L.

3. A valve control system for a gas meter according to claim 2, characterized in that, In response to the fulfillment of the feature determination condition, adjacent even-order groups and adjacent odd-order groups are paired and merged, and the paired flow is calculated, including: Use the preset sliding window that ends at the current time as the current sliding window; The 2nth and 2n-1th metering pulses in the current sliding window metering pulse sequence are paired and merged to obtain a paired merged set; The timestamps corresponding to the paired metering pulses are added together to obtain the corresponding paired time p. n ; Calculate the paired flow q n =2v p / p n ; where v p This represents the single-pulse volume constant.

4. A valve control system for a gas meter according to claim 3, characterized in that, When the flow continuity threshold is greater than zero, a valve closing command is sent to the gas meter, including: When the flow continuity judgment value is greater than zero, the largest pair number in the latter segment is taken as the most recently completed pair number; the valve closing execution time is obtained by extending the timestamp corresponding to the most recently completed pair number by 3 pairs of time; and a valve closing command is issued to the gas meter at the valve closing execution time.

5. A gas meter, characterized in that, Includes a terminal configured to implement a valve control system for a gas meter as described in any one of claims 1-4.

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