Ultrasonic water meter signal gain self-adaption method

Abstract

The invention discloses an ultrasonic water meter signal gain self-adaption method. The method comprises the following steps of: 1, amplifying an original signal as much as possible in a target level range which can be accepted by a signal processing circuit; the amplified original signal comprises N wave crests which are gradually increased and then gradually reduced; n > = 3; 2, finding out a peak with the maximum difference between the peak value of the peak and the peak value of the previous peak, and taking the peak as a target peak; and step 3, amplifying the screened target wave crest to a target range, and determining an optimal amplification factor and a final trigger level. According to the method, the ultrasonic water meter can be automatically debugged to obtain the optimal amplification factor through a program, manual test adjustment is not needed, and the production efficiency is improved.

Description

Technical Field

[0001] The invention belongs to the technical field of ultrasonic water meters, and in particular relates to an ultrasonic water meter signal gain adaptive method. Background Art

[0002] The basic measurement principle of ultrasonic water meter is: Figure 1 As shown, by stimulating an ultrasonic transducer A, the electrical signal is converted into an ultrasonic signal, and the ultrasonic signal is transmitted to another ultrasonic transducer B through the water in the pipe section. The ultrasonic transducer B converts the ultrasonic signal into an electrical signal, and then processes the received electrical signal to obtain the flight time of the ultrasonic wave in the water. The flow rate of the water in the pipe section is calculated based on the flight time.

[0003] Since the amplitude of the original signal received is very small, it is not conducive to the subsequent signal analysis and processing, so the received signal needs to be amplified, so the selection of the amplification factor is very important. However, due to the differences between individual ultrasonic transducers, different ultrasonic transducer distances, different pipe section parameters, and installation errors, the original signals received are different. Obviously, it is not very reasonable for all water meters to use the same set of amplification factors. If each water meter is manually adjusted separately, it will lead to reduced production efficiency.

[0004] In the prior art, the amplification factor of ultrasonic equipment is mostly adjusted by manually adjusting the parameters of the amplifier circuit, such as application number 202221740412.5, utility model name: an adjustable impedance circuit for reducing the influence of individual differences of ultrasonic sensors, specifically, it relates to an adjustable impedance circuit for reducing the influence of individual differences of ultrasonic sensors, including a multiplier circuit, a primary test circuit, a secondary test circuit and a socket circuit, the multiplier circuit includes a control circuit, a primary amplifier circuit and a secondary amplifier circuit, the control circuit is connected to the primary amplifier circuit, the primary amplifier circuit is connected to the secondary amplifier circuit, the secondary amplifier circuit is connected to the socket circuit, the socket circuit is connected to the primary test circuit, and the primary test circuit is connected to the secondary test circuit. The utility model can achieve a consistency error of all sensors within 10% and improve the accuracy of positioning by connecting a high-precision variable resistor in series in the circuit to change the impedance size in the circuit.

[0005] In the above patent, the amplification factor of the ultrasonic device is adjusted by adjusting the impedance of the high-precision variable resistor, which requires manual adjustment of each device individually, resulting in reduced production efficiency. Summary of the invention

[0006] In view of the above-mentioned deficiencies in the prior art, the technical problem to be solved by the present invention is: how to provide an ultrasonic water meter signal gain adaptive method, which can realize automatic adjustment of the ultrasonic water meter to the optimal amplification factor through a program, without the need for manual testing and adjustment, thereby improving production efficiency.

[0007] In order to solve the above technical problems, the present invention adopts the following technical solutions: an ultrasonic water meter signal gain adaptive method, comprising the following steps;

[0008] Step 1: Amplify the original signal as much as possible within the target level range acceptable to the signal processing circuit;

[0009] The original signal is the signal received by the ultrasonic transducer B and has not been amplified; in step 1, the original signal amplified by the amplifier circuit has N peaks, the peak values ​​of the N peaks gradually increase and then gradually decrease, and N≥3.

[0010] Step 2: Find the peak with the largest difference between the peak value and the previous peak value as the target peak;

[0011] Step 3: Amplify the selected target peak to within the target range and determine the optimal amplification factor and final trigger level.

[0012] The key to the ultrasonic water meter signal gain adaptive method is that in step one, the ultrasonic water meter is first placed in still water, the target level range and the trigger level A are set, the target level range is between the trigger level A and the upper limit level of the signal processing circuit, and then the amplification factor is gradually adjusted until the maximum level value of the amplified signal is between the trigger level A and the upper limit level.

[0013] Usually, the upper limit level is 1.5V.

[0014] The key point of the ultrasonic water meter signal gain adaptive method is that the trigger level A is 0.8 times of the upper limit level.

[0015] The key to the ultrasonic water meter signal gain adaptive method is that step 2 includes setting a trigger level B, setting the level value of trigger level B from small to large, triggering level B is first triggered by the previous peak, and when the level value of trigger level B exceeds the previous peak value, it will be triggered by the next peak, so that as the level value of trigger level B increases, it switches to each peak in turn until the highest peak, thereby measuring the peak values ​​from the first peak to the highest peak, recording the peak values ​​of each measured peak, and then screening out the peak with the largest difference from the peak value of the previous peak as the target peak.

[0016] The key to the ultrasonic water meter signal gain adaptive method is that a comparator is provided, and the comparator is provided with two thresholds, namely a low detection level and a high detection level. The two threshold levels are adjusted to successively approach the peak value of the trigger peak determined by the trigger level B, thereby measuring the peak value of the peak. The peak value of the peak can be taken as the average value of the two threshold values.

[0017] The key to the ultrasonic water meter signal gain adaptive method is that in step three, the amplification factor is calculated and adjusted based on the screened target peak and its peak value, so that the peak value of the target peak is within the target level range described in step one, and the amplification factor β is the optimal amplification factor.

[0018] Determine the target peak value and the previous peak value according to the aforementioned method;

[0019] Set the trigger level C to the middle value between the target peak value and the previous peak value; the trigger level C is the final trigger level of the ultrasonic water meter;

[0020] T=(V p1 +V p2 ) / 2;

[0021] Where T is the value of the trigger level C, V p2 is the peak value of the target wave, V p1 is the peak value of the previous peak of the target peak.

[0022] Significant effect: The present invention provides an ultrasonic water meter signal gain self-adaptation method, which can automatically adjust the ultrasonic water meter to the optimal amplification factor through a program, without the need for manual testing and adjustment, and is conducive to improving production efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 This is the basic principle diagram of ultrasonic water meter measurement;

[0024] Figure 2 is the relationship diagram between the original signal and the target range;

[0025] Figure 3 A schematic diagram for amplifying the original signal so that its maximum level value is within the target range;

[0026] Figure 4 The schematic diagram for finding the peak values ​​of each wave peak of the amplified signal in sequence;

[0027] Figure 5 Schematic diagram for adjusting the magnification so that the target peak is within the target range;

[0028] Figure 6 This is a schematic diagram for setting the trigger level;

[0029] Figure 7 The present invention is a flow chart of the method. DETAILED DESCRIPTION

[0030] The present invention will be further described in detail below in conjunction with the accompanying drawings.

[0031] The basic measurement principle of ultrasonic water meter is: Figure 1 As shown, by stimulating an ultrasonic transducer A, the electrical signal is converted into an ultrasonic signal, and the ultrasonic signal is transmitted to another ultrasonic transducer B through the water in the pipe section. The ultrasonic transducer B converts the ultrasonic signal into an electrical signal, and then processes the received electrical signal to obtain the flight time of the ultrasonic wave in the water. The flow rate of the water in the pipe section is calculated based on the flight time.

[0032] Since the amplitude of the original signal received is very small, it is not conducive to the subsequent signal analysis and processing, so the received signal needs to be amplified, so the choice of amplification factor is very important. However, due to the differences between individual ultrasonic transducers, different transducer distances, different pipe section parameters, and installation errors, the original signals received are different. Obviously, it is not very reasonable for all water meters to use the same set of amplification factors. If each water meter is manually adjusted separately, it will lead to reduced production efficiency and increased production costs. Therefore, in response to the above problems, a method is invented to automatically adjust the ultrasonic water meter to the optimal amplification factor through a program.

[0033] like Figure 1-Figure 7 As shown, the present invention relates to an ultrasonic water meter signal gain adaptive method, and the technical solution of the present invention is as follows: it is divided into the following 3 steps.

[0034] Step 1: Amplify the original signal as much as possible within the target level range acceptable to the signal processing circuit.

[0035] First place the water meter in still water, set the target level range and trigger level (take 0.8*upper limit level), such as Figure 2 Usually, the upper limit voltage level is 1.5V.

[0036] Then gradually increase the amplification factor. After adjustment, if the trigger level is not reached, continue to increase the amplification factor. If it exceeds the upper limit level, reduce the amplification factor and gradually approach it until the maximum level value of the amplified signal is between the trigger level and the upper limit level. Figure 3 shown.

[0037] The amplified signal is collected by the sampling circuit, and its maximum value is the maximum level value, that is, the peak value of the maximum wave peak. The amplification factor is adjusted to be between the trigger level and the upper limit level.

[0038] Step 2: Find the peak with the largest difference between the peak value and the previous peak value.

[0039] Set the trigger level value from small to large (when the trigger level value exceeds the previous peak value, it will be triggered by the next peak, so as the trigger level increases, it will switch to different peaks, thereby measuring the peak value of each peak). After each setting, measure the peak value of the corresponding trigger peak by adjusting the low detection level and the high detection level (these two levels can be understood as the two thresholds of the comparator, the purpose is to compare these two values ​​to get the peak value), such as Figure 4 As shown, record the measured peak value until the signal level fails to reach the trigger level (when the trigger level exceeds the largest peak, it cannot be triggered, that is, the subsequent peaks do not need to be measured).

[0040] Then filter out the peak with the largest difference from the previous peak.

[0041] Another way is to collect the amplified signal point by point through a sampling circuit. As the trigger level value gradually increases, when the trigger level value is greater than the first peak, the signal of the first wave can no longer trigger the comparator, and when it is less than the threshold of the comparator, it cannot be triggered. The previous level value of the trigger level is recorded, and the previous level value of the trigger level is the peak value of the first peak.

[0042] Alternatively, the amplified signal is collected at equal intervals by a sampling circuit, and a comparison method is used. If the collected signal is larger than the previous collected signal and the next collected signal, the signal is a peak signal; further, the collected signal is compared with the previous 2 or more signals and the next 2 or more signals. If the signal is the largest, it is a peak signal. The above method can also be used to obtain each peak signal. The maximum value of each peak signal is the maximum peak.

[0043] Step 3: Enlarge the screened target peak to the target range and determine the final trigger level.

[0044] According to the selected target peak and its peak value, calculate and adjust the magnification factor so that the peak value of the target peak is between 0.8*upper limit level-upper limit level described in step 1. Figure 5 The waveform shown.

[0045] At this point, the magnification is adjusted, and finally the trigger level (the principle of signal processing is that when the signal reaches the trigger level, the next zero crossing point is used as the reference point for recording the flight time) is set to the midpoint between the target peak value and the previous peak value; (Because of the influence of the flow direction and flow rate of the water in the pipe section, the amplitude of the received original signal will increase or decrease slightly compared with that in still water, so the amplitude of the amplified signal will also increase or decrease slightly. At this time, the middle value of the two peaks is selected as the trigger level, the acceptable range of signal amplitude fluctuation is larger, the switching of the trigger peak is less likely to occur, and the trigger is more reliable and stable). Figure 6 shown.

[0046] An ultrasonic water meter, which uses the above method to automatically adjust the optimal amplification factor, includes an ultrasonic transducer A for emitting ultrasonic signals, an ultrasonic transducer B for receiving ultrasonic signals emitted by the ultrasonic transducer A; an amplifier circuit, which amplifies the signal of the ultrasonic transducer B and transmits it to a signal processing circuit, the signal processing circuit is used to obtain the amplified signal and convert it into a flow rate signal; and an adjustment circuit, which obtains the output signal of the amplifier circuit and automatically adjusts the optimal amplification factor of the amplifier circuit according to the above method.

[0047] The above are only preferred implementations of the present invention. It should be pointed out that a number of modifications and improved technical solutions made by those skilled in the art without departing from the technical solution should also be deemed to fall within the scope of protection required by the claims.

Claims

1. An ultrasonic water meter signal gain adaptive method, characterized in that: The method comprises the following steps: Step 1: Amplify the original signal as much as possible within the target level range acceptable to the signal processing circuit; Step 2: Find the peak with the largest difference between the peak value and the previous peak value as the target peak; Step 3: Amplify the selected target peak to within the target range and determine the optimal amplification factor and final trigger level.

2. The ultrasonic water meter signal gain adaptive method according to claim 1, characterized in that: In step 1, the amplified original signal has N peaks, the peak values ​​of the N peaks gradually increase and then gradually decrease, and N≥3.

3. The ultrasonic water meter signal gain adaptive method according to claim 1, characterized in that: In step one, first place the ultrasonic water meter in still water, set the target level range and trigger level A, the target level range is between the trigger level A and the upper limit level of the signal processing circuit, and then gradually adjust the amplification factor until the maximum level value of the amplified signal is between the trigger level A and the upper limit level.

4. The ultrasonic water meter signal gain adaptive method according to claim 3, characterized in that: The trigger level A is 0.8 times the upper limit level.

5. The ultrasonic water meter signal gain adaptive method according to claim 1, characterized in that: Step two includes setting a trigger level B, setting the level value of trigger level B from small to large, trigger level B is first triggered by the previous peak, and when the level value of trigger level B exceeds the previous peak value, it will be triggered by the next peak, so that as the level value of trigger level B increases, it switches to each peak in turn until the highest peak, thereby measuring the peak values ​​from the first peak to the highest peak, recording the peak values ​​of each measured peak, and then screening out the peak with the largest difference from the peak value of the previous peak as the target peak.

6. The ultrasonic water meter signal gain adaptive method according to claim 5, characterized in that: A comparator is provided, and the comparator is provided with two thresholds, namely a low detection level and a high detection level. The two threshold levels are adjusted to successively approach the peak value of the trigger wave peak determined by the trigger level B, thereby measuring the peak value of the wave peak.

7. The ultrasonic water meter signal gain adaptive method according to claim 1, characterized in that: In step three, the amplification factor is calculated and adjusted according to the selected target peak and its peak value, so that the peak value of the target peak is within the target level range described in step one. The amplification factor β is the optimal amplification factor.

8. The ultrasonic water meter signal gain adaptive method according to claim 7, characterized in that: Set the trigger level C to the middle value between the target peak value and the previous peak value; the trigger level C is the final trigger level of the ultrasonic water meter; T=(V p1 +V p2 ) / 2; Where T is the value of the trigger level C, V p2 is the peak value of the target wave, V p1 is the peak value of the previous peak of the target peak.

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