CN114111972A

CN114111972A - Method for automatically adjusting echo of ultrasonic meter

Info

Publication number: CN114111972A
Application number: CN202111272091.0A
Authority: CN
Inventors: 李季; 王燕青
Original assignee: Zhejiang Viewshine Intelligent Meter Co Ltd
Current assignee: Zhejiang Viewshine Intelligent Meter Co Ltd
Priority date: 2021-10-29
Filing date: 2021-10-29
Publication date: 2022-03-01
Anticipated expiration: 2041-10-29
Also published as: CN114111972B

Abstract

The invention provides a method for automatically adjusting echoes of an ultrasonic meter, and provides a method for comparing multiple groups of threshold values. The method comprises the steps of setting reference voltages of a plurality of groups of comparators, and automatically adjusting the head wave amplitude of ultrasonic wave echoes according to the average value of the ultrasonic wave flight time obtained by comparing different groups of reference voltages, wherein the head wave amplitude is larger than a high area group in n groups of reference voltages, and the noise of the echoes cannot be larger than a low area group in n groups of reference voltages, so that the reliability of the ultrasonic wave flight time is ensured. The method can quickly realize the automatic adjustment of the size of the ultrasonic wave echo, control the size of the echo within a required range, ensure the accurate measurement of the flight time of the ultrasonic wave and finally ensure the accuracy and the reliability of the ultrasonic wave measurement.

Description

Method for automatically adjusting echo of ultrasonic meter

Technical Field

The invention belongs to the field of ultrasonic gas meter measurement, and particularly relates to a method for automatically adjusting echo of an ultrasonic meter.

Background

Ultrasonic metering technology, with its unique advantages, is becoming more and more focused and focused in the gas and water industries. With the large-scale popularization of domestic and foreign markets for over ten years, the application of the ultrasonic metering technology is more and more mature, and the new metering technology is accepted and accepted by the market. From the development of the current industry, the ultrasonic metering technology will be the trend of the future electronic metering development of the gas and water industry.

However, the core technology of ultrasound is still held in foreign enterprises, such as: loose, love, west gram, etc. Thus, during domestic use, the verbal rights of price and supply are often limited. To get rid of the limitation and fully popularize the ultrasonic metering technology, the localization of the core technology is imperative.

Disclosure of Invention

Aiming at the defects in the prior art, the invention provides a method for automatically adjusting the echo of an ultrasonic meter, which compares the first wave of the echo of the ultrasonic meter with a plurality of groups of threshold values with different sizes and adjusts the amplitude of the first wave of the echo through different flight time difference values obtained after comparison, thereby realizing the automatic gain function of the ultrasonic meter.

In order to solve the phenomenon of wave jump, the method provides a method for comparing a plurality of groups of threshold values. I.e. setting the reference voltages V of the plurality of sets of comparators_refThrough different groups V_refComparing the obtained average value of the flight time of the ultrasonic wave to automatically adjust the head wave amplitude of the ultrasonic wave echo, namely the head wave amplitude is larger than n groups of V_refMedium high block, while the echo noise cannot be larger than n blocks V_refAnd (4) low area group in the middle, thereby ensuring the reliability of the flight time of the ultrasonic wave.

A method for automatically adjusting echo of an ultrasonic meter comprises the following steps:

and (1) setting reference voltages of n groups of comparators according to different proportions of the minimum value of the head wave based on the minimum value of the head wave amplitude required by the ultrasonic flight time timing. Then according to the proportion from large to small, the materials are divided into high area groups V_{ref is high}Middle zone group V_{In ref}And low block group V_{ref is low}；

Step (2), respectively setting normal ranges of echo periods, wherein the normal ranges are respectively T according to the sizes_{Big (a)}、T_SmallAnd the hopping threshold is T.

Step (3) time measurement of one period is carried out according to reference voltages of the n groups of comparators, the flight time of the arriving head wave is collected, and three subareas V are calculated_{ref is high}、V_{In ref}、V_{ref is low}Corresponding time of flight mean T_{Height of}、T_InT_{Is low in}。

And (4) judging the average value of the flight time according to the set normal range size and the wave-hopping threshold of the echo period.

When T is_{Is low in}<T_SmallOr T_{Is low in}>T_{Big (a)}If the noise is judged to be excessive due to an excessive amplification factor, the amplification factor of the variable amplifier is reduced by N times (3. ltoreq. N) of the minimum variable quantity of the variable amplifier. And (4) restarting the step (3).

Step (5) when T is reached_{Height of}<T_SmallOr T_{Height of}>T_{Big (a)}Or T_In<T_SmallOr T_In>T_{Big (a)}The influence of noise is determined. And (4) restarting the step (3).

Step (6) when T is reached_{Height of}-T_In>And T, judging that the 'jump wave' occurs, increasing the amplification factor of the variable amplifier according to the minimum variable quantity of the variable amplifier, restarting the step (3), and measuring a new period until T_{Height of}-T_In<T; when T is_{Height of}-T_{Is low in}<And T, judging the noise influence, ignoring the measurement data of the current round, and performing measurement of a new period again.

Step (7) when T is reached_In-T_{Is low in}>T, judging that the 'jump wave' occurs, increasing the amplification factor of the variable amplifier according to the minimum variable quantity of the variable amplifier, restarting the step (3), and measuring a new period; t is_{Height of}-T_{Is low in}<And T, judging the noise influence, ignoring the current round of measurement data and restarting the step (3).

Step (8) and finally, when T is reached_{Height of}-T_In<T and T_In-T_{Is low in}<T, obtaining the effective flight time T in the quilt period_In。

Further, dividing n groups of comparator reference voltages into partitions according to the proportion of the amplitude of the head wave: when 0.7 Vol is not less than Vref not more than 0.9 Vol, the block is divided into high blocks V_{ref is high}When 0.4 Vol is not more than Vref and less than 0.7 Vol, the intermediate block V is divided into_{In ref}When 0.2 Vol is not more than Vref and less than 0.4 Vol, the low-level block V is divided into_{ref is low}。

The invention has the following beneficial effects:

the method can quickly realize the automatic adjustment of the size of the ultrasonic wave echo, control the size of the echo within a required range, ensure the accurate measurement of the flight time of the ultrasonic wave and finally ensure the accuracy and the reliability of the ultrasonic wave measurement. Of course, the application of this method needs high-quality echo signals as a basis, so the localization of the ultrasonic metering core technology puts high requirements on hardware design.

Drawings

FIG. 1 is a schematic block diagram of an ultrasonic meter receiving section;

FIG. 2 is a diagram of an ultrasonic metrology echo waveform;

FIG. 3 is a waveform diagram of an ultrasonic measurement echo compared to a reference voltage;

fig. 4 is a comparative level change waveform diagram.

Detailed Description

The method of the invention is further described below with reference to the accompanying drawings and examples.

The schematic block diagram of the ultrasonic measurement receiving part is shown in fig. 1, and generally comprises a receiving end ultrasonic transducer, one-stage or multi-stage fixed amplification, two-stage variable amplification, a comparator and a TDC timing chip. The original waveform received by the transducer at the receiving end is generally only dozens of mv different, and enters the comparator after fixed and variable multi-stage amplification, and the comparator outputs standard pulse waves to reach a TDC timing chip to finish time measurement transmitted to the receiving.

The waveform after multistage amplification, i.e. the comparator front-end waveform, is shown as 1 in fig. 2. Wherein the amplitude of the head wave is close to 1 v. Reference voltage V of comparator_refIs a fixed value, assume that V is now_ref500mv, the amplitude of the head wave is larger than V_refThe time of the head wave will be measured as shown in figure 3. However, the amplitude of the original waveform at the receiving end changes with the difference of temperature, pressure and medium components, the amplitude of the head wave before reaching the comparator changes, if the amplitude of the head wave is smaller than the reference voltage of the comparator, the time of the head wave is ignored, the phenomenon is generally called as the wave jump phenomenon of ultrasonic measurement, and the phenomenon is also the ultrasonic measurement technologyThe most central and difficult problem in the art.

Dividing reference voltages of n groups of comparators in a partition mode according to the proportion of the amplitude of the head wave: when 0.7 Vol is not less than Vref not more than 0.9 Vol, the block is divided into high blocks V_{ref is high}When 0.4 Vol is not more than Vref and less than 0.7 Vol, the intermediate block V is divided into_{In ref}When 0.2 Vol is not more than Vref and less than 0.4 Vol, the low-level block V is divided into_{ref is low}。

Step (6) when T is reached_{Height of}-T_In>T, judging outAnd (4) increasing the amplification factor of the variable amplifier according to the minimum variable quantity of the variable amplifier, restarting the step (3), and measuring a new period until T_{Height of}-T_In<T; when T is_{Height of}-T_{Is low in}<And T, judging the noise influence, ignoring the measurement data of the current round, and performing measurement of a new period again.

In this patent, three groups of V are used_refFor example. In connection with FIG. 2, assume three groups V_refAre each V_ref1＝700mv，V_ref2＝500mv，V_ref3300 mv. During a period of time measurement, according to V_ref1、V_ref2、V_ref3The flight times of the collected first arrival waves are respectively T₁、T₂、T₃Magnification is defined as D_xThe normal range of the echo period is T_a、T_bThe hopping threshold is Tc. After completion of a measurement cycle, when T₃<T_bOr T₃>T_aWhen the amplification factor is too large, the noise is too large, and D is set_x＝D_x-5, a new measurement period; when T is_b<T₃<T_aWhile at the same time T_b<T₂<T_aAnd T_b<T₁<T_aEntering a process of judging 'wave jumping', otherwise judging as noise influence, and restarting a new measurement period; after entering judgment of 'wave jump', the signal is processed as T₁-T₂>Tc, judging the occurrence of 'wave jump', at this moment, setting D_X＝D_X+1, restart a new measurement cycle;；T₁-T₂<and Tc, judging the influence of noise, ignoring the measurement data of the current round and restarting a new measurement period. When is-T<T₁-T₂<At Tc, then T is determined₂And T₃. In the same way, when T₂-T₃>Tc, judging the occurrence of 'wave jump', at this moment, setting D_X＝D_X+1, restart a new measurement cycle; t is₂-T₃<And Tc, judging the influence of noise, ignoring the measurement data of the current round and restarting a new measurement period. Finally, when is-Tc<T₃-T₂<Tc, and-Tc<T₂-T₁<Tc, to obtain the effective flight time T₂And applied to subsequent algorithms.

This method has been applied to actual product development, as shown in fig. 4, 2, and achieves good results.

Claims

1. A method for automatically adjusting echo of an ultrasonic meter is characterized by comprising the following steps:

step (1), setting reference voltages of n groups of comparators according to different proportions of the minimum value of the head wave based on the minimum value of the head wave amplitude required by ultrasonic flight time timing; then according to the proportion from large to small, the materials are divided into high area groups V_{ref is high}Middle zone group V_{In ref}And low block group V_{ref is low}；

Step (2), respectively setting normal ranges of echo periods, wherein the normal ranges are respectively T according to the sizes_{Big (a)}、T_SmallThe wave hopping threshold is T;

step (3) time measurement of one period is carried out according to reference voltages of the n groups of comparators, the flight time of the arriving head wave is collected, and three subareas V are calculated_{ref is high}、V_{In ref}、V_{ref is low}Corresponding time of flight mean T_{Height of}、T_InT_{Is low in}；

Step (4), judging the average value of the flight time according to the set normal range size and the wave-hopping threshold value of the echo period;

when T is_{Is low in}<T_SmallOr T_{Is low in}>T_{Big (a)}If the noise is over-large due to over-large amplification factor, reducing the amplification factor of the variable amplifier according to N times (N is more than or equal to 3) of the minimum variable quantity of the variable amplifier; restarting the step (3);

step (5) when T is reached_{Height of}<T_SmallOr T_{Height of}>T_{Big (a)}Or T_In<T_SmallOr T_In>T_{Big (a)}Judging the influence of noise; restarting the step (3);

step (6) when T is reached_{Height of}-T_In>And T, judging that the 'jump wave' occurs, increasing the amplification factor of the variable amplifier according to the minimum variable quantity of the variable amplifier, restarting the step (3), and measuring a new period until T_{Height of}-T_In<T; when T is_{Height of}-T_{Is low in}<T, judging the noise influence, neglecting the measurement data of the current round, and measuring the new period again;

step (7) when T is reached_In-T_{Is low in}>T, judging that the 'jump wave' occurs, increasing the amplification factor of the variable amplifier according to the minimum variable quantity of the variable amplifier, restarting the step (3), and measuring a new period; t is_{Height of}-T_{Is low in}<-T, judging as noise influence, ignoring the current round of measurement data, and restarting the step (3);

2. The method for automatically adjusting the echo of an ultrasonic meter according to claim 1, wherein the n groups of comparator reference voltages are partitioned according to the ratio of the head wave amplitude: when 0.7 Vol is not less than Vref not more than 0.9 Vol, the block is divided into high blocks V_{ref is high}When 0.4 Vol is not more than Vref and less than 0.7 Vol, the intermediate block V is divided into_{In ref}When 0.2 Vol is not more than Vref and less than 0.4 Vol, the low-level block V is divided into_{ref is low}。