KR101764870B1 - Signal processing system for ultrasonic floemeter - Google Patents

Signal processing system for ultrasonic floemeter Download PDF

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KR101764870B1
KR101764870B1 KR1020150134546A KR20150134546A KR101764870B1 KR 101764870 B1 KR101764870 B1 KR 101764870B1 KR 1020150134546 A KR1020150134546 A KR 1020150134546A KR 20150134546 A KR20150134546 A KR 20150134546A KR 101764870 B1 KR101764870 B1 KR 101764870B1
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South Korea
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signal
ultrasonic
cycle
sum
ultrasonic signal
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KR1020150134546A
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Korean (ko)
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KR20170035555A (en
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어용
배일진
김정훈
김성진
고재유
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주식회사 에스앤씨
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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01F—MEASURING VOLUME, VOLUME FLOW, MASS FLOW OR LIQUID LEVEL; METERING BY VOLUME
    • G01F1/00—Measuring the volume flow or mass flow of fluid or fluent solid material wherein the fluid passes through a meter in a continuous flow
    • G01F1/66—Measuring the volume flow or mass flow of fluid or fluent solid material wherein the fluid passes through a meter in a continuous flow by measuring frequency, phase shift or propagation time of electromagnetic or other waves, e.g. using ultrasonic flowmeters
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01F—MEASURING VOLUME, VOLUME FLOW, MASS FLOW OR LIQUID LEVEL; METERING BY VOLUME
    • G01F1/00—Measuring the volume flow or mass flow of fluid or fluent solid material wherein the fluid passes through a meter in a continuous flow
    • G01F1/66—Measuring the volume flow or mass flow of fluid or fluent solid material wherein the fluid passes through a meter in a continuous flow by measuring frequency, phase shift or propagation time of electromagnetic or other waves, e.g. using ultrasonic flowmeters
    • G01F1/662—Constructional details

Abstract

Disclosure relates to a signal processing system of an ultrasonic flowmeter, in which a pair of oscillators for oscillating an ultrasonic signal having a set transmission frequency are arranged on one side and the other side of an object to be measured, respectively, and the pair of oscillators And a pair of receivers respectively disposed on one side and the other side of the object to be measured so as to correspond to the ultrasonic wave flowmeter and the ultrasonic flowmeter, ; And an A / D converter (Analog to Digital Converter) for sampling a signal detected by the detector at a predetermined number of times per period and detecting a waveform of the detected signal, wherein the first periodic ultrasonic signal And And a measuring unit calculating a flow rate at a measurement point at a position shifted by a measurement period set based on the first periodic ultrasonic signal determined by the conversion unit.

Description

TECHNICAL FIELD [0001] The present invention relates to a signal processing system for an ultrasonic flowmeter,

Disclosure relates to a signal processing system of an ultrasonic flowmeter, and more particularly, to a signal processing system of an ultrasonic flowmeter capable of reducing an error of a flow rate measured from a signal obtained from an ultrasonic flowmeter.

Herein, the background art relating to the present invention is provided, and they are not necessarily referred to as known arts.

The speed at which the sound waves travel in the direction of flowing through the fluid is faster than the speed at which they travel in the opposite direction. An ultrasonic flowmeter is a device that measures the velocity of a fluid by comparing the difference between these two propagation velocities.

Ultrasonic flow meters are also used in many semiconductor processes, for example, cleaning and measurement of flow rate of chemical liquid chemicals in etching nozzles.

In the case of the conventional ultrasonic flowmeter, the ultrasonic signal is searched by the frequency only on the receiving side to filter the ultrasonic signal to measure the flow rate. At this time, if the temperature of the semiconductor chemical solution changes suddenly, the ultrasonic wave transmission time may change, and accurate measurement points may be missed, and a flow measurement error may occur by measuring a noise signal at a certain frequency.

Specifically, the digital conversion of the measured ultrasound signal is digitally converted into a square wave pulse using a zero-cross technique in the converter.

The flow rate is displayed after time measurement using TDC (Time to Digital Converter) IC according to the specific signal of the converted pulse.

Accordingly, if the measurement point is not constantly fixed in a specific period of the ultrasonic signal, a flow error due to a time offset is generated.

Even if the frequency of the ultrasound sensor at both ends of the detection unit is constantly maintained, an error still exists.

In order to reduce the error of each waveform period, it is necessary to measure the measurement point while keeping the measurement point always constant.

If the start signal is correctly found, it can be synchronized with the TDC IC according to the specific signal that is the basis of the time measurement.

Conventionally, as a method of finding the start signal and filtering the noise waveform, a frequency equal to the ultrasonic transmission frequency is searched and found on the receiving side.

If a signal of the same frequency as the ultrasonic sensor natural frequency (ex, 2Mhz) is detected, it is judged as a measurement waveform.

This is because the noise waveform can be filtered by the above technique because it does not match with the natural frequency of the ultrasonic signal and continuously changes.

However, the amplitude of the ultrasonic signal may change due to bubbles flowing into the chemical solution inside the detection unit or other environmental factors.

If a decrease in amplitude occurs, the first periodic amplitude of the ultrasonic wave is relatively small and may disappear and may not be detected.

In this case, when the first periodic ultrasonic signal is sensed and the measurement point is moved to a specific period and measured, the measurement point is shifted by one cycle, and a flow error can be generated.

In addition, the noise waveform has a very low probability, but it may cause errors in the measurement by matching with the reference frequency of the ultrasonic sensor. This disadvantage is a disadvantage of the frequency-based waveform filtering method.

1. Patent Document 0001) Japanese Laid-Open Patent Publication No. 2012-193966 2. Patent Document 0002) Korean Patent Publication No. 10-1330032

It is an object of the present invention to provide a signal processing system of an ultrasonic flowmeter capable of minimizing a flow error by detecting a first period ultrasonic signal without error and keeping a measurement point constant.

The present invention is not intended to be exhaustive or to limit the scope of the present invention to the full scope of the present invention. of its features).

In order to solve the above-described problems, the present disclosure relates to an ultrasonic diagnostic apparatus having a pair of oscillators for oscillating an ultrasonic signal at a set transmission frequency, arranged on one side and the other side of an object to be measured, 1. A signal processing system for an ultrasonic flowmeter having a pair of receivers disposed on one side and the other side of a water, comprising: a detector for detecting an ultrasonic signal oscillated from the pair of oscillators from a signal received by the pair of receivers; And an A / D converter (Analog to Digital Converter) for sampling a signal detected by the detector at a predetermined number of times per period and detecting a waveform of the detected signal, wherein the first periodic ultrasonic signal And And a measuring unit calculating a flow rate at a measurement point at a position shifted by a measurement period set based on the first periodic ultrasonic signal determined by the conversion unit.

The present disclosure provides a signal processing system of an ultrasonic flowmeter according to the first invention, wherein the detection unit searches for and detects a signal having the same frequency as the set transmission frequency as a second invention.

The present invention relates to a signal processing system for an ultrasonic flowmeter according to the first aspect of the present invention, wherein the converting unit samples signals of at least cycles longer than the measurement cycle in the forward and backward directions on the basis of the measurement points, A signal processing system of an ultrasonic wave flowmeter for determining the first periodic ultrasonic signal by comparison is provided as a third invention.

The signal processing system of the ultrasonic flowmeter according to the third aspect of the present invention is characterized in that when the sum of the sampling values for each cycle is not less than a predetermined value, the sum of the sampling values for each cycle is compared, A signal processing system of an ultrasonic wave flow meter for determining a signal is provided as a fourth invention.

The signal processing system of the ultrasonic flowmeter according to the third invention is characterized in that when the sum of the sampling values for each cycle continuously increases by three or more cycles, the sum of the sampling values for each cycle is compared, A signal processing system of an ultrasonic wave flow meter for determining a first period ultrasonic signal is provided as a fifth invention.

The present invention provides a signal processing system for an ultrasonic flowmeter according to the third aspect of the present invention, wherein the converting unit comprises: an amplifying unit for amplifying the amplified signal so that a sum of sampling values for each cycle is equal to a set steady- A signal processing system of a flow meter is provided as a sixth invention.

The signal processing system of the ultrasonic flowmeter according to the third aspect of the present invention further comprises a scope unit for outputting the detected ultrasonic signals in real time on the basis of the sampling values for each cycle, This is provided as a seventh invention.

According to the present disclosure, since the ultrasonic signal received by using the A / D converter is sampled to accurately sense the first-period ultrasonic signal, the error of the flow measurement can be minimized.

According to the present disclosure, noise can be discriminated by the size of a sampled ultrasonic signal, and a flow measurement error due to a noise signal can be eliminated.

1 is a block diagram showing an embodiment of a signal processing system of an ultrasonic flowmeter according to the present disclosure;
Fig. 2 is a block diagram showing a modification of Fig. 1. Fig.
Fig. 3 is a block diagram showing another modification of Fig. 1. Fig.

Various embodiments for implementing the signal processing system of the ultrasonic flowmeter according to the present disclosure will be described below with reference to the drawings.

It should be understood, however, that there is no intention to limit the scope of the present disclosure to the embodiments described below, and that those skilled in the art, having the benefit of the teachings of this disclosure, It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit or scope of the invention.

In addition, the terms used below are selected for convenience of explanation. Therefore, in order to grasp the technical contents of the present disclosure, they should be interpreted appropriately in accordance with the technical idea of the present disclosure without being limited to the prior meaning.

1 is a block diagram showing an embodiment of a signal processing system of an ultrasonic flowmeter according to the present disclosure.

1, the signal processing system 10 of the ultrasonic flowmeter according to the present embodiment includes a pair of oscillators 12 attached to an object 11 to be measured and a signal obtained through a pair of receivers 13 And includes a detecting unit 14, a converting unit 15, and a measuring unit 17 for increasing the accuracy of the flow rate measured.

The pair of oscillators 12 oscillate ultrasonic signals of the set transmission frequency and are disposed on one side and the other side of the measured object 11, respectively.

The pair of receivers 13 are respectively disposed on one side and the other side of the measured object 11 so as to correspond to the pair of oscillators 12 and receive ultrasonic signals oscillated by the pair of oscillators 12 And receives a variety of signals including.

The detection unit 14 detects ultrasonic signals oscillated from the pair of oscillators 12 from various signals received by the pair of receivers 13.

The detection unit 14 searches for and detects a signal having the same frequency as the set transmission frequency (for example, 2 MHz) oscillated by the pair of oscillators 12.

The converting unit 15 has an A / D converter 16 (analog to digital converter) that samples the signal detected by the detecting unit 14 a predetermined number of times per cycle and detects the waveform of the detected signal, The first periodic ultrasonic signal is determined based on the waveform of the signal.

Specifically, when the detection of the ultrasonic signal is completed by the detection unit 14, the A / D converter 16 samples the preceding and succeeding five cycles of 16 samples per cycle on the basis of a specific period as a reference of time measurement The ultrasonic signal is internally drawn.

On the other hand, the converting unit 15 can accurately specify the position of the ultrasonic signal by adding all 16 sampling values per one cycle, and then comparing the sum with the sum of the sampling values of the preceding cycle.

The measuring unit 17 calculates the flow rate at the measurement point at a position shifted by a measurement period (for example, three cycles) set on the basis of the first periodic ultrasonic signal determined by the conversion unit 15.

On the other hand, in the present embodiment, the conversion unit 15 compares the sum of the sampling values for each cycle to determine the first cycle ultrasonic signal, provided that the sum of the sampling values for each cycle is equal to or larger than a set value .

Specifically, the conversion unit 15 recognizes the waveform as an ultrasonic waveform if the sum of the sampling values for each cycle is equal to or greater than a predetermined value, and the sum of the sampling values is maintained at a predetermined value or more from the first cycle ultrasonic signal to the next five cycles.

For example, if the sum of the sampling values of the first and second periods is greater than a predetermined value, but the sum of the sampling values of the third and fourth periods is very small or large, it is regarded as noise and re- do.

On the other hand, in the present embodiment, the conversion unit 15 determines the first period ultrasonic signal by comparing the sum of the sampling values for each cycle when the sum of the sampling values for each cycle continuously increases by three or more cycles. That is, since the normal ultrasonic waves are generated in the form of 1 <2 <3 periodic waveforms per period, signals not generated by these rules are regarded as noise and filtered.

2, the converting unit 15 may further include an amplifying unit 18 for amplifying the sum of the sampled values for each cycle to be equal to the set steady wave value to adjust the amplitudes.

The amplifying unit 18 ensures that the effect of the present disclosure by the A / D converter 16 is stably realized. In other words, in order for the effect of the present disclosure by the A / D converter 16 to be realized normally, the amplitude of the ultrasonic waveform must always be kept constant.

When the amplitude of the ultrasonic waveform becomes small, the first waveform disappears and the measurement point can be shifted even if it is sampled by the A / D converter 16.

Accordingly, the amplifying unit 18 implements an automatic amplification function that always maintains the amplitude at a constant magnitude even if the amplitude of the internal pipeline is changed due to inflow of bubbles and external environmental factors.

Specifically, if the sum of the sampling values for each cycle is smaller or larger than the predetermined standing wave value, the amplification unit 18 changes the amplification magnification to be equal to the sum of the sampling values of the standing wave, do. According to this, the error caused by the change of the measurement waveform period due to the amplitude change of the first period can be reduced.

3, it is preferable that the present disclosure further includes a scope unit 19 for outputting detected ultrasound signals in real time on the basis of sampling values for each cycle.

The scope unit 19 refers to a monitoring program. The ultrasonic signal is graphically plotted in real time, so that the user can visually confirm the ultrasonic signal without a separate measuring instrument.

Claims (7)

A pair of oscillators for oscillating an ultrasonic signal of a set transmission frequency are arranged on one side and the other side of the object to be measured and are arranged on one side and the other side of the object to be measured so as to correspond to the pair of oscillators, In a signal processing system of an ultrasonic flowmeter having a receiver of the present invention,
A detector for detecting an ultrasonic signal oscillated from the pair of oscillators from a signal received by the pair of receivers;
And an A / D converter (Analog to Digital Converter) for sampling a signal detected by the detector at a predetermined number of times per period and detecting a waveform of the detected signal, wherein the first periodic ultrasonic signal And And
And a measuring unit for calculating a flow rate at a measurement point at a position shifted by a measurement period set based on the first periodic ultrasonic signal determined by the conversion unit,
Wherein the converting unit samples the signal of at least the period longer than the measurement period before and after the measurement point and compares the sum of the sampling values of each cycle to determine the first periodic ultrasonic signal. Processing system. The method according to claim 1,
Wherein the detection unit searches for and detects a signal having the same frequency as the set transmission frequency. delete The method according to claim 1,
Wherein the converting unit determines the first periodic ultrasonic signal by comparing the sum of the sampling values for each cycle when the sum of the sampling values for each cycle is equal to or greater than a predetermined value. The method according to claim 1,
Wherein the conversion unit determines the first periodic ultrasonic signal by comparing the sum of the sampling values for each cycle when the sum of the sampling values for each cycle continuously increases for three or more cycles. The method according to claim 1,
Wherein the converting unit further comprises an amplifying unit for amplifying the sum of the sampled values for each cycle so as to be equal to the set steady wave value to adjust the amplitude. The method according to claim 1,
And a scope unit for outputting the detected ultrasonic signal in real time based on the sampling value for each cycle.
KR1020150134546A 2015-09-23 2015-09-23 Signal processing system for ultrasonic floemeter KR101764870B1 (en)

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR102372259B1 (en) 2021-09-03 2022-03-10 주식회사 에스앤씨 U type ultrasonic flow meter piping structure

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN107907173A (en) * 2017-12-14 2018-04-13 湖北天禹环保科技有限公司 A kind of analog-digital converter for ultrasonic gas flowmeter
CN116608917B (en) * 2023-07-19 2023-09-22 成都秦川物联网科技股份有限公司 Gas ultrasonic metering instrument metering anti-interference method and intelligent gas Internet of things system

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JP5531993B2 (en) 2011-03-15 2014-06-25 パナソニック株式会社 Flow measuring device
JP5512007B1 (en) 2013-03-15 2014-06-04 株式会社又進 Detection method using DFT cross-correlation method

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR102372259B1 (en) 2021-09-03 2022-03-10 주식회사 에스앤씨 U type ultrasonic flow meter piping structure

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