CN103148897A - Digital intelligent vortex shedding flowmeter based on DSP and metering method of same - Google Patents
Digital intelligent vortex shedding flowmeter based on DSP and metering method of same Download PDFInfo
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Abstract
The invention discloses a digital intelligent vortex shedding flowmeter based on DSP and a metering method of the flowmeter. The digital intelligent vortex shedding flowmeter comprises a signal detection module, a spectrum analysis module, a signal output module, a man-machine interface module, a parameter storage module, a monitoring module and a power supply module, wherein the signal detection module comprises a vortex street signal detection circuit and an interference detection circuit, the spectrum analysis module is achieved through a digital signal processing chip and comprises an analog-digital conversion unit, a digital band pass filtering unit, an interpolation FFT (Fast Fourier Transform Algorithm) calculating unit and an intelligent arithmetic rule unit. According to the metering method provided by the invention, on the basis of two paths of signal detection and spectrum analysis, vortex street signal frequency under the condition that vortex street signal strength is smaller than on-site vibration interference intensity can be efficiently extracted through intelligent algorithmic rule, and the metering method is better on the aspects of anti-interference performance, reliability, stability and the like.
Description
Technical field
The invention belongs to field of flow detection, be specifically related to a kind of digital intelligent vortex shedding flow meter and metering method based on digital signal processor DSP.
Background technology
The vortex shedding flow meter development is rapid, and range of application is more and more extensive, and vortex street sensor and vortex signal frequency abstraction technology are two gordian techniquies in the vortex shedding flow meter design process.Vortex street sensor relates to hydromechanical knowledge, and the correlative study of the secondary instrument that is based on vortex signal frequency abstraction technology that we more pay close attention to.
The method that the tradition vortex signal extracts mainly goes on foot by amplification, filtering, shaping, counting etc. four and realizes, the main work of first three is completed by the analog hardware circuit, and counting is realized by MCU.Range by this vortex signal extracting method designed system is low, is subject to electromagnetism and on-the-spot the interference.The technical essential that can summarize the vortex signal extraction from traditional method has two, is respectively obtaining of signal filtering and vortex signal spectrum information.Because the research of signal spectral analysis method is relatively ripe, therefore in vortex signal extracted, signal analysis methods such as wavelet transformation, modern spectrum analysis, notch filter, FFT had the scholar's research mistake.With respect to traditional method, all the method than traditional is higher for the frequency resolution of the frequency spectrum analysis method that these are realized by software algorithm, but considers the real-time that works offline of secondary instrument, and these methods are fewer in actual applications.FFT can satisfy the requirement of real-time, but owing to existing " fence effect " to tend to cause spectral leakage.
Vortex signal has the easy noise of low-frequency range, the obvious characteristics of high band feature, is subject to on-the-spot noise when low-frequency range.The present research that vortex signal is extracted is often based on one-channel signal, and the result that causes is when undesired signal is better than vortex signal, and the former can cover the latter, and the vortex signal that finally obtains is undesired signal in fact.
Summary of the invention
Be subject to for the hardware signal processing circuit technical matterss such as defective that real-time that external interference, instrument work offline and accuracy requirement and single channel transducing signal gather, the invention provides a kind of digital intelligent vortex shedding flow meter and metering method thereof based on DSP.
A kind of digital intelligent vortex shedding flow meter based on DSP comprises signal detection module, signal output module, human-machine interface module and power module, and described signal detection module comprises vortex signal testing circuit and disturbance detection circuit; Described intelligent vortex shedding flowmeter also comprises spectrum analysis module, and described spectrum analysis module comprises:
AD conversion unit is used for the two-way detection signal of described signal detection module output is converted to digital signal;
The digital band pass filter unit is used for the digital signal of described AD conversion unit output is carried out bandpass filtering;
The interpolation FFT computing unit is used for the filtered digital signal of described digital band pass filter unit output is carried out spectrum analysis, obtains the spectrum information of the harmonic wave of described signal detection module two-way detection signal;
Intelligent algorithm rule unit is used for the spectrum information of the harmonic wave of more described two-way detection signal, extracts the frequency of vortex signal.
Further, described intelligent vortex shedding flowmeter also comprises the monitoring modular that is connected with spectrum analysis module, and described monitoring modular is watchdog circuit.Described watchdog circuit is set certain work period as the time cycle of feeding dog, if intelligent vortex shedding flowmeter work of the present invention is broken down, just can't in time feed dog, watchdog circuit just can be to the reset terminal transmitting system reset signal of dsp chip so.
Further, described intelligent vortex shedding flowmeter also comprises the parameter memory module that is connected with spectrum analysis module, is used for the important parameters such as storage integrated flux, and when preventing the flowmeter power down, parameter is lost.
Further, the hardware circuit of described vortex signal testing circuit and disturbance detection circuit includes sensor, and charge amplifier and pre-filtering circuit, described sensor are piezoelectric sensor.Be used for minute two-way and gather vortex signal and on-the-spot vibration interference, and it is amplified rear by outputing to spectrum analysis module after low-pass filtering and buffering isolation.
Further, described spectrum analysis module is digital signal processor DSP (Digital Signal Processing is called for short DSP).The intelligent algorithm rule that the groundwork of vortex shedding flow meter comprises filtering, signal spectral analysis and rejects on-the-spot dominant interference all realizes by software in DSP.
Further, described digital intelligent vortex shedding flow meter, also comprise mu balanced circuit, described mu balanced circuit comprises a voltage stabilizer, be used for the reference voltage of described power module output is changed into the input voltage of described analog-to-digital conversion module, special voltage stabilizing produces circuit and be better than internal reference voltage on stability.
The invention allows for the metering method based on above-mentioned digital intelligent vortex shedding flow meter, comprise step:
(1), respectively vortex signal and undesired signal are detected acquisition two-way detection signal;
(2), detected two-way detection signal is sampled, change digital signal into;
(3), digital signal is carried out filtering, do the interpolation FFT based on amplitude, obtain the spectrum information of the harmonic wave of two-way detection signal;
(4), the spectrum information of the harmonic wave of two-way detection signal relatively, by the frequency of intelligent algorithm Rule Extraction vortex signal;
(5), through conversion delivery rate metrical information.
Wherein, the spectrum information of described harmonic wave comprises the amplitude mean value of harmonic wave, the amplitude of harmonic wave and the frequency indices value of harmonic wave.
Further, described step (3) comprises step:
(3.1), digital signal is carried out filtering, digital signal after filtering is made FFT, the spectrum information of the corresponding harmonic wave of storage, first of storage array is exactly harmonic amplitude mean value;
(3.2), determine main lobe by frequency spectrum, find the amplitude maximal value spectral line in main lobe, record its amplitude information X1 and frequency indices value K1;
(3.3), find the frequency indices value for (K1-1), (K1+1) corresponding spectral line, in these two spectral lines, the larger spectral line of amplitude is recorded as the second largest value spectral line, its amplitude is X2, the frequency indices value is K2;
(3.4), calculate frequency indices value corrected parameter δ by X1 and X2, specifically be calculated as follows
(3.5), can be obtained at last the frequency indices K of dominant frequency signal by corrected parameter δ and K1, specifically be calculated as follows:
K＝K1±δ。
Further, suppose that A1 is vortex signal branch road harmonic amplitude maximal value, A2 is undesired signal branch road harmonic amplitude maximal value, F1 is the frequency indices value of the corresponding spectral line of vortex signal branch road harmonic amplitude maximal value, F2 is the frequency indices value of the corresponding spectral line of undesired signal branch road harmonic amplitude maximal value, and Aa1 is vortex signal branch road amplitude mean value, and Aa2 is undesired signal branch road amplitude mean value, F is final vortex signal dominant frequency frequency indices value, and described step (4) comprises step:
(4.1) the harmonic amplitude maximal value of two-way detection signal relatively, if A1＜A2, expression is measured and is occurred extremely, is invalid data, vortex shedding flow meter proposes abnormality warnings, and abandons this measurement result; If A1＞=A2 enters next step;
Whether the harmonic amplitude maximal value A1 that (4.2) judges the two-way detection signal equates with A2, if equate to continue the relatively amplitude mean value of two-way harmonic wave, if Aa1=Aa2 can judge that the vortex signal branch road is blank pipe, finishes; If Aa1 ≠ Aa2, with F1, F2 the amplitude of corresponding spectral line make zero, return to step (4.1); If A1〉A2, carry out next step;
(4.3) compare F1 and F2, if F1＞=F2, the frequency indices value that judges vortex signal is F1; Otherwise expression is measured and is occurred extremely being invalid data, and vortex shedding flow meter proposes abnormality warnings, and abandons this measurement result.
Digital intelligent vortex shedding flow meter and metering method thereof based on DSP that the present invention proposes, with respect to classic method, only adopt a DSP, device reduces, cost, anti-interference and reliability strengthen, and use digital Chebyshev's bandpass filter, software algorithm realizes, improved the dirigibility that system carries out filtering; Use satisfies the requirement of real-time of system off-line work based on the interpolation FFT of amplitude, improved simultaneously the deficiency of the spectral leakage that FFT causes due to " fence effect ", improved the accuracy of spectrum analysis; The intelligent algorithm rule has been widened the low-frequency range range, the vortex signal frequency in the time of can effectively extracting vortex signal intensity less than on-the-spot vibration interference intensity simultaneously; Based on the spectrum analysis of two paths of signals detection and two paths of signals, can widen thus the measurement range of low-frequency range, the dominant frequency input when completing interference strength greater than vortex signal intensity.
Description of drawings
Fig. 1 is the structural representation of digital intelligent vortex shedding flow meter of the present invention;
Fig. 2 is the circuit diagram of charge amplifier in testing circuit of the present invention;
Fig. 3 is pre-filtering circuit diagram in testing circuit of the present invention;
Fig. 4 is the circuit diagram of AD conversion unit voltage stabilizing circuit for generating of the present invention;
Fig. 5 is the watchdog circuit figure of monitoring modular of the present invention;
Fig. 6 is digital intelligent flux of vortex street metering method process flow diagram of the present invention;
Fig. 7 is the interpolation FFT algorithm flow chart that the present invention is based on amplitude;
Fig. 8 is intelligent algorithm rule process flow diagram of the present invention.
Embodiment
Below in conjunction with drawings and Examples, technical solution of the present invention is described in further details, following examples do not consist of limitation of the invention.
The invention provides a kind of digital intelligent vortex shedding flow meter based on DSP, its hardware configuration comprises signal detection module, spectrum analysis module, signal output module, human-machine interface module, parameter memory module, monitoring modular and power module as shown in Figure 1.Signal detection module comprises the two paths of signals testing circuit, is respectively vortex signal testing circuit and disturbance detection circuit, and one the tunnel is used for gathering vortex signal, comprising vortex signal and on-the-spot vibration interference, and another road collection site vibration interference.Two alignment detection circuit hardware handles circuit are identical, all comprise sensor, charge amplifier, pre-filtering.
Being illustrated in figure 2 as the charge amplifier unit, is mainly the piezoelectric sensor signal to be carried out electric charge amplify, and it comprises an operational amplifier U2,3 resistance R 3, R4, R5, and 4 capacitor C 3, C4, C5, C6, operational amplifier adopts the OP07 of TI company; Its annexation is: the end of C3, R4, C5 is connected with No. 3 ports of U2, the end of C4, R5, C6 is connected with No. 2 ports of U2,7, No. 4 ports of U2 connect respectively positive and negative 12V direct current, simulating signal after No. 6 port outputs of U2 are amplified also is connected with the other end of R5, C6, the other end of R4, C5 is connected to the ground, the C3 other end, R3 one end are connected with the sensor signal input end, and the C4 other end, another input end of the R3 other end and sensor signal are connected.
Be illustrated in figure 3 as the circuit diagram of pre-filtering, signal is carried out simple low-pass filtering, and play buffering and isolate, it comprises an operational amplifier U1B, 2 resistance R 12, R23,27, one stabilivolt D2 of 1 capacitor C, stabilivolt has played the effect that limits maximum voltage value, and operational amplifier adopts the LM324N of TI; Its annexation is: the end of R12, R23, C27 is connected with No. 5 ports of U1B, the other end of R12 is connected with the output terminal of charge amplifier unit, the other end of R23, C27 is connected to the ground, 6, No. 7 ports of U1B and the end of oppisite phase of stabilivolt D2 are connected, the forward end ground connection of D2, the output terminal of U1B i.e. No. 7 ports are connected with the input end of AD conversion unit (A/D) in spectrum analysis module.
Spectrum analysis module of the present invention adopts digital signal processor DSP to realize, comprises 10 AD conversion unit (A/D), digital band pass filter unit, interpolation FFT computing unit and intelligent algorithm rule unit.The intelligent algorithm rule that the groundwork of vortex shedding flow meter comprises filtering, signal spectral analysis and rejects on-the-spot dominant interference all realizes by software in DSP.It is the TMS32LF2407A of TI company that the present embodiment adopts the DSP main control chip.
Be converted to digital signal after AD conversion unit in the two-way detection signal process DSP of signal detection module output, and be input to the digital band pass filter unit, then calculate by the interpolation FFT computing unit, on the basis of the spectrum information of the two paths of signals that calculates gained, extract the frequency of vortex signal by intelligent algorithm rule unit.Wherein the digital band pass filter unit adopts digital Chebyshev's bandpass filter, avoided the simulation that hardware filtering is brought into to disturb, numeral Chebyshev bandpass filter is a kind of filtering technique commonly used, at first will determine with logical width in design, foundation is the media type of pipe diameter and pipeline inner fluid; Next is that cutoff frequency, pass band damping ripple ratio, stopband attenuation three parameters such as compare and choose, and decides according to engineering demand.Concrete digital filter design divided for four steps, and is as follows:
(1) analog low-pass filter designs;
(2) it is logical that analog frequency band conversion-low pass becomes band;
(3) filter transform-simulation parameter word uses the two-wire conversion;
(4) filter parameters, whether analytical parameters meets design requirement.
Digital Chebyshev's bandpass filter that employing designs is carried out digital band pass filtering to the data of sampling, and this function is mainly the effect that has realized analog hardware filtering in the classic method.
Need to prove, the AD conversion unit in DSP is sampled to the two-way detection signal, and sample frequency is set according to the commercial Application background, and sampling number N is 2 integer power, and for example in the present embodiment, sampling number is 128, is 27 powers.The digital band pass filter unit carries out digital filtering to the data of sampling, what adopt is Chebyshev's bandpass filter, its bandwidth frequency is set according to concrete commercial Application background, and the corresponding vortex signal bandwidth of different bores and fluid media (medium) is different, repeats no more here.
In the DSP sheet, A/D can provide reference voltage by internal circuit, but special voltage stabilizing produces circuit and be better than internal reference voltage on stability, adopt the 2.5V voltage of outside voltage stabilizing circuit for generating generation as the reference source of A/D in the present embodiment, as shown in Figure 4, circuit for generating comprises 1 resistance R 9,1 capacitor C L, a voltage stabilizer U5, that sample in the present embodiment is the TL431 of TI company; Its annexation is: the end of R9, CL, the reference output terminal of U5 are connected with A/D reference source input end, the anode termination VCC of the other end of R9, U5, the negative electrode port ground connection of the other end of CL, U5.
To the sampled data after process digital band pass filtering unit filters, be input to the interpolation FFT computing unit and do frequency spectrum calculating, obtain respectively the spectrum information of the harmonic wave of vortex signal passage, undesired signal passage two-way detection signal, the spectrum information of harmonic wave comprises amplitude mean value, harmonic amplitude and the harmonic frequency index value corresponding with harmonic amplitude of harmonic wave.The algorithm of using is based on the interpolation FFT of amplitude.
The spectrum information of interpolation FFT computing unit output is input to intelligent algorithm rule unit and compares, and extracts the frequency of vortex signal.On the basis of two paths of signals amplitude, frequency indices and three Estimation of Parameters values of amplitude mean value, reject present vibration interference according to the intelligent algorithm rule, obtain the vortex signal frequency.
Signal output module comprises RS485 communication channel, 4 ~ 20mA current output channels and pulse output channel.The RS485 communication is mainly used in the communication of flowmeter and host computer, and current output channels is used for the industry of current transducer should control use, and the pulse output channel is used for integrated flux and quantitatively exports.For preventing external circuit to the impact of main control chip, the hardware circuits such as RS485 communication, pulse output, the output of 4 ~ 20mA electric current all are connected to the I/O of DSP control chip by photoelectric coupled device.
Man-machine interface mainly comprises liquid crystal display and button, and liquid crystal display is used for showing flow velocity and integrated flux, and button is used for the setting of parameter.Parameter memory module adopts EEPROM (Electrically Erasable Programmable Read Only Memo) EEPROM, is used for the important parameters such as storage integrated flux, and when preventing the flowmeter power down, parameter is lost.
For correct monitoring system work, the invention provides sheet external monitor module, the present embodiment adopts watchdog circuit, feed dog take 140ms as the cycle to house dog in the present embodiment, if break down in flowmeter work, just can't in time feed dog, watchdog circuit just can be to the reset terminal transmitting system reset signal of dsp chip so.In the present embodiment, watchdog circuit unit such as Fig. 5 comprise a slice house dog integrated chip U4,1 resistance R 7, and the house dog integrated chip adopts the CAT823 of ON Semiconductor; Its annexation is: No. 1 port of R7 one end, U4 and dsp chip reseting port are connected, No. 2 port ground connection of the R7 other end and U4, No. 3 ports of U4 are connected with button one end of other end ground connection, No. 4 ports of U4 are connected with the dog program delivery outlet of feeding of dsp chip, No. 5 ports of U4 meet VCC, the positive 3V DC voltage of VCC.
The invention also proposes a kind of metering method of the digital intelligent vortex shedding flow meter based on DSP, as shown in Figure 6, comprise step:
Step 61, vortex signal and undesired signal are detected obtain the two-way detection signal respectively;
Step 62, detected two-way detection signal is sampled, change digital signal into;
Step 63, digital signal is carried out filtering, do the interpolation FFT based on amplitude, obtain the spectrum information of the harmonic wave of two-way detection signal;
The spectrum information of the harmonic wave of step 64, comparison two-way detection signal is by the frequency of intelligent algorithm Rule Extraction vortex signal;
Step 65, process conversion delivery rate metrical information.(how frequency information is converted into the flow metering information output?)
Can obtain amplitude and the frequency indices value information of the harmonic wave of the intensity maximum in vortex signal by above-mentioned step 64, this harmonic wave is the dominant frequency vortex signal, and its frequency can calculate by following formula:
In formula, f is the frequency of vortex signal, f
sBe the A/D sample frequency, N is sampling number, and K is above-mentioned frequency indices value.By the vortex signal frequency that calculates, process converts in signal output module, delivery rate information.
The present invention divides two-way to gather respectively vortex signal and undesired signal, and one the tunnel is used for gathering vortex signal, comprising vortex signal and on-the-spot vibration interference, and another road collection site vibration interference; The signal that two-way detects is sampled, change digital signal into, and carry out digital bandpass filtering; Filtered signal is done interpolation FFT, obtain the spectrum information of the harmonic wave of two-way detection signal, then propose vibration interference by the intelligent algorithm rule, obtain the vortex signal frequency.
Particularly, do the interpolation FFT based on amplitude, obtain signal harmonic wave spectrum information method as shown in Figure 7, comprise step:
As to suppose to store array be DATA[], DATA[0 so] be amplitude mean value, DATA[i] and be the amplitude of i harmonic wave, i is the frequency indices value of this harmonic wave.
K＝K1±δ。
The computing method of this frequency spectrum, are revised frequency indices on the basis of FFT with respect to FFT.Corrected parameter obtains by the amplitude information of the spectral line of two amplitude maximums in FFT frequency spectrum main lobe, is estimated and corrected parameter can obtain the frequency information of dominant frequency signal by the frequency indices of the spectral line of amplitude maximum in main lobe.Need to prove, as K1 during K2, dominant frequency signal frequency index is K=K1-δ, when K1＜K2, dominant frequency signal frequency index is K=K1+ δ.The dominant frequency signal here refers to the signal of institute's detection branch.
After obtaining the spectrum information of two paths of signals, can extract the frequency of vortex signal by the intelligent algorithm rule, the flow process that the intelligent algorithm rule realizes comprises step as shown in Figure 8:
In fact work as F1=F2, the frequency of vortex signal equates with the frequency of undesired signal at this moment, and the frequency indices value is all F1, if F1〉F2, the frequency indices value of vortex signal is F1.
Need to prove, carry out two prerequisites of intelligent algorithm rule: one is the hardware prerequisite, is two paths of signals and detects; One is the software prerequisite, is the interpolation FFT spectrum analysis.The intelligent algorithm rule has realized still extracting vortex signal under interference is better than the condition of vortex signal intensity.The most obvious characteristics of vortex signal are exactly that low-frequency range easily is disturbed.Classic method reply low-frequency range is disturbed, and often takes to dwindle the measure of low-frequency range range.Intelligent algorithm rule in the present invention can effectively be improved this deficiency.When the vortex street frequency during greater than interfering frequency, the spectrum signature of two paths of signals is, in the vortex signal branch road, the harmonic amplitude maximal value is greater than harmonic amplitude maximal value in the undesired signal branch road, and the frequency indices of the former correspondence is greater than frequency indices corresponding to the latter; When the vortex street frequency equals interfering frequency, the spectrum signature of two paths of signals is, in the vortex signal branch road, the harmonic amplitude maximal value is not equal to harmonic amplitude maximal value in the undesired signal branch road, but both corresponding frequency indices equates, the amplitude mean value of vortex signal branch road is greater than the amplitude mean value of undesired signal branch road simultaneously; During less than interfering frequency, the spectrum signature of two paths of signals is that in the vortex signal branch road, the harmonic amplitude maximal value equals the harmonic amplitude maximal value in the undesired signal branch road when the vortex street frequency.At this moment, if the amplitude mean value of two-way is equal, the vortex signal branch road is blank pipe as can be known; When the vortex street frequency during less than interfering frequency, the spectrum signature of two paths of signals is, in the vortex signal branch road, the harmonic amplitude maximal value equals the harmonic amplitude maximal value in the undesired signal branch road, if the amplitude mean value of vortex signal branch road is greater than the amplitude mean value of undesired signal branch road, as can be known the undesired signal frequency coverage vortex signal frequency.When interfering frequency covers the vortex signal frequency, in order to obtain vortex street frequency accurately, need the spectrum information of the harmonic wave of the amplitude maximum in the elimination two-way, then in remaining harmonic wave, again extract the vortex street frequency according to algorithmic rule.
Above embodiment is only in order to technical scheme of the present invention to be described but not be limited; in the situation that do not deviate from spirit of the present invention and essence thereof; those of ordinary skill in the art work as can make according to the present invention various corresponding changes and distortion, but these corresponding changes and distortion all should belong to the protection domain of the appended claim of the present invention.
Claims (10)
1. the digital intelligent vortex shedding flow meter based on DSP, comprise signal detection module, signal output module, human-machine interface module and power module, it is characterized in that, described signal detection module comprises vortex signal testing circuit and disturbance detection circuit; Described intelligent vortex shedding flowmeter also comprises spectrum analysis module, and described spectrum analysis module comprises:
AD conversion unit is used for the two-way detection signal of described signal detection module output is converted to digital signal;
The digital band pass filter unit is used for the digital signal of described AD conversion unit output is carried out bandpass filtering;
The interpolation FFT computing unit is used for the filtered digital signal of described digital band pass filter unit output is carried out spectrum analysis, obtains the spectrum information of the harmonic wave of described signal detection module two-way detection signal;
Intelligent algorithm rule unit is used for the spectrum information of the harmonic wave of more described two-way detection signal, extracts the frequency of vortex signal.
2. the digital intelligent vortex shedding flow meter based on DSP according to claim 1, it is characterized in that: described intelligent vortex shedding flowmeter also comprises the monitoring modular that is connected with spectrum analysis module, described monitoring modular is watchdog circuit.
3. the digital intelligent vortex shedding flow meter based on DSP according to claim 1, it is characterized in that: described intelligent vortex shedding flowmeter also comprises the parameter memory module that is connected with spectrum analysis module.
4. according to claim 1,2, the described digital intelligent vortex shedding flow meter based on DSP of 3 arbitrary claims, it is characterized in that: the hardware circuit of described vortex signal testing circuit and disturbance detection circuit includes sensor, charge amplifier and pre-filtering circuit, described sensor are piezoelectric sensor.
5. the digital intelligent vortex shedding flow meter based on DSP according to claim 1, it is characterized in that: described spectrum analysis module is digital signal processor DSP.
6. the digital intelligent vortex shedding flow meter based on DSP according to claim 1, it is characterized in that: described digital intelligent vortex shedding flow meter, also comprise mu balanced circuit, described mu balanced circuit comprises a voltage stabilizer, is used for the reference voltage of described power module output is changed into the input voltage of described analog-to-digital conversion module.
7. the digital intelligent flux of vortex street metering method based on DSP, is characterized in that, comprises step:
(1), respectively vortex signal and undesired signal are detected acquisition two-way detection signal;
(2), detected two-way detection signal is sampled, change digital signal into;
(3), digital signal is carried out filtering, do the interpolation FFT based on amplitude, obtain the spectrum information of the harmonic wave of two-way detection signal;
(4), the spectrum information of the harmonic wave of two-way detection signal relatively, by the frequency of intelligent algorithm Rule Extraction vortex signal;
(5), through conversion delivery rate metrical information.
8. the digital intelligent flux of vortex street metering method based on DSP according to claim 7, is characterized in that, the spectrum information of described harmonic wave comprises the amplitude mean value of harmonic wave, the amplitude of harmonic wave and the frequency indices value of harmonic wave.
9. the digital intelligent flux of vortex street metering method based on DSP according to claim 8, is characterized in that, described step (3) comprises step:
(3.1), digital signal is carried out filtering, digital signal after filtering is made FFT, the spectrum information of the corresponding harmonic wave of storage, first of storage array is exactly harmonic amplitude mean value;
(3.2), determine main lobe by frequency spectrum, find the amplitude maximal value spectral line in main lobe, record its amplitude information X1 and frequency indices value K1;
(3.3), find the frequency indices value for (K1-1), (K1+1) corresponding spectral line, in these two spectral lines, the larger spectral line of amplitude is recorded as the second largest value spectral line, its amplitude is X2, the frequency indices value is K2;
(3.4), calculate frequency indices value corrected parameter δ by X1 and X2, specifically be calculated as follows:
(3.5), can be obtained at last the frequency indices K of dominant frequency signal by corrected parameter δ and K1, specifically be calculated as follows
K＝K1±δ。
10. the digital intelligent flux of vortex street metering method based on DSP according to claim 9, it is characterized in that, suppose that A1 is vortex signal branch road harmonic amplitude maximal value, A2 is undesired signal branch road harmonic amplitude maximal value, F1 is the frequency indices value of the corresponding spectral line of vortex signal branch road harmonic amplitude maximal value, F2 is the frequency indices value of the corresponding spectral line of undesired signal branch road harmonic amplitude maximal value, Aa1 is vortex signal branch road amplitude mean value, Aa2 is undesired signal branch road amplitude mean value, F is final vortex signal dominant frequency frequency indices value, described step (4) comprises step:
(4.1) the harmonic amplitude maximal value of two-way detection signal relatively, if A1＜A2, expression is measured and is occurred extremely, is invalid data, vortex shedding flow meter proposes abnormality warnings, and abandons this measurement result; If A1＞=A2 enters next step;
Whether the harmonic amplitude maximal value A1 that (4.2) judges the two-way detection signal equates with A2, if equate to continue the relatively amplitude mean value of two-way harmonic wave, if Aa1=Aa2 can judge that the vortex signal branch road is blank pipe, finishes; If Aa1 ≠ Aa2, with F1, F2 the amplitude of corresponding spectral line make zero, return to step (4.1); If A1〉A2, carry out next step;
(4.3) compare F1 and F2, if F1＞=F2, the frequency indices value that judges vortex signal is F1; Otherwise expression is measured and is occurred extremely being invalid data, and vortex shedding flow meter proposes abnormality warnings, and abandons this measurement result.
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| CN105067048A (en) * | 2015-07-17 | 2015-11-18 | 合肥科迈捷智能传感技术有限公司 | Vibration interference resisting measuring method of digitalized vortex shedding flowmeter |
| CN109238379A (en) * | 2018-10-30 | 2019-01-18 | 合肥工业大学 | A kind of anti-pipe vibration method and system of vortex-shedding meter that frequency variance calculating is combined with amplitude operation |
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| CN109238379A (en) * | 2018-10-30 | 2019-01-18 | 合肥工业大学 | A kind of anti-pipe vibration method and system of vortex-shedding meter that frequency variance calculating is combined with amplitude operation |
| CN109238379B (en) * | 2018-10-30 | 2020-03-24 | 合肥工业大学 | Method and system for preventing pipeline vibration of vortex shedding flowmeter by combining frequency variance calculation and amplitude calculation |
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