CN115900927A - Frequency division type vibrating wire sensor and frequency measuring device and method thereof - Google Patents
Frequency division type vibrating wire sensor and frequency measuring device and method thereof Download PDFInfo
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Abstract
The invention provides a frequency division type vibrating wire sensor and a frequency measuring device and method thereof, belonging to the technical field of sensor monitoring engineering. The frequency division type vibrating wire sensor comprises a vibrating wire and a stress piece connected with the vibrating wire, the fixed frequency of the vibrating wire is arranged in a preset frequency band interval, the preset frequency band interval uses a preset full scale as a unit to divide the frequency band into at least more than two working frequency bands, and the working frequency bands of the fixed frequency of a plurality of frequency division type vibrating wire sensors arranged on the same channel of the measuring device are different. The frequency division multiplexing method and the frequency division multiplexing device have the advantages that the working frequency range of the signals of the vibrating wire sensors is distributed on the working limit frequency spectrum, and the plurality of frequency division type vibrating wire sensors can be connected in parallel or in series in a frequency division multiplexing mode, so that the frequency values of the plurality of frequency division type vibrating wire sensors can be measured simultaneously through one channel, the application range of a vibrating wire measuring system is greatly expanded, the implementation cost of monitoring projects is saved, and the integration of the monitoring system is simplified.
Description
Technical Field
The invention belongs to the technical field of sensor monitoring engineering, and particularly relates to a frequency division type vibrating wire sensor and a frequency measuring device and method of the frequency division type vibrating wire sensor.
Background
With the rapid development of economy and science and technology, more and more large-scale complex engineering structures can be built, such as large-span bridges, gymnasiums, high-rise buildings, water conservancy facilities and the like. Usually, a vibrating wire sensor is adopted to monitor physical quantities such as pressure, displacement, temperature, deformation quantity, leakage and the like of a project, so that the operation condition of the project is judged, and some geological disasters or project leaks are predicted. The sensing element for the vibrating wire sensor is a metal wire string made of high-elasticity spring steel, martensitic stainless steel or tungsten steel, and is connected and fixed with the force-bearing part of the sensor, and various physical quantities are measured by using the relation between the natural vibration frequency of the steel string and the applied tension of the steel string. The multi-string vibrating wire sensor has several steel strings, each of which has one end fixed and the other end connected to one stress mechanism and may be used in measuring pressure, torque, acceleration and other parameters.
At present, no matter a pulse counting method or a frequency spectrum analysis method is adopted in a vibrating wire measuring technology, for multi-channel vibrating wire collecting equipment, each channel can only be connected with and measure one vibrating wire sensor. Although the prior art aims at the frequency measurement method of the multi-string vibrating wire sensor, the signal line connection mode of the sensor can be improved, only one measurement channel is needed for signal sampling, and the frequency values of a plurality of steel strings of the same multi-string vibrating wire sensor are obtained in one-time collection through the frequency domain calculation method, so that the purpose of reducing the number of channels of the collection equipment is achieved. The reason for this is that the respective vibrations of a plurality of steel strings of the same multi-string vibrating wire sensor are independent mechanical motions, belong to the natural frequencies of the steel strings, are not related to each other, and can be identified even if the frequencies of different steel strings are overlapped. However, in practical practice, because the quantity of parameters monitored by each monitored structure is large, hundreds of sensors are generally required to be installed in order to obtain the corresponding frequencies of the parameters measured by the different sensors, and more vibrating wire collecting devices are required to be matched, so that the implementation cost of monitoring projects and the integration complexity of the system are increased.
Therefore, how to realize that one channel can simultaneously measure a plurality of vibrating wire sensors is very important.
Disclosure of Invention
In order to solve the technical problems, the invention provides a frequency division type vibrating wire sensor and a frequency measuring device and method thereof.
In a first aspect, the invention provides a frequency division type vibrating wire sensor, which includes a vibrating wire and a stressed member connected with the vibrating wire, wherein a fixed frequency of the vibrating wire is set in a preset frequency band interval, the preset frequency band interval is divided into at least two working frequency bands by taking a preset full range as a unit, and the working frequency bands of the fixed frequencies of a plurality of frequency division type vibrating wire sensors installed in a same channel of a measuring device are different.
Compared with the prior art, the invention has the beneficial effects that: by distributing the working frequency band of the signals of the vibrating wire sensors on the working limit frequency spectrum and in a frequency division multiplexing mode, the plurality of frequency division type vibrating wire sensors can be connected in parallel or in series, so that the frequency values of the plurality of frequency division type vibrating wire sensors can be measured simultaneously through one channel, the application range of a vibrating wire measuring system is greatly expanded, the implementation cost of monitoring projects is saved, and the integration of the monitoring system is simplified.
Preferably, an anti-crosstalk frequency band is arranged between two adjacent working frequency bands.
Preferably, discrete digital signals corresponding to the multiple frequency division type vibrating wire sensors in the same channel are acquired according to a sampling theorem, and the digital signals are transformed so as to convert time domain signals of the frequency division type vibrating wire sensors into frequency domain signals, so that frequency values corresponding to the multiple frequency division type vibrating wire sensors are identified through different frequency domain signals.
In a second aspect, the invention provides a frequency measuring device for measuring a vibrating wire frequency of a frequency division vibrating wire sensor according to the first aspect, comprising:
at least one channel;
the channel chip selector is used for switching on and switching off different channels;
the signal conditioner is used for exciting, amplifying, filtering and sampling the vibrating wire signals of the frequency-division vibrating wire sensors connected into one of the channels to form corresponding discrete digital signals;
a digital signal processor for transforming the digital signals into corresponding frequency domain signals to identify the frequency-division vibrating wire sensor;
the frequency division type vibrating wire sensors are connected into the channel in series or in parallel, and the working frequency ranges of the fixed frequencies of the frequency division type vibrating wire sensors connected into the same channel are different; and different channels are connected with a signal conditioner in a mode of selecting by the channel chip selector, the vibrating wire signals of the frequency division type vibrating wire sensors are excited, amplified, filtered and sampled to be converted into discrete digital signals, and the discrete digital signals are subjected to operation processing by the digital signal processor so as to identify the frequency values corresponding to the frequency division type vibrating wire sensors of the same channel.
Compared with the prior art, the invention has the beneficial effects that: the method comprises the steps of connecting a plurality of frequency division vibrating wire sensors with different working frequency ranges at fixed frequency in parallel or in series, enabling the frequency division vibrating wire sensors to pass through one channel, exciting, amplifying, filtering and sampling vibrating wire signals of the vibrating wire sensors to be converted into discrete digital signals, and then carrying out operation processing through a digital signal processor to identify frequency values corresponding to the frequency division vibrating wire sensors of the same channel so as to realize that one channel can simultaneously measure the frequency values of the frequency division vibrating wire sensors.
Preferably, the channel chip selector realizes the on-off switching between different channels by the principle based on a signal relay or an analog switch.
Preferably, the signal conditioner includes an excitation module, an amplification module, a filtering module, and an analog-to-digital conversion module, which are connected in series in sequence.
Preferably, the pass band cut-off frequency interval of the filtering module is consistent with the preset frequency band interval.
Preferably, the sampling rate of the analog-to-digital conversion module matches the requirements of the sampling theorem.
In a third aspect, the invention provides a frequency measurement method applied to the frequency measurement apparatus according to the second aspect; the frequency measurement device comprises at least one channel, a channel chip selector, a signal conditioner and a digital signal processor, wherein a plurality of frequency division type vibrating wire sensors are jointly connected into the channel in a serial or parallel mode, and the working frequency ranges of the fixed frequencies of the frequency division type vibrating wire sensors connected into the same channel are different; the method comprises the following steps:
s01, connecting a plurality of frequency division type vibrating wire sensors with fixed frequencies in different working frequency bands into the same channel in a serial or parallel mode;
s02, selecting one channel chip selector to be connected with the signal conditioner, and carrying out current excitation on the vibrating wire signals of the frequency division type vibrating wire sensors by preset times when the full-load vibrating wire sensors can be excited;
s03, amplifying the excited vibrating wire signal by using an instrumentation amplifier or a low-noise operational amplifier;
s04, filtering the amplified vibrating wire signal through a band-pass filter with the pass-band cut-off frequency interval consistent with the preset frequency band interval;
s05, acquiring the vibrating wire signals subjected to filtering processing at a sampling rate matched with the requirement of the sampling theorem, and converting to obtain discrete digital signals;
and S06, carrying out Fourier transform on the received digital signal, calculating the frequency spectrum of the digital signal, finding a point with the largest energy peak value in each working frequency band through a frequency spectrum peak value detection algorithm, and obtaining a frequency value through a frequency spectrum estimation algorithm so as to identify the frequency values corresponding to a plurality of frequency division type vibrating wire sensors in the same channel.
Compared with the prior art, the invention has the beneficial effects that: the method comprises the steps that a plurality of frequency division type vibrating wire sensors with different working frequency ranges at fixed frequency are connected in parallel or in series, vibrating wire signals of the vibrating wire sensors are excited, amplified, filtered and sampled to be converted into discrete digital signals through one channel, and then the discrete digital signals are subjected to operation processing by the digital signal processor to identify frequency values corresponding to the frequency division type vibrating wire sensors of the same channel, so that the frequency values of the frequency division type vibrating wire sensors can be measured by one channel at the same time.
Preferably, the spectral estimation method is one of direct method, indirect method, interpolation method, bartlett method and Welch method.
Drawings
In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings needed to be used in the embodiments or the prior art descriptions will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings based on these drawings without inventive exercise.
Fig. 1 is a schematic diagram of frequency division adopted by a frequency division vibrating wire sensor according to embodiment 1 of the present invention;
fig. 2 is a position diagram of an operating frequency spectrum of the frequency division vibrating wire sensor provided in embodiment 1 of the present invention in a frequency spectrum diagram;
fig. 3 is a system block diagram of a frequency measurement device according to embodiment 2 of the present invention;
fig. 4 is a block diagram of a signal conditioner according to embodiment 2 of the present invention;
fig. 5 is a schematic diagram of a measured spectrum of the frequency measurement apparatus provided in embodiment 2 of the present invention.
Description of the reference numerals:
10a, 10b, 10c, 10d, 10e, 10f, 10g, 10h, 10j, 10k, 10m, 10 n-frequency division vibrating wire sensors;
20a, 20 b-channels;
30-channel chip selector;
40-a signal conditioner, 41-an excitation module, 42-an amplification module, 43-a filtering module and 44-an analog-to-digital conversion module;
50-a digital signal processor.
Detailed Description
Reference will now be made in detail to embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are illustrative and intended to explain the embodiments of the present invention and should not be construed as limiting the invention.
Furthermore, the terms "first", "second" and "first" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or to implicitly indicate the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of the embodiments of the present invention, "a plurality" means two or more unless specifically limited otherwise.
In the embodiments of the present invention, unless otherwise explicitly specified or limited, the terms "mounted," "connected," "fixed," and the like are to be construed broadly, e.g., as being fixedly connected, detachably connected, or integrated; can be mechanically or electrically connected; either directly or indirectly through intervening media, either internally or in any other relationship. Specific meanings of the above terms in the embodiments of the present invention may be understood by those of ordinary skill in the art according to specific situations.
The sensing element of the vibrating wire sensor is a metal wire, generally called steel wire, vibrating wire or simply called wire, and is usually made of high-elasticity spring steel, martensitic stainless steel or tungsten steel. It is connected and fixed with the force-bearing part of the sensor, and various physical quantities are measured by utilizing the relation between the natural vibration frequency of the steel string and the applied tension on the steel string. The material and mass of the vibrating wire directly affect the accuracy, sensitivity and stability of the sensor. The tungsten wire has stable performance, high hardness, high melting point and high tensile strength, and is a commonly used vibrating wire material. In addition, string-lifting wires, high-strength steel wires, titanium wires and the like can be used as the vibrating wire material.
At present, each channel of the vibrating wire acquisition equipment in the vibrating wire measurement technology can only be connected with and measure one vibrating wire sensor. Even if the vibration of a plurality of steel strings of the same multi-string vibrating wire sensor is mutually independent mechanical motion, the mechanism belongs to the natural frequency mechanism of the steel strings, and the frequency measurement of a plurality of different parameters in the same multi-string vibrating wire sensor can be realized by one channel. However, in specific practice, the quantity of parameters monitored by one monitored structure is large, the measured parameter frequencies of different vibrating wire sensors are overlapped and difficult to distinguish, and in order to distinguish the frequencies of the parameters measured by different vibrating wire sensors, hundreds of sensors are required to be installed, so that more vibrating wire collecting devices are required to be matched, and how to realize the purpose of simultaneously measuring the parameter frequencies corresponding to a plurality of vibrating wire sensors by adopting one channel is provided by the application.
Example 1
In the vibrating wire of the vibrating wire sensor in this embodiment, the fixed frequency of the vibrating wire sensor is set in a preset frequency band interval, and the preset frequency band interval is divided into at least two working frequency bands by taking a preset full-scale range as a unit. For clarity of explanation, the full-scale operating frequency range of the vibrating wire sensor in this embodiment is set to be 200Hz, the preset frequency band interval refers to the operating frequency range of the vibrating wire sensor, in this embodiment, every 200Hz is taken as a unit to divide the total bandwidth of the preset frequency band interval into a plurality of operating frequency bands, each operating frequency band corresponds to one frequency division vibrating wire sensor 10a, 10b, 10c, 10d, 10e, 10f, 10g, 10h, 10j, 10k or 10m, and the processed vibrating wire sensor is the frequency division vibrating wire sensor defined in this embodiment. Preferably, in order to avoid mutual interference between signals of the frequency division type vibrating wire sensors in two adjacent operating frequency bands, a 50Hz crosstalk-proof frequency band is set between each operating frequency band, and a specific frequency spectrum division schematic diagram is shown in fig. 1.
Further, a typical frequency operating limit range based on vibrating wire sensors is between 300Hz to 4000 Hz. For clarity of explanation, the operating frequency range of the vibrating wire sensor is set between 300Hz and 3100Hz in this embodiment, which means that the preset frequency band interval involved by the signals of the frequency division vibrating wire sensor is 2800Hz total bandwidth, so that the 2800Hz total bandwidth can accommodate a maximum of 11 frequency division vibrating wire sensors 10a, 10b, 10c, 10d, 10e, 10f, 10g, 10h, 10j, 10k, 10m (calculation formula of occupied frequency spectrum interval of N frequency division vibrating wire sensors: 300+ (N-1) × 250), and the position of the operating spectrum of the specific frequency division vibrating wire sensor in the frequency spectrum diagram is shown in fig. 2.
In the embodiment, the working frequency bands of the signals of the vibrating wire sensors are distributed on the working limit frequency spectrum to form the frequency division type vibrating wire sensors with the fixed frequencies and different working frequency bands, the frequency division type vibrating wire sensors with the fixed frequencies and different working frequency bands can be connected in parallel in a frequency division multiplexing mode, so that discrete digital signals corresponding to the frequency division type vibrating wire sensors in the same channel can be collected through one channel according to a sampling theorem, the digital signals are converted to convert time domain signals of the frequency division type vibrating wire sensors into frequency domain signals, frequency values corresponding to the frequency division type vibrating wire sensors are identified through different frequency domain signals, the application range of a vibrating wire measuring system is greatly expanded, the implementation cost of monitoring projects is saved, and the integration of the monitoring system is simplified. Of course, it should be noted that a plurality of frequency division vibrating wire sensors with fixed frequencies in different operating frequency bands can also be connected in series, so that the frequency values of the plurality of frequency division vibrating wire sensors can be measured simultaneously through one channel.
Example 2
This embodiment provides a frequency measuring apparatus for measuring the vibrating wire frequency of the frequency division vibrating wire sensor described in embodiment 1. As shown in fig. 3, the frequency measuring device includes two channels 20a, 20b, a channel chip selector 30, a signal conditioner 40 and a digital signal processor 50, which are used to simultaneously measure the frequency values of 11 frequency division vibrating wire sensors 10a, 10b, 10c, 10d, 10e, 10f, 10g, 10h, 10j, 10k and 10m as described in embodiment 1. The channel chip selector 30 is used for switching on and off different channels 20a and 20b, and the signal conditioner 40 is used for exciting, amplifying, filtering and sampling the vibrating wire signals of a plurality of frequency-division vibrating wire sensors connected to one of the channels 20a to form corresponding discrete digital signals; the digital signal processor 50 is configured to transform the digital signal into a corresponding frequency domain signal to identify the frequency division vibrating wire sensor.
Further, in order to enable a plurality of frequency-division vibrating wire sensors 10a, 10b, 10c, 10d, 10e, 10f, 10g, 10h, 10j, 10k, and 10m to perform simultaneous measurement in the same channel 20a by using a frequency division multiplexing method, it is necessary to fix the initial frequency of the vibrating wire sensors at the corresponding set operating frequency to form the frequency-division vibrating wire sensors when the vibrating wire sensors are produced. According to different measuring objects, there are two main measuring modes of compression and tension: the natural frequency of the vibrating wire of the general pressure frequency-division-like vibrating wire sensor can be arranged in the middle-high frequency range of the frequency spectrum, and the vibrating wire fixed frequency of the tension frequency-division-like vibrating wire sensor is arranged in the low-middle frequency range. It should be noted that, in the same channel, two frequency division vibrating wire sensors with the same working frequency band cannot be used, otherwise, signals of the frequency division vibrating wire sensors in the frequency band interfere with each other and cannot be correctly identified by the acquisition equipment.
Furthermore, since the frequency division multiplexing mode is adopted to measure a plurality of frequency division vibrating wire sensors simultaneously, two signal wires of the frequency division vibrating wire sensors can be connected in parallel or in series on one channel. The parallel connection mode is suitable for close-range large-density monitoring, and the series connection mode is suitable for remote single-point monitoring.
Furthermore, the channel chip selector 30 is adopted to expand the channel by chip selection, and a signal chain is used to process the vibrating wire signals of the frequency division vibrating wire sensors 10a, 10b, 10c, 10d, 10e, 10f, 10g, 10h, 10j, 10k and 10 m. In specific practice, the channel chip selector can be implemented by using the principle of a signal relay or an analog switch.
Further, as shown in fig. 4, the signal conditioner 40 includes an excitation module 41, an amplification module 42, a filtering module 43, and an analog-to-digital conversion module 44, which are connected in series in sequence. The excitation module 41 is configured to excite a vibrating wire signal of the frequency-division vibrating wire sensor, the amplification module 42 is configured to amplify the vibrating wire signal subjected to excitation processing, the filtering module 43 is configured to filter the vibrating wire signal subjected to amplification processing from interference and aliasing signals outside an effective signal bandwidth, and the analog-to-digital conversion module 44 is configured to sample and convert the vibrating wire signal subjected to filtering processing to obtain a digital signal. The requirements of each module are as follows:
1. an excitation module: since each channel can be connected with a plurality of frequency division vibrating wire sensors in a cascade mode, the output current of the excitation power supply can meet the requirement of excitation of the sensors. The coil direct current internal resistance of the frequency division type vibrating wire sensor is a fixed value, a plurality of frequency division type vibrating wire sensors are merged into the same channel and are equivalently connected in parallel with resistors, the minimum resistance value of a load can be calculated according to the number of the frequency division type vibrating wire sensors which are accessed to the maximum, so that the required current can be known to excite the frequency division type vibrating wire sensor when the frequency division type vibrating wire sensor is accessed to the full load, the maximum current output capacity of a general excitation power supply is more than 1.5 times of the current when the full load sensor can be excited, and the long-term reliability of the system is ensured.
2. An amplification module: since the signals output by the frequency division vibrating wire sensor are generally in the level of 0.1mV to 10mV and cannot be directly processed by the post-stage, the present embodiment adopts an instrumentation amplifier or a low-noise operational amplifier to amplify the signals.
3. A filtering module: in the embodiment, an active band-pass filter is adopted for filtering out interference and aliasing signals outside the effective signal bandwidth of the vibrating string type sensor. Specifically, the band-pass filter of the present embodiment may be implemented by a combination of low-pass and high-pass, and the passband cutoff frequency is from 300Hz to 3100Hz, covering the entire operating frequency band of the frequency-division vibrating wire sensor signal.
4. An analog-to-digital conversion module: the analog voltage signal output by the frequency division vibrating wire sensor after amplification and filtering is sampled and converted to obtain a digital signal, so that the digital signal can be conveniently processed by a digital signal processor. The sampling rate of the analog-to-digital conversion module in this embodiment needs to meet the requirement of the sampling theorem, and since the signal is analyzed in the frequency domain, the sampling rate does not need to be too high, and the sampling rate of 8Kpsp is adopted in this embodiment.
Further, the digital signal processor 50 samples the signal passing through the signal conditioner 40, and according to the sampling theorem, the sampling rate of the analog-to-digital conversion module 44 is more than twice of the signal bandwidth; and carrying out fast Fourier transform on the sampled digital signals, and converting time domain signals into frequency domain signals, so as to respectively identify signal energy in the frequency domain according to working frequency bands of different sensors. Specifically, the digital signal processor is mainly configured to receive a signal of the frequency division vibrating wire sensor sampled by the analog-to-digital conversion module, perform fast fourier transform, calculate a frequency spectrum of the vibrating wire signal, find a point with a maximum energy peak in a working frequency band of each frequency division vibrating wire sensor through a frequency spectrum peak detection algorithm, and obtain an accurate frequency value through a frequency spectrum estimation algorithm. In this embodiment, the DSP is a dedicated DSP, and is fast in calculation speed and efficient for algorithms such as fast fourier transform, and the result can be calculated quickly. It should be noted that the spectrum estimation method adopted in this embodiment is specifically an interpolation method; other embodiments may also employ one of direct, indirect, bartlett, welch methods.
The working principle of the frequency measuring device of the embodiment is as follows: the frequency division type vibrating wire sensors are connected into the channel together in a parallel mode, and the working frequency ranges of the fixed frequencies of the frequency division type vibrating wire sensors connected into the same channel are different; different channels are connected with a signal conditioner in a mode selected by a channel chip selector, vibrating wire signals of a plurality of frequency division type vibrating wire sensors are excited, amplified, filtered and sampled to be converted into discrete digital signals, then the received digital signals are subjected to Fourier transform through a digital signal processor, the frequency spectrum of the digital signals is calculated, the point with the maximum energy peak value in each working frequency band is found through a frequency spectrum peak value detection algorithm, and a frequency value is obtained through a frequency spectrum estimation algorithm, as shown in figure 5, so that the frequency values corresponding to the frequency division type vibrating wire sensors in the same channel are identified.
In summary, in this embodiment, a plurality of frequency division type vibrating wire sensors with different working frequency bands at which fixed frequencies are located are connected in parallel or in series, so that vibrating wire signals of the plurality of vibrating wire sensors are excited, amplified, filtered, and sampled to be converted into discrete digital signals through one channel, and then are subjected to operation processing by the digital signal processor to identify frequency values corresponding to the plurality of frequency division type vibrating wire sensors in the same channel, so as to implement that one channel can simultaneously measure frequency values of the plurality of frequency division type vibrating wire sensors. The application range of the vibrating wire measuring system can be greatly expanded through the embodiment, the implementation cost of monitoring projects is saved, and the integration of the monitoring system is simplified.
Example 3
This embodiment provides a frequency measurement method applied to the frequency measurement apparatus as described in embodiment 2; the method comprises the following steps:
s01, connecting a plurality of frequency-division vibrating wire sensors with fixed frequencies in different working frequency bands into the same channel in a serial or parallel mode;
s02, selecting one channel chip selector to be connected with the signal conditioner, and carrying out current excitation on the vibrating wire signals of the frequency division type vibrating wire sensors by preset times when the full-load vibrating wire sensors can be excited;
s03, amplifying the excited vibrating wire signal by using an instrumentation amplifier or a low-noise operational amplifier;
s04, filtering the amplified vibrating wire signal through a band-pass filter with the pass-band cut-off frequency interval consistent with the preset frequency band interval;
s05, acquiring the vibrating wire signals subjected to filtering processing at a sampling rate matched with the requirement of the sampling theorem, and converting to obtain discrete digital signals;
and S06, carrying out Fourier transform on the received digital signal, calculating the frequency spectrum of the digital signal, finding a point with the largest energy peak value in each working frequency band through a frequency spectrum peak value detection algorithm, and obtaining a frequency value through a frequency spectrum estimation algorithm so as to identify the frequency values corresponding to a plurality of frequency division type vibrating wire sensors in the same channel.
Through the steps, a plurality of frequency division type vibrating wire sensors with different working frequency ranges at which fixed frequencies are located can be connected in parallel or in series, vibrating wire signals of the vibrating wire sensors are excited, amplified, filtered and sampled to be converted into discrete digital signals through one channel, and then the discrete digital signals are processed through the digital signal processor in an operation mode to identify frequency values corresponding to the frequency division type vibrating wire sensors of the same channel, so that the frequency values of the frequency division type vibrating wire sensors can be measured by one channel at the same time.
The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents and improvements made within the spirit and principle of the present invention are intended to be included within the scope of the present invention.
Claims (10)
1. A frequency division type vibrating wire sensor comprises a vibrating wire and a stress piece connected with the vibrating wire, and is characterized in that the fixed frequency of the vibrating wire is arranged in a preset frequency band interval, the preset frequency band interval is divided into at least more than two working frequency bands by taking a preset full scale as a unit, and the working frequency bands where the fixed frequencies of a plurality of frequency division type vibrating wire sensors arranged on the same channel of a measuring device are different.
2. The frequency division vibrating wire sensor according to claim 1, wherein an anti-crosstalk frequency band is disposed between two adjacent operating frequency bands.
3. The frequency-division vibrating wire sensor according to claim 1, wherein discrete digital signals corresponding to a plurality of frequency-division vibrating wire sensors of the same channel are collected according to a sampling theorem, and the digital signals are transformed so as to convert time domain signals of the frequency-division vibrating wire sensors into frequency domain signals, so as to identify frequency values corresponding to the plurality of frequency-division vibrating wire sensors through different frequency domain signals.
4. A frequency measuring apparatus for measuring a vibrating wire frequency of the frequency division vibrating wire sensor according to claim 3, comprising:
at least one channel;
the channel chip selector is used for switching on and switching off different channels;
the signal conditioner is used for exciting, amplifying, filtering and sampling and converting vibrating wire signals of the frequency-division vibrating wire sensors connected into one channel of the signal conditioner to form corresponding discrete digital signals;
a digital signal processor for transforming the digital signals into corresponding frequency domain signals to identify the frequency-division vibrating wire sensor;
the frequency division type vibrating wire sensors are connected into the channel in series or in parallel, and the working frequency ranges of the fixed frequencies of the frequency division type vibrating wire sensors connected into the same channel are different; and different channels are connected with a signal conditioner in a mode of selecting by the channel chip selector, the vibrating wire signals of the vibrating wire sensors are excited, amplified, filtered and sampled to be converted into discrete digital signals, and the discrete digital signals are subjected to operation processing by the digital signal processor so as to identify the frequency values corresponding to the frequency division vibrating wire sensors of the same channel.
5. The frequency measurement device of claim 4, wherein the channel chip selector implements on-switching between different channels by a signal relay or analog switch based principle.
6. The frequency measurement device according to claim 4, wherein the signal conditioner comprises an excitation module, an amplification module, a filtering module and an analog-to-digital conversion module which are connected in series in sequence.
7. The frequency measurement device according to claim 6, wherein the pass band cut-off frequency of the filter module has a section corresponding to the predetermined frequency band section.
8. The frequency measurement device of claim 6, wherein the sampling rate of the analog-to-digital conversion module matches the requirements of the sampling theorem.
9. A frequency measurement method, characterized in that the method is applied to a frequency measurement apparatus as claimed in any one of claims 4 to 8; the frequency measurement device comprises at least one channel, a channel chip selector, a signal conditioner and a digital signal processor, wherein a plurality of frequency division type vibrating wire sensors are jointly connected into the channel in a serial or parallel mode, and the working frequency ranges of the fixed frequencies of the frequency division type vibrating wire sensors connected into the same channel are different; the method comprises the following steps:
s01, connecting a plurality of frequency-division vibrating wire sensors with fixed frequencies in different working frequency bands into the same channel in a serial or parallel mode;
s02, selecting one channel chip selector to switch on the signal conditioner, and carrying out current excitation on the vibrating wire signals of the frequency division type vibrating wire sensors by preset times when the vibrating wire sensors can be excited fully;
s03, amplifying the excited vibrating wire signal by using an instrumentation amplifier or a low-noise operational amplifier;
s04, filtering the amplified vibrating wire signal through a band-pass filter with the pass-band cut-off frequency interval consistent with the preset frequency band interval;
s05, acquiring the vibrating wire signals after filtering processing at a sampling rate matched with the requirement of the sampling theorem, and converting to obtain discrete digital signals;
and S06, carrying out Fourier transform on the received digital signal, calculating the frequency spectrum of the digital signal, finding a point with the largest energy peak value in each working frequency band through a frequency spectrum peak value detection algorithm, and obtaining a frequency value through a frequency spectrum estimation algorithm so as to identify the frequency values corresponding to a plurality of frequency division type vibrating wire sensors in the same channel.
10. The method of claim 9, wherein the spectral estimation method is one of direct, indirect, interpolation, bartlett, welch.
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| CN118395096A (en) * | 2024-06-27 | 2024-07-26 | 江西飞尚科技有限公司 | Signal frequency correction device, readable storage medium, and electronic apparatus |
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