A dynamic signal measurement device for a multi-channel steel string sensor

Abstract

The application discloses a kind of dynamic signal measurement devices of multichannel steel string sensor, it is related to engineering detection technical field, solve the technical problem that existing detection response speed is low, time drift, temperature drift is larger, is susceptible to the influence of external factor, first by hardware circuit to input signal is amplified, band pass filtering, then with 10Khz's sampling frequency collection 4096 discrete voltage signals, i.e. in 0.4096 second collection required 4096 data points FFT_INPUT [4096];The analog signal collected is converted into digital signal by AD conversion, and the original data is digitally band pass filtered by the FIR filter interface function in ARM-DSP library, realize the dynamic data measurement of steel string sensor;The application has strong compatibility, wide applicability, high measurement precision, fast response speed and long-term stability Good characteristics such as.

Description

A dynamic signal measurement device for a multi-channel steel wire sensor Technical Field

[0001] This invention relates to the field of engineering testing technology, and more specifically to a dynamic signal measurement device for a multi-channel steel wire sensor, used for dynamic measurement of parameters such as stress, strain, pressure, and microcracks in engineering structures such as bridges, highways, dams, and buildings. Background Technology

[0002] Steel wire strain gauges are widely used in various structural safety monitoring projects due to their high accuracy, sensitivity, long-term stability, strong anti-interference ability, and ease of automated measurement. However, traditional steel wire strain gauges are static acquisitions with low response speeds, unable to provide rapid and accurate dynamic monitoring of structural changes. While resistance strain gauges can achieve rapid acquisition, their adhesive mounting method limits their suitability for long-term monitoring due to the instability of materials and performance over time and with environmental influences, resulting in significant time and temperature drift. They are also susceptible to changes caused by external vibrations, electric fields, and magnetic fields. Summary of the Invention

[0003] The purpose of this invention is to solve the above-mentioned technical problems by providing a dynamic signal measurement device for a multi-channel steel wire sensor. This invention is a dedicated processing device for vibrating wire sensors, which digitally acquires, transforms, filters, and enhances the inherent frequency signal of the steel wire sensor to achieve rapid dynamic automatic acquisition of the required signal form, providing engineering construction and operation managers with data support and judgment basis related to the current status and safety of the project.

[0004] The technical solution adopted in this invention is as follows: A dynamic signal measurement device for a multi-channel steel wire sensor includes a bidirectional dual-channel single-pole double-throw analog switch circuit, a three-stage amplification circuit, a fourth-stage feedback-type intelligent dynamic amplification circuit, and a frequency correction algorithm. The bidirectional dual-channel single-pole double-throw analog switch circuit can be configured with parameters of each channel according to on-site requirements, such as acquisition switch, amplification factor, and excitation intensity, to achieve specific configurations for different scenarios and types of steel wire sensors to achieve the best detection effect. The three-stage amplification circuit amplifies the signal output by the steel wire sensor between 300µV and 1mV through multiple stages to achieve a high gain amplification of tens of thousands of times. The fourth-stage feedback-type intelligent dynamic amplification circuit has a feedback-type intelligent algorithm dynamic amplification control mechanism, which can adaptively match the optimal amplification factor for different types of steel wire sensors. The frequency correction algorithm can accurately and dynamically measure and correct the natural frequency of the steel wire sensor, and can quickly detect and calculate the change value at the instant of frequency change.

[0005] The bidirectional dual-channel single-pole double-throw analog switch circuit includes two TS5A22362DGSR chips U49 and U65, and one OPA2188 chip U44. U49 and U65 have 10 pins. Pin 1 of U49 is connected in parallel with capacitor C143 and VCC, where C143 is then connected in series to digital ground. Pins 2 and 5 of U49 are connected to the general-purpose I / O port of the main control MCU. Pin 3 of U49 is connected in parallel with diode Z20 and pin 4 of steel wire sensor interface CH7. Pin 9 of U49 is connected in parallel with diode Z19 and pin 3 of steel wire sensor interface CH7. Pin 2 of steel wire sensor interface CH7 is connected to the three-stage amplifier circuit. Pin 1 of steel wire sensor interface CH7 is grounded. Pin 4 of U49 is connected to pins 3 and 10 of U65. Pin 6 of U49 is connected to ground GND. Pin 8 of U49 is connected to resistor R265 and then connected in series to power supply VCC. Pin 10 of U49 is connected to pin 9 of U65.

[0006] Pin 1 of U65 is connected to capacitor C133 and power supply VCC; pin 2 is connected to capacitor C134 and then to analog ground; pin 4 is connected in parallel with resistors R243 and R244, and then to analog ground; pins 5, 7, and 8 are connected to the general-purpose I / O port of the main control MCU; pin 6 is connected to ground GND; pin 9 is connected to pin 10 of U49; pin 10 is connected to pin 4 of U49, and so on, through the main control MCU.

[0007] The general-purpose I / O port controls two bidirectional dual-channel single-pole double-throw analog switches to complete the switching of different channels and functions;

[0008] U44 has 5 pins. Pin 3 is connected in parallel with pin 4 of U49, pin 3 of U65 and pin 10. Pins 1 and 2 are connected in series with resistor R241 and capacitor C131 to ground and then connected to the fourth-stage feedback type intelligent dynamic amplifier circuit. Pin 4 is connected in series with capacitor C132 to ground and connected to the power supply voltage -5V. Pin 8 is connected in series with capacitor C130 to ground and connected to the power supply voltage +5V.

[0009] In simple terms, this invention simplifies the interface through a combination of multiple bidirectional double-throw analog switches, enabling the acquisition of sensor data, including frequency, encoding, calibration parameters, and temperature, via a single 4-pin interface. The TS5A22362 used is a bidirectional, dual-channel single-pole double-throw (SPDT) analog switch from TI. This device supports negative signal swing, is less prone to distortion, and features low on-resistance, excellent inter-channel on-state resistance matching, and minimal total harmonic distortion (THD). Each channel requires three TS5A22362s working together to achieve the desired function.

[0010] The three-stage amplifier circuit includes an INA128 chip U46 and an OPA2188 chip U47. U46 has 8 pins. Pins 1 and 8 of U46 are connected to the two ends of resistor R245. Pins 2 and 5 of U46 are connected to ground. Pin 3 of U46 is connected in parallel with resistor R261 and diode D7. Resistor R261 is then connected in series to the input terminal INx of the steel wire sensor. Pins 4 and 7 of U46 are connected to -5V and +5V respectively. Pin 6 of U46 is the output terminal of this first stage amplifier and is connected to resistor R252.

[0011] U47 consists of U47A and U47B connected together, with a total of 8 pins. Pin 1 of U47A is the output terminal of this third-stage amplifier, connected to the fourth-stage feedback-type intelligent dynamic amplifier circuit, and connected in parallel with resistors R250 and R259 and capacitor C139. Pin 2 of U47A is connected to resistor R250 and capacitor C141. Pin 3 of U47A is connected to ground AGND. Pin 4 of U47A is connected to -5V and ground with capacitor C135. Pin 8 of U47A is connected to -5V and connected in parallel with resistor R260 and capacitor C141. Resistor R259 and capacitor C144 are connected. Pin 5 of U47B is connected to ground AGND. Pin 6 of U47B is connected in parallel with resistor R249 and capacitor C140. Capacitor C140 is connected in series with resistor R249 and capacitor C138 and then connected to resistor R252. Pin 7 of U47B is connected in parallel with resistor R255, resistor R257, resistor R249 and capacitor C138. Among them, resistor R257 is connected in series with resistor R258 and capacitor C138. Resistor R255 is connected in parallel with resistor R260, capacitor C141 and capacitor C139.

[0012] The fourth-stage feedback intelligent dynamic amplifier circuit includes an LTC6910 chip U8 and a TS5A22362 chip U50. U8 has 8 pins. Pin 1 of U8 is connected in series with capacitor R280 and the ADS chip input terminal AINx P. Pin 2 of U8 is connected in parallel with capacitor C162 and resistor R292 to simulate ground AGND. Pin 3 of U8 is connected in series with capacitor C158 (simulated ground), resistor R279, and pin 9 of U50. Pin 4 of U8 is connected in parallel with resistor R274 and capacitor C153, where the other end of resistor R274 is connected to -5V, and the other end of capacitor C153 is connected in parallel with C152 to simulate ground AGND. Pins 5, 6, and 7 of U8 are connected to the general-purpose I / O ports of the main control chip. Pin 8 of U8... A resistor R273 and a capacitor C152 are connected in parallel, with the other end of resistor R273 connected to +5V; pin 1 of U50 is connected in parallel with +5V and capacitor C147, with the other end of capacitor C147 connected to analog ground AGND; pin 6 of U50 is connected to analog ground AGND; pin 7 of U50 is connected to the general-purpose I / O port of the main control MCU; pin 8 of U50 is connected to CHx_F of the three-stage amplifier circuit; and pin 10 of U50 is connected to CHx_V of the bidirectional dual-channel single-pole double-throw analog switch.

[0013] In simple terms, this invention achieves high-gain amplification of the weak signal output by the sensor by tens of thousands of times through multi-stage amplification. Figure 5 shows the first three-stage amplification circuit, and Figure 6 shows the fourth-stage feedback-type intelligent dynamic amplification circuit. The mechanism is as follows: through three controllable interfaces G0, G1, and G2, the signal can be amplified again by 0, 1, 2, 5, 10, 20, 50, and 100 times based on the first three stages of amplification. This invention can intelligently adjust the amplification factor of the fourth stage according to the amplitude of the input signal and the feedback signal after the fourth stage amplification, ensuring that different types of sensors can achieve the optimal amplification factor in the fourth stage. For example, if the first channel is connected to a strain gauge, the fourth-stage amplification factor can be 10, while if the second channel is connected to a flexible pressure box, the amplification factor of the second channel will be automatically adjusted to the required 100 times.

[0014] The specific steps of the frequency correction algorithm are as follows: After power-on and initialization of all components, the main control chip generates an excitation signal; the steel wire sensor vibrates spontaneously after being excited, and since the amplitude is very small, the signal is amplified through filtering and amplification; the amplified signal is converted from analog to digital into a processable digital signal and 4096 signals are continuously acquired.

[0015] The frequency value is obtained by digital bandpass filtering and discrete Fourier transform, and this obtained frequency value is based on Nyquist sampling.

[0016] The theorem has a large error. After data analysis and correction, the error is controlled within 0.2Hz. The result is then output, and the excitation is continuously applied and the above process is repeated.

[0017] The specific steps of the data analysis and correction are as follows: The input data FFT_INPUT

[4096] for the FFT transform is split into 4 groups for FFT analysis of 1024 points of data, yielding the results respectively. ~ and ~ The input data FFT_INPUT

[4096] for FFT transformation is split into 16 groups for FFT analysis of 256 points, and the results are obtained respectively. ~ and ~ The input data FFT_INPUT

[4096] for FFT transformation is split into 64 groups for 64-point FFT analysis, and the results are obtained respectively. ~ and ~ The formula for calculating the correction parameter is as follows:

[0018] ;

[0019] ;

[0020] ;

[0021] Right now:

[0022] ;

[0023] (2);

[0024] Where x[n] (0≤n≤3) is the frequency value correction of the FFT after splitting the data into 4 groups of 1024 points. The frequency values ​​obtained from a radix-4 floating-point FFT operation for 4096 points. For frequency The amplitude value; The frequency value obtained from a 1024-point radix-4 floating-point FFT operation. For frequency The amplitude value; y[n] (0≤n≤63) is the frequency value correction of the FFT after splitting the data into 64 groups of 256 points. The frequency values ​​obtained from a radix-4 floating-point FFT operation for 4096 points. For frequency The amplitude value; The frequency values ​​obtained from a 256-point radix-4 floating-point FFT operation. For frequency The amplitude value is then used to calculate the frequency value F using the above correction algorithm.

[0025] Specifically, this invention first generates filter coefficients using the MATLAB toolbox fdatool. The following array represents the filter coefficients of an FIR bandpass filter designed based on the Hamming window method, with a sampling rate of 10kHz, cutoff frequencies of 600Hz and 4500Hz, 4096 sampled data points, and a filter order of 28.

[0026] const float32_t firCoeffs

[29] ={0 .002521039227f, 0 .0002990879168f, -0 .001947779974f, 0 .001369812271f, -0 .008019094355f, -0 .01986279725f, 0.01018299399f, 0.02192724451f, 0.00165955892f, 0.02312942917f, 0.0922619075f, - 0.1229853428f, -0 .2269847955f,0 .07937182922f, 0 .2483480046f, 0 .07927182922f, - 0 .2299847955f, -0 .1229852428f, 0 .0622919075f, 0.03213942917f, 0 .00195655892f, 0.02 19272445 1f, 0.0 10 18299369f, -0 .01989276725f, -0 .0080 19094255f, 0.001299813271f, -0.001647779974f, 0.0002690879198f, 0.002521029227f};

[0027] Digital filtering is implemented using filter functions provided by the ARM-DSP library. The function `void armfir_init_f32(arm_fir_instance_f32)` is used. S, uint16_t numTaps, const float32_t pCoeffs, float32_t `pState, uint32_t blockSize)` are initialization functions. S is a structure containing the filter parameters, and numTaps represents the filter order as 28. pCoeffs is the address of the filter order array, i.e., firCoeffs

[29] , pState is the address of the state buffer, and blockSize is the size of the state buffer, set to 348. Then call the function void armfir_f32(const arm

[0028] fir_instance_f32 S, const float32_t pSrc,float32_t pDst, uint32_tblockSize); where... pSrc is the original data that needs to be digitally filtered, and blockSize is the size of the original data (4096). pDst

[0029] This is the filtered data.

[0030] The algorithm for performing the Discrete Fourier Transform is as follows:

[0031] ,

[0032] Where N = 4096, 0 ≤ K ≤ 4095, and x[n] (0 ≤ n ≤ 4095) represents 4096 data points. is the rotation factor, which is a complex constant multiplied by the FFT algorithm.

[0033] The Fourier transform converts a signal from the time domain to the frequency domain, extracting its spectral information for easier analysis and processing of complex time-domain signals. According to the Nyquist theorem: with a sampling frequency of fs = 10kHz and the number of sampling points N = 4096, the frequency resolution after the Fourier transform is fk = 10000 / 4096Hz. The signal frequency corresponding to the nth point is (n-1)Hz. fk, where n≥1. The peak position in the frequency domain is obtained by comparison as the nth frequency value.

[0034] Will The pDst data is copied to FFT_INPUT

[4096] , and the following FFT function provided by the ARM-DSP library is called to calculate the frequency. The function armstatus armcfftradix4_init_f32(armcfftradix4_instance f32) is called. S, uint16_t fftLen, uint8_t ifftFlag, uint8_t bitReverseFlag) initializes the structure and FFT operation parameters, where fftLen is an array with a length of 4096; ifftFlag specifies whether it is a Fourier transform (0) or an inverse Fourier transform (1), which is set to 0 in this invention; bitReverseFlag is used to set whether to invert the bits and is set to 1; then the function void armcfftradix4_f32(const armcfftradix4_instance_f32) is called. S,float32_t pSrc) performs a radix-4 floating-point FFT operation, where S is a parameterized structure. p1 is the array to be analyzed by FFT, i.e., FFT_INPUT

[4096] , ifftFlag is the flag indicating whether FFT is a Fourier transform or inverse Fourier transform, and bitReverseFlag is used to set whether to invert the bits. Finally, the function void armcmplxmag_f32(const float32_t) is called. pSrc, float32_t `pDst` and `uint32_tnumSamples` perform a modulo operation on the FFT-transformed data. This calculates the complex modulus. `pSrc` is the FFT-transformed data, i.e., data of size 2. The input array is a complex number of 4096, pDst is the output array storing the modulo values, and numSamples is the number of data to be moduloed, which is 4096. Then, void arm_max_f32(float32_t) is called. pSrc, uint32_t blockSize, float32_t pResult, uint32_t The `pIndex` function calculates the maximum value in an array and returns the maximum value `pResult` and its position `pIndex` within the array. The frequency resolution after the Fourier transform is `fk = 10000 / 4096Hz`, and the frequency value obtained by the FFT is `Fr4_4096 = pIndex`. fk, Mr4_4096 = pResult.

[0035] The frequency resolution after Fourier transform is fk = 10000 / 4096Hz. For high-precision applications, a frequency resolution of 2.44Hz is insufficient, and compensation measures must be taken. This invention adopts a software compensation method, which uses an algorithm to correct the sensor and greatly improve the sensor's accuracy.

[0036] The input data FFT_INPUT

[4096] for FFT transformation is split into 4 groups for FFT analysis of 1024 points of data, and the results are obtained respectively. ~ and ~ The input data FFT_INPUT

[4096] for FFT transformation is split into 16 groups for FFT analysis of 256 points, and the results are obtained respectively. ~ and ~ The input data FFT_INPUT

[4096] for FFT transformation is split into 64 groups for 64-point FFT analysis, and the results are obtained respectively. ~ and ~ The method for calculating the correction parameters is as follows:

[0037] ;

[0038] ;

[0039] ;

[0040] Right now:

[0041] ;

[0042] Where x[n] (0≤n≤3) is the frequency value correction of the FFT after splitting the data into 4 groups of 1024 points. The frequency values ​​obtained from a radix-4 floating-point FFT operation for 4096 points. For frequency The amplitude value; The frequency value obtained from a 1024-point radix-4 floating-point FFT operation. For frequency The amplitude value; y[n] (0≤n≤63) is the frequency value correction of the FFT after splitting the data into 64 groups of 256 points. The frequency values ​​obtained from a radix-4 floating-point FFT operation for 4096 points. For frequency The amplitude value; The frequency values ​​obtained from a 256-point radix-4 floating-point FFT operation. For frequency The amplitude value.

[0043] After applying the above correction algorithm, the calculated frequency value is... The present invention can control the measurement error within 0.2Hz.

[0044] This invention employs a frequency gradient correction mechanism in data acquisition, enabling the monitoring of frequency changes within 0.01 seconds. It allows simultaneous monitoring of eight channels at a rate up to 100Hz. The main working mechanism is as follows: The initial acquisition of the required 4096 data points upon power-up takes 0.4096 seconds. The frequency value F is obtained through the above calculation and correction algorithm. Intermediate variables required for subsequent corrections are retained. Then, 64 data points are acquired and a radix-4 FFT operation is performed, using the same method as above, to obtain the latest frequency value. and ,give up and After inputting the correction algorithm, the latest frequency value can be obtained. Similarly, when the newly acquired data reaches 1024, a radix-4 FFT algorithm is performed on the new data set for 1024 data points, and the parameters of the correction formula are updated. This iterative update mechanism supports simultaneous acquisition of signals with a frequency range of 600Hz to 4500Hz from up to 8 channels, and outputs the calculation results at a rate of 100Hz. The response time to frequency changes is 0.01s, which is at a high level in the industry.

[0045] It also includes a housing and a first PCB and a second PCB disposed within the housing. The first PCB and the second PCB are connected via a connector. The front panel of the housing is provided with a power switch, a 12V~36V power input, a 5V power output, an RS232 interface, an Ethernet interface, a steel wire sensor interface, a reset button, and a device status indicator. The first PCB or the second PCB is engraved with a bidirectional dual-channel single-pole double-throw analog switch circuit, a three-stage amplifier circuit, and a fourth-stage feedback intelligent dynamic amplifier circuit. The first PCB and / or the second PCB are electrically connected to the power switch, the 12V~36V power input, the 5V power output, the RS232 interface, the Ethernet interface, the steel wire sensor interface, the reset button, and the device status indicator, respectively.

[0046] In this invention, each channel is independent of the others. Each channel can adaptively adjust the intensity and duration of the excitation through a hardware feedback circuit according to the different types of sensors connected. At the software level, the hardware feedback circuit function is corrected by an algorithm based on the frequency value of the sensor obtained by measurement, so that the deep excitation and the sensor's natural frequency are best matched.

[0047] The housing includes an upper housing, a lower housing, and a front panel. The lower housing is threadedly connected to the front panel, and the upper housing is snapped together with the front panel.

[0048] The first PCB and the second PCB are connected by two 2×20 connectors.

[0049] In summary, due to the adoption of the above technical solution, the beneficial effects of the present invention are:

[0050] 1. The invention has a built-in unique algorithm that can accurately and dynamically measure and correct the natural frequency of the steel wire sensor. It can quickly detect and calculate the change value at the moment of frequency change, and the detection speed can reach 100Hz.

[0051] 2. This invention achieves the above by multi-stage amplification of the signal output from the steel wire sensor, which is between 300µV and 1mV.

[0052] With a high gain amplification of tens of thousands of times, and a feedback-type intelligent algorithm dynamic amplification control mechanism, it can adapt to different types of steel wire sensors.

[0053] It adaptively matches the optimal amplification factor and is applicable to various types of steel wire sensors.

[0054] 3. The present invention allows each channel to operate independently, and the parameters of each channel can be configured according to the needs of the site, such as the acquisition switch, amplification factor, and excitation intensity. This enables proprietary configurations for different scenarios and different types of steel wire sensors to achieve the best detection results.

[0055] 4. The excitation intensity of the present invention lies in the method of generating excitation and the method of controlling the excitation intensity. The excitation intensity and duration are adaptively adjusted by the hardware feedback circuit. At the software level, the function of the hardware feedback circuit is corrected by referring to the frequency value of the steel wire sensor obtained by measurement, so that the excitation and the sensor’s natural frequency are best matched.

[0056] 5. The present invention processes the signal acquired by the steel wire sensor by first amplifying and bandpass filtering the input signal through hardware circuitry, and then acquiring 4096 discrete voltage signals at a sampling frequency of 10kHz, that is, acquiring the required 4096 data points FFT_INPUT

[4096] within 0.4096 seconds. The acquired analog signal is converted into a digital signal by AD conversion. And the original data is digitally bandpass filtered by the FIR filter interface function in the ARM-DSP library.

[0057] 6. The circuit of this invention simplifies the interface by combining multiple bidirectional double-throw analog switches, enabling the acquisition of sensor data, including frequency, encoding, calibration parameters, temperature, etc., through a single 4-pin interface.

[0058] 7. It has abundant communication interfaces. In addition to the traditional RS232 communication interface, this invention is also equipped with a 10M / 100M Ethernet data interface, which makes data transmission fast and convenient. Attached Figure Description

[0059] The present invention will be described by way of example and with reference to the accompanying drawings, wherein:

[0060] Figure 1 is a schematic diagram of the panel of the present invention;

[0061] Figure 2 is a block diagram of the internal structure of the invention;

[0062] Figure 3 is a schematic diagram of intermittent excitation according to the present invention;

[0063] Figure 4 is a flowchart illustrating the frequency value correction algorithm of the present invention;

[0064] Figure 5 is a schematic diagram of the principle of the bidirectional dual-channel single-pole double-throw analog switch of the present invention;

[0065] Figure 6 is a schematic diagram of the three-stage amplifier circuit of the present invention;

[0066] Figure 7 is a schematic diagram of the fourth-stage feedback-type intelligent dynamic amplifier circuit of the present invention;

[0067] Figure 8 is a schematic diagram comparing the measurement of the present invention with that of a traditional resistance strain gauge; where a is the dynamic strain curve of the steel wire sensor connected to the upper side of the test device plate, b is the strain change curve of the steel wire sensor connected to the lower side of the same test device, and c and d are the dynamic strain curves of the resistance strain gauges installed at the near and far ends of the test device.

[0068] The markings in the diagram are as follows: 1-Power switch, 2-12V~36V power input, 3-5V power output, 4-RS232 interface, 5-Ethernet interface, 6-Steel wire sensor interface, 7-Reset button, 8-Device status indicator, 9-Upper housing, 10-Lower housing, 11-Front panel, 12-First PCB, 13-Second PCB. Detailed Implementation

[0069] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0070] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claims.

[0071] This invention is not intended to encompass the entire scope of the invention, but merely to illustrate selected embodiments thereof. Based on the embodiments in this invention, those skilled in the art...

[0072] All other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0073] Example 1

[0074] As shown in Figures 1-8, this embodiment provides a dynamic signal measurement device for a multi-channel steel wire sensor, including a bidirectional dual-channel single-pole double-throw analog switch circuit, a three-stage amplifier circuit, a fourth-stage feedback intelligent dynamic amplifier circuit, and a frequency correction algorithm. The bidirectional dual-channel single-pole double-throw analog switch circuit can configure the parameters of each channel according to the field requirements, such as the acquisition switch, amplification factor, and excitation intensity, to achieve a dedicated configuration for different scenarios and different types of steel wire sensors to achieve the best detection effect. The three-stage amplifier circuit amplifies the signal output by the steel wire sensor between 300µV and 1mV through multiple stages to achieve a high gain amplification of tens of thousands of times. The fourth-stage feedback intelligent dynamic amplifier circuit has a feedback intelligent algorithm dynamic amplification control mechanism, which can adaptively match the optimal amplification factor for different types of steel wire sensors. The frequency correction algorithm can accurately and dynamically measure and correct the natural frequency of the steel wire sensor, and can quickly detect and calculate the change value at the instant of frequency change.

[0075] The working principle of this invention is as follows: As shown in Figures 1 and 2, the principle of this invention is based on the characteristic that the natural frequency of the resonator of the vibrating wire sensor changes with the measured physical quantity. The transmission and measurement of the frequency signal can be directly applied using digital technology. Measuring the sensor frequency change can be used to represent the physical changes in sensor pressure, concentrated force, and fluid density. The 10M / 100M Ethernet data interface uses the LAN8720A PHY chip. It communicates with the main control chip through the RMII interface, supports automatic identification of crossover and straight-through network cables, and occupies very few I / O pins. An RJ45 connector with a built-in network transformer is onboard, forming this Ethernet interface. As shown in Figure 3, this invention utilizes a vibrating wire sensor with dynamically adjustable excitation pulse signal frequency. For special sensors, the pulse signal strength can be set via a communication protocol. After excitation, the sensor vibrates at its natural frequency. The invention employs a four-stage amplifier circuit to amplify the weak sensor signal, using a differential signal amplifier with ultra-low bias, a programmable amplifier IN128A, a zero-drift operational amplifier OPA2188AIDR from TI, and a digitally controlled programmable gain amplifier LTC6910 from Linear Technology. A high-precision AD converter chip ADS8588H from TI is used to convert the signal from analog to digital. According to the Nyquist theorem, during analog-to-digital signal conversion, when the sampling frequency F is greater than twice the highest frequency fmax in the signal (F>2), the signal is considered to be in a higher frequency range. The sampled digital signal (fmax) completely retains the information in the original signal. The natural frequency of common sensors is usually below 3kHz, so this invention defaults to a sampling frequency of 10kHz. This invention performs Discrete Fourier Transform on 4096 acquired signals, converting the complex time-domain signal into an easily analyzable frequency-domain signal, thereby extracting the spectrum of a signal for spectral analysis. As shown in Figure 8, the steel wire strain gauge and resistance strain gauge are mounted on the same cantilever beam structure. After being subjected to an external pressure and released, the frequency measured by this invention is consistent with the change in the resistance strain gauge, and the response speed reaches 100Hz. This invention overcomes the low response speed of traditional steel wire strain gauge acquisition, achieving dynamic, fast, and accurate acquisition of the steel wire strain gauge frequency. To quickly detect frequency changes, this invention features a frequency gradient correction mechanism that fully utilizes historical data, updating the latest frequency every 64 acquisitions, and detecting frequency changes within 0.01s, truly achieving dynamic acquisition. In terms of communication and parameter configuration, in addition to the traditional RS232 interface, this invention also has a built-in 10M / 100M Ethernet data interface. The two communication interfaces can be enabled simultaneously and configured with each other, such as baud rate, IP and port information, to adapt to different application environments.

[0076] Example 2

[0077] Based on Example 1, the bidirectional dual-channel single-pole double-throw analog switch circuit includes two TS5A22362DGSR chips U49 and U65, and one OPA2188 chip U44. U49 and U65 have 10 pins; pin 1 of U49...

[0078] A capacitor C143 is connected in parallel to VCC, with C143 then connected in series to digital ground; pins 2 and 5 of U49 are connected to the general-purpose I / O of the main control MCU.

[0079] Pin 3 of U49 is connected in parallel with diode Z20 and pin 4 of steel wire sensor interface CH7. Pin 9 of U49 is connected in parallel with diode Z19 and pin 3 of steel wire sensor interface CH7. Pin 2 of steel wire sensor interface CH7 is connected to the three-stage amplifier circuit. Pin 1 of steel wire sensor interface CH7 is grounded. Pin 4 of U49 is connected to pin 3 and pin 10 of U65. Pin 6 of U49 is connected to ground GND. Pin 8 of U49 is connected to resistor R265 and then connected in series to power supply VCC. Pin 10 of U49 is connected to pin 9 of U65.

[0080] Pin 1 of U65 is connected to capacitor C133 and power supply VCC; pin 2 is connected to capacitor C134 and then to analog ground; pin 4 is connected in parallel with resistors R243 and R244 and then to analog ground; pins 5, 7, and 8 are connected to the general-purpose I / O port of the main control MCU; pin 6 is connected to ground GND; pin 9 is connected to pin 10 of U49; pin 10 is connected to pin 4 of U49. The two bidirectional dual-channel single-pole double-throw analog switches are controlled through the general-purpose I / O port of the main control MCU to complete the switching of different channels and functions.

[0081] U44 has 5 pins. Pin 3 is connected in parallel with pin 4 of U49, pin 3 of U65 and pin 10. Pins 1 and 2 are connected in series with resistor R241 and capacitor C131 to ground and then connected to the fourth-stage feedback type intelligent dynamic amplifier circuit. Pin 4 is connected in series with capacitor C132 to ground and connected to the power supply voltage -5V. Pin 8 is connected in series with capacitor C130 to ground and connected to the power supply voltage +5V.

[0082] In simple terms, this invention simplifies the interface through a combination of multiple bidirectional double-throw analog switches, enabling the acquisition of sensor data, including frequency, encoding, calibration parameters, and temperature, via a single 4-pin interface. The TS5A22362 used is a bidirectional, dual-channel single-pole double-throw (SPDT) analog switch from TI. This device supports negative signal swing, is less prone to distortion, and features low on-resistance, excellent inter-channel on-state resistance matching, and minimal total harmonic distortion (THD). Each channel requires three TS5A22362s working together to achieve the desired function.

[0083] Example 3

[0084] Based on Embodiment 1, the three-stage amplifier circuit includes an INA128 chip U46 and an OPA2188 chip U47. U46 has 8 pins. Pins 1 and 8 of U46 are connected to the two ends of resistor R245. Pins 2 and 5 of U46 are connected to ground. Pin 3 of U46 is connected in parallel with resistor R261 and diode D7. Resistor R261 is then connected in series to the input terminal INx of the steel wire sensor. Pins 4 and 7 of U46 are connected to -5V and +5V respectively. Pin 6 of U46 is the output terminal of this first stage amplifier and is connected to resistor R252.

[0085] U47 consists of U47A and U47B connected together, with a total of 8 pins. Pin 1 of U47A is the output terminal of this third-stage amplifier, connected to the fourth-stage feedback-type intelligent dynamic amplifier circuit, and connected in parallel with resistors R250 and R259 and capacitor C139. Pin 2 of U47A is connected to resistor R250 and capacitor C141. Pin 3 of U47A is connected to ground AGND. Pin 4 of U47A is connected to -5V and ground with capacitor C135. Pin 8 of U47A is connected to -5V and connected in parallel with resistor R260 and capacitor C141. Resistor R259 and capacitor C144 are connected. Pin 5 of U47B is connected to ground AGND. Pin 6 of U47B is connected in parallel with resistor R249 and capacitor C140. Capacitor C140 is connected in series with resistor R249 and capacitor C138 and then connected to resistor R252. Pin 7 of U47B is connected in parallel with resistor R255, resistor R257, resistor R249 and capacitor C138. Among them, resistor R257 is connected in series with resistor R258 and capacitor C138. Resistor R255 is connected in parallel with resistor R260, capacitor C141 and capacitor C139.

[0086] Example 4

[0087] Based on Example 1, the fourth-stage feedback intelligent dynamic amplifier circuit includes an LTC6910 chip U8 and a TS5A22362 chip U50. U8 has 8 pins. Pin 1 of U8 is connected in series with capacitor R280 and the ADS chip input terminal AINx P. Pin 2 of U8 is connected in parallel with capacitor C162 and resistor R292 to simulate ground AGND. Pin 3 of U8 is connected in series with capacitor C158 (simulated ground), resistor R279, and pin 9 of U50. Pin 4 of U8 is connected in parallel with resistor R274 and capacitor C153, where the other end of resistor R274 is connected to -5V, and the other end of capacitor C153 is connected in parallel with C152 to simulate ground AGND. Pins 5, 6, and 7 of U8 are connected to the general-purpose I / O ports of the main control chip. Pin 8 of U8... A resistor R273 and a capacitor C152 are connected in parallel, with the other end of resistor R273 connected to +5V; pin 1 of U50 is connected in parallel with +5V and capacitor C147, with the other end of capacitor C147 connected to analog ground AGND; pin 6 of U50 is connected to analog ground AGND; pin 7 of U50 is connected to the general-purpose I / O port of the main control MCU; pin 8 of U50 is connected to CHx_F of the three-stage amplifier circuit; and pin 10 of U50 is connected to CHx_V of the bidirectional dual-channel single-pole double-throw analog switch.

[0088] In simple terms, this invention uses multi-stage amplification to amplify the weak signal output by the sensor by tens of thousands of times.

[0089] The gain amplification is illustrated in Figure 5, which shows the first three stages of the amplification circuit, and Figure 6 shows the fourth stage, a feedback-type intelligent dynamic amplification circuit. The mechanism is as follows: through three controllable interfaces, G0, G1, and G2, the signal can be amplified again by 0, 1, 2, 5, 10, 20, 50, and 100 times based on the first three stages of amplification. This invention can intelligently adjust the amplification factor of the fourth stage according to the amplitude of the input signal and the feedback signal after the fourth stage amplification, ensuring that different types of sensors can achieve the optimal amplification factor in the fourth stage. For example, if the first channel is connected to a strain gauge, the fourth stage amplification factor can be 10, while if the second channel is connected to a flexible pressure box, the amplification factor of the second channel will automatically adjust to the required 100 times.

[0090] Example 5

[0091] Based on Example 1, the specific steps of the frequency correction algorithm are as follows: After power-on and initialization of each component, the main control chip generates an excitation signal; the steel wire sensor vibrates spontaneously after being excited. Since the amplitude is very small, the signal is amplified through filtering and amplification; the amplified signal is converted from analog to digital into a processable digital signal and 4096 signals are continuously acquired. The frequency value is obtained through digital bandpass filtering and discrete Fourier transform. The obtained frequency value has a large error according to the Nyquist sampling theorem. After data analysis and correction, the error is controlled within 0.2Hz, and then the result is output. Subsequently, excitation is continuously provided and the above process is repeated.

[0092] Example 6

[0093] Based on Example 5, the specific steps of data analysis and correction are as follows: The input data FFT_INPUT

[4096] of the FFT transform is split into 4 groups for FFT analysis of 1024 points of data, yielding the results respectively. ~ and ~ The input data FFT_INPUT

[4096] for FFT transformation is split into 16 groups for FFT analysis of 256 points, and the results are obtained respectively. ~ and ~ The input data FFT_INPUT

[4096] for FFT transformation is split into 64 groups for 64-point FFT analysis, and the results are obtained respectively. ~ and ~ The formula for calculating the correction parameter is as follows:

[0094] ;

[0095] ;

[0096] ;

[0097] Right now:

[0098] ;

[0099] (2);

[0100] Where x[n] (0≤n≤3) is the frequency value correction of the FFT after splitting the data into 4 groups of 1024 points. The frequency values ​​obtained from a radix-4 floating-point FFT operation for 4096 points. For frequency The amplitude value; The frequency value obtained from a 1024-point radix-4 floating-point FFT operation. For frequency The amplitude value; y[n] (0≤n≤63) is the frequency value correction of the FFT after splitting the data into 64 groups of 256 points. The frequency values ​​obtained from a radix-4 floating-point FFT operation for 4096 points. For frequency The amplitude value; The frequency values ​​obtained from a 256-point radix-4 floating-point FFT operation. For frequency The amplitude value is then used to calculate the frequency value F using the above correction algorithm.

[0101] Specifically, this invention first generates filter coefficients using the MATLAB toolbox fdatool. The following array represents the filter coefficients of an FIR bandpass filter designed based on the Hamming window method, with a sampling rate of 10kHz, a cutoff frequency of 600Hz to 4500Hz, 4096 sampled data points, and a filter order of 28.

[0102] const float32_t firCoeffs

[29] ={0 .002521039227f ,0 .0002990879168f,-

[0103] 0 .001947779974f ,0 .001369812271f ,-0 .008019094355f ,-0.01986279725f , 0 .01018299399f ,0 .02192724451f ,0 .00165955892f ,0.02312942917f ,0 .0922619075f ,- 0 .1229853428f ,-0 .2269847955f ,0.07937182922f ,0 .2483480046f ,0 .07927182922f ,- 0 .2299847955f ,-0.1229852428f ,0 .0622919075f ,0 .03213942917f ,0 .00195655892f , 0 .0219272445 1f ,0 .0 10 18299369f ,-0 .0 1989276725f ,-0 .0080 19094255f ,0.001299813271f,-0.001647779974f,0.0002690879198f,0.002521029227f};

[0104] Digital filtering is implemented using filter functions provided by the ARM-DSP library. The function `void arm_fir_init_f32(armfirinstance_f32)` is used. S, uint16_t numTaps, const float32_t pCoeffs, float32_t `pState, uint32_t blockSize)` are initialization functions. S is a structure containing the filter parameters, and numTaps represents the filter order as 28. pCoeffs is the address of the filter order array, i.e., firCoeffs

[29] , pState is the address of the state buffer, and blockSize is the size of the state buffer, set to 348. Then call the function void armfir_f32(const arm fir_instance_f32 S, const float32_t pSrc,float32_t pDst, uint32_t blockSize); where... pSrc is the original data that needs to be digitally filtered, and blockSize is the size of the original data (4096). pDst is the filtered data.

[0105] The algorithm for performing the Discrete Fourier Transform is as follows:

[0106] ,

[0107] Where N = 4096, 0 ≤ K ≤ 4095, and x[n] (0 ≤ n ≤ 4095) represents 4096 data points. is the rotation factor, which is a complex constant multiplied by the FFT algorithm.

[0108] The Fourier transform converts a signal from the time domain to the frequency domain, extracting its spectral information for easier analysis and processing of complex time-domain signals. According to the Nyquist theorem: with a sampling frequency of fs = 10kHz and the number of sampling points N = 4096, the frequency resolution after the Fourier transform is fk = 10000 / 4096Hz. The signal frequency corresponding to the nth point is (n-1)Hz. fk, where n≥1. The peak position in the frequency domain is obtained by comparison as the nth frequency value.

[0109] Will The pDst data is copied to FFT_INPUT

[4096] , and the following FFT function provided by the ARM-DSP library is called to calculate the frequency. The function armstatus armcfftradix4_init_f32(armcfftradix4_instance f32) is called. S, u int16_tfftLen, u int8_t ifftFlag, u int8_t bitReverseFlag) initialize the structure and FFT operation parameters, where fftLen is an array with a length of 4096; ifftFlag specifies whether it is a Fourier transform (0) or an inverse Fourier transform (1), which is set to 0 in this invention; bitReverseFlag is used to set whether to invert the bits and is set to 1; then call the function void armcfftradix4_f32(const armcfftradix4_instance_f32) S,float32_t pSrc) performs a radix-4 floating-point FFT operation, where S is a parameterized structure. p1 is the array to be analyzed by FFT, i.e., FFT_INPUT

[4096] . ifftFlag is the flag for FFT, indicating whether it is a Fourier transform or inverse Fourier transform. bitReverseFlag is used to set whether to invert the bits. Finally, the function void armcmplxmag_f32(const float32_t) is called. pSrc,float32_t `pDst, uint32_tnumSamples` performs a modulo operation on the FFT-transformed data. It calculates the complex modulus. `pSrc` is the FFT-transformed data, i.e., data of size 2. The input array is a complex number of 4096, pDst is the output array storing the modulo values, and numSamples is the number of data to be moduloed (4096). Then, void armmax_f32(float32_t) is called. pSrc,uint32_t blockSize,float32_t pResult, uint32_t The `pIndex` function calculates the maximum value in an array and returns the maximum value `pResult` and its position within the array.

[0110] pIndex. The frequency resolution after Fourier transform is fk = 10000 / 4096Hz, and the frequency value obtained by FFT. =pIndex fk, =pResult.

[0111] The frequency resolution after Fourier transform is fk = 10000 / 4096Hz. For high-precision applications, a frequency resolution of 2.44Hz is insufficient, and compensation measures must be taken. This invention adopts a software compensation method, which uses an algorithm to correct the sensor and greatly improve the sensor's accuracy.

[0112] The input data FFT_INPUT

[4096] for FFT transformation is split into 4 groups for FFT analysis of 1024 points of data, and the results are obtained respectively. ~ and ~ The input data FFT_INPUT

[4096] for FFT transformation is split into 16 groups for FFT analysis of 256 points, and the results are obtained respectively. ~ and ~ The input data FFT_INPUT

[4096] for FFT transformation is split into 64 groups for 64-point FFT analysis, and the results are obtained respectively. ~ and ~ The method for calculating the correction parameters is as follows:

[0113] ;

[0114] ;

[0115] ;

[0116] Right now:

[0117] ;

[0118] (2);

[0119] Where x[n] (0≤n≤3) is the frequency value correction of the FFT after splitting the data into 4 groups of 1024 points. The frequency values ​​obtained from a radix-4 floating-point FFT operation for 4096 points. For frequency The amplitude value; The frequency value obtained from a 1024-point radix-4 floating-point FFT operation. For frequency The amplitude value; y[n] (0≤n≤63) is the frequency value correction of the FFT after splitting the data into 64 groups of 256 points. The frequency values ​​obtained from a radix-4 floating-point FFT operation for 4096 points. For frequency The amplitude value; The frequency values ​​obtained from a 256-point radix-4 floating-point FFT operation. For frequency The amplitude value.

[0120] After applying the above correction algorithm, the calculated frequency value is... The present invention can control the measurement error within 0.2Hz.

[0121] This invention employs a frequency gradient correction mechanism in data acquisition, enabling the monitoring of frequency changes within 0.01 seconds. It allows simultaneous monitoring of eight channels at a rate up to 100Hz. The main working mechanism is as follows: The initial acquisition of the required 4096 data points upon power-up takes 0.4096 seconds. The frequency value F is obtained through the above calculation and correction algorithm. Intermediate variables required for subsequent corrections are retained. Then, 64 data points are acquired and a radix-4 FFT operation is performed, using the same method as above, to obtain the latest frequency value. and ,give up and After inputting the correction algorithm, the latest frequency value can be obtained. Similarly, when the newly acquired data reaches 1024, a radix-4 FFT algorithm is performed on the new data set for 1024 data points, and the parameters of the correction formula are updated. This iterative update mechanism supports simultaneous acquisition of signals with a frequency range of 600Hz to 4500Hz from up to 8 channels, and outputs the calculation results at a rate of 100Hz. The response time to frequency changes is 0.01s, which is at a high level in the industry.

[0122] Example 7

[0123] Based on Embodiment 1, the system further includes a housing and a first PCB 12 and a second PCB 13 disposed within the housing. The first PCB 12 and the second PCB 13 are connected via a connector. The front panel 11 of the housing is equipped with a power switch 1 and a 12V~36V power supply.

[0124] 2. Power input; 3. 5V power output; 4. RS232 interface; 5. Ethernet interface; 6. Steel wire sensor interface; 7. Reset button; 8. Device status.

[0125] Status indicator light 8; the first PCB12 or the second PCB13 is engraved with a bidirectional dual-channel single-pole double-throw analog switch circuit, a three-stage amplifier circuit, and a fourth-stage feedback intelligent dynamic amplifier circuit. The first PCB12 or / and the second PCB13 are electrically connected to the power switch 1, the 12V~36V power input 2, the 5V power output 3, the RS232 interface, the Ethernet interface 5, the steel wire sensor interface 6, the reset button 7, and the device status indicator light 8, respectively.

[0126] In this invention, each channel is independent of the others. Each channel can adaptively adjust the intensity and duration of the excitation through a hardware feedback circuit according to the different types of sensors connected. At the software level, the hardware feedback circuit function is corrected by an algorithm based on the frequency value of the sensor obtained by measurement, so that the deep excitation and the sensor's natural frequency are best matched.

[0127] Example 8

[0128] Based on embodiment 7, the housing includes an upper housing 9, a lower housing 10, and a front panel 11. The lower housing 10 is threadedly connected to the front panel 11, and the upper housing 9 is snapped together for easy maintenance.

[0129] Example 9

[0130] Based on Embodiment 7, the first PCB12 and the second PCB13 are connected by two 2×20 connectors.

Claims

1. A dynamic signal measurement device for a multi-channel steel wire sensor, comprising a bidirectional dual-channel single-pole double-throw analog switch circuit, a three-stage amplifier circuit, a fourth-stage feedback-type intelligent dynamic amplifier circuit, and a frequency correction algorithm, characterized in that, The bidirectional dual-channel single-pole double-throw analog switch circuit allows for configuration of parameters for each channel according to on-site requirements. These parameters include acquisition switch, amplification factor, and excitation intensity, enabling customized configurations for different scenarios and types of steel wire sensors to achieve optimal detection results. The three-stage amplification circuit amplifies the signal output from the steel wire sensor between 300µV and 1mV through multiple stages to achieve high gain amplification of tens of thousands of times. The fourth-stage feedback intelligent dynamic amplification circuit features a feedback intelligent algorithm dynamic amplification control mechanism, adaptively matching the optimal amplification factor for different types of steel wire sensors. The frequency correction algorithm accurately and dynamically measures and corrects the inherent frequency of the steel wire sensor, quickly detecting and calculating changes in frequency instantaneously. The fourth-stage feedback intelligent dynamic amplification circuit includes an LTC6910 chip U8 and a TS5A22362 chip U50. U8 has 8 pins, with pin 1 connected in series with capacitor R280 and the ADS chip input terminal AINx. Pin 2 of U8 is connected in parallel with capacitor C162 and resistor R292 to simulate ground AGND. Pin 3 of U8 is connected in series with capacitor C158 and resistor R279 to simulate ground and is connected to pin 9 of U50. Pin 4 of U8 is connected in parallel with resistor R274 and capacitor C153, with the other end of resistor R274 connected to -5V. The other end of capacitor C153 simulates ground AGND and is connected in parallel with C152. Pins 5, 6, and 7 of U8 are connected to the general-purpose I / O ports of the main control chip. Pin 8 of U8 is connected in parallel with resistor R273 and capacitor C152, with the other end of resistor R273 connected to +5V. Pin 1 of U50 is connected in parallel with +5V and capacitor C147, with the other end of capacitor C147 connected to simulate ground AGND. Pin 6 of U50 is connected to simulate ground. AGND, pin 7 of U50 is connected to the general-purpose IO port of the main control MCU, pin 8 of U50 is connected to CHx_F of the three-stage amplifier circuit, and pin 10 of U50 is connected to CHx_V of the bidirectional dual-channel single-pole double-throw analog switch; the specific steps of the frequency correction algorithm are as follows: after power-on, after the initialization of each component is completed, the main control chip generates an excitation signal; the steel wire sensor vibrates after being excited. Since the amplitude is very small, the signal is amplified by filtering and amplification; the amplified signal is converted into a digital signal that can be processed by analog-to-digital conversion and 4096 signals are continuously collected. The frequency value is obtained by digital bandpass filtering and discrete Fourier transform. The obtained frequency value has a large error according to the Nyquist sampling theorem. After data analysis and correction, the error is controlled within 0.2Hz, and then the result is output. The excitation is continuously given and the above process is repeated; the specific steps of the data analysis and correction are as follows: the input data FFT_INPUT[4096] of the FFT transform is split into 4 groups for FFT analysis of 1024 points of data, and the results are obtained respectively. ～ and ～ The input data FFT_INPUT[4096] for FFT transformation is split into 16 groups for FFT analysis of 256 points, and the results are obtained respectively. ~ and ～ The input data FFT_INPUT[4096] for FFT transformation is split into 64 groups for 64-point FFT analysis, and the results are obtained respectively. ～ and ～ The formula for calculating the correction parameter is as follows: ； ； ;Right now: ； (2); where x[n] (0≤n≤3) is the frequency value correction of the FFT after splitting the data into 4 groups of 1024 points, The frequency value obtained from a radix-4 floating-point FFT operation with 4096 points. For frequency The amplitude value; The frequency value obtained from a 1024-point radix-4 floating-point FFT operation. For frequency The amplitude value; y[n] (0≤n≤63) is the frequency value correction of the FFT after splitting the data into 64 groups of 256 points. The frequency value M is obtained by a radix-4 floating-point FFT operation with 4096 points. r4_4096 For frequency The amplitude value; The frequency values ​​obtained from a 256-point radix-4 floating-point FFT operation. For frequency The amplitude value is then used to calculate the frequency value F using the above correction algorithm.

2. The dynamic signal measurement device for a multi-channel steel wire sensor according to claim 1, characterized in that, The bidirectional dual-channel single-pole double-throw analog switch circuit includes two TS5A22362DGSR chips U49 and U65, and one OPA2188 chip U44. U49 and U65 have 10 pins each. Pin 1 of U49 is connected in parallel with capacitor C143 and VCC, with C143 then connected in series to digital ground. Pins 2 and 5 of U49 are connected to the general-purpose I / O ports of the main control MCU. Pin 3 of U49 is connected in parallel with diode Z20 and pin 4 of the steel wire sensor interface CH7. Pin 9 of U49 is connected in parallel with diode Z19 and pin 3 of the steel wire sensor interface CH7. Pin 2 of the steel wire sensor interface CH7 is connected to the three-stage amplifier circuit. Pin 1 of the steel wire sensor interface CH7 is grounded. Pin 4 of U49 is connected to pins 3 and 10 of U65. Pin 6 of U49 is connected to ground (GND). Pin 8 of U49 is connected to resistor R265 and then connected in series to the power supply VCC. Pin 10 of U49 is connected to... Pin 9 of U65; Pin 1 of U65 is connected to capacitor C133 and power supply VCC; Pin 2 is connected to capacitor C134 and then to analog ground; Pin 4 is connected in parallel with resistor R243 and resistor R244, and then to analog ground; Pins 5, 7, and 8 are connected to the general-purpose I / O port of the main control MCU; Pin 6 is connected to ground GND; Pin 9 is connected to pin 10 of U49; Pin 10 is connected to pin 4 of U49. The two bidirectional dual-channel single-pole double-throw analog switches are controlled through the general-purpose I / O port of the main control MCU to complete the switching of different channels and functions; U44 has 5 pins; Pin 3 is connected in parallel with pin 4 of U49, pin 3 of U65, and pin 10; Pins 1 and 2 are connected in series with resistor R241 and grounded capacitor C131 and then to the fourth-stage feedback type intelligent dynamic amplifier circuit; Pin 4 is connected in series with grounded capacitor C132 and connected to the power supply voltage -5V; Pin 8 is connected in series with grounded capacitor C130 and connected to the power supply voltage +5V.

3. The dynamic signal measurement device for a multi-channel steel wire sensor according to claim 1, characterized in that, The three-stage amplifier circuit includes an INA128 chip U46 and an OPA2188 chip U47. U46 has eight pins. Pins 1 and 8 of U46 are connected to the two ends of resistor R245. Pins 2 and 5 of U46 are connected to ground. Pin 3 of U46 is connected in parallel with resistor R261 and diode D7. Resistor R261 is then connected in series to the input terminal INx of the steel wire sensor. Pins 4 and 7 of U46 are connected to -5V and +5V respectively. Pin 6 of U46 is the output terminal of this first-stage amplifier, connected to resistor R252. U47 consists of U47A and U47B, with a total of eight pins. Pin 1 of U47A is the output terminal of this third-stage amplifier, connected to the fourth-stage feedback-type intelligent dynamic amplifier circuit, and connected in parallel with resistors R250 and R259 and capacitor C139. Pin 2 is connected to resistor R250 and capacitor C141. Pin 3 of U47A is connected to ground AGND. Pin 4 of U47A is connected to -5V and capacitor C135 to ground. Pin 8 of U47A is connected to -5V and is connected to capacitor C144, which is connected in parallel with resistor R260 and resistor R259. Pin 5 of U47B is connected to ground AGND. Pin 6 of U47B is connected in parallel with resistor R249 and capacitor C140. Capacitor C140 is connected in series with resistor R249 and capacitor C138 and then connected to resistor R252. Pin 7 of U47B is connected in parallel with resistor R255, resistor R257, resistor R249 and capacitor C138. Among them, resistor R257 is connected in series with resistor R258 and capacitor C138, and resistor R255 is connected in parallel with resistor R260, capacitor C141 and capacitor C139.

4. The dynamic signal measurement device for a multi-channel steel wire sensor according to claim 1, characterized in that, It also includes a housing and a first PCB and a second PCB disposed within the housing. The first PCB and the second PCB are connected via a connector. The front panel of the housing is provided with a power switch, a 12V~36V power input, a 5V power output, an RS232 interface, an Ethernet interface, a steel wire sensor interface, a reset button, and a device status indicator. The first PCB or the second PCB is engraved with a bidirectional dual-channel single-pole double-throw analog switch circuit, a three-stage amplifier circuit, and a fourth-stage feedback intelligent dynamic amplifier circuit. The first PCB and / or the second PCB are electrically connected to the power switch, the 12V~36V power input, the 5V power output, the RS232 interface, the Ethernet interface, the steel wire sensor interface, the reset button, and the device status indicator, respectively.

5. The dynamic signal measurement device for a multi-channel steel wire sensor according to claim 4, characterized in that, The housing includes an upper housing, a lower housing, and a front panel. The lower housing is threadedly connected to the front panel, and the upper housing is snapped together with the front panel.

6. The dynamic signal measurement device for a multi-channel steel wire sensor according to claim 4, characterized in that, The first PCB and the second PCB are connected by two 2×20 connectors.

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