A vortex flowmeter signal processing circuit and gas appliance

Abstract

The utility model provides a kind of vortex shedding flowmeter signal processing circuit and gas equipment, the circuit includes single-ended input charge processing module, signal adjusting module and second-order filter module connected in turn, the input end of single-ended input charge processing module generates the inductive element of charge signal, to receive charge signal and convert it into first voltage;Signal adjusting module is used for based on first voltage adjusting amplification gain, and according to amplification gain, first voltage is amplified as second voltage, second-order filter module is used for based on the working frequency of inductive element and medium frequency band generation filter parameter, to generate target voltage based on filter parameter to second voltage filtering.The signal processing circuit provided by the utility model uses simple structure single-ended input charge processing module, improve the anti-interference ability of circuit;The amplification multiple of circuit, filter parameter can be adjusted according to actual situation, widen the application range of vortex shedding flowmeter, and the signal processing circuit is simple in structure, low in cost and convenient to operate.

Description

Technical Field

[0001] This utility model relates to the field of instrumentation technology, and in particular to a signal processing circuit for a vortex flowmeter and a gas-using device. Background Technology

[0002] In an era of rapid industrial development, flow detection is a critical process parameter that needs precise monitoring and control. Flow measurement is essential for cost calculation, product quality assurance, and actual safety. Due to its robust structure, versatility, and linear output, the vortex flow meter has become one of the backbone flow instruments in key fields such as energy metering, petrochemicals, and heating and cooling systems.

[0003] The signal strength and output impedance of the sensing element in the vortex flowmeter are weak. The weak original signal is easily superimposed by external electromagnetic noise, mechanical vibration noise, etc. during transmission and processing, which interferes with the effective signal. At the same time, the high impedance signal is very sensitive to the insulation of the transmission line and the distribution around the conductor during transmission.

[0004] In existing technologies, signal processing generally involves combining differential charge amplifiers and filter circuits to amplify and filter the original signal to obtain the output signal. However, differential charge amplifier circuits are complex in structure, difficult to design, and costly. Their common-mode rejection performance is greatly affected by the environment and components. In actual calculations, if the input cable lengths are inconsistent or the distributed capacitance is asymmetrical, common-mode interference may be converted into differential-mode interference, resulting in poor filtering capability, a decrease in common-mode rejection ratio over time, and reduced anti-interference capability. Furthermore, the filtering frequency band of the filter circuit is inflexible, and there may be situations where the filtering segment is not suitable. Utility Model Content

[0005] This utility model provides a signal processing circuit for a vortex flowmeter and a gas-using device to solve the technical problems of complex structure, high design difficulty, high cost, common-mode suppression effect greatly affected by the environment and components, and poor filtering effect of the vortex flowmeter signal processing circuit.

[0006] This utility model provides a signal processing circuit for a vortex flowmeter, comprising: A single-ended input charge processing module for converting a charge signal into a first voltage, a signal conditioning module for adjusting the amplification gain based on the first voltage and amplifying the first voltage based on the adjusted amplification gain to generate a second voltage, and a second-order filtering module for determining filtering parameters based on the operating frequency of the sensing element and the frequency band of the medium in the measuring pipe and filtering the second voltage based on the filtering parameters to generate a target voltage, wherein the input end of the single-ended input charge processing module is connected to the sensing element in the vortex flowmeter that generates the charge signal, the output end of the single-ended input charge processing module is connected to the input end of the signal conditioning module, and the output end of the signal conditioning module is connected to the input end of the second-order filtering module.

[0007] In one embodiment of this utility model, the single-ended input charge processing module includes a first resistor, a second resistor, a third resistor, a first capacitor, a second capacitor, a third capacitor, a fourth capacitor, a fifth capacitor, a sixth capacitor, a seventh capacitor, an eighth capacitor, a ninth capacitor, a first operational amplifier, and a first chip. The first terminal of the first capacitor is connected to the inverting input terminal of the first operational amplifier, the second terminal of the first capacitor is connected to the first terminal of the second capacitor, the second terminal of the second capacitor is connected to the first channel selection terminal of the first chip, the first terminal of the first resistor is connected to the inverting input terminal of the first operational amplifier, the output terminal of the first operational amplifier is connected to the first terminal of the second resistor, the second terminal of the first resistor is connected to the second terminal of the second resistor, and the second terminal of the second resistor is also connected to the second common terminal of the first chip. The third capacitor is connected in parallel with the first resistor, and the first terminal of the first resistor is also connected to the first terminal of the fourth capacitor, the first terminal of the fifth capacitor, and the ninth capacitor. The first terminal of the capacitor is connected to the first common terminal of the first chip. The second terminal of the fourth capacitor is connected to the second channel selection terminal of the first chip. The second terminal of the fifth capacitor is connected to the third channel selection terminal of the first chip. The second terminal of the sixth capacitor is connected to the fourth channel selection terminal of the first chip. The first terminal of the third resistor is connected to the non-inverting input terminal of the first operational amplifier. The first terminal of the seventh capacitor is connected to the first terminal of the third resistor. The second terminal of the seventh capacitor is connected to the second terminal of the third resistor. The second terminal of the third resistor is connected to a reference voltage. The positive power supply terminal of the first operational amplifier is connected to the power supply terminal of the first chip. The positive power supply terminal of the first operational amplifier is grounded after passing through the eighth capacitor. The power supply terminal of the first chip is grounded after passing through the ninth capacitor. The ground terminal of the first chip is grounded. The first terminal of the first capacitor is the input terminal of the single-ended input charge processing module, and the second terminal of the second resistor is the output terminal of the single-ended input charge processing module.

[0008] In one embodiment of this utility model, the signal conditioning module includes a fourth resistor, a fifth resistor, a sixth resistor, a seventh resistor, an eighth resistor, a tenth capacitor, an eleventh capacitor, a second operational amplifier, and a second chip. The first end of the eighth resistor is connected to the inverting input of the second operational amplifier, and the second end of the eighth resistor is connected to the output of the second operational amplifier. The tenth capacitor is connected in parallel with the eighth resistor. The first end of the eighth resistor is also connected to the first ends of the fourth, fifth, sixth, and seventh resistors. The second end of the fourth resistor is connected to the first channel selection terminal of the second chip, the second end of the fifth resistor is connected to the second channel selection terminal of the second chip, the second end of the sixth resistor is connected to the third channel selection terminal of the second chip, and the second end of the seventh resistor is connected to the fourth channel selection terminal of the second chip. The power supply terminal of the second chip is grounded via the eleventh capacitor, and the ground terminal of the second chip is grounded. The non-inverting input of the second operational amplifier is the input terminal of the signal conditioning module, and the output terminal of the second operational amplifier is the output terminal of the signal conditioning module.

[0009] In one embodiment of the present invention, the second-order filtering module includes a filtering unit for determining filtering parameters based on the operating frequency of the sensing element and the frequency band of the medium in the measuring pipe, and filtering the second voltage according to the filtering parameters to generate a transition voltage, and an output unit for outputting the target voltage following the second voltage. The input terminal of the filtering unit is connected to the output terminal of the signal conditioning module, and the output terminal of the filtering unit is connected to the input terminal of the output unit.

[0010] In one embodiment of this utility model, the filtering unit includes a ninth resistor, a tenth resistor, an eleventh resistor, a twelfth resistor, a twelfth capacitor, a thirteenth capacitor, a fourteenth capacitor, a fifteenth capacitor, a sixteenth capacitor, a seventeenth capacitor, an eighteenth capacitor, a third operational amplifier, and a third chip. The first terminal of the twelfth capacitor is connected to the first terminal of the tenth resistor via the ninth resistor. The first terminal of the tenth resistor is grounded via the thirteenth capacitor. The first terminal of the tenth resistor is connected to the first terminal of the fourteenth capacitor. The second terminal of the fourteenth capacitor is connected to the first channel selection terminal of the third chip. The first terminal of the tenth resistor is connected to the output terminal of the third operational amplifier via the eleventh resistor. The second terminal of the tenth resistor is connected to the output terminal of the third operational amplifier via the fifteenth capacitor. The output terminal of the third operational amplifier is also connected to... The first common terminal of the third chip is connected to the first terminal of the tenth resistor, the second terminal of the tenth resistor is connected to the inverting input terminal of the third operational amplifier, the second terminal of the tenth resistor is connected to the first terminal of the sixteenth capacitor, the second terminal of the sixteenth capacitor is connected to the second channel selection terminal of the third chip, the first terminal of the twelfth resistor is connected to the non-inverting input terminal of the third operational amplifier, the second terminal of the twelfth resistor is connected to the reference voltage, the negative power supply terminal of the third operational amplifier is grounded, the positive power supply terminal of the third operational amplifier is connected to the power supply terminal of the third chip, the power supply terminal of the third chip is grounded through the eighteenth capacitor, and the positive power supply terminal of the third operational amplifier is grounded through the seventeenth capacitor. The second terminal of the twelfth capacitor is the input terminal of the filter unit, and the output terminal of the third operational amplifier is the output terminal of the filter unit.

[0011] In one embodiment of the present invention, the output unit includes a thirteenth resistor, a nineteenth capacitor, and a fourth operational amplifier. The inverting input terminal of the fourth operational amplifier is connected to the output terminal of the fourth operational amplifier, and the output terminal of the fourth operational amplifier is connected to the first terminal of the thirteenth resistor. The second terminal of the thirteenth resistor is also grounded after passing through the nineteenth capacitor. The non-inverting input terminal of the fourth operational amplifier is the input terminal of the output unit, and the second terminal of the thirteenth resistor is the output terminal of the output unit.

[0012] This utility model also provides a gas-using device, which includes the vortex flowmeter signal processing circuit as described above.

[0013] The beneficial effects of this utility model are as follows: This utility model provides a signal processing circuit for a vortex flowmeter and a gas-using device. The circuit includes: a single-ended input charge processing module for converting a charge signal into a first voltage; a signal conditioning module for adjusting the amplification gain based on the first voltage and amplifying the first voltage based on the adjusted amplification gain to generate a second voltage; and a second-order filtering module for determining filtering parameters based on the operating frequency of the sensing element and the frequency band of the medium in the measuring pipe, and filtering the second voltage based on the filtering parameters to generate a target voltage. The input end of the single-ended input charge processing module is connected to the sensing element in the vortex flowmeter that generates the charge signal, the output end of the single-ended input charge processing module is connected to the input end of the signal conditioning module, and the output end of the signal conditioning module is connected to the input end of the second-order filtering module. The signal processing circuit provided by this utility model adopts a single-ended input charge processing module with simple structure and strong anti-interference capability, which avoids the common-mode suppression effect of the circuit being affected by the environment and components, thus reducing the anti-interference capability and improving the anti-interference capability of the circuit. The overall circuit amplification factor is adjustable, and the filtering frequency band can be adjusted according to the actual situation, improving the accuracy and precision of the target signal, making the application range of vortex flowmeter more extensive. This signal processing circuit has a simple structure, low cost, and convenient operation. Attached Figure Description

[0014] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments conforming to the present invention and, together with the description, serve to explain the principles of the present invention. It is obvious that the drawings described below are merely some embodiments of the present invention, and those skilled in the art can obtain other drawings based on these drawings without any inventive effort.

[0015] In the attached diagram: Figure 1 This is a block diagram of the signal processing circuit of the vortex flowmeter provided in one embodiment of the present invention; Figure 2 This is a detailed structural diagram of a single-ended input charge processing module provided in one embodiment of the present invention; Figure 3 This is a detailed structural diagram of the signal conditioning module provided in one embodiment of the present invention; Figure 4 This is a structural diagram of a second-order filtering module provided in one embodiment of the present invention.

[0016] The attached figures are labeled as follows: 110 - Single-ended input charge processing module; 120 - Signal conditioning module; 130 - Second-order filtering module; 411 - Filtering unit; 412 - Output unit; Q1 - Charge signal; V1 - First voltage; V2 - Second voltage; Vd - Target voltage; VREF - Reference voltage. Detailed Implementation

[0017] The following specific examples illustrate the implementation of this utility model. Those skilled in the art can easily understand other advantages and effects of this utility model from the content disclosed in this specification. This utility model can also be implemented or applied through other different specific embodiments. Various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of this utility model. In the absence of conflict, the following embodiments and features in the embodiments can be combined with each other.

[0018] It should be noted that the illustrations provided in the following embodiments are only schematic representations of the basic concept of the present invention. The drawings only show the components related to the present invention and are not drawn according to the actual number, shape and size of the components. In actual implementation, the form, quantity and proportion of each component can be arbitrarily changed, and the layout of the components may also be more complex.

[0019] In the following description, numerous details are explored to provide a more thorough explanation of embodiments of the present invention. However, it will be apparent to those skilled in the art that embodiments of the present invention may be practiced without these specific details. In other embodiments, well-known structures and devices are shown in block diagram form rather than in detail to avoid obscuring embodiments of the present invention.

[0020] In an era of rapid industrial development, flow detection is a critical process parameter that needs precise monitoring and control. Flow measurement is essential for cost calculation, product quality assurance, and actual safety. Due to its robust structure, versatility, and linear output, the vortex flow meter has become one of the backbone flow instruments in key fields such as energy metering, petrochemicals, and heating and cooling systems.

[0021] In vortex flow meters, sensing elements include thermal, capacitive, ultrasonic, and piezoelectric sensors. Piezoelectric sensors are the most commonly used sensing element. The lift force detected by the probe of a piezoelectric sensor is converted into an alternating charge signal. The original output signal is weak and contains various noise components. During the processing of the original signal, false noise is filtered out, retaining the true flow information, and obtaining a target voltage whose frequency is proportional to the flow rate.

[0022] Due to the weak original signal strength and high output impedance of piezoelectric sensors, their output interference resistance is poor. The weak original signal is easily superimposed by external electromagnetic noise, mechanical vibration noise, etc., during transmission and processing, thus interfering with the effective signal. At the same time, high-impedance signals are very sensitive to the insulation of the transmission line and the distribution of materials around the conductor during transmission.

[0023] In existing technologies, the processing of the raw signal output from piezoelectric sensors generally includes a differential charge amplifier and a filter circuit to amplify and filter the raw signal to obtain the output signal. However, differential charge amplifier circuits are complex in structure, difficult to design, and costly. Their common-mode rejection performance is greatly affected by the environment and components. In practical applications, if the input cable lengths are inconsistent or the distributed capacitance is asymmetrical, common-mode interference may be converted into differential-mode interference, weakening the filtering effect. Long-term use of asymmetrical circuits leads to a decrease in the common-mode rejection ratio over time, reducing anti-interference capability. Furthermore, the filtering frequency band of the filter circuit is inflexible, and the filtering frequency may not completely cover the entire frequency range of the signal.

[0024] like Figure 1 As shown, this utility model provides a signal processing circuit for a vortex flowmeter, comprising: A single-ended input charge processing module 110 is used to convert the charge signal Q1 into a first voltage V1; a signal conditioning module 120 is used to adjust the amplification gain based on the first voltage V1 and amplify the first voltage V1 based on the adjusted amplification gain to generate a second voltage V2; and a second-order filtering module 130 is used to determine the filtering parameters based on the operating frequency of the sensing element and the frequency band of the medium in the measuring pipe and filter the second voltage V2 based on the filtering parameters to generate a target voltage Vd. The input terminal of the single-ended input charge processing module 110 is connected to the sensing element that generates the charge signal in the vortex flowmeter, the output terminal of the single-ended input charge processing module 110 is connected to the input terminal of the signal conditioning module 120, and the output terminal of the signal conditioning module 120 is connected to the input terminal of the second-order filtering module 130.

[0025] Specifically, such as Figure 1 As shown, the single-ended input charge processing module 110 is connected to the charge signal Q1 output by the piezoelectric sensor in the vortex flowmeter. The single-ended input charge processing module 110 converts the charge signal Q1 into a charge-voltage signal to obtain a first voltage V1. The input of the signal conditioning module 120 is connected to the output of the single-ended input charge processing module 110. The signal conditioning module 120 amplifies the first voltage V1 and adjusts the amplification gain according to the value of the first voltage V1 to obtain a second voltage V2. The input of the second-order filtering module 130 is connected to the output of the signal conditioning module 120. The second-order filtering module 130 filters the second voltage V2 and configures the corresponding filtering parameters according to the operating frequency of the piezoelectric sensor and the frequency range of the medium in the measuring pipe to obtain the target voltage Vd.

[0026] In detail, such as Figure 2As shown, the single-ended input charge processing module 110 includes a first resistor R1, a second resistor R2, a third resistor R3, a first capacitor C1, a second capacitor C2, a third capacitor C3, a fourth capacitor C4, a fifth capacitor C5, a sixth capacitor C6, a seventh capacitor C7, an eighth capacitor C8, a ninth capacitor C9, a first operational amplifier COMP1, and a first chip U1. The first terminal of the first capacitor C1 is connected to the inverting input terminal of the first operational amplifier COMP1, the second terminal of the first capacitor C1 is connected to the first terminal of the second capacitor C2, and the second terminal of the second capacitor C2 is connected to the first terminal of the first chip U1. The selection terminal S11 is connected as follows: the first terminal of the first resistor R1 is connected to the inverting input terminal of the first operational amplifier COMP1; the output terminal of the first operational amplifier COMP1 is connected to the first terminal of the second resistor R2; the second terminal of the first resistor R1 is connected to the second terminal of the second resistor R2; the second terminal of the second resistor R2 is also connected to the second common terminal COM2 of the first chip U1; the third capacitor C3 is connected in parallel with the first resistor R1; the first terminal of the first resistor R1 is also connected to the first terminals of the fourth capacitor C4, the fifth capacitor C5, the sixth capacitor C6, and the first common terminal COM1 of the first chip U1. The second terminal of the fourth capacitor C4 is connected to the second channel selection terminal S12 of the first chip U1; the second terminal of the fifth capacitor C5 is connected to the third channel selection terminal S13 of the first chip U1; the second terminal of the sixth capacitor C6 is connected to the fourth channel selection terminal S14 of the first chip U1; the first terminal of the third resistor R3 is connected to the non-inverting input terminal of the first operational amplifier COMP1; the first terminal of the seventh capacitor C7 is connected to the first terminal of the third resistor R3; the second terminal of the seventh capacitor C7 is connected to the second terminal of the third resistor R3; the second terminal of the third resistor R3 is connected to the reference voltage VREF; and the positive terminal of the first operational amplifier COMP1... The power supply terminal is connected to the power supply terminal SAVCC of the first chip U1. The positive power supply terminal of the first operational amplifier COMP1 is grounded after passing through the eighth capacitor C8. The power supply terminal of the first chip U1 is grounded after passing through the ninth capacitor C9. The ground terminal of the first chip U1 is grounded. The first end of the first capacitor C1 is the input terminal of the single-ended input charge processing module 110. The input terminal of the single-ended input charge processing module 110 is connected to the charge signal Q1. The second end of the second resistor R2 is the output terminal of the single-ended input charge processing module 110. The output terminal of the single-ended input charge processing module 110 outputs the first voltage V1.

[0027] In detail, such as Figure 3As shown, the signal conditioning module 120 includes a fourth resistor R4, a fifth resistor R5, a sixth resistor R6, a seventh resistor R7, an eighth resistor R8, a tenth capacitor C10, an eleventh capacitor C11, a second operational amplifier COMP2, and a second chip U2. The first terminal of the eighth resistor R8 is connected to the inverting input terminal of the second operational amplifier COMP2, and the second terminal of the eighth resistor R8 is connected to the output terminal of the second operational amplifier COMP2. The tenth capacitor C10 is connected in parallel with the eighth resistor R8. The first terminal of the eighth resistor R8 is also connected to the first terminals of the fourth resistor R4, the fifth resistor R5, the sixth resistor R6, and the seventh resistor R7. The second terminal of the fourth resistor R4 is connected to the first channel selection terminal S21 of the second chip U2, and the second terminal of the fifth resistor R5 is connected to the first channel selection terminal S21 of the second chip U2. The second channel selection terminal S22 is connected to the second terminal of the sixth resistor R6, which is connected to the third channel selection terminal S23 of the second chip U2. The second terminal of the seventh resistor R7 is connected to the fourth channel selection terminal S24 of the second chip U2. The power supply terminal SAVCC of the second chip U2 is grounded through the eleventh capacitor C11, and the ground terminal of the second chip U2 is grounded. The non-inverting input terminal of the second operational amplifier COMP2 is the input terminal of the signal conditioning module 120, which is connected to the first voltage V1. The output terminal of the second operational amplifier COMP2 is the output terminal of the signal conditioning module 120, which outputs the second voltage V2. The four common terminals (COM1, COM2, COM3, COM4) of the second chip U2 are connected to the reference voltage VREF.

[0028] In detail, the second-order filtering module 130 includes a filtering unit 411 for determining filtering parameters based on the operating frequency of the sensing element and the frequency band of the medium in the measuring pipe, and filtering the second voltage V2 according to the filtering parameters to generate a transition voltage, and an output unit 412 for outputting a target voltage Vd following the second voltage V2. The input terminal of the filtering unit 411 is connected to the output terminal of the signal conditioning module 120, and the output terminal of the filtering unit 411 is connected to the input terminal of the output unit 412.

[0029] More in detail, such as Figure 4As shown, the filter unit 411 includes a ninth resistor R9, a tenth resistor R10, an eleventh resistor R11, a twelfth resistor R12, a twelfth capacitor C12, a thirteenth capacitor C13, a fourteenth capacitor C14, a fifteenth capacitor C15, a sixteenth capacitor C16, a seventeenth capacitor C17, an eighteenth capacitor C18, a third operational amplifier COMP3, and a third chip U3. The first terminal of the twelfth capacitor C12 is connected to the first terminal of the tenth resistor R10 via the ninth resistor R9. The first terminal of the tenth resistor R10 is grounded via the thirteenth capacitor C13. The first terminal of the tenth resistor R10 is connected to the first terminal of the fourteenth capacitor C14. The second terminal of the fourteenth capacitor C14 is connected to the first channel selection terminal S31 of the third chip. The first terminal of the tenth resistor R10 is connected to the output terminal of the third operational amplifier COMP3 via the eleventh resistor R11. The second terminal of the tenth resistor R10 is connected to the output terminal of the third operational amplifier COMP3 via the fifteenth capacitor C15. The output terminal of the third operational amplifier COMP3 is connected to the first common terminal COM of the third chip U3. 1. The second terminal of the tenth resistor R10 is connected to the inverting input terminal of the third operational amplifier COMP3. The second terminal of the tenth resistor R10 is connected to the first terminal of the sixteenth capacitor C16. The second terminal of the sixteenth capacitor C16 is connected to the second channel selection terminal S32 of the third chip U3. The first terminal of the twelfth resistor R12 is connected to the non-inverting input terminal of the third operational amplifier COMP3. The second terminal of the twelfth resistor R12 is connected to the reference voltage VREF. The negative power supply terminal of the third operational amplifier COMP3 is grounded. The positive power supply terminal of the third operational amplifier COMP3 is connected to the power supply terminal SAVCC of the third chip U3. The power supply terminal SAVCC of the third chip U3 is grounded through the eighteenth capacitor C18. The positive power supply terminal of the third operational amplifier COMP3 is grounded through the seventeenth capacitor C17. The second terminal of the twelfth capacitor C12 is the input terminal of the filter unit 411. The input terminal of the filter unit 411 is connected to the second voltage V2. The output terminal of the third operational amplifier COMP3 is the output terminal of the filter unit 411. The output terminal of the filter unit 411 outputs a transition voltage.

[0030] In detail, such as Figure 4 As shown, the output unit 412 includes a thirteenth resistor R13, a nineteenth capacitor C19, and a fourth operational amplifier COMP4. The inverting input of the fourth operational amplifier COMP4 is connected to its output, and its output is connected to the first terminal of the thirteenth resistor R13. The second terminal of the thirteenth resistor R13 is grounded via the nineteenth capacitor C19. The non-inverting input of the fourth operational amplifier COMP4 is the input of the output unit 412. The input of the output unit 412 is connected to a transition signal, and the second terminal of the thirteenth resistor R13 is the output of the output unit 412. The output of the output unit 412 outputs the target voltage Vd.

[0031] It should be noted that the four input terminals (Control1A, Control2A, Control3A, Control4A) of the first chip U1 are connected to the controller, and the controller controls the four channel selection terminals (S11, S12, S13, S14) of the first chip U1 to select and conduct; the four input terminals (Control5A, Control6A, Control7A, Control8A) of the second chip U1 are connected to the controller, and the controller controls the four channel selection terminals (S21, S22, S23, S24) of the second chip U2 to select and conduct; the two input terminals (Control9A, Control10A) of the third chip U3 are connected to the controller, and the controller controls the two channel selection terminals (S31, S32) of the third chip U3 to select and conduct.

[0032] Please see Figures 1 to 4 The working principle of the vortex flowmeter signal processing circuit provided by this utility model is as follows: like Figure 1 As shown, the single-ended input charge processing module 110 receives a charge signal Q1 at a single input terminal. The module converts the charge signal Q1 into a voltage signal to obtain a first voltage V1. The first capacitor C1 and the second capacitor C2 in the single-ended input charge processing module 110 are DC blocking capacitors, adjusted according to the medium in the measuring pipe, which may be liquid or gas. The third capacitor C3, the fourth capacitor C4, the fifth capacitor C5, and the sixth capacitor C6 are feedback capacitors, adjusted according to the diameter of the measuring pipe. The first resistor R1 is a feedback resistor, designed to prevent the feedback capacitor from saturating while ensuring that the charge accumulated on it does not leak. The third resistor R3 is a bias resistor, forming a DC path based on the reference voltage VREF. The seventh capacitor C7 is a filter capacitor, preventing differential input voltage from being generated when the reference voltage VREF is input, thus reducing circuit offset.

[0033] The expression for the generation of the first voltage V1 is shown in (1): (1) Where V1 is the first voltage and Q1 is the charge signal. VREF is the total feedback capacitance of capacitors C3, C4, C5, and C6, and is the reference voltage.

[0034] By turning on the four channel selection terminals in the first chip U1, the third capacitor C3, the fourth capacitor C4, the fifth capacitor C5, and the sixth capacitor C6 are controlled to connect to the single-ended input charge processing module 110, so as to output different feedback capacitors.

[0035] The combinations of the total feedback capacitor Ct1 are shown in Table 1: Table 1. Combination of total feedback capacitance Ct1

[0036] like Figure 1 As shown, the first voltage V1 is amplified by the signal conditioning module 120. During the amplification process, the amplification gain of the signal conditioning module 120 is adjusted according to the magnitude of the first voltage V1 to obtain the second voltage V2. In the signal conditioning module 120, the fourth resistor R4, the fifth resistor R5, the sixth resistor R6, and the seventh resistor R7 are the operational amplifier input resistors, the eighth resistor R8 is the operational amplifier feedback resistor, and the tenth capacitor C10 is the operational amplifier feedback capacitor, used for filtering.

[0037] The generation of the second voltage V2 is shown in expression (2): (2) Where V2 is the second voltage and Q1 is the charge signal. Rt1 is the total feedback capacitor of the third capacitor C3, the fourth capacitor C4, the fifth capacitor C5, and the sixth capacitor C6; Rt1 is the total adjustment resistor of the fourth resistor R4, the fifth resistor R5, the sixth resistor R6, and the seventh resistor R7; R8 is the eighth resistor; and VREF is the reference voltage.

[0038] By turning on the four channel selection terminals in the second chip U2, the total resistance Rt1 of the fourth resistor R4, the fifth resistor R5, the sixth resistor R6, and the seventh resistor R7 is controlled and connected to the signal conditioning module 120 to output different gain resistors.

[0039] The conduction modes of the total resistance Rt1 are shown in Table 2: Table 2. Conduction methods for adjusting the total resistance Rt1

[0040] like Figure 1 As shown, the second voltage V2 is filtered by a second-order filter module 130, and the filter frequency is configured according to the natural frequency of the piezoelectric sensor and the frequency range of the transmission medium in the pipeline. Figure 4 As shown, resistors R9 (ninth) and R11 (eleventh) are used to construct the feedback loop and voltage divider network. The gain and stability of the filter unit are changed by adjusting the resistance values. Capacitors C13 (thirteenth), C14 (fourteenth), C15 (fifteenth), and C16 (sixteenth) work together with the resistors to form a low-pass filter channel, achieving signal filtering through frequency-selective attenuation.

[0041] The expression for the filtering frequency f of the low-pass filter composed of filtering unit 411 is shown in (3): (3) Where f is the low-pass filter frequency, R10 is the tenth resistor, and R11 is the eleventh resistor. Ct3 is the total filter capacitance formed by the combination of the thirteenth capacitor C13 and the fourteenth capacitor C14, and Ct3 is the total filter capacitance formed by the combination of the fifteenth capacitor C15 and the sixteenth capacitor C16.

[0042] By controlling the conduction of the two channel selection terminals of the third chip U3, the fourteenth capacitor C14 and the sixteenth capacitor are connected to the filter unit 411, thereby adjusting the filtering combination of the total filter capacitors Ct2 and Ct3 and changing the value of the total filter capacitor. The filtering combination of the total filter capacitors Ct2 and Ct3 is shown in Table 3. Table 3 Low-pass filter capacitor combinations

[0043] The expression for the low-frequency amplification factor A1 of filter unit 411 is shown in (4): (4) Where A1 is the low-frequency amplification factor, R9 is the ninth resistor, and R11 is the eleventh resistor.

[0044] Based on the above analysis, the overall voltage amplification factor of the entire signal processing circuit is shown in expression (5): (5) Where A2 is the overall voltage amplification factor, R9 is the ninth resistor, R11 is the eleventh resistor, Rt1 is the total adjustment resistance of the fourth resistor R4, the fifth resistor R5, the sixth resistor R6, and the seventh resistor R7, and R8 is the eighth resistor.

[0045] This utility model also provides a gas-using device, which includes the vortex flowmeter signal processing circuit as described above, to improve the accuracy and precision of flow detection in the gas-using device.

[0046] This utility model provides a signal processing circuit for a vortex flowmeter and a gas-using device. The circuit includes: a single-ended input charge processing module for converting a charge signal into a first voltage; a signal conditioning module for adjusting the amplification gain based on the first voltage and amplifying the first voltage based on the adjusted amplification gain to generate a second voltage; and a second-order filtering module for determining filtering parameters based on the operating frequency of the sensing element and the frequency band of the medium in the measuring pipe, and filtering the second voltage based on the filtering parameters to generate a target voltage. The input terminal of the single-ended input charge processing module is connected to the sensing element in the vortex flowmeter that generates the charge signal, the output terminal of the single-ended input charge processing module is connected to the input terminal of the signal conditioning module, and the output terminal of the signal conditioning module is connected to the input terminal of the second-order filtering module. The signal processing circuit provided by this utility model adopts a single-ended input charge processing module with simple structure and strong anti-interference capability, which avoids the common-mode suppression effect of the circuit being affected by the environment and components, thus reducing the anti-interference capability and improving the anti-interference capability of the circuit. The overall circuit amplification factor is adjustable, and the filtering frequency band can be adjusted according to the actual situation, improving the accuracy and precision of the target signal, making the application range of vortex flowmeter more extensive. This signal processing circuit has a simple structure, low cost, and convenient operation.

[0047] The above embodiments are merely illustrative of the principles and effects of this utility model and are not intended to limit the scope of this utility model. Any person skilled in the art can modify or alter the above embodiments without departing from the spirit and scope of this utility model. Therefore, all equivalent modifications or alterations made by those skilled in the art without departing from the spirit and technical concept disclosed in this utility model should still be covered by the claims of this utility model.

Claims

1. A signal processing circuit for a vortex flowmeter, characterized in that, The signal processing circuit includes: A single-ended input charge processing module for converting a charge signal into a first voltage, a signal conditioning module for adjusting the amplification gain based on the first voltage and amplifying the first voltage based on the adjusted amplification gain to generate a second voltage, and a second-order filtering module for determining filtering parameters based on the operating frequency of the sensing element and the frequency band of the medium in the measuring pipe and filtering the second voltage based on the filtering parameters to generate a target voltage, wherein the input end of the single-ended input charge processing module is connected to the sensing element in the vortex flowmeter that generates the charge signal, the output end of the single-ended input charge processing module is connected to the input end of the signal conditioning module, and the output end of the signal conditioning module is connected to the input end of the second-order filtering module.

2. The vortex flowmeter signal processing circuit according to claim 1, characterized in that, The single-ended input charge processing module includes a first resistor, a second resistor, a third resistor, a first capacitor, a second capacitor, a third capacitor, a fourth capacitor, a fifth capacitor, a sixth capacitor, a seventh capacitor, an eighth capacitor, a ninth capacitor, a first operational amplifier, and a first chip. The first terminal of the first capacitor is connected to the inverting input terminal of the first operational amplifier, and the second terminal of the first capacitor is connected to the first terminal of the second capacitor. The second terminal of the second capacitor is connected to the first channel selection terminal of the first chip. The first terminal of the first resistor is connected to the inverting input terminal of the first operational amplifier, and the output terminal of the first operational amplifier is connected to the first terminal of the second resistor. The second terminal of the first resistor is also connected to the second common terminal of the first chip. The third capacitor is connected in parallel with the first resistor, and the first terminal of the first resistor is also connected to the first terminals of the fourth, fifth, and sixth capacitors. The first common terminal of the first chip, the second terminal of the fourth capacitor is connected to the second channel selection terminal of the first chip, the second terminal of the fifth capacitor is connected to the third channel selection terminal of the first chip, the second terminal of the sixth capacitor is connected to the fourth channel selection terminal of the first chip, the first terminal of the third resistor is connected to the non-inverting input terminal of the first operational amplifier, the first terminal of the seventh capacitor is connected to the first terminal of the third resistor, the second terminal of the seventh capacitor is connected to the second terminal of the third resistor, the second terminal of the third resistor is connected to a reference voltage, the positive power supply terminal of the first operational amplifier is connected to the power supply terminal of the first chip, the positive power supply terminal of the first operational amplifier is grounded after passing through the eighth capacitor, the power supply terminal of the first chip is grounded after passing through the ninth capacitor, and the ground terminal of the first chip is grounded. The first terminal of the first capacitor is the input terminal of the single-ended input charge processing module, and the second terminal of the second resistor is the output terminal of the single-ended input charge processing module.

3. The vortex flowmeter signal processing circuit according to claim 1, characterized in that, The signal conditioning module includes a fourth resistor, a fifth resistor, a sixth resistor, a seventh resistor, an eighth resistor, a tenth capacitor, an eleventh capacitor, a second operational amplifier, and a second chip. The first end of the eighth resistor is connected to the inverting input of the second operational amplifier, and the second end of the eighth resistor is connected to the output of the second operational amplifier. The tenth capacitor is connected in parallel with the eighth resistor. The first end of the eighth resistor is also connected to the first ends of the fourth, fifth, sixth, and seventh resistors. The second end of the fourth resistor is connected to the first channel selection terminal of the second chip, the second end of the fifth resistor is connected to the second channel selection terminal of the second chip, the second end of the sixth resistor is connected to the third channel selection terminal of the second chip, and the second end of the seventh resistor is connected to the fourth channel selection terminal of the second chip. The power supply terminal of the second chip is grounded via the eleventh capacitor, and the ground terminal of the second chip is grounded. The non-inverting input of the second operational amplifier is the input terminal of the signal conditioning module, and the output terminal of the second operational amplifier is the output terminal of the signal conditioning module.

4. The vortex flowmeter signal processing circuit according to claim 2, characterized in that, The second-order filtering module includes a filtering unit for determining filtering parameters based on the operating frequency of the sensing element and the frequency band of the medium in the measuring pipe, and filtering the second voltage according to the filtering parameters to generate a transition voltage, and an output unit for outputting the target voltage following the second voltage. The input terminal of the filtering unit is connected to the output terminal of the signal conditioning module, and the output terminal of the filtering unit is connected to the input terminal of the output unit.

5. The vortex flowmeter signal processing circuit according to claim 4, characterized in that, The filtering unit includes a ninth resistor, a tenth resistor, an eleventh resistor, a twelfth resistor, a twelfth capacitor, a thirteenth capacitor, a fourteenth capacitor, a fifteenth capacitor, a sixteenth capacitor, a seventeenth capacitor, an eighteenth capacitor, a third operational amplifier, and a third chip. The first terminal of the twelfth capacitor is connected to the first terminal of the tenth resistor via the ninth resistor. The first terminal of the tenth resistor is grounded via the thirteenth capacitor. The first terminal of the tenth resistor is connected to the first terminal of the fourteenth capacitor. The second terminal of the fourteenth capacitor is connected to the first channel selection terminal of the third chip. The first terminal of the tenth resistor is connected to the output terminal of the third operational amplifier via the eleventh resistor. The second terminal of the tenth resistor is connected to the output terminal of the third operational amplifier via the fifteenth capacitor. The output terminal of the third operational amplifier is also connected to the third chip. The first common terminal, the second terminal of the tenth resistor is connected to the inverting input terminal of the third operational amplifier, the second terminal of the tenth resistor is connected to the first terminal of the sixteenth capacitor, the second terminal of the sixteenth capacitor is connected to the second channel selection terminal of the third chip, the first terminal of the twelfth resistor is connected to the non-inverting input terminal of the third operational amplifier, the second terminal of the twelfth resistor is connected to the reference voltage, the negative power supply terminal of the third operational amplifier is grounded, the positive power supply terminal of the third operational amplifier is connected to the power supply terminal of the third chip, the power supply terminal of the third chip is grounded through the eighteenth capacitor, and the positive power supply terminal of the third operational amplifier is grounded through the seventeenth capacitor. The second terminal of the twelfth capacitor is the input terminal of the filter unit, and the output terminal of the third operational amplifier is the output terminal of the filter unit.

6. The vortex flowmeter signal processing circuit according to claim 4, characterized in that, The output unit includes a thirteenth resistor, a nineteenth capacitor, and a fourth operational amplifier. The inverting input of the fourth operational amplifier is connected to its output, and the output of the fourth operational amplifier is connected to the first end of the thirteenth resistor. The second end of the thirteenth resistor is also grounded via the nineteenth capacitor. The non-inverting input of the fourth operational amplifier is the input of the output unit, and the second end of the thirteenth resistor is the output of the output unit.

7. A gas-using device, characterized in that, The gas-using equipment includes the vortex flowmeter signal processing circuit as described in any one of claims 1-6.

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