Vibrating wire acquisition module capable of automatically adjusting excitation mode and vibrating wire acquisition equipment

Abstract

The utility model provides a vibrating wire acquisition module and vibrating wire acquisition equipment capable of automatically adjusting an excitation mode, the module is used for acquiring an output signal of a vibrating wire sensor, the module comprises a microcontroller and a signal switching circuit electrically connected with the vibrating wire sensor, the microcontroller is electrically connected with the signal switching circuit through an excitation unit, and the signal switching circuit is electrically connected with the vibrating wire sensor. The signal switching circuit is electrically connected with the envelope detection circuit through the adjusting unit, and the envelope detection circuit is electrically connected with the microcontroller through the digital-to-analog converter. An envelope signal is collected through the envelope detection circuit, the microcontroller autonomously adjusts the sending form of the excitation voltage or the excitation pulse of the excitation unit according to the attenuation rate of the envelope signal and the maximum amplitude of the signal, adaptive adjustment of the excitation mode is achieved, the applicability of the excitation mode is improved, then the output signal of the vibrating wire sensor reaches the optimal signal-to-noise ratio, and the output signal of the vibrating wire sensor reaches the optimal signal-to-noise ratio. And the measurement precision is improved.

Description

Technical Field

[0001] The utility model relates to the technical field of engineering measurement, in particular to a vibrating string acquisition module and a vibrating string acquisition device capable of automatically adjusting an excitation mode. Background Art

[0002] With the continuous development of science and technology, sensor technology has been widely used in various fields. As a common type of sensor, the vibrating string sensor is used to output signals when the vibration amplitude and phase of the vibrating string are changed by external forces.

[0003] The manufacturing processes of vibrating string sensors from different manufacturers are different, and the vibrating string sensors produced by the same manufacturer will also have a certain degree of discreteness in electrical performance. In addition, in actual applications, the signal-to-noise ratio of the vibrating string sensor output signal will be affected to varying degrees due to various factors such as the working environment, cable length, and cable quality. When the performance of the sensor itself and the external environmental parameters are fixed, the signal-to-noise ratio of the vibrating string sensor output signal can only be improved by changing the excitation parameters of the acquisition module, such as adjusting the excitation voltage, excitation pulse mode, etc.

[0004] Currently, the excitation mode of the acquisition module of the vibrating string sensor mostly adopts a fixed excitation mode, which cannot be adaptively adjusted according to different working conditions and has poor applicability. Utility Model Content

[0005] In view of the deficiencies in the prior art, the purpose of the utility model is to provide a vibrating string acquisition module and a vibrating string acquisition device that can automatically adjust the excitation mode, aiming to solve the technical problems in the prior art that the excitation mode of the vibrating string acquisition module is fixed, it is difficult to adapt to different working conditions, and the applicability is poor.

[0006] In order to achieve the above-mentioned purpose, the first aspect of the utility model provides a vibrating-wire acquisition module with automatic adjustment of excitation mode, which is used to collect the output signal of a vibrating-wire sensor. The vibrating-wire acquisition module with automatic adjustment of excitation mode includes a microcontroller and a signal switching circuit electrically connected to the vibrating-wire sensor, the microcontroller is electrically connected to the signal switching circuit through an excitation unit, the signal switching circuit is electrically connected to an envelope detection circuit through an adjustment unit, the envelope detection circuit is used to obtain the envelope of the positive half-cycle waveform of the output signal to output an envelope signal, the envelope detection circuit is electrically connected to the microcontroller through a digital-to-analog converter, the digital-to-analog converter is used to convert the envelope signal into discrete data, and the microcontroller is used to control the excitation mode of the excitation unit based on the discrete data.

[0007] Compared with the prior art, the utility model has the beneficial effects of: the connection of the vibrating-string sensor can be switched through the signal switching circuit, the vibrating-string sensor and the excitation unit are connected through the signal switching circuit, the excitation unit can excite the vibrating-string sensor, the vibrating-string sensor and the adjustment unit are connected through the signal switching circuit, after the adjustment unit completes the adjustment of the output signal, the envelope signal is collected through the envelope detection circuit, the microcontroller autonomously adjusts the excitation voltage of the excitation unit or the sending form of the excitation pulse according to the attenuation rate of the envelope signal and the maximum amplitude of the signal, realizes adaptive adjustment of the excitation mode, improves its applicability, and thereby enables the output signal of the vibrating-string sensor to achieve the optimal signal-to-noise ratio, thereby improving the measurement accuracy.

[0008] Furthermore, the excitation unit includes a digital adjustable power supply and an electronic switch, the microcontroller is electrically connected to the digital adjustable power supply, and the digital adjustable power supply is electrically connected to the signal switching circuit through the electronic switch.

[0009] Furthermore, the electronic switch includes a MOS tube T1 and a transistor Q1, the digital adjustable power supply is electrically connected to the MOS tube T1 and the transistor Q1, and the MOS tube T1 is electrically connected to the signal switching circuit.

[0010] Furthermore, a self-recovery fuse F1 is arranged between the digital adjustable power supply and the MOS tube T1, and a Schottky diode D1 is arranged between the MOS tube T1 and the signal switching circuit.

[0011] Furthermore, the digital adjustable power supply includes an input filter capacitor, a buck controller U4, a buck capacitor U10 and an output filter capacitor, the input filter capacitor is electrically connected to the buck controller U4, the first pin of the buck controller U4 is electrically connected to the boost capacitor C6, the boost capacitor C6 is electrically connected to the input end of the energy storage inductor L1, the output end of the energy storage inductor L1 is connected to the output filter capacitor, the fourth pin of the buck controller U4 and the output end of the energy storage inductor L1 are electrically connected to the resistor R11 and the noise reduction capacitor C10, and the fourth pin of the buck controller U4 is electrically connected to the digital potentiometer U5 through the resistor R12.

[0012] Furthermore, the regulating unit includes an amplifier circuit and a filter circuit, the signal switching circuit is electrically connected to the amplifier circuit, and the amplifier circuit is electrically connected to the envelope detection circuit through the filter circuit.

[0013] Furthermore, the envelope detection circuit includes a diode D2 and an operational amplifier U3A, the adjustment unit is electrically connected to the non-inverting input terminal of the operational amplifier U3A, and the output terminal of the operational amplifier U3A is electrically connected to the negative phase input terminal of the operational amplifier U3A through the diode D2.

[0014] Furthermore, the regulating unit is also electrically connected to the digital-to-analog converter.

[0015] In a second aspect, the utility model further provides a vibrating string acquisition device, comprising a vibrating string sensor and a vibrating string acquisition module for automatically adjusting the excitation mode electrically connected to the vibrating string sensor, wherein the vibrating string acquisition module for automatically adjusting the excitation mode is the vibrating string acquisition module for automatically adjusting the excitation mode as described in the first aspect above. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 This is a structural block diagram of a vibrating string acquisition module that automatically adjusts the excitation mode in Example 1 of the utility model;

[0017] Figure 2 for Figure 1 Circuit diagram of electronic switch in;

[0018] Figure 3 for Figure 1 Circuit diagram of digital adjustable power supply;

[0019] Figure 4 for Figure 1 Circuit diagram of the envelope detection circuit;

[0020] Description of main component symbols:

[0021] 1. Vibrating string sensor; 2. Signal switching circuit; 3. Electronic switch; 4. Digital adjustable power supply; 5. Amplifier circuit; 6. Filter circuit; 7. Envelope detection circuit; 8. Digital-to-analog converter; 9. Microcontroller.

[0022] The following specific implementation manner will further illustrate the present utility model in conjunction with the above-mentioned drawings. DETAILED DESCRIPTION

[0023] In order to facilitate the understanding of the present invention, the present invention will be described more fully below with reference to the relevant drawings. Several embodiments of the present invention are given in the drawings. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the disclosure of the present invention more thorough and comprehensive.

[0024] It should be noted that when an element is referred to as being "fixed to" another element, it may be directly on the other element or there may be a central element. When an element is considered to be "connected to" another element, it may be directly connected to the other element or there may be a central element at the same time. The terms "vertical", "horizontal", "left", "right" and similar expressions used herein are for illustrative purposes only.

[0025] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art in the technical field of the present invention. The terms used herein in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. The term "and / or" used herein includes any and all combinations of one or more related listed items.

[0026] See also Figure 1 Embodiment 1 of the utility model provides a vibrating-string acquisition module with automatic adjustment of excitation mode, which is used to collect the output signal of a vibrating-string sensor 1. The vibrating-string acquisition module with automatic adjustment of excitation mode includes a microcontroller 9 and a signal switching circuit 2 electrically connected to the vibrating-string sensor 1. The microcontroller 9 is electrically connected to the signal switching circuit 2 through an excitation unit. The excitation unit is used to provide excitation to the vibrating-string sensor 1 so that the vibrating-string sensor 1 outputs an output signal with a better signal-to-noise ratio.

[0027] Specifically, the excitation unit includes a digital adjustable power supply 4 and an electronic switch 3. The microcontroller 9 is electrically connected to the digital adjustable power supply 4. The digital adjustable power supply 4 is electrically connected to the signal switching circuit 2 through the electronic switch 3. Initially, the microcontroller 9 controls the enable pin of the electronic switch 3 to send an enable signal with a certain pulse width, so that the electronic switch 3 loads the output of the digital adjustable power supply 4 onto the vibrating string sensor 1 according to the length of the pulse width to complete the initial excitation.

[0028] See also Figure 2The electronic switch 3 includes a MOS tube T1 and a transistor Q1. The digital adjustable power supply 4 is electrically connected to the MOS tube T1 and the transistor Q1. The MOS tube T1 is electrically connected to the signal switching circuit 2. The transistor Q1 is used to drive the P-channel MOS tube T1. A resistor R1 and a resistor R2 are set between the MOS tube T1 and the transistor Q1. When the MOS tube T1 sends an excitation pulse signal, it works in a high-speed switching state. The resistance values ​​of the resistors R1 and R2 need to meet the switching speed of the MOS tube T1 to avoid affecting the excitation effect. A self-recovery fuse F1 is set between the digital adjustable power supply 4 and the MOS tube T1. The self-recovery fuse F1 is used to protect the digital adjustable power supply 4 when sending an excitation signal. A Schottky diode D1 is set between the MOS tube T1 and the signal switching circuit 2. Since the coil of the vibrating string sensor 1 is an inductive load, the Schottky diode D1 is used to prevent the reverse peak pulse of the coil when sending an excitation signal. When the electronic switch 3 is stationary, the microcontroller 9 sets the PS pin to a low level, and the MOS transistor T1 and the transistor Q1 are turned off. When sending a single pulse, multi-pulse sweep frequency, or resonance excitation signal, the microcontroller 9 applies a pulse signal to the PS pin.

[0029] See also Figure 3 The digital adjustable power supply 4 includes an input filter capacitor, a buck controller U4, a buck capacitor U10 and an output filter capacitor. The input filter capacitor includes capacitors C7, C8 and C9, and the output filter capacitor includes capacitors C11 and C12. The input filter capacitor is electrically connected to the buck controller U4. The first pin of the buck controller U4 is electrically connected to the boost capacitor C6. The boost capacitor C6 is electrically connected to the input end of the energy storage inductor L1. The output end of the energy storage inductor L1 is connected to the output filter capacitor. The fourth pin of the buck controller U4 is electrically connected to the output end of the energy storage inductor L1 by resistor R11 and noise reduction capacitor C10. The fourth pin of the buck controller U4 is electrically connected to the digital potentiometer U5 through resistor R12. The buck controller U4 adjusts its output voltage by sampling the voltage value of the connection point between the resistor R11 and the resistor R12. The output voltage U of the digital adjustable power supply 4 is 1.221*(R11 / (R12+Rx)+1), where Rx is the current resistance value of the digital potentiometer U5. Generally, the range of Rx is 0K to 5K, and the output voltage of the digital adjustable power supply 4 is 3.2V to 11.4V.

[0030] The signal switching circuit 2 is electrically connected to the envelope detection circuit 7 through the adjustment unit. The adjustment unit includes an amplifier circuit 5 and a filter circuit 6. The signal switching circuit 2 is electrically connected to the amplifier circuit 5. The amplifier circuit 5 is electrically connected to the envelope detection circuit 7 through the filter circuit 6. The amplifier circuit 5 amplifies the output signal of the vibrating string sensor 1 to improve the signal-to-noise ratio of the signal, which is convenient for subsequent circuit processing. Generally, the amplifier circuit 5 selects a corresponding scheme according to the signal conditioning type at the front end of the signal chain. If the output signal is a differential signal, the amplifier circuit 5 uses an instrumentation amplifier for amplification. If the output signal is a single-ended signal, the amplifier circuit 5 uses in-phase proportional amplification or reverse proportional amplification for conditioning. The filter circuit 6 is used to filter out interference and noise outside the bandwidth range of the output signal.

[0031] The envelope detection circuit 7 is used to obtain the envelope of the positive half-cycle waveform of the output signal to output an envelope signal. The envelope detection circuit 7 is electrically connected to the microcontroller 9 via a digital-to-analog converter 8. The digital-to-analog converter 8 is used to convert the envelope signal into discrete data. The microcontroller 9 is used to control the excitation mode of the excitation unit based on the discrete data.

[0032] The connection of the vibrating-string sensor 1 can be switched through the signal switching circuit 2, the vibrating-string sensor 1 and the excitation unit are connected through the signal switching circuit 2, the excitation unit can excite the vibrating-string sensor 1, the vibrating-string sensor 1 and the adjustment unit are connected through the signal switching circuit 2, after the adjustment unit completes the adjustment of the output signal, the envelope signal is collected through the envelope detection circuit 7, the microcontroller 9 autonomously adjusts the excitation voltage of the excitation unit or the sending form of the excitation pulse according to the attenuation rate of the envelope signal and the maximum amplitude of the signal, realizes adaptive adjustment of the excitation mode, improves its applicability, and further enables the output signal of the vibrating-string sensor 1 to achieve the optimal signal-to-noise ratio, thereby improving the measurement accuracy.

[0033] See also Figure 4, the envelope detection circuit 7 includes a diode D2 and an operational amplifier U3A, the adjustment unit is electrically connected to the non-inverting input terminal of the operational amplifier U3A, the output terminal of the operational amplifier U3A is electrically connected to the negative input terminal of the operational amplifier U3A through the diode D2, and the diode D2 and the operational amplifier U3A form an ideal diode circuit to eliminate the error caused by the diode charging voltage drop. The output terminal of the operational amplifier U3A is connected to the non-inverting input terminal of the operational amplifier U3B through a diode D3, and the diode D3 is used to clamp the signal when re-establishing the peak value to prevent the circuit from responding to the country when negative saturation occurs. A discharge resistor R10 and a capacitor C5 are set between the diode D3 and the operational amplifier U3B, and the voltage on the capacitor C5 tracks the envelope voltage of the signal. The diode D2 is connected to the negative input terminal of the operational amplifier U3B through a current limiting resistor R9, and the current limiting resistor R9 is used to suppress the injection current of the operational amplifier U3A. The operational amplifier U3B is a voltage follower for impedance matching.

[0034] During actual use, the cable connection between the vibrating string acquisition module that automatically adjusts the excitation mode and the vibrating string sensor 1 is completed. The vibrating string acquisition module that automatically adjusts the excitation mode first performs an initial test on the vibrating string sensor 1 according to the default excitation mode and excitation voltage. For example, single pulse excitation is used by default. This excitation mode is similar to unit pulse excitation, which can make the steel string closer to free vibration after vibrating. The excitation voltage is set to an intermediate value.

[0035] Specifically, the signal switching circuit 2 switches the vibrating string sensor 1 to be connected to the electronic switch 3 to form a loop, and the output of the digital adjustable power supply 4 is loaded on the input end of the electronic switch 3. The microcontroller 9 controls the enable pin of the electronic switch 3 to send an enable signal of a certain pulse width, so that the electronic switch 3 loads the output of the digital adjustable power supply 4 on the vibrating string sensor 1 according to the length of the pulse width. The default value of the pulse width is the reciprocal of the maximum value of the signal bandwidth of the vibrating string sensor 1. The pulse width parameter is adjustable, and the microcontroller 9 will select the best pulse width parameter according to the effectiveness of the induced signal after different pulse width excitations.

[0036] When the vibrating-string sensor 1 is excited, the microcontroller 9 controls the signal switching circuit 2 to disconnect the vibrating-string sensor 1 from the circuit of the electronic switch 3 and connect it to the regulating unit. The output signal is amplified by the amplifying circuit 5, and then filtered out interference and noise outside the signal bandwidth by the filtering circuit 6, and then sent to the envelope detection circuit 7. The output of the envelope detection circuit 7 is then connected to the digital-to-analog converter 8. In this embodiment, the regulating unit is also electrically connected to the digital-to-analog converter 8, that is, after the output signal passes through the filtering circuit 6, it is also sent to the digital-to-analog converter 8 at the same time.

[0037] The digital-to-analog converter 8 will simultaneously process the output signal after the filter circuit 6 and the envelope signal after the envelope detection circuit 7. The output signal after the filter circuit 6 is converted by the digital-to-analog converter 8 according to the set sampling rate to obtain the time domain discrete data of the output signal, and transmit it to the microcontroller 9 for temporary storage; the envelope detection circuit 7 detects the envelope of the positive half-cycle waveform of the output signal after the filter circuit 6, and the digital-to-analog converter 8 converts the envelope signal into discrete data according to a certain sampling rate and transmits it to the microcontroller 9. The microcontroller 9 calculates the following based on the envelope signal: signal attenuation rate β: that is, the starting voltage value Va and the ending voltage value Vb of a section of data in the middle of the envelope signal, β = Vb / Va, generally taking 20% ​​to 80% of the data in the middle of the discrete envelope signal to avoid switching interference and low signal-to-noise ratio signals; signal maximum amplitude Vmax: generally taking Vmax = Va. The microcontroller 9 determines whether to use the discretized data of the current output signal or reselect the excitation method for re-measurement according to the signal attenuation rate β and the value of the maximum signal amplitude Vmax. Generally, when the maximum signal amplitude Vmax is less than a certain value, the excitation voltage needs to be increased, and when the signal attenuation rate β is less than a certain value, the form of the excitation pulse needs to be changed. The microcontroller 9 changes the excitation voltage value by adjusting the digital potentiometer of the digital adjustable power supply 4, adjusts the excitation pulse width by adjusting the value of the internal timer, or outputs a sweeping excitation signal or a resonance excitation signal.

[0038] Embodiment 2 of the present invention provides a vibrating string acquisition device, comprising a vibrating string sensor and a vibrating string acquisition module for automatically adjusting the excitation mode electrically connected to the vibrating string sensor, wherein the vibrating string acquisition module for automatically adjusting the excitation mode is the vibrating string acquisition module for automatically adjusting the excitation mode as described in the above embodiment 1.

[0039] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the utility model. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0040] The above-mentioned embodiments only express several implementation methods of the utility model, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the patent of the utility model. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the utility model, and these all belong to the protection scope of the utility model. Therefore, the protection scope of the utility model patent shall be based on the attached claims.

Claims

1. A vibrating string acquisition module with automatic adjustment of excitation mode, used for collecting output signals of vibrating string sensors, characterized in that: The vibrating-wire acquisition module for automatically adjusting the excitation mode includes a microcontroller and a signal switching circuit electrically connected to the vibrating-wire sensor, the microcontroller is electrically connected to the signal switching circuit via an excitation unit, the signal switching circuit is electrically connected to an envelope detection circuit via an adjustment unit, the envelope detection circuit is used to obtain the envelope of the positive half-cycle waveform of the output signal to output an envelope signal, the envelope detection circuit is electrically connected to the microcontroller via a digital-to-analog converter, the digital-to-analog converter is used to convert the envelope signal into discrete data, and the microcontroller is used to control the excitation mode of the excitation unit based on the discrete data.

2. The vibrating string acquisition module for automatically adjusting the excitation mode according to claim 1, characterized in that: The excitation unit includes a digital adjustable power supply and an electronic switch. The microcontroller is electrically connected to the digital adjustable power supply, and the digital adjustable power supply is electrically connected to the signal switching circuit through the electronic switch.

3. The vibrating string acquisition module for automatically adjusting the excitation mode according to claim 2, characterized in that: The electronic switch includes a MOS tube T1 and a triode Q1 , the digital adjustable power supply is electrically connected to the MOS tube T1 and the triode Q1 , and the MOS tube T1 is electrically connected to the signal switching circuit.

4. The vibrating string acquisition module for automatically adjusting the excitation mode according to claim 3, characterized in that: A self-recovery fuse F1 is arranged between the digital adjustable power supply and the MOS tube T1, and a Schottky diode D1 is arranged between the MOS tube T1 and the signal switching circuit.

5. The vibrating string acquisition module for automatically adjusting the excitation mode according to claim 2, characterized in that: The digital adjustable power supply includes an input filter capacitor, a buck controller U4, a buck capacitor U10 and an output filter capacitor. The input filter capacitor is electrically connected to the buck controller U4. The first pin of the buck controller U4 is electrically connected to the boost capacitor C6. The boost capacitor C6 is electrically connected to the input end of the energy storage inductor L1. The output end of the energy storage inductor L1 is connected to the output filter capacitor. The fourth pin of the buck controller U4 and the output end of the energy storage inductor L1 are electrically connected to the resistor R11 and the noise reduction capacitor C10. The fourth pin of the buck controller U4 is electrically connected to the digital potentiometer U5 through the resistor R12.

6. The vibrating string acquisition module for automatically adjusting the excitation mode according to claim 1, characterized in that: The regulating unit includes an amplifier circuit and a filter circuit. The signal switching circuit is electrically connected to the amplifier circuit. The amplifier circuit is electrically connected to the envelope detection circuit through the filter circuit.

7. The vibrating string acquisition module for automatically adjusting the excitation mode according to claim 6, characterized in that: The envelope detection circuit includes a diode D2 and an operational amplifier U3A, the adjustment unit is electrically connected to the non-inverting input terminal of the operational amplifier U3A, and the output terminal of the operational amplifier U3A is electrically connected to the negative phase input terminal of the operational amplifier U3A through the diode D2.

8. The vibrating string acquisition module for automatically adjusting the excitation mode according to claim 1, characterized in that: The regulating unit is also electrically connected to the digital-to-analog converter.

9. A vibrating string acquisition device, comprising a vibrating string sensor and a vibrating string acquisition module electrically connected to the vibrating string sensor and capable of automatically adjusting the excitation mode, characterized in that: The vibrating string acquisition module for automatically adjusting the excitation mode is the vibrating string acquisition module for automatically adjusting the excitation mode as claimed in any one of claims 1 to 8.

Images