A displacement sensor circuit for monitoring settlement in a water diversion tunnel

Abstract

This invention discloses a displacement sensor circuit for monitoring settlement in a water diversion tunnel. The sensor circuit includes a compensation circuit, a monitoring circuit, a phase adjustment circuit, and a gain amplification circuit. The monitoring circuit is connected to the compensation circuit, the phase adjustment circuit, and the gain amplification circuit. The compensation circuit is connected to the phase adjustment circuit and the gain amplification circuit. The phase adjustment circuit or the gain amplification circuit adjusts the phase or amplitude of the signal output by the detection probe based on the type of the compensation signal, either forward or reverse. The monitoring circuit monitors the DC voltage signal output by the detector before and after compensation and outputs a switching signal based on the monitoring result. The compensation circuit outputs a compensation signal.

Description

Technical Field

[0001] This invention relates to the field of detection technology, and in particular to a displacement sensor circuit for monitoring settlement in water diversion tunnels. Background Technology

[0002] In tunnel settlement monitoring, when a tunnel experiences settlement displacement, the closer the displacement distance, the smaller the amplitude. This effective signal is usually very weak and easily drowned out by power frequency electromagnetic noise. Therefore, existing displacement sensor circuits use paired reference and detection probes to allow power frequency electromagnetic noise interference to act on both simultaneously, forming a common-mode signal. The difference between these two signals is then calculated by a differential amplifier to suppress common-mode interference, retaining only the effective differential signal caused by the displacement. This signal is then amplified and converted by a post-processing circuit. This method can significantly improve the displacement detection accuracy. However, in practical applications, because the two probes are located in different positions in space, power frequency interference will cause the two probes to be at different phase points of the electromagnetic field. This results in a small phase and amplitude shift in the signals output by the two probes, i.e., residual noise that is not completely suppressed. The presence of residual noise can drown out or interfere with the effective signal caused by small displacements, thus slightly limiting the detection accuracy. Summary of the Invention

[0003] To address the aforementioned technical problems, the present invention aims to provide a displacement sensor circuit for monitoring settlement in water diversion tunnels. The sensor circuit includes a compensation circuit, a monitoring circuit, a phase adjustment circuit, and a gain amplification circuit. The monitoring circuit is connected to the compensation circuit, phase adjustment circuit, and gain amplification circuit. The compensation circuit is also connected to the phase adjustment circuit and the gain amplification circuit. The phase adjustment circuit or gain amplification circuit adjusts the phase or amplitude of the signal output by the detection probe based on the type of the compensation signal (positive or negative). The monitoring circuit monitors the DC voltage signal output by the detector before and after compensation and outputs a switching signal based on the monitoring results. The compensation circuit outputs a compensation signal.

[0004] Furthermore, the compensation circuit includes a NOT gate U1, a gating switch U2, an operational amplifier U3, a capacitor C1, and resistors R1, R2, R3, R4, and R5. The input terminal of the NOT gate U1 is connected to the IN2 terminal of the gating switch U2 and one end of the resistor R4, and the output terminal is connected to the IN1 terminal of the gating switch U2. The IN3 terminal of the gating switch U2 is connected to the clock signal, the IN4 terminal is connected to one end of the resistor R5, the D1 terminal is connected to the D2 terminal and the S3 terminal, the D3 terminal is connected to one end of the resistor R3, the D4 terminal is connected to one end of the resistor R2, the other end of the resistor R3, one end of the capacitor C1, and the inverting input of the operational amplifier U3. The S4 terminal is connected to the other end of the resistor R2, the other end of the capacitor C1, and the output terminal of the operational amplifier U3. The non-inverting input of the operational amplifier U3 is connected to one end of the resistor R1. The VDD and VSS terminals of the gating switch U2 are connected to the power supply. The other ends of the resistors R1, R4, and R5, and the GND terminal of the gating switch U2 are grounded.

[0005] Furthermore, the sensor circuit also includes a differential amplifier and a detector. The differential amplifier is connected to the gain amplifier and the detector. The differential amplifier outputs a differential signal based on the detection probe and the reference probe, and the detector outputs a corresponding DC voltage signal based on the differential signal.

[0006] Furthermore, the type of the selector switch U2 is ADG1211.

[0007] Furthermore, the NOT gate U1 is model number 74HC04.

[0008] Furthermore, the operational amplifier U3 is model number TL072.

[0009] The beneficial effects of this invention compared to the prior art are:

[0010] This invention can adaptively adjust the phase and amplitude of the detection probe based on residual noise when the detection probe is not detecting, thereby eliminating residual noise caused by the physical position of the two probes and improving detection accuracy. Attached Figure Description

[0011] To more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings used in the prior art and embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0012] Figure 1 This is a schematic diagram of the overall structure of the displacement sensor circuit provided by the present invention.

[0013] Figure 2 This is a schematic diagram of the compensation circuit structure in the displacement sensor circuit provided by the present invention.

[0014] Figure 3 This is a schematic diagram of the overall structure of an existing displacement sensor circuit provided by the present invention. Detailed Implementation

[0015] To make the objectives and advantages of the present invention clearer, the present invention will be specifically described below in conjunction with embodiments. It should be understood that the following text is only used to describe one or more specific embodiments of the present invention and does not strictly limit the scope of protection specifically claimed by the present invention.

[0016] This invention discloses a displacement sensor circuit for monitoring settlement in a water diversion tunnel. The sensor circuit includes a compensation circuit, a monitoring circuit, a phase adjustment circuit, and a gain amplification circuit. The monitoring circuit is connected to the compensation circuit, the phase adjustment circuit, and the gain amplification circuit. The compensation circuit is connected to the phase adjustment circuit and the gain amplification circuit. The phase adjustment circuit or the gain amplification circuit adjusts the phase or amplitude of the signal output by the detection probe based on the type of the compensation signal, either forward or reverse. The monitoring circuit monitors the DC voltage signal output by the detector before and after compensation and outputs a switching signal based on the monitoring result. The compensation circuit outputs a compensation signal.

[0017] Specifically, the compensation circuit includes a NOT gate U1, a gating switch U2, an operational amplifier U3, a capacitor C1, and resistors R1, R2, R3, R4, and R5. The input terminal of the NOT gate U1 is connected to the IN2 terminal of the gating switch U2 and one end of the resistor R4, and the output terminal is connected to the IN1 terminal of the gating switch U2. The IN3 terminal of the gating switch U2 is connected to the clock signal, the IN4 terminal is connected to one end of the resistor R5, the D1 terminal is connected to the D2 terminal and the S3 terminal, the D3 terminal is connected to one end of the resistor R3, the D4 terminal is connected to one end of the resistor R2, the other end of the resistor R3, one end of the capacitor C1, and the inverting input of the operational amplifier U3. The S4 terminal is connected to the other end of the resistor R2, the other end of the capacitor C1, and the output terminal of the operational amplifier U3. The non-inverting input of the operational amplifier U3 is connected to one end of the resistor R1. The VDD and VSS terminals of the gating switch U2 are connected to the power supply. The other ends of the resistors R1, R4, and R5, and the GND terminal of the gating switch U2 are grounded.

[0018] Specifically, the sensor circuit further includes a differential amplifier and a detector. The differential amplifier is connected to the gain amplifier and the detector. The differential amplifier outputs a differential signal based on the detection probe and the reference probe, and the detector outputs a corresponding DC voltage signal based on the differential signal.

[0019] Specifically, the type of the selector switch U2 is ADG1211.

[0020] Specifically, the NOT gate U1 is model 74HC04.

[0021] Specifically, the operational amplifier U3 is model number TL072.

[0022] See appendix Figure 1 In practical applications, the two probes are positioned differently in space. Power frequency interference causes the two probes to be at different phase points in the electromagnetic field, resulting in a small phase and amplitude shift in the output signals. Therefore, when the detection probe is not detecting the target, the differential amplifier outputs a differential signal containing an AC component, i.e., residual noise that is not completely suppressed. The presence of residual noise can overwhelm or interfere with the effective signal caused by minute displacements, thus slightly limiting the detection accuracy. The signal output from the detection probe is input to the differential amplifier after passing through a phase adjustment circuit and a gain amplification circuit. The signal output from the reference probe is also input to the differential amplifier. The differential amplifier outputs a differential signal to the detector. When the input is a stable DC level, the detector outputs 0V. When there are AC fluctuations in the input, the detector outputs an amplitude (envelope) equal to the amplitude of the fluctuating signal. When the detection probe is not detecting a target, a proportional DC voltage signal is sent. The monitoring circuit then feeds back a compensation start signal to the compensation circuit, phase adjustment circuit, or gain amplifier circuit. The phase adjustment circuit or gain amplifier circuit grants the compensation circuit adjustment permission (the input channel of the compensation signal). The compensation circuit outputs a compensation signal to the phase adjustment circuit or gain amplifier circuit. Based on the type of compensation signal (positive or negative), the phase adjustment circuit or gain amplifier circuit adjusts the phase or amplitude of the signal output by the detection probe in either the forward or reverse direction. The first compensation by the compensation circuit is a test compensation, and the compensation signal during the test compensation is a positive compensation signal. After compensation, the monitoring circuit monitors the DC voltage signal output by the detector before and after compensation. If the signal rises, a switching signal is fed back to the compensation circuit to switch the compensation direction. If the signal falls, no switching signal is fed back, and the compensation circuit maintains the current compensation direction until the detector output is 0V to complete the alignment of the phase or amplitude of the signals output by the two probes. When the phase or amplitude of the signals output by the two probes is aligned, the monitoring circuit stops feeding back the compensation start signal, the phase adjustment circuit or gain amplification circuit closes the adjustment authority and maintains the current adjustment, and the compensation signal is cleared to zero. During adjustment, the phase is adjusted first, and then the amplitude is adjusted. By repeatedly adjusting the phase and amplitude iteratively, the common-mode rejection ratio can be further improved to eliminate residual noise. When the detection probe detects the target, the monitoring circuit restricts the feedback of the compensation start signal.

[0023] See appendix Figure 2The selector switch U2 has the following terminals: S1, S2, S3, and S4 are input terminals; D1, D2, D3, and D4 are output terminals; IN1, IN2, IN3, and IN4 are control terminals; VDD and VSS are power input terminals; and GND is the ground terminal. S1 and S2 input positive and negative reference signals respectively. Resistor R4 is a pull-down resistor for the input of NOT gate U1. The switching signal is input to the input of NOT gate U1 and the IN2 terminal of selector switch U2. The switching signal is fed back by the monitoring circuit, and NOT gate U1 outputs the switching signal in reverse. The selector switch U2's S1 and S2 terminals input positive and negative reference signals respectively, and the selector switch U2's D1 and D2 terminals... Connected in parallel to its S3 terminal, when the switching signal is high, the IN1 terminal of the selector switch U2 is low and the IN2 terminal is high. The signal at the S1 terminal of the selector switch U2 is output through the D1 terminal, making its S3 terminal a positive reference signal. When the switching signal is low, the IN1 terminal of the selector switch U2 is high and the IN2 terminal is low. The signal at the S2 terminal of the selector switch U2 is output through the D2 terminal, making its S3 terminal a negative reference signal. A pulse signal is input to the IN3 terminal of the selector switch U2. When the pulse signal is high, there is no output signal at the D3 terminal. When the IN3 terminal is low, the signal at the S3 terminal is output through the D3 terminal. The signal at the D3 terminal is fed back to the inverting terminal of the operational amplifier U3 through resistor R3. Resistor R1 is... The non-inverting input of op-amp U3 is balanced by resistor R2, which is the feedback resistor for op-amp U3. R3 is the input resistor for op-amp U3, and capacitor C1 is the feedback capacitor for op-amp U3. When a positive reference signal is fed back to the inverting input of op-amp U3 via resistor R3, the output of op-amp U3 integrates in the inverting phase. When a negative reference signal is fed back to the inverting input of op-amp U3 via resistor R3, the output of op-amp U3 integrates in the non-inverting phase. The signal from the output of op-amp U3 is input to the S4 terminal of gating switch U2. The IN4 terminal of gating switch U2 receives the compensation start signal, which is fed back from the monitoring circuit. The compensation start signal is high. If no compensation signal is received, the signal from the S4 terminal of gating switch U2 is fed back to op-amp U3 via the D4 terminal. The inverting input of U3 limits the output voltage of op-amp U3 to its non-inverting input voltage, i.e., 0V. When the compensation start signal is obtained, there is no feedback signal at the D4 terminal of the gating switch U2. Each time the IN3 terminal of the gating switch U2 is at a low level, the output of op-amp U3 performs a corresponding integration based on the signal type at the D3 terminal (positive reference signal or negative reference signal). Adjusting the signal amplitude at the S1 and S2 terminals of the gating switch U2 can adjust the rise amplitude of the output signal of op-amp U3 during each integration. The output signal of op-amp U3 is the compensation signal. When the compensation circuit does not receive a switching signal, its compensation signal is the positive compensation signal of positive integration; otherwise, it is the negative compensation signal of inverted integration.

[0024] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from its spirit or essential characteristics. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of equivalents of the claims are intended to be included within the present invention. No markings in the claims should be construed as limiting the scope of the claims.

Claims

1. A diversion tunnel settlement monitoring displacement sensor circuit, characterised in that, The sensor circuit comprises a compensation circuit, a monitoring circuit, a phase adjustment circuit, a gain amplification circuit, a differential amplifier, a detector, a detection probe and a reference probe, the detection probe, the phase adjustment circuit, the gain amplification circuit, the differential amplifier, the detector, the monitoring circuit and the compensation circuit are connected in sequence, the reference probe is connected with the differential amplifier, the compensation circuit is connected with the phase adjustment circuit and the gain amplification circuit, the differential amplifier outputs a differential signal based on the detection probe and the reference probe, the detector outputs a corresponding direct current voltage signal based on the differential signal, the phase adjustment circuit or the gain amplification circuit compensates and adjusts the phase or amplitude of the signal output by the detection probe based on the compensation signal type in a forward or reverse direction, the monitoring circuit is used for monitoring the direct current voltage signal output by the detector before and after compensation and outputs a switching signal based on the monitoring result, and the compensation circuit is used for outputting a compensation signal.

2. The penstock settlement monitoring displacement sensor circuit of claim 1, wherein, The compensation circuit comprises a NOT gate U1, a gating switch U2, an operational amplifier U3, a capacitor C1, resistors R1, R2, R3, R4 and R5, the input end of the NOT gate U1 is connected with the IN2 end of the gating switch U2 and the one end of the resistor R4, the output end is connected with the IN1 end of the gating switch U2, the IN3 end of the gating switch U2 is connected with a clock signal, the IN4 end is connected with the one end of the resistor R5, the D1 end is connected with the D2 end and the S3 end, the D3 end is connected with the one end of the resistor R3, the D4 end is connected with the one end of the resistor R2, the other end of the resistor R3, the one end of the capacitor C1 and the inverting end of the operational amplifier U3, the S4 end is connected with the other end of the resistor R2, the other end of the capacitor C1 and the output end of the operational amplifier U3, the non-inverting end of the operational amplifier U3 is connected with the one end of the resistor R1, the VDD end and the VSS end of the gating switch U2 are connected with a power supply, the other end of the resistor R1, the other end of the resistor R4, the other end of the resistor R5 and the GND end of the gating switch U2 are connected with the ground, and the model of the gating switch U2 is ADG1211.

3. The penstock settlement monitoring displacement sensor circuit of claim 2, wherein, The model of the NOT gate U1 is 74HC04.

4. The penstock settlement monitoring displacement sensor circuit of claim 2, wherein, The model of the operational amplifier U3 is TL072.

Images