Liquid leak location detection apparatus and method

Abstract

The application provides a liquid leakage positioning detection device, which comprises a controller and a first detection unit and a second detection unit connected with the controller, the first detection unit comprises a first switch, a first voltage collector, a first insulated wire, a first induction line, a second voltage collector, a second switch and a reference resistance connected in series, the second detection unit comprises a third switch, a third voltage collector, a second insulated wire, a second induction line, a fourth voltage collector, a fourth switch and a reference resistance connected in series, the first induction line and the second induction line are equal in length and are arranged at intervals, the first voltage collector, the second voltage collector, the third voltage collector and the fourth voltage collector are connected with the controller in communication, and a liquid leakage positioning detection method is also provided. The liquid leakage positioning detection device and method provided by the application have multiple detection functions and high detection precision.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of liquid leakage detection, in particular to a liquid leakage positioning detection device and method. BACKGROUND

[0002] At present, liquid is transported by pipeline, such as water pipes and oil pipelines. When liquid pipeline leaks, not only resources are wasted and the environment is polluted, but also safety accidents may occur. Therefore, it is particularly important to report the liquid leakage in a timely and accurate manner.

[0003] At present, the detection method of liquid leakage is relatively single. The detection device in the prior art has few detection functions and low detection precision. In the leakage detection process, many interference problems exist, which also affect the detection precision and accuracy. SUMMARY

[0004] The present application aims to overcome the deficiencies in the prior art and provide a liquid leakage positioning detection device and method to solve the problems of few detection functions and low detection precision.

[0005] To achieve the above-mentioned purpose, the technical scheme adopted by the present application is as follows:

[0006] A liquid leakage positioning detection device comprises a controller and a detection circuit connected to the controller in a circuit;

[0007] The detection circuit comprises a first detection unit and a second detection unit. The first detection unit comprises a first switch, a first voltage collector, a first insulated wire, a first induction line, a second voltage collector, a second switch and a reference resistor connected in series respectively. The first insulated wire is connected to the positive pole of a power supply, and the reference resistor is connected to the negative pole of the power supply.

[0008] The second detection unit comprises a third switch, a third voltage collector, a second insulated wire, a second induction line, a fourth voltage collector, a fourth switch and the reference resistor connected in series respectively. The second insulated wire is connected to the positive pole of a power supply, and the reference resistor is connected to the negative pole of the power supply.

[0009] The first induction line and the second induction line are equal in length and are arranged at intervals. The first voltage collector, the second voltage collector, the third voltage collector and the fourth voltage collector are respectively connected to the controller in communication.

[0010] Further improvement of the above technical scheme is as follows:

[0011] The controller comprises an MCU, a power input port, a communication port, a detection circuit interface and a relay output port; the detection circuit is connected with the controller through the detection circuit interface.

[0012] The MCU is connected with a high-frequency filter circuit.

[0013] The first and second sensing lines are non-insulated conductive wires with constant resistance value per unit length, a first fixed resistance is connected in series between the first sensing line and the second switch, a second fixed resistance is connected in series between the second sensing line and the fourth switch, and the first and second fixed resistances are used to increase the resistance value of the loop.

[0014] The non-insulated conductive wires are metal wires sleeved with conductive rubber.

[0015] The first and second voltage collectors are communicatively connected with a first analog-to-digital converter, and the third and fourth voltage collectors are communicatively connected with a second analog-to-digital converter; the first and second analog-to-digital converters are communicatively connected with the controller.

[0016] A first voltage follower is connected between the first voltage collector and the first analog-to-digital converter, a second voltage follower is connected between the second voltage collector and the first analog-to-digital converter, a third voltage follower is connected between the third voltage collector and the second analog-to-digital converter, and a fourth voltage follower is connected between the fourth voltage collector and the second analog-to-digital converter.

[0017] The application further provides a liquid leakage positioning and detecting method for the liquid leakage positioning and detecting device.

[0018] The first and fourth switches are controlled to be in a closed state, and the second and third switches are controlled to be in an open state.

[0019] The voltage values collected by the first, second, third and fourth voltage collectors are acquired respectively.

[0020] When the voltage value collected by the fourth voltage collector is 0, it is judged as a normal state, otherwise, it is judged as a liquid leakage state.

[0021] When the liquid leakage state is judged, the position of the leakage point is calculated, and the specific calculation method is as follows: the ratio of the voltage value collected by the fourth voltage collector to the reference resistance value is calculated to obtain the current value I N3 in the loop at this time; the voltage value collected by the third voltage collector, the voltage value collected by the fourth voltage collector and the current value I N3The resistance value R of the second induction line in the circuit is calculated N3 ; the resistance value R N3 is calculated, and the distance value between the leakage point and the original point is obtained by the ratio of the resistance value R

[0022] Further, the method further comprises a fault detection step:

[0023] The first switch and the second switch are controlled to be closed, and the third switch and the fourth switch are controlled to be opened. When the voltage value collected by the second voltage collector is 0, it is determined that the first detection unit is broken; when the voltage value collected by the second voltage collector is not 0, it is determined that the first detection unit is normal.

[0024] The third switch and the fourth switch are controlled to be closed, and the first switch and the second switch are controlled to be opened. When the voltage value collected by the fourth voltage collector is 0, it is determined that the second detection unit is broken; when the voltage value collected by the fourth voltage collector is not 0, it is determined that the second detection unit is normal.

[0025] Further, the method further comprises the following steps:

[0026] The first switch and the second switch are controlled to be closed, and the third switch and the fourth switch are controlled to be opened. The ratio of the voltage value collected by the second voltage collector and the resistance value of the reference resistance is calculated to obtain the current value in the current circuit. The resistance value of the first induction line is calculated according to the voltage value collected by the first voltage collector, the voltage value collected by the second voltage collector, and the current value in the current circuit. The total length of the first induction line is obtained by calculating the ratio of the resistance value of the first induction line and the resistivity of the first induction line.

[0027] The third switch and the fourth switch are controlled to be closed, and the first switch and the second switch are controlled to be opened. The ratio of the voltage value collected by the fourth voltage collector and the resistance value of the reference resistance is calculated to obtain the current value in the current circuit. The resistance value of the second induction line is calculated according to the voltage value collected by the third voltage collector, the voltage value collected by the fourth voltage collector, and the current value in the current circuit. The total length of the second induction line is obtained by calculating the ratio of the resistance value of the second induction line and the resistivity of the second induction line.

[0028] The average value of the total length of the first induction line and the total length of the second induction line is calculated.

[0029] According to the technical scheme of the present application, the controller of the liquid leakage positioning detection device can control the detection circuit and receive the voltage value collected by the voltage collector, and the four wires are used to accurately measure the liquid leakage point. The detection circuit includes two detection units, and the insulated wire and the induction wire in each detection unit are connected with separate switches and voltage collectors in series, and the two voltage collectors in each detection unit work at the same time, which can effectively reduce the common mode interference and improve the detection accuracy of the detection device. The liquid leakage positioning detection device can be used to measure the total length of the induction wire and detect the fault of the detection circuit, and has powerful functions and is convenient to use. The liquid leakage positioning detection method of the present application can quickly detect whether the liquid leaks, and can calculate the distance value between the leakage point and the origin through the controller, so as to accurately position the leakage point, discover the liquid leakage accident in time, and avoid greater economic loss and safety accidents. BRIEF DESCRIPTION OF DRAWINGS

[0030] Figure 1 It is a structure schematic view of the detection circuit of the liquid leakage positioning detection device of the embodiment of the present application.

[0031] Figure 2 It is a structure schematic view of the controller of the liquid leakage positioning detection device of the embodiment of the present application.

[0032] Figure 3 It is a first loop and a second loop schematic view of the liquid leakage positioning detection method of the embodiment of the present application.

[0033] Figure 4 It is a third loop schematic view of the liquid leakage positioning detection method of the embodiment of the present application.

[0034] Figure 5 It is a flow chart of the liquid leakage positioning detection method of the embodiment of the present application. DETAILED DESCRIPTION

[0035] In order to facilitate the understanding of the present application, the present application will be described more fully below with reference to the related drawings. The preferred embodiments of the present application are shown in the drawings. However, the present application can be realized in many different forms and is not limited to the embodiments described herein. On the contrary, these embodiments are provided to make the disclosure of the present application more thorough and comprehensive.

[0036] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the present application belongs. The terms used in the specification of the present application herein are only for the purpose of describing the specific embodiments and are not intended to limit the present application.

[0037] Example 1: as Figures 1 to 4As shown, the liquid leak location detection device of this embodiment includes a controller and a detection circuit connected to the controller. The controller is used to control the detection circuit and receive the data detected by the detection circuit.

[0038] like Figure 2 As shown, the controller includes an MCU, a power input port, a communication port, a detection circuit interface, and a relay output port. The detection circuit is connected to the controller via the detection circuit interface. The MCU includes a control module, a calculation module, a judgment module, and a storage module. The relay output port is used to connect to an external alarm device. When a liquid leak is detected, the controller first issues an alarm and triggers the relay, simultaneously activating the external alarm device. The communication port is an RS485 interface used to connect to a remote monitoring system. There are four detection circuit interfaces, each used to connect to the detection circuit's wiring.

[0039] like Figure 1 As shown, the detection circuit includes a first detection unit and a second detection unit. The first detection unit includes a first switch, a first voltage acquisition device, a first insulated wire, a first induction wire, a first fixed resistor, a second voltage acquisition device, a second switch, and a reference resistor, which are connected in series. The first insulated wire is used to connect to the positive terminal of the power supply, and the reference resistor is used to connect to the negative terminal of the power supply.

[0040] The second detection unit includes a third switch, a third voltage acquisition unit, a second insulated wire, a second induction wire, a second fixed resistor, a fourth voltage acquisition unit, a fourth switch, and the reference resistor, which are connected in series respectively; the second insulated wire is used to connect to the positive terminal of the power supply, and the reference resistor is used to connect to the negative terminal of the power supply.

[0041] The reference resistors in the two detection units described above can be shared. Specifically, the first switch, first voltage acquisition unit, first insulated wire, first induction wire, first fixed resistor, second voltage acquisition unit, and second switch are connected in series, and then connected in parallel with the third switch, third voltage acquisition unit, second insulated wire, second induction wire, second fixed resistor, fourth voltage acquisition unit, and fourth switch, which are connected in series sequentially. These two parallel circuits are then connected in series with the reference resistor. Additionally, for ease of detection, a fifth voltage acquisition unit can be installed on the side of the reference resistor connected to the positive terminal of the power supply.

[0042] In this embodiment, the resistance values ​​of the first fixed resistor and the second fixed resistor are both 500Ω. The first fixed resistor and the second fixed resistor are set to increase the resistance value of the circuit, thereby increasing the measured voltage value and facilitating the detection of leakage.

[0043] The first sensing line and the second sensing line are equal in length and are arranged at intervals; the first voltage collector, the second voltage collector, the third voltage collector, the fourth voltage collector and the fifth voltage collector are respectively in communication connection with the controller.

[0044] The first sensing line and the second sensing line are both non-insulated conductive wires with constant resistance per unit length, such as bare metal wires, and in the embodiment, the metal wires are preferably sleeved with conductive rubber. The conductive rubber on one hand does not affect the conductive function of the metal wire, and on the other hand can prevent corrosion and wear, which is conducive to prolonging the service life of the sensing line. The first insulated conductive wire and the second insulated conductive wire need to be insulated in order to avoid the two conductive wires from conducting electricity due to liquid leakage, which affects the detection of liquid leakage.

[0045] The first insulated conductive wire, the first sensing line, the second insulated conductive wire and the second sensing line are directly connected with the four interfaces of the detection circuit interface, and in a specific implementation, they can also be connected with the detection circuit interface through the setting of lead-out wires.

[0046] The first voltage collector and the second voltage collector are in communication connection with the first analog-to-digital converter, and the third voltage collector and the fourth voltage collector are in communication connection with the second analog-to-digital converter; the first analog-to-digital converter and the second analog-to-digital converter are respectively in communication connection with the controller.

[0047] The first voltage collector is connected with the VIN+ port of the first analog-to-digital converter after being connected in series with the first voltage follower; the second voltage collector is connected with the VIN- port of the first analog-to-digital converter after being connected in series with the second voltage follower. The third voltage collector is connected with the VIN+ port of the second analog-to-digital converter after being connected in series with the third voltage follower; the fourth voltage collector is connected with the VIN- port of the fourth analog-to-digital converter after being connected in series with the fourth voltage follower.

[0048] The analog-to-digital converter (ADC) in the embodiment adopts a high-impedance differential double AD acquisition IC, which has high precision. The ADC transmits the converted values to the MCU through the SPI interface. Since the input circuit of the ADC is in differential mode, the VIN+ and VIN- two input ports collect at the same time, and the common-mode interference can be offset through double-ended input, which can reduce interference and improve the accuracy of the sampling result. The voltage follower operates with high input impedance, which reduces the influence on the input signal, reduces the output impedance of the signal source, and minimizes the influence of the AD input impedance on the input signal, making the sampling of the ADC more accurate.

[0049] The MCU is connected with a high-frequency filter circuit, and high frequency is filtered through the filter circuit. In the embodiment, the filter circuit is a parallel capacitor and a third fixed resistor, one end of the parallel capacitor and the third fixed resistor is connected with the MCU, and the other end is grounded.

[0050] In the embodiment, a first fixed resistor is connected in series on the first induction line, and a second fixed resistor is connected in series on the second induction line. The first fixed resistor and the second fixed resistor can increase the loop impedance, increase the offset of the collected voltage, solve the detection error caused by the large offset of the zero voltage collection of the device, and finally solve the problem of insufficient accuracy in the measurement of the near end in the prior art.

[0051] As shown in Figure 3 and Figure 4 The embodiment also provides a liquid leakage positioning detection method, which is used for the liquid leakage positioning detection device and includes the following steps.

[0052] S1, fault detection: the first switch S1 and the second switch S2 are controlled to be closed, the third switch S3 and the fourth switch S4 are controlled to be opened, the first loop N1 is formed, the voltage value collected by the second voltage collector is acquired, when the acquired voltage value collected by the second voltage collector is 0, that is, the second voltage collector cannot collect voltage, it is judged that the first detection unit is open, and a fault alarm is sent; when the acquired voltage value collected by the second voltage collector is not 0, it is judged that the first detection unit is normal.

[0053] The third switch S3 and the fourth switch S4 are controlled to be closed, the first switch S1 and the second switch S2 are controlled to be opened, the second loop N2 is formed, the voltage value collected by the fourth voltage collector is acquired, when the acquired voltage value collected by the fourth voltage collector is 0, that is, the fourth voltage collector cannot collect voltage, it is judged that the second detection unit is open, and a fault alarm is sent; when the acquired voltage value collected by the fourth voltage collector is not 0, it is judged that the second detection unit is normal.

[0054] S2, total length calculation of induction line:

[0055] S2.1, total length calculation of first induction line: the first switch S1 and the second switch S2 are controlled to be closed, the third switch S3 and the fourth switch S4 are controlled to be opened, the first loop N1 is formed, the ratio of the voltage value U5 collected by the fifth voltage collector to the resistance value R3 of the reference resistor is calculated, and the current value I in the current loop is obtained N1 , and the specific calculation formula is as follows N1 I = U5 / R3. According to the voltage value U1 collected by the first voltage collector, the voltage value U2 collected by the second voltage collector, and the current value I of the current loopN1 The resistance R of the first induction line is calculated N1 The specific calculation formula is as follows R N1 =(U1-U2) / I N1 -R1, wherein R1 is the resistance of the first constant resistance. The ratio of the resistance R N1 of the first induction line to the resistivity p1 of the first induction line is calculated to obtain the total length L1 of the first induction line. The specific calculation formula is as follows L1=R N1 / p1.

[0056] S2.2, total length calculation of the second induction line: the third switch S3 and the fourth switch S4 are controlled to be closed, the first switch S1 and the second switch S2 are controlled to be opened, a second loop N2 is formed, the ratio of the voltage value U5 collected by the fifth voltage collector to the resistance R3 of the reference resistance is calculated to obtain the current value I N2 in the current loop. The specific calculation formula is as follows I N2 =U5 / R3. The resistance R N2 of the second induction line is calculated according to the voltage value U3 collected by the third voltage collector, the voltage value U4 collected by the fourth voltage collector, and the current value I N2 in the current loop. The specific calculation formula is as follows R N2 =(U3-U4) / I N2 -R2, wherein R2 is the resistance of the second constant resistance. The ratio of the resistance R N2 of the second induction line to the resistivity p2 of the second induction line is calculated to obtain the total length L2 of the second induction line. The specific calculation formula is as follows L2=R N2 / p2.

[0057] S2.3, average value calculation: the average value of the total length L1 of the first induction line and the total length L2 of the second induction line is calculated. The specific calculation formula is as follows L=(L1+L2) / 2, wherein L is the final measurement value of the total length of the induction line.

[0058] The method of taking the average value twice can effectively improve the accuracy of the measurement value.

[0059] S3, leakage point positioning detection: the first switch S1 and the fourth switch S4 are controlled to be in a closed state, and the second switch S2 and the third switch S3 are controlled to be in an opened state. When the liquid leaks, a third loop N3 is formed. When the liquid does not leak, the third loop N3 is opened.

[0060] The voltage values U1, U2, U3, U4 and U5 collected by the first voltage collector, the second voltage collector, the third voltage collector, the fourth voltage collector and the fifth voltage collector are obtained respectively.

[0061] When the acquired voltage value collected by the fifth voltage collector is 0, it is judged as a normal state, otherwise it is judged as a liquid leakage state.

[0062] When it is judged as a liquid leakage state, the position of the leakage point is calculated, and the specific calculation method is as follows: the ratio of the voltage value U5 collected by the fifth voltage collector to the resistance value R3 of the reference resistance is calculated to obtain the current value I in the circuit at this time N3 , and the specific calculation formula is as follows I N3 =U5 / R3. According to the voltage value U3 collected by the third voltage collector, the voltage value U4 collected by the fourth voltage collector, and the current value I N3 , the resistance value R N3 of the second induction line in the circuit at this time is calculated, and the specific calculation formula is as follows R N3 =(U3-U4) / I N3 -R2, wherein R2 is the resistance value of the second constant resistance. The ratio of the resistance value R N3 to the resistivity p2 of the second induction line is calculated to obtain the distance value d of the leakage point from the origin, and the specific calculation formula is as follows d=R N3 / p2.

[0063] When the liquid leaks, since the first induction line and the second induction line are non-insulated lines, the first induction line and the second induction line are conducted at the liquid leakage position (H in the figure), and form a current along the direction indicated by the arrow in the figure. When the liquid does not leak, only S1 and S4 are closed, and the circuit cannot be conducted, so the fifth voltage collector cannot collect the voltage value. Since the liquid is needed to conduct the first induction line and the second induction line to measure the leakage point, the liquid to be detected in the present application needs to be a non-pure substance containing conductive particles.

[0064] In the specific detection process, the controller can continuously execute the S1, S2 and S3 steps, or can individually measure a certain step according to the instruction, such as when detecting liquid leakage, the controller can execute the S3 step multiple times, and compensate the distance value d obtained by multiple measurements to improve the measurement accuracy. For example, the average value of multiple measurement values can be taken, or the average value can be calculated by removing the maximum value and the minimum value, etc.

[0065] The liquid leakage positioning detection device and method of the present application connect voltage followers on the R, G, Y and B four lines of the controller, utilize the high input impedance characteristics of the operational amplifier to reduce the influence on the input signal, reduce the output impedance of the signal source, minimize the influence of the AD input impedance on the input signal, and ensure the conversion accuracy of the AD. Two 16-bit high-precision ADC chips are used, and each chip is connected to one of the two channels formed by the four-core detection lines. The input circuit of the ADC uses a differential mode, and in the differential working mode, the ADC converts the voltage difference of the two pins VIN+ and VIN-. The measurement value (ADC sampling value) is (VIN+)-(VIN-), and the two pins VIN+ and VIN- are collected at the same time. The two differential lines are distributed together, and the common mode interference is reduced when inputting the ADC, so that the interference can be eliminated to a greater extent. Because when the sensing line contacts the liquid, the liquid is electrolyzed under the action of direct current, the current decreases, and the voltage also decreases accordingly. The decrease in voltage leads to a decrease in positioning accuracy. To address this impact, we compensate the measurement results by the first fixed resistor and the second fixed resistor, thereby improving the accuracy of the leakage detection positioning. When an external voltage is connected, it will generate a certain high-frequency interference to the product, thereby affecting the positioning accuracy. To address this situation, a high-frequency filter circuit is added to connect the PCB to the ground to filter out the high frequency, thereby improving the detection accuracy.

[0066] The technical features of the above embodiments can be combined in any manner. To make the description concise, not all possible combinations of the technical features in the above embodiments are described, but as long as the combinations of the technical features do not contradict, they should be considered as within the scope of the present disclosure.

[0067] The above embodiments only express the preferred embodiments of the present application, which are described in detail and specifically, but should not be construed as limiting the scope of the patent. It should be noted that for those skilled in the art, without departing from the concept of the present application, a number of modifications and improvements can be made, which are within the scope of the present application. Therefore, the scope of protection of the present application should be subject to the appended claims.

Claims

1. A method of detecting a liquid leak location, the method comprising: A liquid leakage positioning detection device comprises a controller and a detection circuit connected with the controller; The detection circuit comprises a first detection unit and a second detection unit, the first detection unit comprises a first switch, a first voltage collector, a first insulated wire, a first induction line, a second voltage collector, a second switch and a reference resistor connected in series respectively; the first insulated wire is connected with a positive pole of a power supply, and the reference resistor is connected with a negative pole of the power supply; The second detection unit comprises a third switch, a third voltage collector, a second insulated wire, a second induction line, a fourth voltage collector, a fourth switch and the reference resistor connected in series respectively; the second insulated wire is connected with the positive pole of the power supply, and the reference resistor is connected with the negative pole of the power supply; The first induction line and the second induction line are equal in length and are arranged at intervals; the first voltage collector, the second voltage collector, the third voltage collector and the fourth voltage collector are connected with the controller in communication respectively; The liquid leakage positioning detection method comprises the following steps: controlling the first switch and the fourth switch to be in a closed state and controlling the second switch and the third switch to be in an open state; acquiring voltage values collected by the first voltage collector, the second voltage collector, the third voltage collector and the fourth voltage collector respectively; when the voltage value collected by the fourth voltage collector is 0, it is judged as a normal state, otherwise it is judged as a liquid leakage state; When the liquid leakage state is judged, the leakage point position is calculated, and the specific calculation method is as follows: the ratio of the voltage value collected by the fourth voltage collector to the resistance value of the reference resistance is calculated to obtain the current value I in the circuit at this time N3 ; the voltage value collected by the third voltage collector, the voltage value collected by the fourth voltage collector, and the current value I N3 are calculated to obtain the resistance value RN3 of the second sensing line in the circuit at this time; the ratio of the resistance value R N3 to the resistivity of the second sensing line is calculated to obtain the distance value of the leakage point from the origin.

2. The method of claim 1, wherein, further comprising a fault detection step: controlling the first switch and the second switch to be closed and controlling the third switch and the fourth switch to be open, when the voltage value collected by the second voltage collector is 0, it is judged that the first detection unit is open; when the voltage value collected by the second voltage collector is not 0, it is judged that the first detection unit is normal; controlling the third switch and the fourth switch to be closed and controlling the first switch and the second switch to be open, when the voltage value collected by the fourth voltage collector is 0, it is judged that the second detection unit is open; when the voltage value collected by the fourth voltage collector is not 0, it is judged that the second detection unit is normal.

3. The method of claim 1, wherein, further comprising the following steps: controlling the first switch and the second switch to be closed and controlling the third switch and the fourth switch to be open, calculating a ratio of the voltage value collected by the second voltage collector to the resistance value of the reference resistor to obtain a current value in a current loop; calculating a resistance value of the first induction line according to the voltage value collected by the first voltage collector, the voltage value collected by the second voltage collector and the current value of the current loop; calculating a ratio of the resistance value of the first induction line to the resistivity of the first induction line to obtain a total length of the first induction line; controlling the third switch and the fourth switch to be closed and controlling the first switch and the second switch to be open, calculating a ratio of the voltage value collected by the fourth voltage collector to the resistance value of the reference resistor to obtain a current value in a current loop; The resistance of the second induction line is calculated according to the voltage value collected by the third voltage collector, the voltage value collected by the fourth voltage collector and the current value of the current loop; The total length of the second induction line is calculated according to the ratio of the resistance of the second induction line and the resistivity of the second induction line; The average of the total length of the first induction line and the total length of the second induction line is calculated.

4. The method of claim 1, wherein: The controller comprises an MCU, a power input port, a communication port, a detection circuit interface and a relay output port; the detection circuit is connected with the controller through the detection circuit interface.

5. The method of claim 4, wherein: The MCU is connected with a high-frequency filter circuit.

6. The method of claim 4, wherein: The first induction line and the second induction line are non-insulated conductive wires with constant resistance per unit length, a first fixed resistance is connected in series between the first induction line and the second switch, a second fixed resistance is connected in series between the second induction line and the fourth switch, and the first fixed resistance and the second fixed resistance are used to increase the resistance value of the loop.

7. The method of claim 6, wherein: The non-insulated conductive wires are metal wires sleeved with conductive rubber.

8. The method of claim 4, wherein: The first voltage collector and the second voltage collector are connected with a first analog-to-digital converter, the third voltage collector and the fourth voltage collector are connected with a second analog-to-digital converter, and the first analog-to-digital converter and the second analog-to-digital converter are connected with the controller.

9. The method of claim 8, wherein: A first voltage follower is connected between the first voltage collector and the first analog-to-digital converter, a second voltage follower is connected between the second voltage collector and the first analog-to-digital converter, a third voltage follower is connected between the third voltage collector and the second analog-to-digital converter, and a fourth voltage follower is connected between the fourth voltage collector and the second analog-to-digital converter.

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