Liquid level sensor and measurement method

Abstract

The application relates to a liquid level sensor and a measuring method, the sensor comprising a printed circuit board and one reference detection element, at least one auxiliary detection element and at least one liquid level detection element arranged on the printed circuit board; the reference detection element is used for identifying the type of a to-be-detected medium; the length value of the liquid level detection element is equal to the maximum depth value of the to-be-detected medium in a container, and the liquid level detection element is used for generating a capacitance value by mutual induction with any one of the auxiliary detection elements to continuously monitor the liquid level height of the to-be-detected medium; in the case of mutual induction between the liquid level detection element and the auxiliary detection element, one of the liquid level detection element and the auxiliary detection element is a grounding terminal. The liquid level detection element can be in contact with the to-be-detected medium at all times, the liquid level height is continuously monitored, and any one of the liquid level detection element and the auxiliary detection element can serve as the grounding terminal, so that the installation mode of the sensor is more flexible.

Description

Technical Field

[0001] This application relates to the field of liquid level sensor technology, and in particular to a liquid level sensor and a measurement method thereof. Background Technology

[0002] Liquid level sensors are widely used in various industries for measuring liquid level height, enabling real-time monitoring and early warning of liquid levels. They are an important component of various liquid level control devices. However, current liquid level sensors use a multi-point probe detection scheme, which can only measure liquid levels at fixed heights and cannot achieve continuous monitoring of liquid level height. Furthermore, the probe design of current liquid level sensors has a fixed common electrode and uses simple ground-based AD sampling logic, which can only use fixed AD sampling values, resulting in low signal conversion and processing accuracy. The limitation of the common electrode also restricts the sensor's installation methods, making it difficult to flexibly adapt to liquid tanks of various shapes. Summary of the Invention

[0003] The technical problem to be solved by the embodiments of this application is to provide a liquid level sensor and measurement method. The length of the liquid level detection element of this application is equal to the maximum depth of the medium to be measured in the container. Regardless of whether the medium to be measured is rising or falling, the liquid level detection element can always be in contact with the medium to be measured. The liquid level detection element is used to generate a capacitance value by mutual induction with any auxiliary detection element, so that the liquid level detection element can continuously monitor the liquid level height of the medium to be measured. Either the liquid level detection element or the auxiliary detection element can be used as a ground terminal, without the need to design a fixed common electrode, making the installation method of the sensor more flexible.

[0004] According to a first aspect of this application, this application provides a liquid level sensor, including a printed circuit board and a reference detection element, at least one auxiliary detection element, and at least one liquid level detection element disposed on the printed circuit board; The reference detection element is used to identify the type of the medium to be tested; The length of the liquid level detection element is equal to the maximum depth of the medium to be measured in the container. The liquid level detection element is used to generate a capacitance value by mutual induction with any of the auxiliary detection elements, so as to continuously monitor the liquid level height of the medium to be measured. When the liquid level detection element and the auxiliary detection element sense each other, one of the liquid level detection element and the auxiliary detection element is a ground terminal.

[0005] In one feasible embodiment, the end of the reference detection element away from the printed circuit board is a dynamic full calibration reference point, and the distance between the dynamic full calibration reference point and the printed circuit board along the length direction of the reference detection element is the overflow judgment distance of the liquid level sensor.

[0006] In one feasible embodiment, the length of the auxiliary detection element is less than the length of the liquid level detection element, the end of the auxiliary detection element away from the printed circuit board is a dynamic empty calibration base point, and the distance between the dynamic empty calibration base point along the length direction of the auxiliary detection element and the bottom of the container is the empty judgment distance of the liquid level sensor.

[0007] In one feasible embodiment, the liquid level height of the medium to be measured is calculated using the following formula: Lever = (ΔD) 液位 +ΔD 辅助 ) / (D max -D min )*H; Wherein, Lever represents the liquid level height of the medium to be measured; ΔD 液位 This indicates the amount of change detected by the liquid level detection element; ΔD 辅助 This indicates the amount of change detected by the auxiliary detection element; D max This represents the full reference value, which is the sum of the changes detected by the liquid level detection element and the auxiliary detection element when the container is full. D min The empty reference value represents the sum of the changes detected by the liquid level detection element and the auxiliary detection element when the container is empty; H represents the length of the liquid level detection element.

[0008] In one feasible embodiment, the reference detection element, the auxiliary detection element, and the liquid level detection element are all detection wires.

[0009] In one feasible embodiment, the fixed end of the probe wire is connected to the printed circuit board, and the free end of the probe wire is arranged along a first direction.

[0010] In one feasible embodiment, the reference detection element, the auxiliary detection element, and the liquid level detection element are all probes.

[0011] In one feasible embodiment, the reference detection element, the auxiliary detection element, and the liquid level detection element are respectively connected to the printed circuit board via electrical wires.

[0012] In one feasible embodiment, the probes are all disposed on the printed circuit board along a first direction.

[0013] In one feasible embodiment, the first direction is perpendicular to the printed circuit board.

[0014] In one feasible embodiment, the probe structure includes a metal probe and an insulating layer covering the outer surface of the metal probe.

[0015] In one feasible embodiment, the insulating layer comprises one or more of plastic and silicone.

[0016] According to a second aspect of this application, this application provides a liquid level sensor measurement method, applied to the liquid level sensor, comprising, The side of the printed circuit board with the liquid level detection element is positioned facing the container, so that the liquid level sensor is located inside the container; The liquid level detection element and any one of the auxiliary detection elements induce a capacitance value. The length of the liquid level detection element is equal to the maximum depth of the medium to be measured in the container, so that the liquid level detection element is in contact with the medium to be measured, so as to continuously monitor the liquid level height of the medium to be measured. When the liquid level detection element and the auxiliary detection element sense each other, one of the liquid level detection element and the auxiliary detection element is a ground terminal.

[0017] In one feasible embodiment, the liquid level sensor is placed in front of the container, and an absolute empty calibration is performed on the liquid level sensor; the absolute empty calibration involves collecting capacitance reference values ​​of the liquid level detection element, the auxiliary detection element, and the reference detection element respectively, and obtaining the initial capacitance changes of the liquid level detection element, the auxiliary detection element, and the reference detection element.

[0018] In one feasible embodiment, the liquid level sensor is located after the container. When the medium to be measured comes into contact with the reference detection element and the change detected by the reference detection element is greater than the full reference point threshold, the full reference value of the liquid level sensor is recalibrated.

[0019] In one feasible embodiment, the liquid level sensor is located after the container. When the medium to be measured is only in contact with the liquid level detection element, and the difference between the change detected by the liquid level detection element and the auxiliary detection element is less than the empty reference point threshold, the empty reference value of the liquid level sensor is recalibrated.

[0020] The length of the liquid level detection element in this application is equal to the maximum depth of the medium to be measured in the container. Regardless of whether the medium to be measured is rising or falling, the liquid level detection element can always be in contact with the medium to be measured. The liquid level detection element is used to generate a capacitance value by mutual induction with any auxiliary detection element, so that the liquid level detection element can continuously monitor the liquid level height of the medium to be measured. Either the liquid level detection element or the auxiliary detection element can be used as a ground terminal, without the need to design a fixed common electrode, making the installation method of the sensor more flexible.

[0021] It should be understood that the above general description and the following detailed description are exemplary and explanatory only, and do not limit this application. Attached Figure Description

[0022] To more clearly illustrate the technical solutions in the embodiments or prior art of this specification, the accompanying drawings used in the description of the embodiments or prior art will be briefly introduced below. Obviously, the drawings described below are merely some embodiments recorded in this specification. For those skilled in the art, other drawings can be obtained from these drawings without any creative effort.

[0023] Figure 1 This is a perspective view of a liquid level sensor in one embodiment of this application; Figure 2 This is a top view of a liquid level sensor in one embodiment of this application; Figure 3 This is a side view of a liquid level sensor in one embodiment of this application; Figure 4 This is a flowchart illustrating the steps of the liquid level sensor measurement method of this application.

[0024] In the attached diagram: 100, printed circuit board; 200, reference probe; 300, auxiliary probe; 400, liquid level probe; 500, probe structure; 510, metal probe; 520, insulating layer; 600, mounting hole. Detailed Implementation

[0025] To make the above-mentioned objectives, features, and advantages of this application more apparent and understandable, the specific embodiments of this application are described in detail below with reference to the accompanying drawings. Many specific details are set forth in the following description to provide a thorough understanding of this application. However, this application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of this application. Therefore, this application is not limited to the specific embodiments disclosed below.

[0026] It should be noted that when a component is said to be "fixed to" another component, it can be directly attached to the other component or there may be an intervening component. When a component is said to be "connected to" another component, it can be directly connected to the other component or there may be an intervening component. The terms "vertical," "horizontal," "left," "right," and similar expressions used in this document are for illustrative purposes only.

[0027] 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 this application belongs. The terminology used herein in the specification of this application is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0028] Currently, liquid level sensors have poor adaptability to different types of liquids and cannot correct detection deviations based on liquid characteristics. This makes them prone to errors in level detection results due to variations in liquid type, and the versatility and accuracy of detection need improvement. Furthermore, the circuitry of liquid level sensors requires an additional isolation module to achieve liquid-electric isolation. To address the technical problems existing in the prior art, this application proposes a liquid level sensor that can at least continuously monitor the liquid level height. Regardless of whether the medium in the container is rising or falling, the liquid level detection element can always maintain contact with the medium, eliminating the need for a fixed common electrode and making the sensor installation more flexible.

[0029] The following description, with reference to the accompanying drawings, illustrates some preferred embodiments of the present application. It should be noted that the following description is for illustrative purposes only and is not intended to limit the scope of protection of this application.

[0030] The liquid level sensor of this application includes a printed circuit board and a reference detection element, at least one auxiliary detection element, and at least one liquid level detection element disposed on the printed circuit board; A reference detection element is used to identify the type of medium being tested; The length of the liquid level detection element is equal to the maximum depth of the medium being measured in the container. The liquid level detection element is used to generate capacitance by mutual induction with any auxiliary detection element in order to continuously monitor the liquid level height of the medium being measured. When the liquid level detection element and the auxiliary detection element sense each other, one of the liquid level detection element and the auxiliary detection element is the ground terminal.

[0031] The detection element can be a detection wire (an electrical wire used for detection) or a probe. The probe can be directly inserted into the printed circuit board (PCB) or connected to the PCB via an electrical wire. The detection wire and probe can be arranged perpendicular to the PCB. It should be noted that regardless of whether the detection element is a wire or a probe, the liquid level detection principle of the liquid level sensor formed by its combination with the PCB remains unchanged. Therefore, the following description uses the case where the detection element is a probe. In this embodiment, the reference detection element is a reference probe, the auxiliary detection element is an auxiliary probe, and the liquid level detection element is a liquid level probe. (Refer to...) Figure 1 , Figure 1 This is a perspective view of a liquid level sensor according to one embodiment of this application, including a printed circuit board 100, with reference to... Figure 3 , Figure 3 This is a side view of a liquid level sensor. The printed circuit board 100 is provided with a reference probe 200 extending in a first direction, at least one auxiliary probe 300, and at least one liquid level probe 400. The reference probe 200 is used to identify the type of medium under test and also for reference calibration. The length of the liquid level probe 400 is equal to the maximum depth of the medium to be measured in the container. The liquid level probe 400 is used to generate capacitance value by mutual induction with any auxiliary probe 300 in order to continuously monitor the liquid level height of the medium to be measured. Wherein, the first direction is perpendicular to the plane where the printed circuit board 100 is located; when the liquid level probe 400 and the auxiliary probe 300 sense each other, one of the liquid level probe 400 and the auxiliary probe 300 is the ground terminal.

[0032] The reference probe 200 identifies the type of medium by acquiring its dielectric constant. The reference probe 200 and the container wall (or another independent probe) are considered as the two plates of a capacitor, with the liquid as the intermediate medium. The system measures this capacitance value, which is directly related to the dielectric constant of the liquid. Calibration allows for the identification of different media.

[0033] For example, the first direction is as follows Figure 1 As shown by arrow A1, the reference probe 200, auxiliary probe 300 and liquid level probe 400 are respectively disposed on the printed circuit board 100 along the first direction. The printed circuit board 100 includes a hardware circuit based on a capacitance detection main chip. The printed circuit board 100 is used to detect and determine the electrical parameters corresponding to the liquid level height in real time. When the liquid level probe 400 and the auxiliary probe 300 sense each other, the liquid level probe 400 can be a ground terminal, or the auxiliary probe 300 can be a ground terminal. In other words, the liquid level probe 400 and the auxiliary probe 300 can be interchanged as ground terminals without the need to design a fixed common electrode, making the sensor installation method more flexible and adaptable to containers of different shapes; wherein the medium to be measured is liquid.

[0034] In one feasible embodiment, the end of the reference probe 200 furthest from the printed circuit board 100 is a dynamic full-calibration reference point. The distance from the dynamic full-calibration reference point along the length of the reference probe 200 to the printed circuit board 100 is the overflow judgment distance of the liquid level sensor. The overflow judgment distance is as follows: Figure 3 The distance A shown is used to determine whether the medium in the container will be excessive, and to prevent the medium from overflowing.

[0035] In one feasible embodiment, the length of the auxiliary probe 300 is less than the length of the liquid level probe 400. The end of the auxiliary probe 300 away from the printed circuit board 100 is a dynamic empty calibration base point. The distance between the dynamic empty calibration base point and the bottom of the container along the length direction of the auxiliary probe 300 is the empty judgment distance of the liquid level sensor.

[0036] For example, the length of the auxiliary probe 300 is set proportionally to the length of the liquid level probe 400; the length difference between the auxiliary probe 300 and the liquid level probe 400 is 10mm, which can detect the entire range of liquid level height to the maximum extent, while leaving a judgment time to give feedback signals in a timely manner.

[0037] The distance to the empty judgment is as follows Figure 3 The distance C shown is used to determine whether the medium in the container is empty. It can provide early warnings, and when the liquid level reaches the set value, it can be predicted that the medium is about to be empty.

[0038] Continue to refer to Figure 3 This application also includes a distance B, within which the liquid levels of the auxiliary probe 300 and the liquid level probe 400 change synchronously, so the auxiliary probe 300 and the liquid level probe 400 need to participate together in the fitting calculation of the liquid level.

[0039] In one feasible embodiment, the reference probe 200, the auxiliary probe 300 and the liquid level probe 400 have the same probe structure 500, which includes a metal probe 510 and an insulating layer 520 covering the outer surface of the metal probe. The insulating layer includes one or more of plastics and silicone.

[0040] For example, such as Figure 1As shown, all three probes are covered with an insulating layer so that the probe does not come into direct contact with the medium being tested. This non-contact testing means that the printed circuit board 100 does not need to be designed with an electrohydraulic isolation module, reducing costs and the risk of failure.

[0041] When the sensor is inserted into a container containing the medium to be measured, it does not come into direct contact with the medium. At this time, the metal probe is one electrode, the liquid being measured is another electrode, and the insulating layer outside the probe is the capacitor dielectric. The three of them constitute a complete capacitor structure.

[0042] When the liquid level in the container changes, the capacitive coupling area between the probe and the medium changes continuously and linearly: as the liquid level rises, the coupling area increases, and the capacitance value increases; as the liquid level falls, the coupling area decreases, and the capacitance value decreases. Furthermore, the printed circuit board 100 is a multi-channel hardware circuit based on the MCP1085 design, possessing a detection frequency higher than 20MHz, high signal penetration, and reducing interference from liquid conductivity characteristics and wall residues on capacitance detection, ensuring that the capacitance change accurately reflects the liquid level change.

[0043] Reference Figure 2 , Figure 2 This is a top view of the liquid level sensor. The liquid level sensor also includes mounting holes 600, which are located on both sides of the printed circuit board 100 and are used to fix the liquid level sensor to the equipment that needs to measure the liquid level.

[0044] In one feasible embodiment, the liquid level height of the medium to be measured is calculated using the following formula: Lever = (ΔD) 液位 +ΔD 辅助 ) / (D max -D min )*H; Where Lever represents the liquid level height of the medium being measured; ΔD 液位 This indicates the amount of change detected by the level probe 400; ΔD 辅助 This indicates the amount of change detected by the auxiliary probe 300; D max This represents the full reference value, which is the sum of the changes detected by the level probe 400 and the auxiliary probe 300 when the container is full. D min The empty reference value represents the sum of the changes detected by the liquid level probe 400 and the auxiliary probe 300 when the container is empty; H represents the length of the 400mm level probe.

[0045] In some embodiments, the length H of the liquid level probe 400 is 2000 mm, and the sum D of the changes in the liquid level probe 400 and the auxiliary probe 300 is...min= 20mm is used as the empty chamber calibration value, and the sum of the changes in the liquid level probe 400 and the auxiliary probe 300 is D. max= 220mm is used as the full-load calibration value.

[0046] Substituting the changes detected by the level probe 400 and the auxiliary probe 300 into the above formula, we obtain the current total change ΔD. 液位 +ΔD 辅助 =85+65=150mm, D max -D min =200mm, Lever=150mm / 200mm*2000mm=1500mm. (Through D) max and D min Perform two-point calibration: full position and empty position, and linearly fit the actual height; D max -D min This represents the entire effective measurement range from empty to full. In the formula, it's used for linear normalization, transforming the original signal into 0%~100%; ΔD 液位 +ΔD 辅助 This represents the sum of the two probes, which can be used to cancel out interference and obtain a pure signal that is directly proportional to the liquid level.

[0047] Accordingly, this application also relates to a liquid level sensor measurement method, applied to a liquid level sensor, with reference to... Figure 4 , Figure 4 The liquid level sensor measurement method of this application includes, In step S100, the side of the printed circuit board 100 with the liquid level detection element is positioned facing the container, so that the liquid level sensor is located inside the container. In step S200, the liquid level detection element and any auxiliary detection element induce a capacitance value with each other. The length of the liquid level detection element is equal to the maximum depth of the medium to be measured in the container, so that the liquid level detection element is always in contact with the medium to be measured, so as to continuously monitor the liquid level height of the medium to be measured. The first direction is perpendicular to the plane of the printed circuit board 100; when the liquid level detection element and the auxiliary detection element sense each other, one of the liquid level detection element and the auxiliary detection element is the ground terminal.

[0048] In one feasible embodiment, the liquid level sensor is placed before the container, and an absolute empty calibration is performed on the liquid level sensor. The absolute empty calibration involves acquiring capacitance reference values ​​for the liquid level detection element, auxiliary detection element, and reference detection element respectively, obtaining the initial capacitance changes of the liquid level detection element, auxiliary detection element, and reference detection element. Before detection, the initial capacitance values ​​of each probe are acquired in an empty container state, providing a unified zero-point reference for calculating the changes.

[0049] In one feasible embodiment, the level sensor is positioned after the container. When the medium to be measured comes into contact with the reference detection element, and the change detected by the reference detection element exceeds the full reference threshold, the full reference value of the level sensor is recalibrated. When the liquid level contacts the reference detection element, and the change in capacitance of the reference detection element exceeds the threshold, D is automatically corrected. max To adapt to different liquid properties (such as differences in dielectric constant). In one feasible embodiment, the level sensor is positioned after the container. When the medium being measured is only in contact with the level detection element, and the difference between the changes detected by the level detection element and the auxiliary detection element is less than the empty reference point threshold, the empty reference value of the level sensor is recalibrated. When the level moves away from the auxiliary detection element, and the difference in the capacitance changes of the two needles reaches the threshold, D is automatically corrected. min This eliminates errors caused by temperature drift and residue buildup on the equipment walls.

[0050] In the description of this specification, the references to "one embodiment," "an embodiment," and / or "some embodiments," "some embodiments," "other embodiments," "ideal embodiments," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of the present invention. In this specification, the illustrative descriptions of the above terms do not necessarily refer to the same embodiment or example, and certain features, structures, or characteristics in one or more embodiments of this specification may be appropriately combined.

[0051] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0052] The above embodiments merely illustrate several implementation methods of the present invention, and their descriptions are relatively specific and detailed, but they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this invention patent should be determined by the appended claims.

[0053] The basic concepts have been described herein. It is obvious that the detailed disclosure above is merely illustrative and does not constitute a limitation of this specification. Although not explicitly stated herein, various modifications, improvements, and corrections may be made to this specification by those skilled in the art. Such modifications, improvements, and corrections are suggested in this specification and therefore remain within the spirit and scope of the exemplary embodiments described herein.

[0054] Furthermore, unless expressly stated in the claims, the order of elements and sequences, the use of numbers and letters, or other names in this specification are not intended to limit the order of the processes and methods described herein. Although various examples have been discussed in the foregoing disclosure of some embodiments of the invention that are currently considered useful, it should be understood that such details are for illustrative purposes only, and the appended claims are not limited to the disclosed embodiments; rather, the claims are intended to cover all modifications and equivalent combinations that conform to the spirit and scope of the embodiments described herein. For example, while the system components described above can be implemented using hardware devices, they can also be implemented solely using software solutions, such as installing the described system on an existing server or mobile device.

[0055] Similarly, it should be noted that, in order to simplify the description disclosed herein and thus aid in the understanding of one or more embodiments of the invention, the foregoing description of embodiments in this specification may sometimes combine multiple features into a single embodiment, drawing, or description thereof. However, this method of disclosure does not imply that the subject matter of this specification requires more features than those mentioned in the claims. In fact, the embodiments contain fewer features than all the features of a single embodiment disclosed above.

[0056] In some embodiments, numbers describing the quantity of components and attributes are used. It should be understood that such numbers used in the description of embodiments are sometimes modified by the terms "approximately," "approximately," or "generally." Unless otherwise stated, "approximately," "approximately," or "generally" indicates that the numbers are allowed to vary. Accordingly, in some embodiments, the numerical parameters used in the specification and claims are approximate values, which may be changed depending on the characteristics required by individual embodiments. In some embodiments, numerical parameters are taken into account a specified number of significant digits and employ a general method of digit reservation. Although the numerical ranges and parameters used to confirm their breadth of range in some embodiments of this specification are approximate values, in specific embodiments, such values ​​are set as precisely as feasible.

[0057] For each patent, patent application, patent application publication, and other material, such as articles, books, specifications, publications, and documents, referenced in this specification, the entire contents of which are incorporated herein by reference. This excludes historical application documents that are inconsistent with or conflict with the content of this specification, as well as documents that limit the broadest scope of the claims in this specification (currently or subsequently appended to this specification). It should be noted that in the event of any inconsistency or conflict between the descriptions, definitions, and / or terminology used in the supplementary materials and the content of this specification, the descriptions, definitions, and / or terminology used in this specification shall prevail.

[0058] Finally, it should be understood that the embodiments in this specification are merely illustrative of the principles of the embodiments described herein. Other variations may also fall within the scope of this specification. Therefore, alternative configurations of the embodiments in this specification are intended to be illustrative rather than limiting, and should be considered consistent with the teachings of this specification. Accordingly, the embodiments in this specification are not limited to those explicitly described and illustrated herein.

Claims

1. A liquid level sensor, characterized in that, It includes a printed circuit board and a reference detection element, at least one auxiliary detection element, and at least one liquid level detection element disposed on the printed circuit board; The reference detection element is used to identify the type of the medium to be tested; The length of the liquid level detection element is equal to the maximum depth of the medium to be measured in the container. The liquid level detection element is used to generate a capacitance value by mutual induction with any of the auxiliary detection elements, so as to continuously monitor the liquid level height of the medium to be measured. When the liquid level detection element and the auxiliary detection element sense each other, one of the liquid level detection element and the auxiliary detection element is a ground terminal.

2. The liquid level sensor according to claim 1, characterized in that, The end of the reference detection element away from the printed circuit board is the dynamic full calibration base point, and the distance between the dynamic full calibration base point and the printed circuit board along the length direction of the reference detection element is the overflow judgment distance of the liquid level sensor.

3. The liquid level sensor according to claim 1, characterized in that, The length of the auxiliary detection element is less than the length of the liquid level detection element. The end of the auxiliary detection element away from the printed circuit board is a dynamic empty calibration base point. The distance between the dynamic empty calibration base point and the bottom of the container along the length direction of the auxiliary detection element is the empty judgment distance of the liquid level sensor.

4. The liquid level sensor according to claim 1, characterized in that, The liquid level height of the medium to be measured is calculated using the following formula. Lever=(ΔD 液位 +ΔD 辅助 ) / (D max -D min )*H; Wherein, Lever represents the liquid level height of the medium to be measured; ΔD 液位 This indicates the amount of change detected by the liquid level detection element; ΔD 辅助 This indicates the amount of change detected by the auxiliary detection element; D max This represents the full reference value, which is the sum of the changes detected by the liquid level detection element and the auxiliary detection element when the container is full. D min The empty reference value represents the sum of the changes detected by the liquid level detection element and the auxiliary detection element when the container is empty; H represents the length of the liquid level detection element.

5. The liquid level sensor according to claim 1, characterized in that, The reference detection element, the auxiliary detection element, and the liquid level detection element are all detection wires.

6. The liquid level sensor according to claim 5, characterized in that, The fixed end of the detection wire is connected to the printed circuit board, and the free end of the detection wire is arranged along a first direction.

7. The liquid level sensor according to claim 1, characterized in that, The reference detection element, the auxiliary detection element, and the liquid level detection element are all probes.

8. The liquid level sensor according to claim 7, characterized in that, The reference detection element, the auxiliary detection element, and the liquid level detection element are respectively connected to the printed circuit board via electrical wires.

9. The liquid level sensor according to claim 8, characterized in that, The probes are all disposed on the printed circuit board along the first direction.

10. The liquid level sensor according to claim 6 or 9, characterized in that, The first direction is perpendicular to the printed circuit board.

11. The liquid level sensor according to claim 8, characterized in that, The probe structure includes a metal probe and an insulating layer covering the outer surface of the metal probe.

12. The liquid level sensor according to claim 11, characterized in that, The insulating layer includes one or more of plastic and silicone.

13. A liquid level sensor measurement method, characterized in that, The liquid level sensor used in any one of claims 1-12 includes, The side of the printed circuit board with the liquid level detection element is positioned facing the container, so that the liquid level sensor is located inside the container; The liquid level detection element and any one of the auxiliary detection elements induce a capacitance value. The length of the liquid level detection element is equal to the maximum depth of the medium to be measured in the container, so that the liquid level detection element is in contact with the medium to be measured, so as to continuously monitor the liquid level height of the medium to be measured. When the liquid level detection element and the auxiliary detection element sense each other, one of the liquid level detection element and the auxiliary detection element is a ground terminal.

14. The liquid level sensor measurement method according to claim 13, characterized in that, The liquid level sensor is placed in front of the container, and an absolute empty calibration is performed on the liquid level sensor. The absolute empty calibration involves collecting capacitance reference values ​​of the liquid level detection element, the auxiliary detection element, and the reference detection element to obtain the initial capacitance changes of the liquid level detection element, the auxiliary detection element, and the reference detection element.

15. The liquid level sensor measurement method according to claim 13, characterized in that, The liquid level sensor is located after the container. When the medium to be measured comes into contact with the reference detection element and the change detected by the reference detection element is greater than the full reference point threshold, the full reference value of the liquid level sensor is recalibrated.

16. The liquid level sensor measurement method according to claim 13, characterized in that, The liquid level sensor is located after the container. When the medium to be measured is only in contact with the liquid level detection element, and the difference between the change detected by the liquid level detection element and the auxiliary detection element is less than the empty reference point threshold, the empty reference value of the liquid level sensor is recalibrated.

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