Anti-fouling and sewage discharge control method and system based on capacitive liquid level switch

Abstract

The present invention discloses an anti-fouling and sewage discharge control method and system based on a capacitive liquid level switch, and relates to the field of capacitive liquid level switches. The method and system are provided with a first electrode pin and a second electrode pin arranged in an interval arrangement at one end of a control board close to a detection head of the capacitive liquid level switch, and the first electrode pin and the second electrode pin are used to detect an initial environmental capacitance value, and the capacitance value in a fouling state is set according to the initial environmental capacitance value; during the use of a sewage tank, the real-time mutual capacitance between the first electrode pin and the second electrode pin is obtained, and when the real-time mutual capacitance increases to the capacitance value in the fouling state, an MCU processor is used to control an early warning prompt circuit to output an early warning signal; based on the set first electrode pin and second electrode pin, the output of the second electrode pin is turned off by the MCU processor to control the discharge of sewage. The present invention realizes sewage discharge control and fouling detection of the capacitive liquid level switch based on the first electrode pin and the second electrode pin.

Description

Technical Field

[0001] The present invention relates to the field of capacitance liquid level switches, and in particular to an anti-fouling and sewage discharge control method and system based on a capacitance liquid level switch. Background Art

[0002] In the field of rail transit, the liquid level switch currently used in the sewage tank of a motor vehicle is in a mixed liquid such as human excrement, water, and paper towels for a long time, and the surface of the liquid level switch may be sticky with dirt or hung with paper towels, causing problems such as failure of the liquid level detection switch or false detection. In order to solve the problem of failure of the liquid level switch or false detection caused by dirt (scaling) or hanging on the surface of the liquid level switch, and to realize the pollution detection of the capacitive liquid level switch while realizing sewage discharge control, the present invention proposes an anti-fouling and sewage discharge control method and system based on a capacitive liquid level switch. Summary of the invention

[0003] In order to realize sewage discharge control and fouling detection of a capacitive liquid level switch at the same time, the present invention proposes an anti-fouling and sewage discharge control method based on a capacitive liquid level switch, wherein the capacitive liquid level switch comprises a control board, and one end of the control board close to the capacitive liquid level switch detection head comprises a first electrode pin and a second electrode pin arranged at intervals, and the control board is arranged between the first electrode pin and the second electrode pin, and the control board comprises a capacitance detection circuit, and the capacitance detection circuit is provided with an MCU processor, a switch output circuit and an early warning prompt circuit, and the capacitive liquid level switch is arranged in a sewage tank, and the anti-fouling and sewage discharge control method comprises:

[0004] In the initial environment where the capacitive liquid level switch detection head is free of contamination, the MCU processor controls the second electrode pin to provide a digital voltage and the first electrode pin to receive a charge to detect the mutual capacitance between the first electrode pin and the second electrode pin, and stores it as an initial environmental capacitance value, and sets the capacitance value in the contamination state by the initial environmental capacitance value; during the use of the sewage tank, the real-time mutual capacitance between the first electrode pin and the second electrode pin is obtained, and when the real-time mutual capacitance increases to the capacitance value in the contamination state, the MCU processor controls the early warning prompt circuit to output an early warning signal;

[0005] The output of the second electrode pin is turned off by the MCU processor to stop the detection of the mutual capacitance between the first electrode pin and the second electrode pin, and at the same time, the first electrode pin and the wall of the sewage tank form a parallel plate capacitor. During the use of the sewage tank, the real-time liquid level capacitance value is obtained through the first electrode pin, and when the real-time liquid level capacitance value is greater than or equal to the first liquid level capacitance setting value, the MCU processor controls the switch output circuit to be turned on to output a control signal, and controls the sewage tank to discharge sewage through the control signal. During the discharge process, it is determined in real time whether the real-time liquid level capacitance value is less than or equal to the second liquid level capacitance setting value. If so, the MCU processor controls the switch output circuit to be disconnected to stop sewage discharge. The first liquid level capacitance setting value is the capacitance value when the liquid level immerses the capacitor liquid level switch detection head, and the second liquid level capacitance setting value is the capacitance value when the liquid level drops below the liquid level switch detection head.

[0006] Furthermore, the control board also includes a power supply circuit for filtering the input power supply and inputting the filtered power supply to the capacitor detection circuit after reducing the voltage to VCC.

[0007] Furthermore, the power supply circuit includes a filter circuit and a step-down circuit;

[0008] The filtering circuit includes: a fifth TVS tube, the positive terminal of the fifth TVS tube is grounded, the negative terminal is connected to the second wiring hole in the first wiring row, the fourth wiring hole in the first wiring row is connected to the power supply, the first varistor and one end of the second four capacitors in sequence, and then connected to one end of the self-recovery fuse, the third wiring hole in the first wiring row is grounded, and the first wiring hole is grounded; the other end of the second four capacitors is grounded and connected to one end of the second five capacitors, the other end of the second five capacitors is simultaneously connected to the other end of the first varistor, the positive terminal of the third TVS tube, the second zero capacitor, and one end of the second first capacitor, and then connected to the grounding end of the first step-down module in the step-down circuit; the other end of the self-recovery fuse is connected to one end of the second inductor, the other end of the second inductor is connected to the positive terminal of the second rectifier diode, the negative terminal of the second rectifier diode is simultaneously connected to the negative terminal of the third TVS tube, the second zero capacitor, and the other end of the second first capacitor, and then connected to the input end of the first step-down module in the step-down circuit.

[0009] Furthermore, the step-down circuit comprises:

[0010] A first step-down module, wherein a ground end of the first step-down module is connected to one end of a first zero capacitor, one end of a first one capacitor, a ground end of a second step-down module, one end of a third capacitor, and one end of a sixth capacitor; the ground end of the second step-down module is grounded at the same time; the output end of the first step-down module is connected to the other end of the first zero capacitor and the first one capacitor and then connected to the input end of the second step-down module; the output end of the second step-down module is connected to the other end of the third capacitor and the sixth capacitor and then connected to a capacitance detection circuit to provide power for the capacitance detection circuit.

[0011] Furthermore, the capacitance detection circuit comprises:

[0012] An MCU processor, wherein a first pin of the MCU processor is connected to one end of a first second resistor, and the other end of the first second resistor is connected to a first electrode pin; a fifth pin of the MCU processor is connected to one end of a second resistor, and the other end of the second resistor is connected to a second electrode pin; a second eight pin of the MCU processor is grounded; a second seven pin of the MCU processor is connected to one end of a first six capacitor and a first five capacitor and then connected to a power supply, and the other end of the first six capacitor is connected to the other end of the first five capacitor and then connected to ground; a second six pin of the MCU processor is connected to one end of a first seven capacitor while being connected to a power supply, and the other end of the first seven capacitor is grounded; a second five pin of the MCU processor is connected to one end of a second first resistor, and the other end of the second first resistor is connected to one end of a first first resistor, and the other end of the first first resistor is connected to a power supply; a second one pin of the MCU processor is connected to an early warning prompt circuit; a second zero pin of the MCU processor is connected to a switch output circuit; a first seven pin of the MCU processor is connected to one end of a first eight capacitor, and the other end of the first eight capacitor is grounded.

[0013] Furthermore, the early warning circuit includes:

[0014] A first signal light, wherein one end of the first signal light is connected to the second first pin of the MCU processor, and the other end of the first signal light is connected to one end of the first three resistors, and the other end of the first three resistors is connected to a power supply.

[0015] Furthermore, the switch output circuit comprises:

[0016] A ninth resistor, one end of the ninth resistor is connected to the second zero pin of the MCU processor, the other end of the ninth resistor is connected to the base of the first transistor, the collector of the first transistor is connected to one end of the eighth resistor, and the other end of the eighth resistor is output; the emitter of the first transistor is connected to one end of the first zero resistor, and the other end of the first zero resistor is grounded.

[0017] The present invention also proposes an anti-fouling and sewage discharge control system based on a capacitive liquid level switch, wherein the capacitive liquid level switch comprises a control board, wherein one end of the control board close to the capacitive liquid level switch detection head comprises a first electrode pin and a second electrode pin arranged at intervals, wherein the control board is arranged between the first electrode pin and the second electrode pin, wherein the control board comprises a capacitive detection circuit, wherein the capacitive detection circuit is provided with an MCU processor, a switch output circuit and an early warning prompt circuit, wherein the capacitive liquid level switch is arranged in a sewage tank, and wherein the system comprises:

[0018] The anti-fouling module is used to control the second electrode pin to provide a digital voltage and the first electrode pin to receive a charge to detect the mutual capacitance between the first electrode pin and the second electrode pin through the MCU processor in an initial environment where the capacitive liquid level switch detection head is free of contamination, and store the value as an initial environmental capacitance value, and set the capacitance value in the contamination state through the initial environmental capacitance value; during the use of the sewage tank, the real-time mutual capacitance between the first electrode pin and the second electrode pin is obtained, and when the real-time mutual capacitance increases to the capacitance value in the contamination state, the MCU processor is used to control the early warning prompt circuit to output an early warning signal;

[0019] The sewage discharge control module is used to turn off the output of the second electrode pin through the MCU processor to stop the detection of the mutual capacitance between the first electrode pin and the second electrode pin, and at the same time make the first electrode pin and the box wall of the sewage tank form a parallel plate capacitor. During the use of the sewage tank, the real-time liquid level capacitance value is obtained through the first electrode pin, and when the real-time liquid level capacitance value is greater than or equal to the first liquid level capacitance setting value, the MCU processor controls the switch output circuit to be turned on to output a control signal, and controls the sewage tank to discharge sewage through the control signal. During the discharge process, it is determined in real time whether the real-time liquid level capacitance value is less than or equal to the second liquid level capacitance setting value. If so, the MCU processor controls the switch output circuit to be disconnected to stop sewage discharge. The first liquid level capacitance setting value is the capacitance value when the liquid level immerses the capacitor liquid level switch detection head, and the second liquid level capacitance setting value is the capacitance value when the liquid level drops below the liquid level switch detection head.

[0020] Compared with the prior art, the present invention has at least the following beneficial effects:

[0021] (1) The present invention sets a first electrode pin and a second electrode pin arranged at intervals at one end of the control board close to the capacitive liquid level switch detection head. In an initial environment where the capacitive liquid level switch detection head is free of contamination, the first electrode pin and the second electrode pin are first used to detect an initial environmental capacitance value, and the capacitance value in the contamination state is set according to the initial environmental capacitance value; during the use of the sewage tank, the real-time mutual capacitance between the first electrode pin and the second electrode pin is obtained, and when the real-time mutual capacitance increases to a capacitance value in the contamination state (a preset capacitance value, when it increases to this capacitance value, it indicates that the contamination has reached a certain thickness), the MCU processor controls the early warning prompt circuit to output an early warning signal to notify the staff to clean and maintain the capacitive liquid level switch, thereby preventing the capacitive liquid level switch from being damaged in the sewage due to contamination on the surface. When liquid level detection is performed in the discharge control, the detection value is inaccurate or the detection fails (the function of the capacitor liquid level switch fails), which leads to the problem that the sewage tank cannot be used; on the basis of the set first electrode pin and the second electrode pin, after the output of the second electrode pin is turned off by the MCU processor, during the use of the sewage tank, the real-time liquid level capacitance value is obtained through the first electrode pin, and when the real-time liquid level capacitance value is greater than or equal to the first liquid level capacitance setting value, the MCU processor controls the switch output circuit to be turned on to output a control signal, and controls the sewage tank to discharge sewage through the control signal. The present invention realizes sewage discharge control and contamination detection of the capacitor liquid level switch based on the first electrode pin and the second electrode pin, thereby avoiding the problem that the sewage tank fails and is unavailable due to contamination of the capacitor liquid level switch during the use of the sewage tank;

[0022] (2) The present invention avoids the problem of inaccurate liquid level detection of the capacitor liquid level switch during the use of the sewage tank due to contamination, which makes the sewage tank unable to discharge normally through the early warning prompt circuit in the capacitor detection circuit. At the same time, the present invention realizes the control of sewage discharge and the contamination detection of the capacitor liquid level switch through the combination of the early warning prompt circuit and the switch output circuit, so that the sewage tank is in a normal discharge or normal use state for a long time, avoiding the problem of long-term out of use of the toilet. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 is the power supply circuit diagram;

[0024] Figure 2 It is the capacitance detection circuit diagram;

[0025] Figure 3 Schematic diagram of the capacitive liquid level switch detection head. DETAILED DESCRIPTION

[0026] The following are specific embodiments of the present invention and the accompanying drawings to further describe the technical solution of the present invention, but the present invention is not limited to these embodiments.

[0027] Embodiment 1

[0028] In order to realize sewage discharge control and contamination detection of a capacitive liquid level switch at the same time, so as to avoid the problem that the capacitive liquid level switch has inaccurate detection value or detection failure when performing liquid level detection in sewage discharge control due to contamination on the surface, the present invention proposes an anti-contamination and sewage discharge control method based on a capacitive liquid level switch, wherein the capacitive liquid level switch includes a control board, such as Figure 3 As shown, one end of the control board close to the capacitive liquid level switch detection head includes a first electrode pin and a second electrode pin arranged at intervals, the control board is arranged between the first electrode pin and the second electrode pin, the control board includes a capacitance detection circuit, the capacitance detection circuit is provided with an MCU processor, a switch output circuit and an early warning prompt circuit, the capacitance liquid level switch is arranged in a sewage tank, and the anti-fouling and sewage discharge control method includes:

[0029] In the initial environment where the capacitive liquid level switch detection head is free of contamination, the MCU processor controls the second electrode pin to provide a digital voltage and the first electrode pin to receive a charge to detect the mutual capacitance between the first electrode pin and the second electrode pin (the charge received by the first electrode pin CDS1 is proportional to the mutual capacitance between the two electrode pins), and stores it as the initial environmental capacitance value, and sets the capacitance value in the contamination state by the initial environmental capacitance value; during the use of the sewage tank, the real-time mutual capacitance between the first electrode pin and the second electrode pin is obtained, and when the real-time mutual capacitance increases to the capacitance value in the contamination state, the MCU processor controls the early warning prompt circuit to output an early warning signal;

[0030] It should be noted that as the capacitive liquid level switch is used for a longer time, the thickness of the surface fouling (scaling) increases, and the mutual capacitance between the second electrode pin CDS2 and the first electrode pin CDS1 will increase. In this embodiment, when the thickness of the fouling (scaling) on ​​the surface of the capacitive liquid level switch reaches 3 mm, the corresponding capacitance is set to the capacitance value under the fouling state.

[0031] The output of the second electrode pin is turned off by the MCU processor (equivalent to grounding the second electrode pin) to stop the detection of the mutual capacitance between the first electrode pin and the second electrode pin, and at the same time, the first electrode pin and the wall of the sewage tank form a parallel plate capacitor. During the use of the sewage tank, the real-time liquid level capacitance value is obtained through the first electrode pin, and when the real-time liquid level capacitance value is greater than or equal to the first liquid level capacitance setting value, the MCU processor controls the switch output circuit to be turned on to output a control signal, and controls the sewage tank to discharge sewage through the control signal (at the same time, the MCU processor controls the early warning prompt circuit to output an early warning signal to increase the brightness of the first signal light), and during the discharge process, it is judged in real time whether the real-time liquid level capacitance value is less than or equal to the second liquid level capacitance setting value. If so, the MCU processor controls the switch output circuit to be disconnected to stop sewage discharge (at the same time, the MCU processor controls the early warning prompt circuit to stop outputting to turn off the first signal light), the first liquid level capacitance setting value is the capacitance value when the liquid level immerses the capacitor liquid level switch detection head, and the second liquid level capacitance setting value is the capacitance value when the liquid level drops below the liquid level switch detection head.

[0032] The present invention avoids the problem that the liquid level detection of the capacitor liquid level switch is inaccurate due to contamination during the use of the sewage tank, which makes the sewage tank unable to discharge normally. At the same time, the present invention realizes the control of sewage discharge and the contamination detection of the capacitor liquid level switch at the same time through the combination of the early warning prompt circuit and the switch output circuit, so that the sewage tank is in a normal discharge or normal use state for a long time, avoiding the problem of long-term out of use of the toilet.

[0033] The control board also includes a power supply circuit for filtering the input power supply and inputting the filtered power supply to the capacitor detection circuit after reducing the voltage to VCC.

[0034] like Figure 1 As shown, the power supply circuit includes a filter circuit and a step-down circuit;

[0035] The filtering circuit includes: a fifth TVS tube, the positive terminal of the fifth TVS tube is grounded, the negative terminal is connected to the second wiring hole in the first wiring row, the fourth wiring hole in the first wiring row is connected to the power supply, the first varistor and one end of the second four capacitors in sequence, and then connected to one end of the self-recovery fuse, the third wiring hole in the first wiring row is grounded, and the first wiring hole is grounded; the other end of the second four capacitors is grounded and connected to one end of the second five capacitors, the other end of the second five capacitors is simultaneously connected to the other end of the first varistor, the positive terminal of the third TVS tube, the second zero capacitor, and one end of the second first capacitor, and then connected to the grounding end of the first step-down module (DC step-down module) in the step-down circuit; the other end of the self-recovery fuse is connected to one end of the second inductor, the other end of the second inductor is connected to the positive terminal of the second rectifier diode, the negative terminal of the second rectifier diode is simultaneously connected to the negative terminal of the third TVS tube, the second zero capacitor, and the other end of the second first capacitor, and then connected to the input end of the first step-down module in the step-down circuit.

[0036] The step-down circuit comprises:

[0037] A first step-down module, wherein the ground end of the first step-down module is connected to one end of a first zero capacitor, one end of a first one capacitor, the ground end of a second step-down module, one end of a third capacitor, and one end of a sixth capacitor; the ground end of the second step-down module is grounded at the same time; the output end of the first step-down module is connected to the other end of the first zero capacitor and the first one capacitor and then connected to the input end of a second step-down module (DC step-down module); the output end of the second step-down module is connected to the other end of the third capacitor and the sixth capacitor and then connected to a capacitor detection circuit to provide power for the capacitor detection circuit.

[0038] It should be noted that, in the power supply circuit, the second zero capacitor C20 and the second first capacitor C21 are used to filter the input power supply, and the third capacitor C3, the sixth capacitor C6, the first zero capacitor C10 and the first first capacitor C11 are secondary step-down filter capacitors.

[0039] like Figure 2 As shown, the capacitance detection circuit includes:

[0040] MCU processor U2, the first pin of the MCU processor is connected to one end of the first two resistors, and the other end of the first two resistors is connected to the first electrode pin; the fifth pin of the MCU processor is connected to one end of the second resistor, and the other end of the second resistor is connected to the second electrode pin; the second eight pins of the MCU processor are grounded; the second seven pins of the MCU processor are connected to one end of the first six capacitors and the first five capacitors and then connected to the power supply, and the other end of the first six capacitors is connected to the other end of the first five capacitors and then grounded; the second six pins of the MCU processor are connected to one end of the first seven capacitors while being connected to the power supply, and the other end of the first seven capacitors is grounded; the second five pins of the MCU processor are connected to one end of the second one resistor, the other end of the second one resistor is connected to one end of the first one resistor, and the other end of the first one resistor is connected to the power supply; the second one pin of the MCU processor is connected to the early warning prompt circuit; the second zero pin of the MCU processor is connected to the switch output circuit; the first seven pins of the MCU processor are connected to one end of the first eight capacitors, and the other end of the first eight capacitors is grounded.

[0041] The early warning prompt circuit comprises:

[0042] A first signal light, wherein one end of the first signal light is connected to the second first pin of the MCU processor, and the other end of the first signal light is connected to one end of the first three resistors, and the other end of the first three resistors is connected to a power supply.

[0043] The switch output circuit comprises:

[0044] A ninth resistor, one end of the ninth resistor is connected to the second zero pin of the MCU processor, the other end of the ninth resistor is connected to the base of the first transistor, the collector of the first transistor is connected to one end of the eighth resistor, and the other end of the eighth resistor is output; the emitter of the first transistor is connected to one end of the first zero resistor, and the other end of the first zero resistor is grounded.

[0045] It should be noted that, in the capacitance detection circuit, the first resistor R11 and the second resistor R21 constitute a reset circuit; the eighth resistor R8, the ninth resistor R9, the first zero resistor R10, and the first transistor Q1 constitute a switch output circuit; the C18 capacitor is the reference capacitor of the first electrode pin CDS1; the first five capacitors C15, the first six capacitors C16, and the first seven capacitors C17 are filter capacitors for the MCU processor power input; the second resistor R02 and the first two resistors R12 are current limiting resistors for the capacitor pins.

[0046] The present invention sets a first electrode pin and a second electrode pin arranged at intervals at one end of a control board close to a capacitive liquid level switch detection head. In an initial environment where the capacitive liquid level switch detection head is free of contamination, the first electrode pin and the second electrode pin are first used to detect an initial environmental capacitance value, and a capacitance value in a contamination state is set according to the initial environmental capacitance value; during the use of the sewage tank, the real-time mutual capacitance between the first electrode pin and the second electrode pin is obtained, and when the real-time mutual capacitance increases to a capacitance value in a contamination state (a preset capacitance value, when increased to this capacitance value, it indicates that the contamination has reached a certain thickness), an MCU processor is used to control an early warning prompt circuit to output an early warning signal, so as to notify a staff member to clean and maintain the capacitive liquid level switch, thereby preventing the capacitive liquid level switch from being discharged into the sewage due to contamination on the surface. When liquid level detection is performed in the discharge control, the detection value is inaccurate or the detection fails (the function of the capacitor liquid level switch fails), which leads to the problem that the sewage tank cannot be used; on the basis of the set first electrode pin and the second electrode pin, after the output of the second electrode pin is turned off by the MCU processor, during the use of the sewage tank, the real-time liquid level capacitance value is obtained through the first electrode pin, and when the real-time liquid level capacitance value is greater than or equal to the first liquid level capacitance setting value, the MCU processor controls the switch output circuit to be turned on to output a control signal, and controls the sewage tank to discharge sewage through the control signal. The present invention realizes sewage discharge control and contamination detection of the capacitor liquid level switch based on the first electrode pin and the second electrode pin, thereby avoiding the problem of the sewage tank failing and being unavailable due to contamination of the capacitor liquid level switch during the use of the sewage tank.

[0047] Embodiment 2

[0048] The present invention also proposes an anti-fouling and sewage discharge control system based on a capacitive liquid level switch, wherein the capacitive liquid level switch comprises a control board, wherein one end of the control board close to the capacitive liquid level switch detection head comprises a first electrode pin and a second electrode pin arranged at intervals, wherein the control board is arranged between the first electrode pin and the second electrode pin, wherein the control board comprises a capacitive detection circuit, wherein the capacitive detection circuit is provided with an MCU processor, a switch output circuit and an early warning prompt circuit, wherein the capacitive liquid level switch is arranged in a sewage tank, and wherein the system comprises:

[0049] The anti-fouling module is used to control the second electrode pin to provide a digital voltage and the first electrode pin to receive a charge to detect the mutual capacitance between the first electrode pin and the second electrode pin through the MCU processor in an initial environment where the capacitive liquid level switch detection head is free of contamination, and store the value as an initial environmental capacitance value, and set the capacitance value in the contamination state through the initial environmental capacitance value; during the use of the sewage tank, the real-time mutual capacitance between the first electrode pin and the second electrode pin is obtained, and when the real-time mutual capacitance increases to the capacitance value in the contamination state, the MCU processor is used to control the early warning prompt circuit to output an early warning signal;

[0050] The sewage discharge control module is used to turn off the output of the second electrode pin through the MCU processor to stop the detection of the mutual capacitance between the first electrode pin and the second electrode pin, and at the same time make the first electrode pin and the box wall of the sewage tank form a parallel plate capacitor. During the use of the sewage tank, the real-time liquid level capacitance value is obtained through the first electrode pin, and when the real-time liquid level capacitance value is greater than or equal to the first liquid level capacitance setting value, the MCU processor controls the switch output circuit to be turned on to output a control signal, and controls the sewage tank to discharge sewage through the control signal. During the discharge process, it is determined in real time whether the real-time liquid level capacitance value is less than or equal to the second liquid level capacitance setting value. If so, the MCU processor controls the switch output circuit to be disconnected to stop sewage discharge. The first liquid level capacitance setting value is the capacitance value when the liquid level immerses the capacitor liquid level switch detection head, and the second liquid level capacitance setting value is the capacitance value when the liquid level drops below the liquid level switch detection head.

[0051] It should be noted that the present invention can periodically enable the anti-fouling module to avoid failure or false alarm of the liquid level switch due to fouling (scaling) on ​​the outer surface of the capacitive liquid level switch, thereby improving the stability and reliability of the system.

[0052] It should be noted that all directional indications in the embodiments of the present invention (such as up, down, left, right, front, back, etc.) are only used to explain the relative position relationship, movement status, etc. between the components under a certain specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indication will also change accordingly.

[0053] In addition, in the present invention, descriptions such as "first", "second", "one", etc. are only used for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" or "second" may explicitly or implicitly include at least one of the features. In the description of the present invention, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0054] In the present invention, unless otherwise clearly specified and limited, the terms "connection", "fixation", etc. should be understood in a broad sense. For example, "fixation" can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0055] In addition, the technical solutions between the various embodiments of the present invention can be combined with each other, but it must be based on the fact that ordinary technicians in the field can implement it. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

Claims

1. A method for anti-fouling and sewage discharge control based on a capacitive liquid level switch, characterized in that: The capacitive liquid level switch comprises a control board, and one end of the control board close to the capacitive liquid level switch detection head comprises a first electrode pin and a second electrode pin arranged at intervals, and the control board is arranged between the first electrode pin and the second electrode pin, and the control board comprises a capacitance detection circuit, and the capacitance detection circuit is provided with an MCU processor, a switch output circuit and an early warning prompt circuit, and the capacitive liquid level switch is arranged in a sewage tank; the control board also comprises a power supply circuit, which is used to filter the input power supply, and after reducing the filtered power supply to the VCC voltage, input the power supply to the capacitance detection circuit; The power supply circuit includes a filter circuit and a step-down circuit; The filtering circuit includes: a fifth TVS tube, the positive terminal of the fifth TVS tube is grounded, the negative terminal is connected to the second wiring hole in the first wiring row, the fourth wiring hole in the first wiring row is connected to the power supply, the first varistor and one end of the second four capacitors in sequence, and then connected to one end of the self-recovery fuse, the third wiring hole in the first wiring row is grounded, and the first wiring hole is grounded; the other end of the second four capacitors is grounded and connected to one end of the second five capacitors, the other end of the second five capacitors is simultaneously connected to the other end of the first varistor, the positive terminal of the third TVS tube, the second zero capacitor, and one end of the second first capacitor, and then connected to the grounding end of the first buck module in the buck circuit; the other end of the self-recovery fuse is connected to one end of the second inductor, the other end of the second inductor is connected to the positive terminal of the second rectifier diode, the negative terminal of the second rectifier diode is simultaneously connected to the negative terminal of the third TVS tube, the second zero capacitor, and the other end of the second first capacitor, and then connected to the input end of the first buck module in the buck circuit; The step-down circuit comprises: A first step-down module, wherein a ground end of the first step-down module is connected to one end of a first zero capacitor, one end of a first capacitor, a ground end of a second step-down module, one end of a third capacitor, and one end of a sixth capacitor; a ground end of the second step-down module is grounded at the same time; an output end of the first step-down module is connected to the other end of the first zero capacitor and the first capacitor and then connected to the input end of the second step-down module; an output end of the second step-down module is connected to the other end of the third capacitor and the sixth capacitor and then connected to a capacitance detection circuit to provide power for the capacitance detection circuit; The capacitance detection circuit comprises: MCU processor, the first pin of the MCU processor is connected to one end of the first two resistors, and the other end of the first two resistors is connected to the first electrode pin; the fifth pin of the MCU processor is connected to one end of the second resistor, and the other end of the second resistor is connected to the second electrode pin; the second eight pins of the MCU processor are grounded; the second seven pins of the MCU processor are connected to one end of the first six capacitors and the first five capacitors and then connected to the power supply, and the other end of the first six capacitors is connected to the other end of the first five capacitors and then grounded; the second six pins of the MCU processor are connected to one end of the first seven capacitors while being connected to the power supply, and the other end of the first seven capacitors is grounded; the second five pins of the MCU processor are connected to one end of the second one resistor, and the other end of the second one resistor is connected to one end of the first one resistor, and the other end of the first one resistor is connected to the power supply; the second one pin of the MCU processor is connected to the early warning prompt circuit; the second zero pin of the MCU processor is connected to the switch output circuit; the first seven pins of the MCU processor are connected to one end of the first eight capacitors, and the other end of the first eight capacitors is grounded; the anti-fouling and sewage discharge control method comprises: In the initial environment where the capacitive liquid level switch detection head is free of contamination, the MCU processor controls the second electrode pin to provide a digital voltage and the first electrode pin to receive a charge to detect the mutual capacitance between the first electrode pin and the second electrode pin, and stores it as an initial environmental capacitance value, and sets the capacitance value in the contamination state by the initial environmental capacitance value; during the use of the sewage tank, the real-time mutual capacitance between the first electrode pin and the second electrode pin is obtained, and when the real-time mutual capacitance increases to the capacitance value in the contamination state, the MCU processor controls the early warning prompt circuit to output an early warning signal; The output of the second electrode pin is turned off by the MCU processor to stop the detection of the mutual capacitance between the first electrode pin and the second electrode pin, and at the same time, the first electrode pin and the wall of the sewage tank form a parallel plate capacitor. During the use of the sewage tank, the real-time liquid level capacitance value is obtained through the first electrode pin, and when the real-time liquid level capacitance value is greater than or equal to the first liquid level capacitance setting value, the MCU processor controls the switch output circuit to be turned on to output a control signal, and controls the sewage tank to discharge sewage through the control signal. During the discharge process, it is determined in real time whether the real-time liquid level capacitance value is less than or equal to the second liquid level capacitance setting value. If so, the MCU processor controls the switch output circuit to be disconnected to stop sewage discharge. The first liquid level capacitance setting value is the capacitance value when the liquid level immerses the capacitor liquid level switch detection head, and the second liquid level capacitance setting value is the capacitance value when the liquid level drops below the liquid level switch detection head.

2. The anti-fouling and sewage discharge control method based on a capacitive liquid level switch according to claim 1 is characterized in that: The early warning prompt circuit comprises: A first signal light, wherein one end of the first signal light is connected to the second first pin of the MCU processor, and the other end of the first signal light is connected to one end of the first three resistors, and the other end of the first three resistors is connected to a power supply.

3. The anti-fouling and sewage discharge control method based on a capacitive liquid level switch according to claim 2 is characterized in that: The switch output circuit comprises: A ninth resistor, one end of the ninth resistor is connected to the second zero pin of the MCU processor, the other end of the ninth resistor is connected to the base of the first transistor, the collector of the first transistor is connected to one end of the eighth resistor, and the other end of the eighth resistor is output; the emitter of the first transistor is connected to one end of the first zero resistor, and the other end of the first zero resistor is grounded. 4.An anti-fouling and sewage discharge control system based on a capacitive liquid level switch, characterized in that: The capacitive liquid level switch comprises a control board, and one end of the control board close to the capacitive liquid level switch detection head comprises a first electrode pin and a second electrode pin arranged at intervals, and the control board is arranged between the first electrode pin and the second electrode pin, and the control board comprises a capacitance detection circuit, and the capacitance detection circuit is provided with an MCU processor, a switch output circuit and an early warning prompt circuit, and the capacitive liquid level switch is arranged in a sewage tank; the control board also comprises a power supply circuit, which is used to filter the input power supply, and after reducing the filtered power supply to the VCC voltage, input the power supply to the capacitance detection circuit; The power supply circuit includes a filter circuit and a step-down circuit; The filtering circuit includes: a fifth TVS tube, the positive terminal of the fifth TVS tube is grounded, the negative terminal is connected to the second wiring hole in the first wiring row, the fourth wiring hole in the first wiring row is connected to the power supply, the first varistor and one end of the second four capacitors in sequence, and then connected to one end of the self-recovery fuse, the third wiring hole in the first wiring row is grounded, and the first wiring hole is grounded; the other end of the second four capacitors is grounded and connected to one end of the second five capacitors, the other end of the second five capacitors is simultaneously connected to the other end of the first varistor, the positive terminal of the third TVS tube, the second zero capacitor, and one end of the second first capacitor, and then connected to the grounding end of the first buck module in the buck circuit; the other end of the self-recovery fuse is connected to one end of the second inductor, the other end of the second inductor is connected to the positive terminal of the second rectifier diode, the negative terminal of the second rectifier diode is simultaneously connected to the negative terminal of the third TVS tube, the second zero capacitor, and the other end of the second first capacitor, and then connected to the input end of the first buck module in the buck circuit; The step-down circuit comprises: A first step-down module, wherein a ground end of the first step-down module is connected to one end of a first zero capacitor, one end of a first capacitor, a ground end of a second step-down module, one end of a third capacitor, and one end of a sixth capacitor; a ground end of the second step-down module is grounded at the same time; an output end of the first step-down module is connected to the other end of the first zero capacitor and the first capacitor and then connected to the input end of the second step-down module; an output end of the second step-down module is connected to the other end of the third capacitor and the sixth capacitor and then connected to a capacitance detection circuit to provide power for the capacitance detection circuit; The capacitance detection circuit comprises: MCU processor, the first pin of the MCU processor is connected to one end of the first two resistors, and the other end of the first two resistors is connected to the first electrode pin; the fifth pin of the MCU processor is connected to one end of the second resistor, and the other end of the second resistor is connected to the second electrode pin; the second eight pins of the MCU processor are grounded; the second seven pins of the MCU processor are connected to one end of the first six capacitors and the first five capacitors and then connected to the power supply, and the other end of the first six capacitors is connected to the other end of the first five capacitors and then grounded; the second six pins of the MCU processor are connected to one end of the first seven capacitors while being connected to the power supply, and the other end of the first seven capacitors is grounded; the second five pins of the MCU processor are connected to one end of the second one resistor, and the other end of the second one resistor is connected to one end of the first one resistor, and the other end of the first one resistor is connected to the power supply; the second one pin of the MCU processor is connected to the early warning prompt circuit; the second zero pin of the MCU processor is connected to the switch output circuit; the first seven pins of the MCU processor are connected to one end of the first eight capacitors, and the other end of the first eight capacitors is grounded; the system includes: The anti-fouling module is used to control the second electrode pin to provide a digital voltage and the first electrode pin to receive a charge to detect the mutual capacitance between the first electrode pin and the second electrode pin through the MCU processor in an initial environment where the capacitive liquid level switch detection head is free of contamination, and store the value as an initial environmental capacitance value, and set the capacitance value in the contamination state through the initial environmental capacitance value; during the use of the sewage tank, the real-time mutual capacitance between the first electrode pin and the second electrode pin is obtained, and when the real-time mutual capacitance increases to the capacitance value in the contamination state, the MCU processor is used to control the early warning prompt circuit to output an early warning signal; The sewage discharge control module is used to turn off the output of the second electrode pin through the MCU processor to stop the detection of the mutual capacitance between the first electrode pin and the second electrode pin, and at the same time make the first electrode pin and the box wall of the sewage tank form a parallel plate capacitor. During the use of the sewage tank, the real-time liquid level capacitance value is obtained through the first electrode pin, and when the real-time liquid level capacitance value is greater than or equal to the first liquid level capacitance setting value, the MCU processor controls the switch output circuit to be turned on to output a control signal, and controls the sewage tank to discharge sewage through the control signal. During the discharge process, it is determined in real time whether the real-time liquid level capacitance value is less than or equal to the second liquid level capacitance setting value. If so, the MCU processor controls the switch output circuit to be disconnected to stop sewage discharge. The first liquid level capacitance setting value is the capacitance value when the liquid level immerses the capacitor liquid level switch detection head, and the second liquid level capacitance setting value is the capacitance value when the liquid level drops below the liquid level switch detection head.

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