Liquid level detection method, circuit and washing machine

Abstract

The application discloses a liquid level detection method, a circuit and a washing machine, and relates to the technical field of liquid level detection. The liquid level detection circuit comprises an AD detection module, a filter circuit, a liquid level probe and a clamping circuit. The AD detection module is used for detecting the AD value of the circuit. The filter circuit is connected with the AD detection module. The liquid level probe comprises a first probe and a second probe. The first probe is connected with the input end of the filter circuit. The first probe is connected with a first output port. The second probe is connected with a second output port. The clamping circuit is connected with the second probe. The application can determine whether the probe is separated from the liquid according to the detected AD value. Meanwhile, the clamping circuit is arranged to control the voltage within a specified range, thereby improving the accuracy of AD detection and the accuracy of the liquid level detection result.

Description

Technical Field

[0001] This invention belongs to the field of liquid level detection technology, specifically, it relates to a liquid level detection method, circuit, and washing machine. Background Technology

[0002] In traditional washing machines, users need to manually add detergent to the drum when washing clothes. The amount of detergent is specified by the user and depends on their experience. This not only adds extra work for the user, but the amount of detergent added by the user is often inaccurate, affecting the washing effect on the clothes.

[0003] With technological advancements, washing machines equipped with detergent dispensers have emerged. Users pre-add detergent to the dispenser, and during washing, the washing machine determines the amount of detergent to add based on parameters such as the quantity, material, and level of soiling of the clothes. This eliminates the need for manual addition by the user, reducing user intervention and ensuring precise detergent dispensing, preventing waste and providing excellent washing results. Typically, the detergent dispenser is equipped with a liquid level detection device to monitor the liquid level and promptly notify the user when the detergent level is low, allowing them to refill the dispenser.

[0004] An existing Chinese patent discloses a probe-based automatic liquid depletion detection system. This system sends a control signal to a first probe and receives a feedback signal from a second probe, determining whether the liquid is depleted based on the second probe's feedback signal. However, relying solely on the AD voltage value returned by the second probe in this detection process can easily lead to inaccurate results.

[0005] In view of this, the present invention is proposed. Summary of the Invention

[0006] The technical problem to be solved by the present invention is to overcome the shortcomings of the prior art and provide a liquid level detection method, circuit and washing machine that can improve the accuracy of liquid level detection results.

[0007] To solve the above-mentioned technical problems, the basic concept of the technical solution adopted by the present invention is as follows: A liquid level detection circuit, comprising: An AD detection module is used to detect the AD value of a circuit. The filter circuit, whose output is connected to the AD detection module; A liquid level probe, comprising a first probe and a second probe, wherein the first probe is connected to the input terminal of a filter circuit, the first probe is connected to a first output port, and the second probe is connected to a second output port; The clamping circuit is connected to the first probe.

[0008] Preferably, the clamping circuit includes a first diode and a second diode, the anode of the first diode is grounded, the cathode of the second diode is connected to the power supply terminal, and both the cathode of the first diode and the anode of the second diode are connected to the first probe.

[0009] Preferably, the filter circuit includes a resistor R2 and a capacitor C14. The first end of the resistor R2 is connected to the AD detection module, the first end of the resistor R2 is grounded through the capacitor C14, and the second end of the resistor R2 is connected to the first probe.

[0010] Preferably, it includes a second clamping circuit, which includes a third diode and a fourth diode. The positive terminal of the third diode and the negative terminal of the fourth diode are both connected to the second probe. The negative terminal of the third diode is connected to the power supply terminal, and the positive terminal of the fourth diode is grounded.

[0011] Preferably, the dispensing box is equipped with multiple sets of liquid level probes, which are arranged in descending order of height, and each set of liquid level probes is connected to a detection circuit board.

[0012] Another objective of this invention is to provide a liquid level detection method for a liquid level detection circuit as described above, wherein the method obtains the AD value AD_Z1 detected by the AD detection module when the liquid level detection circuit is forward-energized, obtains the AD value AD_F1 detected by the AD detection module when the liquid level detection circuit is reverse-energized, calculates the final AD value AD_Z based on the AD value AD_Z1 when forward-energized and the AD value AD_F1 when reverse-energized, and determines that the probe and the liquid have detached if the final AD value AD_Z is less than a preset AD value.

[0013] Preferably, the step of calculating the final AD value AD_Z based on the AD value AD_Z1 during forward energization and the AD value AD_F1 during reverse energization includes the final AD value AD_Z being: AD_Z = AD_Z1 - AD_F1 + 256.

[0014] Preferably, after determining that the final AD value AD_Z is less than the preset AD value, the number of jumps in the final AD value AD_Z during the liquid level detection process is obtained. If the number of jumps in the final AD value reaches the preset number, it is determined that the probe and the liquid have separated.

[0015] Another object of the present invention is to provide a washing machine, including a dispensing box and a detection circuit board, wherein the dispensing box is provided with a liquid level probe, and the detection circuit board is provided with a liquid level detection circuit as described in any one of the above, and the liquid level probe is connected to the detection circuit board.

[0016] Preferably, the dispensing box is equipped with multiple sets of liquid level probes, each set of liquid level probes including a first probe and a second probe.

[0017] By adopting the above technical solution, the present invention has the following beneficial effects compared with the prior art: 1. This invention detects liquid level by applying alternating current to the liquid level detection circuit, reducing corrosion of the liquid level probe and extending its service life. During the detection process, the system automatically determines whether the probe has detached from the liquid based on the detected AD value, resulting in high detection accuracy and precise judgment.

[0018] 2. In detecting liquid level, this invention increases the number of jumps in the final AD value AD_Z. The liquid level probe is then used to determine whether it has detached based on the final AD value AD_Z and the number of jumps in the final AD value AD_Z, thereby improving the accuracy of the liquid level detection results.

[0019] 3. By setting a clamping circuit, the present invention controls the voltage at the liquid level probe within a specified range, avoiding excessively high or low voltage, thereby enhancing the accuracy of AD detection results and improving the accuracy of liquid level detection results.

[0020] The specific embodiments of the present invention will now be described in further detail with reference to the accompanying drawings. Attached Figure Description

[0021] The accompanying drawings, as part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments and descriptions of the invention are used to explain the invention, but do not constitute an undue limitation of the invention. Obviously, the drawings described below are merely some embodiments, and those skilled in the art can obtain other drawings based on these drawings without creative effort. In the drawings: Figure 1 This is a schematic diagram of a liquid level detection circuit according to the present invention.

[0022] It should be noted that these accompanying drawings and textual descriptions are not intended to limit the scope of the invention in any way, but rather to illustrate the concept of the invention to those skilled in the art by referring to specific embodiments. Detailed Implementation

[0023] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments will be clearly and completely described below with reference to the accompanying drawings. The following embodiments are used to illustrate the present invention, but are not intended to limit the scope of the present invention.

[0024] In the description of this invention, it should be noted that the terms "upper", "lower", "front", "rear", "left", "right", "vertical", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limiting this invention.

[0025] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0026] This invention provides a liquid level detection method. A liquid level detection circuit is forward-energized for a first preset time, and an AD detection module detects an AD value AD_Z1. A liquid level detection circuit is then reverse-energized for a second preset time, and the AD detection module detects an AD value AD_F1. The final AD value AD_Z is calculated based on AD_Z1 and AD_F1. If the final AD value AD_Z is less than a preset value, it is determined that the liquid level probe has detached from the liquid level.

[0027] During liquid level detection, a liquid level probe is inserted into the liquid whose level needs to be detected. The liquid level probe includes a first probe and a second probe. As the liquid level probe changes from being inserted into the liquid to being removed from the liquid, a significant change in resistance occurs between the first probe and the second probe.

[0028] This invention uses alternating current for liquid level detection. First, a forward current (Xms) is applied to the liquid level detection circuit. During this process, the first output port (OUT_PIN) outputs a high level, and the second output port (OUT_B) outputs a low level. The AD value Z1 during the forward current is detected by the AD detection module. Then, a reverse current (Yms) is applied to the liquid level detection circuit. During this process, the first output port (OUT_PIN) outputs a low level, and the second output port (OUT_B) outputs a high level. The AD detection module detects the AD value F1 during the reverse current. Based on the AD values ​​Z1 during the forward current and F1 during the reverse current, the final AD value AD_Z is calculated. The final AD value AD_Z is: AD_Z = Z1 - F1 + 256; If the final AD value is less than the preset value, it is considered that the liquid level probe and the liquid level have separated, and the liquid level is lower than the minimum height of the probe.

[0029] This invention detects liquid level by applying alternating current to the liquid level detection circuit, reducing corrosion of the liquid level probe and extending its service life. During detection, the system automatically determines whether the probe has detached from the liquid based on the detected AD value, resulting in high detection accuracy and precise judgment.

[0030] In this embodiment of the invention, during the liquid level detection process, the number of jumps in the final AD value AD_Z is determined. If the number of jumps in the final AD value AD_Z reaches a preset number and the final AD value AD_Z is less than a preset AD value, then it is considered that the liquid level probe has detached from the liquid.

[0031] This invention adds a step to determine the number of jumps in the final AD value AD_Z when detecting liquid level. The liquid level probe is then used to determine whether it has detached based on the final AD value AD_Z and the number of jumps in the final AD value AD_Z, thereby improving the accuracy of the liquid level detection results.

[0032] like Figure 1 As shown in the figure, an embodiment of the present invention introduces a liquid level detection circuit, including an AD detection module AD_PIN_DET, a liquid level probe, a clamping circuit, and a filtering circuit. The liquid level probe includes a first probe and a second probe. The first probe is connected to the input terminal of the filtering circuit, and the output terminal of the filtering circuit is connected to the AD detection module AD_PIN_DET. The first probe is connected to the first output port OUT_G_D&S, and the second probe is connected to the second output port OUT_5V_PIN1.

[0033] During liquid level detection, the liquid level detection circuit is first powered in the forward direction, and the AD detection module AD_PIN_DET detects the AD value AD_Z1. Then, the liquid level detection circuit is powered in the reverse direction, and the AD detection module AD_PIN_DET detects the AD value AD_F1. Based on the AD values ​​AD_Z1 and AD_F1, the final AD value AD_Z is calculated. At the same time, the number of transitions of the final AD value AD_Z is also determined. If the number of transitions of the final AD value AD_Z reaches the preset number and the final AD value AD_Z is less than the preset AD value, it is determined that the liquid level probe has become detached from the liquid level.

[0034] This invention improves the accuracy of liquid level detection by determining whether the liquid level in the dispensing box is lower than the liquid level probe based on the AD value and the changes in the AD value.

[0035] like Figure 1 As shown in the embodiment of the present invention, the clamping circuit includes a first diode and a second diode. The positive terminal of the first diode is grounded, the negative terminal of the second diode is connected to the power supply terminal, and the negative terminal of the first diode and the positive terminal of the second diode are both connected to the first probe.

[0036] A diode has unidirectional conduction characteristics; the voltage across its terminals is constant when the diode is conducting. For example... Figure 1 The cathode of the second diode is connected to a 5V power supply. If the voltage drop between the first and second diodes is 0.7V, then when the voltage at the first probe is greater than 5.7V, since the anode of the first diode is grounded, its anode voltage is 0V, and the first diode is cut off. The cathode voltage of the second diode is 5V, so the second diode conducts, and its anode voltage is clamped at 5.7V, meaning the voltage at the first probe is 5.7V. If the voltage at the first probe is lower than -0.7V, the first diode conducts, the second diode is cut off, and the voltage at the first probe is clamped to -0.7V. If the voltage at the first probe is within the range of -0.7V to 5.7V, then both the first and second diodes are cut off, and the clamping circuit does not function.

[0037] This invention uses a clamping circuit to clamp the voltage at the first probe within a specified range, preventing the voltage from being too high or too low, thereby enhancing the accuracy of AD detection results.

[0038] In this embodiment of the invention, the filter circuit includes a resistor R2 and a capacitor C14. The first end of the resistor R2 is connected to the AD detection module, the first end of the resistor R2 is grounded through the capacitor C14, and the second end of the resistor R2 is connected to the first probe.

[0039] This invention improves the accuracy of liquid level detection by setting a filtering circuit between the AD detection module AD_PIN_DET and the first probe to filter the detection signal of the first probe, thereby removing interference signals.

[0040] like Figure 1 As shown in the embodiment of the present invention, a second clamping circuit is further provided in the liquid level detection circuit. The second clamping circuit includes a third diode and a fourth diode. The positive terminal of the third diode and the negative terminal of the fourth diode are both connected to the first probe. The negative terminal of the third diode is connected to the power supply terminal, and the positive terminal of the fourth diode is grounded.

[0041] This invention utilizes a second clamping circuit to clamp the voltage at the second probe within a specified range, preventing the voltage at the second probe from being too high or too low, thereby enhancing the accuracy of the AD detection results. The clamping circuit in this invention uses a BAV99 switching diode.

[0042] like Figure 1 As shown in the embodiment of the present invention, the liquid level detection circuit includes multiple sets of liquid level probes. Each set of liquid level probes includes a first probe and a second probe. The first probes are all connected to the input terminal of the filter circuit, and each second probe is connected to its corresponding second clamping circuit.

[0043] For example, the liquid level detection circuit has four sets of liquid level probes. Each set of liquid level probes includes a first probe and a second probe. The liquid level detection circuit also has a connector CN3. All the first probes are connected to pin 1 of connector CN3. Pin 1 of connector CN3 is connected to the input terminal of the filter circuit. The four sets of liquid level probes include four second probes. The four second probes are respectively connected to pins 2, 3, 4, and 5 of connector CN3. Pins 2, 3, 4, and 5 of connector CN3 are respectively connected to switching diodes D4, D5, D6, and D1.

[0044] This invention, by setting multiple sets of liquid level probes, can detect different liquid level heights, allowing users to understand the liquid level height more accurately and making it more convenient for users.

[0045] This invention provides a washing machine, which includes a dispensing box and a detection circuit board. The dispensing box can store detergent, fabric softener, washing aids, etc., and is automatically dispensed during washing machine operation. The detection circuit board is equipped with a liquid level detection circuit as described in any of the above embodiments, and a liquid level probe is connected to the detection circuit board.

[0046] When the liquid level in the dispenser is high, the level probe extends into the liquid. After multiple washes in the washing machine, the liquid level in the dispenser decreases. When the liquid level in the dispenser is lower than the level probe, the level probe detaches from the liquid in the dispenser, and the resistance between the level probes changes.

[0047] This invention uses alternating current for liquid level detection. First, the liquid level detection circuit is forward-energized for Xms. At this time, the first output port OUT_PIN outputs a high level, and the second output port OUT_B outputs a low level. The AD value Z1 during forward energization is detected by the AD detection module. Then, the liquid level detection circuit is reverse-energized for Yms. At this time, the first output port OUT_PIN outputs a low level, and the second output port OUT_B outputs a high level. The AD detection module detects the AD value F1 during reverse energization. The final AD value AD_Z is calculated based on the AD value Z1 during forward energization and the AD value F1 during reverse energization. At the same time, the number of transitions of the final AD value AD_Z is also determined. If the number of transitions of the final AD value AD_Z reaches a preset number and the final AD value AD_Z is less than the preset AD value, it is determined that the liquid level probe has become detached from the liquid level.

[0048] This invention improves the accuracy of liquid level detection by determining whether the liquid level in the dispensing box is lower than the level probe based on the AD value and its fluctuations. Simultaneously, it can estimate the remaining liquid in the dispensing box after the level probe detaches, accurately predicting whether liquid is low based on the dispensing amount, and promptly reminding the user to replenish the liquid when needed.

[0049] In this embodiment of the invention, multiple sets of liquid level probes are provided in the dispensing box. The multiple sets of liquid level probes are arranged in descending order in the dispensing box, and all of the multiple sets of liquid level probes are connected to the detection circuit board.

[0050] This invention, by setting multiple sets of liquid level probes, can detect different liquid level heights, allowing users to understand the liquid level height more accurately and making it more convenient for users.

[0051] Numerous specific details are set forth in the specification provided herein. However, it will be understood that embodiments of the invention may be practiced without these specific details. In some instances, well-known methods, structures, and techniques have not been shown in detail so as not to obscure the understanding of this specification.

[0052] Except where at least some of such features and / or processes or units are mutually exclusive, any combination may be used to combine all features disclosed in this specification (including the accompanying claims, abstract, and drawings) and all processes or units of any method or apparatus so disclosed. Unless otherwise expressly stated, each feature disclosed in this specification (including the accompanying claims, abstract, and drawings) may be replaced by an alternative feature that serves the same, equivalent, or similar purpose.

[0053] Furthermore, those skilled in the art will understand that although some embodiments described herein include certain features included in other embodiments but not others, combinations of features from different embodiments are meant to be within the scope of the invention and form different embodiments.

[0054] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some modifications or alterations to the above-described technical content to create equivalent embodiments without departing from the scope of the present invention. The implementation schemes in the above embodiments can also be further combined or replaced. Any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the scope of the present invention.

Claims

1. A liquid level detection circuit, characterized in that, include: An AD detection module is used to detect the AD value of a circuit. The filter circuit, whose output is connected to the AD detection module; A liquid level probe, comprising a first probe and a second probe, wherein the first probe is connected to the input terminal of a filter circuit, the first probe is connected to a first output port, and the second probe is connected to a second output port; A clamping circuit, used to control the voltage range, is connected to the first probe; The AD value AD_Z1 detected by the AD detection module when the liquid level detection circuit is energized in the forward direction is obtained, and the AD value AD_F1 detected by the AD detection module when the liquid level detection circuit is energized in the reverse direction is obtained. The final AD value AD_Z is calculated based on the AD value AD_Z1 when energized in the forward direction and the AD value AD_F1 when energized in the reverse direction. If the final AD value AD_Z is less than the preset AD value, it is determined that the probe has detached from the liquid.

2. The liquid level detection circuit according to claim 1, characterized in that, The clamping circuit includes a first diode and a second diode. The positive terminal of the first diode is grounded, and the negative terminal of the second diode is connected to the power supply terminal. Both the negative terminal of the first diode and the positive terminal of the second diode are connected to the first probe.

3. The liquid level detection circuit according to claim 1, characterized in that, The filter circuit includes a resistor R2 and a capacitor C14. The first end of the resistor R2 is connected to the AD detection module, and the first end of the resistor R2 is grounded through the capacitor C14. The second end of the resistor R2 is connected to the first probe.

4. The liquid level detection circuit according to claim 1, characterized in that, The device includes a second clamping circuit, which includes a third diode and a fourth diode. The positive terminal of the third diode and the negative terminal of the fourth diode are both connected to the second probe. The negative terminal of the third diode is connected to the power supply terminal, and the positive terminal of the fourth diode is grounded.

5. A liquid level detection circuit according to any one of claims 1-4, characterized in that, It includes multiple sets of liquid level probes, each set of liquid level probes includes a first probe and a second probe. The first probes are all connected to the input terminal of the filter circuit, and each second probe is connected to its respective second clamping circuit.

6. A liquid level detection circuit according to any one of claims 1-4, characterized in that, The calculation of the final AD value AD_Z based on the AD value AD_Z1 during forward energization and the AD value AD_F1 during reverse energization includes the following: The final AD value AD_Z is: AD_Z = AD_Z1 - AD_F1 + 256.

7. A liquid level detection circuit according to claim 6, characterized in that, After determining that the final AD value AD_Z is less than the preset AD value, the number of jumps in the final AD value AD_Z during the liquid level detection process is obtained. If the number of jumps in the final AD value reaches the preset number, it is determined that the probe and the liquid have separated.

8. A washing machine, comprising a dispensing box and a detection circuit board, characterized in that, The dispensing box is equipped with a liquid level probe, and the detection circuit board is equipped with a liquid level detection circuit as described in any one of claims 1-7 above, and the liquid level probe is connected to the detection circuit board.

9. A washing machine according to claim 8, characterized in that, Multiple sets of liquid level probes are installed inside the dispensing box. The multiple sets of liquid level probes are arranged in order of height in the dispensing box, and all of the multiple sets of liquid level probes are connected to the detection circuit board.

10. A washing machine according to claim 8, characterized in that, When there is a large amount of liquid stored in the dispensing box, the liquid level probe extends into the liquid. After multiple washes in the washing machine, the liquid level in the dispenser drops. When the liquid level in the dispenser is lower than the liquid level probe, the liquid level probe detaches from the liquid in the dispenser, and the resistance value between the liquid level probes changes.

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