Water level switch inspection device and water level switch inspection method

Abstract

The application discloses a water level switch checking method, belongs to the field of pressure testing, and solves the problem of misjudgment in the prior art. The technical scheme comprises the following steps: water level is controlled by detecting the air pressure change caused by water level change; the water level switch checking method comprises the following steps: in the first water pressure verification, the verification water pressure is set to 0, the actual water pressure in the target container is set to 0, the actual water pressure in the target container is obtained, if the difference between the actual water pressure and the target value does not exceed the first threshold value, it is judged that the water level switch meets the requirements, otherwise, it is judged that the water level switch is abnormal; in the second water pressure verification, the verification water pressure is set to the target value, the target value is greater than 0, the actual water pressure in the target container is set by the water level switch, the actual water pressure in the target container is obtained, if the difference between the actual water pressure and the target value does not exceed the second threshold value, it is judged that the water level switch meets the requirements, otherwise, it is judged that the water level switch is abnormal. The application effectively reduces misjudgment. The application further discloses a water level switch checking device.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of testing pressure, in particular to a water level switch checking device and a water level switch checking method. BACKGROUND

[0002] The water level switch is mainly used for water level control in devices such as washing machines, dishwashers and toilets. In order to ensure that the washing machine, dishwasher and toilet operate normally within the required water level range, there are also methods and devices for checking the water level switch in the prior art. Among them, the prior art water level switch checking method disclosed in the invention patent CN118010136A obtains a calibration signal by triggering a calibration process through a start signal, and then obtains a first validity parameter. At the same time, the flow parameter and the water level change parameter are obtained within the target period after starting, and the flow parameter and the water level change parameter are compared and calculated to obtain a second validity parameter. It is judged whether the water level difference exceeds the first threshold value. If it is judged that the water level difference exceeds the first threshold value, it is determined that the water level sensor has a fault. On the one hand, there is a lack of checking in the no water pressure state, which is one of the basic working states of the equipment. If there is no checking in this state, it may not be able to ensure the normal operation of the water level switch under the basic condition, and it may lead to more false positive or false negative results in the checking under the pressure condition. This means that it is possible to judge the actual problem equipment as normal, or conversely, to incorrectly mark the normal equipment as abnormal. On the other hand, when the air pressure type water level switch is used to monitor the equipment, as the water level of the equipment rises, the air space becomes smaller and smaller, and the reduction of the air volume also becomes smaller, resulting in a decrease in the air pressure change rate, and the error of the water level switch checking is larger. The prior art always uses the same threshold value at different water levels, which is easy to misjudge the normal water level switch as defective.

[0003] Secondly, the prior art water level switch checking device such as the invention patent CN101290257A discloses a water level pressure switch production detection device and detection method. An air inlet solenoid valve is arranged on the pipeline between the buffer air bag and the compressed air pump, and an air outlet solenoid valve for emptying the buffer air bag is connected to the buffer air bag. One end of the hose is fixedly connected to the buffer air bag, and the other end of the hose is connected to the water level switch. A pressure sensor is led out from the buffer air bag, and the pressure sensor is connected to the analog input port of the input / output circuit board. The high and low water level switch contacts of the pressure sensor are connected to the digital input port of the input / output circuit board. The digital output port of the input / output circuit board is connected to the compressed air pump, the air inlet solenoid valve and the air outlet solenoid valve. The input / output circuit board is installed in the computer. However, the analog air pressure of the buffer air bag may have errors and instability, thereby affecting the checking accuracy of the water level switch. SUMMARY

[0004] The water level switch inspection method solves the problem of easy misjudgment in the prior art and reduces the misjudgment.

[0005] In order to achieve the above object, the present application adopts the following technical scheme: a water level switch inspection method, the water level switch controls the water level by detecting the air pressure change caused by the water level change, the water level switch inspection method comprises a first water pressure verification: setting the verification water pressure as 0, setting the actual water pressure in the target container as 0, then verifying, obtaining the actual water pressure of the target container, if the difference between the actual water pressure and the target value does not exceed the first threshold value, it is judged that the water level switch meets the requirements, otherwise it is judged that the water level switch is abnormal.

[0006] The second water pressure verification: setting the verification water pressure as the target value, the target value is greater than zero, setting the actual water pressure in the target container through the water level switch, verifying, obtaining the actual water pressure in the target container, if the difference between the actual water pressure and the target value does not exceed the second threshold value, it is judged that the water level switch meets the requirements, otherwise it is judged that the water level switch is abnormal.

[0007] The first threshold value is less than the second threshold value.

[0008] The application has the following advantages: in actual operation, the water pressure faced by the water level switch is not an absolutely accurate fixed value, but fluctuates within a certain reasonable range, the first threshold value and the second threshold value are set to define clear boundaries for performance evaluation of the water level switch, effectively reducing misjudgment caused by ambiguous pressure boundaries, and making the inspection result more consistent with the actual use scenario. If the first threshold value is not less than the second threshold value, the characteristic differences of the water level switch under different water pressure conditions are not considered, so that the inspection result cannot accurately reflect the real performance of the water level switch under different working conditions, which means that a large error is allowed between the actual water pressure and the target value in the initial state, which reduces the inspection requirement for the accuracy of the water level switch in the initial state, and may cause some water level switches with large errors in the initial state to be misjudged as meeting the requirements, while these errors may be further amplified under subsequent normal working water pressure, affecting the overall performance and accuracy of the water level switch, increasing the misjudgment rate of the entire inspection process, and affecting the accurate evaluation of the quality of the water level switch. By setting the first water pressure verification as a no-water pressure state (0 water pressure), the inspection of whether the water level switch normally operates under basic working conditions is realized, the zero error is eliminated, a reference state is provided for subsequent verification and inspection work, false positive or false negative results caused by the lack of state inspection under pressure conditions are avoided as much as possible, the accuracy and reliability of the inspection result are improved, and under zero pressure (first verification), the system is usually in a relatively ideal and controlled state, so a smaller first threshold value can be set to ensure high accuracy, and under non-zero pressure (second verification), due to various factors in the actual operating environment, more fluctuations may occur, a larger second threshold value allows a certain degree of normal fluctuation, and misjudgment caused by minor errors is avoided. The second water pressure verification sets the verification water pressure as the target value to simulate the water pressure in actual work. This verification process gradually increases the complexity from no pressure to pressure, more comprehensively covers the water pressure range that the water level switch may face, and more scientifically tests the performance of the water level switch under different water pressure conditions, avoiding inspection loopholes caused by single test conditions.

[0009] Further, in the second water pressure verification, the inspection is performed from the high water level to the low water level in sequence, and the second threshold value decreases as the water level decreases.

[0010] By using the foregoing technical solution, as the water level decreases, the air pressure change rate also changes. Generally, when the water level is high, the air pressure change is relatively large, so a larger threshold value is allowed to determine whether the water level switch normally works, and when the water level is low, a smaller air pressure change requires higher inspection accuracy. By adjusting the threshold value to decrease as the water level decreases, the actual working state under different water levels can be more accurately reflected, and the possibility of misjudgment can be reduced. A more stringent error range is used under low water level conditions, effectively avoiding error accumulation.

[0011] Further, the setting program is configured to output multiple groups of frequencies corresponding to different target values, the different target values of the frequencies representing different target values of water levels, and the frequencies corresponding to the different target values of the water levels being arranged in different rows of the program in sequence, and the water level switch checking method further comprises a single-step operation mode:

[0012] S1: selecting the single-step operation mode and starting a drainage state;

[0013] S2: setting a target frequency according to a current row number;

[0014] S3: checking whether a current frequency is greater than the target frequency, and if yes, executing S4, otherwise, continuing to maintain the drainage state;

[0015] S4: decreasing the current row number by 1.

[0016] By adopting the foregoing technical solution, multiple groups of frequencies corresponding to different target values are outputted and arranged in different rows of the program in sequence, thereby providing a more comprehensive and accurate reference system for water level switch checking. Different target values simulate actual frequency environments that the water level switch may face under various water levels, so as to avoid as much as possible problems caused by limited checking range, and greatly improve the accuracy and reliability of the checking result. The design of the single-step operation mode greatly improves the checking efficiency and operability, and the whole process is simple and intuitive without complex manual operation. During the checking process, the system automatically judges the size relationship between the current frequency and the target frequency according to the set program logic, and performs corresponding operations. This automatic checking process reduces human intervention, not only reduces the working strength of the operator, but also avoids human operation errors, so that the checking process is more efficient and smooth, and the performance of the water level switch under different frequency targets can be quickly checked.

[0017] Further, the setting program is configured to output multiple groups of frequencies corresponding to different target values of water levels arranged in descending order, and the water level switch checking method further comprises an automatic operation mode:

[0018] S1: selecting the automatic operation mode and starting a drainage state;

[0019] S2: reading a program and executing the program according to a set program number;

[0020] S3: stopping the drainage state when the frequency of the smallest water level is executed;

[0021] S4: popping up a result display interface.

[0022] The water level switch is checked in an environment close to actual use, and the performance of the water level switch in the entire working range is comprehensively evaluated as much as possible.

[0023] Further, a program is set to output a plurality of frequency values corresponding to different target water levels, and the water level switch checking method further comprises water inlet verification.

[0024] S1: Select the water inlet verification mode and delay for 1 second;

[0025] S2: Start the water inlet state;

[0026] S3: Detect the frequency, if the current frequency is less than the smallest frequency in the current program number, execute S4, otherwise continue to maintain the water inlet state in S2;

[0027] S4: Stop the water inlet state.

[0028] In normal use, the water inlet process is a dynamic process, the water level gradually rises, and the frequency also changes accordingly. The water inlet verification process simulates this real water inlet process, and the water level switch is checked in an environment close to actual use by starting and stopping the water inlet state. By setting different target values and corresponding frequencies through the programming mode, the water level change under various actual working conditions can be simulated more accurately. This ensures more detailed evaluation of the response of the water level switch under different conditions, and determines whether the response of the water level switch to the change of the frequency when water is filled is normal, thereby improving the accuracy of the test.

[0029] Further, a program is set to output a plurality of frequency values corresponding to different target water levels, and the water level switch checking method further comprises water inlet verification.

[0030] S1: Select the water inlet verification mode and delay for 1 second;

[0031] S2: Detect the current frequency, if the current frequency is greater than the initial frequency in the current program number, execute S3, otherwise continue to maintain the water inlet state in S1;

[0032] S3: Stop the water inlet state.

[0033] The water level switch checking device is used for checking the water level switch in the actual use environment, and the response of the water level switch to the frequency change during the drainage is judged.

[0034] Another object of the present application is to provide a water level switch checking device to improve the checking accuracy. To achieve the above object, the present application adopts the following technical scheme: a water level switch checking device, the target container comprises a U-shaped tube for simulating the water level, the water level switch checking device further comprises a water tank, a pressure sensor and an interactive and control module with a display interface, the U-shaped tube is connected with the water tank, the interactive and control module is electrically connected with the water level switch, the pressure sensing end of the pressure sensor is connected to the U-shaped tube, the signal output end of the pressure sensor is electrically connected with the interactive and control module, the target water level value is set through the interactive and control module and the actual water level of the U-shaped tube is adjusted through the water level switch, the water level difference on both sides of the U-shaped tube forms an air pressure difference, the pressure sensor outputs an inductive signal by sensing the air pressure change in the U-shaped tube, the interactive and control module identifies the inductive signal to display the water level pressure of the actual water level, and checks the water level pressure of the actual water level with the water level pressure of the target water level value, the interactive and control module has a programming mode and a water pressure checking mode, the programming mode can set the program of the target water level value and the target frequency value, and the water pressure checking mode is used to realize the steps in any one of the water level switch checking methods.

[0035] According to Pascal's law, when there is a water level difference between the two U-shaped tubes, an air pressure corresponding to the water level height can be stably generated. Compared with the air pressure generated by relying on the elastic deformation of the buffer air bag, the air pressure generated based on the basic physical law has higher stability and accuracy, so that the water level switch can be more accurately tested. The pressure sensor is directly connected to the U-shaped tube, so that the air pressure change in the U-shaped tube caused by the water level difference can be captured in the first time. There is no intermediate conversion link, which reduces the possibility of signal attenuation, distortion and external interference. The inductance signal output by the pressure sensor can also quickly and more accurately reflect the air pressure in the U-shaped tube, so that the water level pressure check is more timely and accurate. The check delay and error caused by the intermediate link are effectively avoided, the check efficiency and stability of the water level switch are greatly improved, and the design of the entire check device is simplified without complex auxiliary equipment (such as a compressed air pump). Finally, the display interface of the interaction and control module brings great convenience to the operator. The operator can easily set the target water level value on the interface. The interaction and control module will automatically verify the water level pressure of the target water level value corresponding to the actual air pressure generated by the U-shaped tube, and display the result in real time. This process does not require the operator to manually calculate the complex air pressure and water level relationship. Through the intuitive display, the operator can clearly understand the working state of the water level switch and whether the check is up to standard. The operation process is greatly simplified, the accuracy and efficiency of the check are improved, and the probability of human operation errors is reduced. The interaction and control module has a programming mode and a water pressure verification mode, which greatly enriches the functions of the device. In the programming mode, the target water level value and the target cycle value can be freely set, allowing the operator to configure them individually according to the specific test requirements. After setting the required parameters in advance, the system can automatically execute the test process according to these settings, reducing the time and complexity of manual adjustment, thereby improving the overall work efficiency.

[0036] Further, the water level switch check device further comprises a cycle detection module connected in communication with the U-shaped tube, the cycle detection module detects the cycle generated by the water level change and outputs an inductance signal, and the interaction and control module identifies the inductance signal to display the cycle of the actual water level.

[0037] According to the foregoing technical scheme, the addition of the cycle detection module enriches the check dimension. In the past, the water level pressure was simply detected by the pressure sensor, which had certain limitations. The cycle, as another key parameter closely related to the water level, can provide more information for the performance evaluation of the water level switch. The check result can verify the performance of the water level switch from multiple angles, enhance the comprehensiveness of the check, and further improve the accuracy of the check result, avoiding missing hidden faults due to single parameter check.

[0038] Further, the water level switch and the U-shaped tube are further provided with a pneumatic electromagnetic valve, when the water level switch is not working, the pneumatic electromagnetic valve is closed to keep the water level switch and the U-shaped tube closed, when the water level switch is working, the pneumatic electromagnetic valve is opened to make the U-shaped tube and the water level switch communicate.

[0039] By using the foregoing technical scheme, since the water level switch has certain limitations in the sealing performance, it is difficult to maintain stable air pressure, and the closing of the pneumatic electromagnetic valve effectively makes up for the deficiency, maintains the stability of the system air pressure, guarantees the accuracy of the high water level, and reduces the misjudgment as much as possible.

[0040] Further, the water tank and the U-shaped tube are provided with a water pump, a water inlet electromagnetic valve and a drainage electromagnetic valve, the water pump is communicated with the U-shaped tube through two branches, the water inlet electromagnetic valve and the drainage electromagnetic valve are arranged on the two branches respectively, and the water pump, the water inlet electromagnetic valve and the drainage electromagnetic valve are electrically connected with the interaction and control module, the interaction and control module controls the operation of the water pump, the water inlet electromagnetic valve and the drainage electromagnetic valve through the signal of the water level switch.

[0041] By using the foregoing technical scheme, the water pump, the water inlet electromagnetic valve and the drainage electromagnetic valve can more truly simulate the working state of the device with the water level switch, and provide a more actual test environment for the water level switch, thereby improving the accuracy of the inspection result. BRIEF DESCRIPTION OF DRAWINGS

[0042] The application will be further described below with reference to the drawings:

[0043] Figure 1 The flow chart of the single-step operation mode of the application;

[0044] Figure 2 The flow chart of the automatic operation mode of the application;

[0045] Figure 3 The flow chart of the water inlet verification of the application;

[0046] Figure 4 The flow chart of the water drainage verification of the application. DETAILED DESCRIPTION

[0047] To make the purpose, technical scheme and advantages of the embodiments of the application more clear, the technical scheme in the embodiments of the application will be described clearly and completely below with reference to the drawings of the embodiments of the application. Obviously, the described embodiments are only part of the embodiments of the application, but not all the embodiments of the application.

[0048] The terms "first", "second", "third", "fourth" and the like in the description and in the claims of the present application, and above-mentioned drawings, if any, are used to distinguish between similar objects and not necessarily for describing a specific sequential or chronological order. It is to be understood that the use of the terms so construed herein is merely for convenience and only to aid in understanding of the application and is in no way intended to limit the application to a specific order or sequence.

[0049] It should be understood that, in various embodiments of the present application, the magnitude of the serial numbers as related to the processes does not mean the order of execution, the execution order of the processes should be determined according to their functions and inherent logic, and should not constitute any limitation on the implementation process of the embodiments of the present application.

[0050] It should be understood that in the present application, "include" and "have" and any variations thereof are intended to cover non-exclusive inclusion, for example, a process, method, system, product or device that includes a series of steps or units does not have to be limited to only those steps or units clearly listed, but can include other steps or units not clearly listed or inherent to these processes, methods, products or devices.

[0051] It should be understood that in the present application, "a plurality of" means two or more. "And / or" is only a description of the association relationship between the associated objects, which means that there can be three relationships, for example, X and / or Y can represent three cases: X alone, X and Y exist at the same time, and Y alone. The character " / " generally represents that the associated objects before and after are in an "or" relationship. "Including X, Y and Z", "including X, Y, Z" means that X, Y and Z are all included, "including X, Y or Z" means that one of X, Y and Z is included, and "including X, Y and / or Z" means that any one or any two or all of X, Y and Z is included.

[0052] The technical solutions of the present application will be described in detail below with specific examples. The following specific examples can be combined or replaced according to actual conditions, and the same or similar concepts or processes may not be described in some embodiments.

[0053] Embodiment one: the present application provides a water level switch checking method, the water level switch controls the water level by detecting the air pressure change caused by the water level change, the water level switch checking method includes first water pressure verification: setting the verification water pressure to 0, setting the actual water pressure in the target container to 0, then verifying, obtaining the actual water pressure of the target container, if the difference between the actual water pressure and the target value does not exceed the first threshold value, it is judged that the water level switch meets the requirements, otherwise it is judged that the water level switch is abnormal;

[0054] The second water pressure verification: set the verification water pressure as a target value, the target value is greater than zero, set the actual water pressure in the target container through the water level switch, perform verification, obtain the actual water pressure in the target container, if the difference between the actual water pressure and the target value does not exceed the second threshold value, it is judged that the water level switch meets the requirements, otherwise it is judged that the water level switch is abnormal;

[0055] The first threshold value is less than the second threshold value.

[0056] In actual operation, the water pressure faced by the water level switch is not an absolutely precise fixed value, but fluctuates within a certain reasonable range. Setting the first threshold value and the second threshold value clearly defines the boundary for water level switch performance evaluation, effectively reduces false positives caused by ambiguous pressure boundaries, and makes the inspection results more consistent with actual use scenarios. If the first threshold value is not less than the second threshold value, the characteristic differences of the water level switch under different water pressure conditions are not considered, which means that a large error between the actual water pressure and the target value is allowed in the initial state, which reduces the inspection requirements for the accuracy of the water level switch in the initial state, and may cause some water level switches with large errors in the initial state to be falsely judged as meeting the requirements. These errors may be further amplified under subsequent normal working water pressure, affecting the overall performance and accuracy of the water level switch, increasing the false positive rate of the entire inspection process, and affecting the accurate evaluation of the quality of the water level switch. By setting the first water pressure verification as a no water pressure state (0 water pressure), it is realized to check whether the water level switch is working normally under the basic working condition, eliminate the zero error, provide a reference state for subsequent verification and inspection work, and as far as possible avoid false positive or false negative results when checking under pressure conditions, improve the accuracy and reliability of the inspection results. Under zero pressure (first verification), the system is usually in a relatively ideal and controlled state, so a smaller first threshold value can be set to ensure high accuracy. Under non-zero pressure (second verification), due to various factors in the actual operating environment, more fluctuations may occur. A larger second threshold value allows for some normal fluctuations, avoiding false positives due to minor errors. The second water pressure verification sets the verification water pressure as the target value, simulating the water pressure in actual work. This verification process gradually increases the complexity from no pressure to pressure, more comprehensively covers the water pressure range that the water level switch may face, and more scientifically tests the performance of the water level switch under different water pressure conditions, avoiding inspection loopholes caused by single test conditions. Thus, the water level switch meets the requirements of QB / T1292.

[0057] It should be noted that if the water level switch is abnormal in the first water pressure calibration, it may be caused by poor pipeline sealing or other potential air source interference. At this time, the air pressure abnormality problem needs to be immediately investigated and solved, and then the first water pressure calibration is performed again to ensure that the check is completed in a stable zero air pressure environment to ensure the accuracy of the reference value and avoid subsequent measurement errors caused by checking instruments from the root cause.

[0058] It should be noted that the target container can also be provided with a scale, and the actual water level can also be directly read through the scale. The target water pressure can also be converted into the target water level, and the first threshold and the second threshold can also be converted into the threshold of the water level. The actual water level and the target water level are compared to determine whether the water level switch is abnormal.

[0059] The water level switch controls the water level by detecting the air pressure change caused by the change of the water level. Since the existing technology usually checks from low water level to high water level, the water flow falling from high place will cause unstable water pressure, resulting in large error of the checking result. Therefore, in the present application, in the second water pressure calibration, the checking is performed from high water level to low water level in turn. In the whole calibration process, there is no need to go through the water inflow stage which increases the instability of water pressure caused by water falling from high place. When the calibration starts at high water level, the water is in a relatively static state and will not cause water pressure fluctuation due to the impact of water drop when water inflows. This provides a more stable initial condition for the calibration, thereby effectively reducing the checking error caused by unstable water pressure. In addition, when the water level is low, as the water volume increases, the air volume in the closed system rapidly decreases, which will cause the pressure to relatively quickly rise, and the water level switch is easy to check. When the water level is high, the air space becomes smaller and smaller, and the reduction amount of air volume will also become smaller, so the checking of the water level switch is more difficult. In other words, as the water level rises, the pressure change of the internal air relatively slows down, and the checking of the water level switch becomes more difficult. Therefore, in the present application, the second threshold decreases as the water level decreases, which can more accurately reflect the actual working state at different water levels and reduce the possibility of misjudgment. The use of a more stringent error range under low water level conditions effectively avoids error accumulation.

[0060] In order to increase the convenience of checking, as shown in Figure 1 The program is set to output multiple sets of frequencies corresponding to different target values. Different target values of the frequency represent different water levels of the target value, and the frequencies corresponding to different water levels of the target value are arranged in different rows of the program in turn. The water level switch checking method further includes a single-step running mode.

[0061] S1: Select the single-step running mode and open the drainage state;

[0062] S2: Set the target frequency according to the current row number;

[0063] S3: Check if the current frequency is greater than the target frequency, if greater, execute S4, otherwise continue to keep the drainage state;

[0064] S4: Current row number minus 1.

[0065] Output multiple sets of frequencies corresponding to different target values, and arrange them in order according to different program rows, to provide a more comprehensive and accurate reference system for water level switch inspection. Different target values simulate the actual frequency environment that the water level switch may face under various water levels, avoiding as much as possible the problems caused by limited inspection range, greatly improving the accuracy and reliability of the inspection results. The design of single-step operation mode greatly improves the inspection efficiency and operability, and the whole process is simple and intuitive without complex manual operation. During the inspection process, the system automatically determines the size relationship between the current frequency and the target frequency according to the set program logic, and performs the operation accordingly. This automated inspection process reduces human intervention, not only reducing the work intensity of the operator, but also avoiding human operation errors, making the inspection process more efficient and smooth, and quickly completing the performance inspection of the water level switch under different frequency targets.

[0066] It should be noted that in the present embodiment, there are 8 water levels, and the current row number minus 1 in S4 means that if it is the first time to run, the current program number is downloaded, the program content is read, the program content includes rows controlling various devices and rows containing frequencies, etc. All rows containing frequencies are arranged in order, and according to the program content, the last row with frequency is selected as the starting row. Each time the single-step operation is pressed, the operation is completed, and the current row number is automatically reduced by 1. In the present embodiment, there are eight water levels, specifically water level 1, water level 2, water level 3, water level 4, water level 5, water level 6, water level 7 and water level 8. The water level is changed by controlling the drainage state. When the frequency row corresponding to water level 8 is run to the end, the interface is switched to the result display, indicating that a program has been run, and the next time it will start again.

[0067] It should be noted that in the single-step operation, if it is run to the end, the result will be automatically jumped out.

[0068] As shown in Figure 2 , the setting program is used to output multiple sets of frequencies corresponding to different target value water levels arranged in descending order, and the water level switch inspection method also has an automatic operation mode:

[0069] S1: Select the automatic operation mode and start the drainage state;

[0070] S2: Read the program according to the set program number and execute the program;

[0071] S3: When the frequency of the minimum water level is run to the end, stop the drainage state;

[0072] S4: pop up the result display interface.

[0073] By pre-setting the frequency values corresponding to multiple different water levels and executing them in descending order, the water level switch can be checked in an environment close to actual use, which can ensure comprehensive evaluation of the performance of the water level switch in the entire working range. Users only need to select the automatic operation mode, and the system can automatically complete all preset steps. After the check is completed, the result display interface is automatically popped up, and the operator can intuitively view the check results.

[0074] It should be noted that the frequency is proportional to the water level, and when the water level is sorted from high to low in eight groups in turn:

[0075] Water level 1: frequency is 36.58 HZ, target water level is 460±26mm, actual water level is 457mm, which meets the requirements;

[0076] Water level 2: frequency is 37.10 HZ, target water level is 410±23mm, actual water level is 409mm, which meets the requirements;

[0077] Water level 3: frequency is 37.66 HZ, target water level is 360±20mm, actual water level is 359mm, which meets the requirements;

[0078] Water level 4: frequency is 38.38 HZ, target water level is 300±17mm, actual water level is 299mm, which meets the requirements;

[0079] Water level 5: frequency is 39.01 HZ, target water level is 250±15mm, actual water level is 250mm, which meets the requirements;

[0080] Water level 6: frequency is 39.46 HZ, target water level is 215±12mm, actual water level is 214mm, which meets the requirements;

[0081] Water level 7: frequency is 40.54 HZ, target water level is 130±8mm, actual water level is 127mm, which meets the requirements;

[0082] Water level 8: frequency is 41.15 HZ, target water level is 80±5mm, actual water level is 76mm, which meets the requirements;

[0083] It should be noted that the second threshold is the ± value of the above content, and the second threshold decreases proportionally as the water level decreases.

[0084] In normal use, the water inlet process is a dynamic process, and the water level gradually rises, so the frequency will also change accordingly. Therefore, as shown in Figure 3 , a program is set for outputting multiple groups of frequencies corresponding to different target water levels, and the water level switch checking method further includes water inlet verification:

[0085] S1: Select the water inlet verification mode and delay for 1 second;

[0086] S2: Start the water inlet state;

[0087] S3: Detect the frequency. If the current frequency is less than the smallest frequency in the current program number, execute S4, otherwise continue to maintain the water inlet state in S2;

[0088] S4: Stop the water inlet state.

[0089] The flow of water inlet verification simulates the actual water inlet process by starting and stopping the water inlet state, allowing the water level switch to be tested in an environment close to actual use. By setting different target values and corresponding frequencies through the programming mode, the water level changes under various actual working conditions can be simulated more accurately. This ensures a detailed evaluation of the response of the water level switch under different conditions and determines whether the response of the water level switch to the frequency change during water inlet is normal, improving the accuracy of the test.

[0090] In actual operation, the water level will drop during the drainage process, and the frequency will change accordingly. Therefore, as shown in Figure 4 , a program is set to output multiple sets of frequencies corresponding to different target water levels. The water level switch checking method also includes drainage verification:

[0091] S1: Select the drainage verification mode and start the drainage state;

[0092] S2: Detect whether the current frequency is greater than the initial frequency in the current program number. If the detected current frequency is greater than the initial frequency in the current program number, execute S3, otherwise continue to maintain the drainage state in S1;

[0093] S3: Stop the water inlet state.

[0094] In actual operation, the water level will drop during the drainage process, and the frequency will change accordingly. This highly simulates the actual drainage process, which allows the water level switch to be tested in an environment close to actual use and determines whether the response of the water level switch to the frequency change during drainage is normal.

[0095] It should be noted that the water level switch checking method is not only applicable to the water level switch checking of washing machines, but also can be extended to other types of equipment and systems that need to accurately check the water level switch, such as industrial water tank level control, intelligent irrigation systems, ship ballast water monitoring, etc., and has wide application prospects and universality.

[0096] In the embodiment, a water level switch checking device is provided, the target container comprises a U-shaped tube for simulating the water level, the water level switch checking device further comprises a water tank, a pressure sensor and an interaction and control module with a display interface, the U-shaped tube is connected with the water tank, the interaction and control module is electrically connected with the water level switch, the pressure sensing end of the pressure sensor is connected to the U-shaped tube, the signal output end of the pressure sensor is electrically connected with the interaction and control module, the target water level value is set through the interaction and control module, and the actual water level of the U-shaped tube is adjusted through the water level switch, the water level difference on both sides of the U-shaped tube forms an air pressure difference, the pressure sensor outputs an inductive signal by sensing the air pressure change in the U-shaped tube, the interaction and control module identifies the inductive signal to display the water level pressure of the actual water level, and verifies the water level pressure of the actual water level with the water level pressure of the target water level value, the interaction and control module has a programming mode and a water pressure verification mode, the programming mode can set the programs of the target water level value and the target cycle value, and the water pressure verification mode is used to realize the steps in any one of the water level switch checking methods.

[0097] When there is a water level difference between the two U-shaped tubes, according to Pascal's law, an air pressure corresponding to the water level height can be stably generated. This air pressure generation method based on the basic physical law has higher stability and accuracy compared with the buffer air bag relying on its own elastic deformation to simulate the air pressure, thereby realizing more accurate testing of the water level switch. The pressure sensor is directly connected to the U-shaped tube, can capture the air pressure change in the U-shaped tube in the first time, has no intermediate conversion link, reduces the possibility of signal attenuation, distortion and external interference, and the inductive signal output by the pressure sensor can also quickly and more accurately reflect the air pressure in the U-shaped tube, so that the checking of the water level pressure is more timely and accurate, effectively avoids the checking delay and error caused by the intermediate link, greatly improves the checking efficiency and stability of the water level switch, and simplifies the design of the whole checking device without the need of complex auxiliary equipment (such as a compressed air pump). Finally, the display interface of the interaction and control module brings great convenience to the operator, the operator can easily set the target water level value on the interface, the interaction and control module will automatically verify the water level pressure corresponding to the actual air pressure generated by the U-shaped tube with the water level pressure of the target water level value, and display the result in real time. This process does not require the operator to manually calculate the complex air pressure and water level relationship, and the working state of the water level switch and whether the checking is up to standard can be clearly mastered through the intuitive display, greatly simplifying the operation process, improving the accuracy and efficiency of the checking, and reducing the probability of human operation errors. The interaction and control module has a programming mode and a water pressure verification mode, which greatly enriches the functions of the device. In the programming mode, the target water level value and the target cycle value can be freely set, allowing the operator to configure individually according to the specific testing requirements, and after setting the required parameters in advance, the system can automatically execute the testing process according to these settings, reducing the time and complexity of manual adjustment, thereby improving the overall work efficiency.

[0098] It should be noted that the prior art usually adopts a straight pipe, and the liquid in the straight pipe is easily affected by external interference, such as washing machine vibration, water flow impact, etc., resulting in inaccurate measurement, while the U-shaped pipe can utilize the gravity of the liquid (usually water) to form a more stable liquid level difference on both sides, thereby more accurately reflecting the pressure change in the washing machine.

[0099] It should be noted that since the place to be checked may be at high altitude or in a basin, the environmental pressure is different, and therefore, in the present application, the interaction and control module is built-in with an adaptive algorithm. When first used or specific settings are made, the current environmental pressure and other parameters will be checked to automatically adjust the related parameters of the water level control, so that the checking device adapts to the pressure conditions of the region where it is located, to ensure the accuracy of the water level control and to minimize false positives.

[0100] It should be noted that the U-shaped pipe is provided with a scale, and the actual water level can also be directly read through the scale, the target water pressure can also be converted into the target water level, and the first threshold and the second threshold can also be converted into the threshold of the water level. The actual water level and the target water level are compared to determine whether the water level switch is abnormal.

[0101] Further, a water pump, a water inlet electromagnetic valve and a drainage electromagnetic valve are arranged between the water tank and the U-shaped pipe. The water pump is connected to the U-shaped pipe through two branches, and the water inlet electromagnetic valve and the drainage electromagnetic valve are arranged on the two branches respectively. The water pump, the water inlet electromagnetic valve and the drainage electromagnetic valve are electrically connected to the interaction and control module, and the interaction and control module controls the operation of the water pump, the water inlet electromagnetic valve and the drainage electromagnetic valve through the signal of the water level switch. The working state of the device with the water level switch can be simulated more realistically, and a test environment closer to the actual situation is provided for the water level switch, thereby improving the accuracy of the checking result.

[0102] In the past, the water level pressure was simply checked by relying on the pressure sensor, and the single parameter checking had certain limitations and was prone to missing hidden faults. Therefore, in the present application, the water level switch checking device further comprises a frequency detection module connected to the U-shaped pipe. The frequency detection module detects the frequency generated by the change of the water level and outputs an inductance signal, and the interaction and control module identifies the inductance signal to display the frequency of the actual water level. The addition of the frequency detection module enriches the detection dimension. In the past, the water level pressure was simply detected by relying on the pressure sensor, which had certain limitations. The frequency, as another key parameter closely related to the water level, can provide more information for the performance evaluation of the water level switch, verify the performance of the water level switch from multiple angles, enhance the comprehensiveness of the detection, and further improve the accuracy of the detection result, thereby avoiding missing hidden faults due to single parameter detection.

[0103] It should be noted that the frequency is directly proportional to the water level, and when the water level is sequentially sorted from high to low:

[0104] When the water level is 460±26mm, the frequency is 36.58HZ;

[0105] When the water level is 410±23mm, the frequency is 37.10HZ;

[0106] When the water level is 360±20mm, the frequency is 37.66HZ;

[0107] When the water level is 300±17m, the frequency is 38.38HZ;

[0108] When the water level is 250±15mm, the frequency is 39.01HZ;

[0109] When the water level is 215±12mm, the frequency is 39.46HZ;

[0110] When the water level is 130±8mm, the frequency is 40.54HZ;

[0111] When the water level is 80±5mm, the frequency is 41.15HZ.

[0112] Because the water level switch itself has certain limitations in sealing performance, it is difficult to maintain a stable air pressure. Therefore, in this application, a pneumatic solenoid valve is also provided between the water level switch and the U-tube. When the water level switch is not working, the pneumatic solenoid valve is closed to keep the water level switch and the U-tube sealed. When the water level switch is working, the pneumatic solenoid valve is opened to connect the U-tube and the water level switch. The closure of the pneumatic solenoid valve effectively compensates for this deficiency, maintains stable system air pressure, ensures high water level accuracy, and minimizes misjudgments.

[0113] It should be noted that if the liquid level in the U-tube fluctuates during the inspection, the air pressure solenoid valve's sealing performance and other components of the system should be checked for leaks or other problems.

[0114] It should be noted that in this application, the interaction and control module includes a touch screen, a PLC (Programmable Logic Controller), and a base plate. The base plate is connected to both the pressure sensor and the PLC, and the PLC is connected to the touch screen. The pressure sensor senses changes in the water level in the U-tube and transmits the signal to the base plate. The base plate processes the acquired frequency signal by converting a sine wave to a square wave, and the processed signal is transmitted to the PLC, which controls the entire system according to a preset program. The touch screen has a visual display interface. The PLC, with its powerful data processing capabilities, quickly analyzes and processes signals to intelligently determine the working status of the water level switch. Furthermore, by writing specific programs, it can achieve real-time display, storage, abnormal alarm, and remote transmission of inspection data, improving inspection efficiency and intelligence.

[0115] The display interface includes a standby interface, a programming interface, a water pressure calibration interface and a result display interface, the standby interface displays a programming button for entering a programming mode, a pressure calibration button for entering a water pressure calibration mode, a result viewing button for entering a result interface, a drainage button for entering a drainage calibration, a water inlet button for entering a water inlet calibration, a single-step operation button for entering a single-step operation mode, an automatic operation button for entering an automatic operation mode, a target frequency, a current frequency, a target water pressure, a current water pressure and a current program serial number. The programming interface has an input area of water level frequency and water level pressure. The water pressure calibration interface displays a calibration water pressure and a calibration button. The result display interface displays a serial number, a target frequency, an actual frequency, a target minimum pressure, a target maximum pressure and an actual pressure, if the actual pressure is within the target minimum pressure and the target maximum pressure, the background color is green, if not, the background color will change to red, indicating that it does not meet the requirements.

[0116] It should be noted that the water level switch checking device is not only suitable for checking the water level switch of the washing machine, but also can be extended to other types of devices and systems that need to accurately check the water level switch, such as industrial water tank liquid level control, intelligent irrigation system, ship ballast water monitoring and other fields, and has wide application prospect and universality.

[0117] It should be noted that by optimizing the PLC program, it has a one-key report output function. After the instrument completes the water level switch check, it can automatically generate a report containing check data, result determination and other information. At the same time, the program internally integrates a comparison and analysis module, which can compare the real-time check data with the preset standard value, quickly determine whether the check result is qualified, that is, output OK or NG result, and accurately locate the check point that is consistent or inconsistent with the standard water level frequency, greatly improving the analysis efficiency and accuracy of the check result.

[0118] It should be noted that for batch checking scenarios, the instrument has a quality trend management function. When 20 workpieces are accumulated, the system automatically analyzes the check data of these workpieces, draws a data trend chart, and through the analysis of the data trend, potential quality problems in the production process of the water level sensor can be found in time, such as performance drift and consistency deviation, etc., which provides data support for manufacturers to optimize production process and improve product quality.

[0119] In addition to the above preferred embodiments, the present application has other embodiments, based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative labor belong to the scope of the present application.

Claims

1. A water level switch checking method characterized by, The water level switch controls the water level by detecting the air pressure change caused by the water level change, and the water level switch checking method comprises a first water pressure verification: setting the verification water pressure as a target value 0, setting the actual water pressure in the target container as 0, then verifying, obtaining the actual water pressure of the target container, if the difference between the actual water pressure and the target value does not exceed a first threshold value, it is judged that the water level switch meets the requirements, otherwise it is judged that the water level switch is abnormal; The second water pressure verification: set the verification water pressure as a target value, the target value is greater than zero, set the actual water pressure in the target container through the water level switch, verify, obtain the actual water pressure in the target container, if the difference between the actual water pressure and the target value does not exceed a second threshold value, it is judged that the water level switch meets the requirements, otherwise it is judged that the water level switch is abnormal; The first threshold value is less than the second threshold value; In the second water pressure verification, the verification is carried out from high water level to low water level in turn, and the second threshold value decreases with the decrease of the water level.

2. The water level switch checking method according to claim 1, characterized by, The program is set to output a plurality of groups of different target values of frequency, the different target values of frequency represent different target values of water level, and the frequencies corresponding to different target values of water level are arranged in different lines of the program in turn, and the water level switch checking method further comprises a single step running mode: S1: select the single step running mode, start the drainage state; S2: set the target frequency according to the current line number; S3: check whether the current frequency is greater than the target frequency, if yes, execute S4, otherwise continue to maintain the drainage state; S4: decrease the current line number by 1.

3. The water level switch checking method according to claim 1, characterized by, The program is set to output a plurality of groups of different target values of water level in descending order, and the water level switch checking method further comprises an automatic running mode: S1: select the automatic running mode, start the drainage state; S2: read the program according to the set program number, and execute the program; S3: stop the drainage state when the frequency of the minimum water level is executed; S4: pop up the result display interface.

4. The water level switch checking method according to claim 1, characterized by, The program is set to output a plurality of groups of different target values of water level, and the water level switch checking method further comprises a water inflow verification: S1: select the water inflow verification mode and delay for 1 second; S2: start the water inflow state; S3: detect the frequency, if the current frequency is less than the minimum frequency in the current program number, execute S4, otherwise continue to maintain the water inflow state in S2; S4: stop the water inflow state.

5. The water level switch checking method according to claim 1, characterized by, The program is set to output a plurality of groups of different target values of water level, and the water level switch checking method further comprises a water inflow verification: S1: select the water inflow verification mode and delay for 1 second; S2: start the water inflow state; S3: detect the frequency, if the current frequency is less than the minimum frequency in the current program number, execute S4, otherwise continue to maintain the water inflow state in S2; S4: stop the water inflow state. S1: select the water inflow verification mode and delay for 1 second; S2: start the water inflow state; S3: detect the frequency, if the current frequency is less than the minimum frequency in the current program number, execute S4, otherwise continue to maintain the water inflow state in S2; S4: stop the water inflow state.

6. A water level switch checking device characterized by comprising: The target container comprises a U-shaped tube for simulating water level, the water level switch checking device further comprises a water tank, a pressure sensor and an interaction and control module with a display interface, the U-shaped tube is connected with the water tank, the interaction and control module is electrically connected with the water level switch, the pressure sensing end of the pressure sensor is connected to the U-shaped tube, the signal output end of the pressure sensor is electrically connected with the interaction and control module, the target water level value is set through the interaction and control module and the actual water level of the U-shaped tube is adjusted through the water level switch, the water level difference on both sides of the U-shaped tube forms an air pressure difference, the pressure sensor senses the air pressure change in the U-shaped tube to output an inductive signal, the interaction and control module identifies the inductive signal to display the water level pressure of the actual water level, and the water level pressure of the actual water level and the water level pressure of the target water level value are checked, the interaction and control module has a programming mode and a water pressure checking mode, the programming mode can set the program of the target water level value and the target cycle value, and the water pressure checking mode is used to realize the steps in the water level switch checking method of any one of claims 1 to 5.

7. The water level switch checking device according to claim 6, characterized in that The water level switch checking device further comprises a cycle detection module in communication with the U-shaped tube, the cycle detection module detects the cycle generated by the water level change and outputs an inductive signal, and the interaction and control module identifies the inductive signal to display the cycle of the actual water level.

8. The water level switch checking device according to claim 6, characterized in that An air pressure electromagnetic valve is further arranged between the water level switch and the U-shaped tube, when the water level switch is not working, the air pressure electromagnetic valve is closed to keep the water level switch and the U-shaped tube closed, and when the water level switch is working, the air pressure electromagnetic valve is opened to make the U-shaped tube and the water level switch communicate.

9. The water level switch checking device according to claim 6, characterized in that A water pump, a water inlet electromagnetic valve and a drainage electromagnetic valve are arranged between the water tank and the U-shaped tube, the water pump is connected with the U-shaped tube through two branches, the water inlet electromagnetic valve and the drainage electromagnetic valve are arranged on the two branches respectively, the water pump, the water inlet electromagnetic valve and the drainage electromagnetic valve are electrically connected with the interaction and control module, and the interaction and control module controls the operation of the water pump, the water inlet electromagnetic valve and the drainage electromagnetic valve through the signal of the water level switch.

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