Water level detection circuit

Abstract

The utility model relates to a water level detection circuit, which belongs to the technical field of circuits and comprises a main control module, a conversion module, a measurement module and a comparison module. The problem that the detection module generates incrustation due to long-time use can be avoided, and the reliability and the service life of the product are effectively improved.

Description

Technical Field

[0001] The utility model belongs to the technical field of circuits, and in particular relates to a water level detection circuit. Background Art

[0002] In order to detect the water level in the water tank, a water level detection device is often installed on the water tank. However, general water level detection devices use direct current to detect the water level. During the operation of the water level detection device, the water level probe is always at a high potential and the water tank wall is at a low potential. Therefore, negative ions always flow to the probe, gradually covering the surface of the water level probe with scale, making the detection invalid. At the same time, when the conductivity of water is low, it is not conducive to detection and judgment, and the detection results are prone to errors. Utility Model Content

[0003] The utility model aims to solve at least one of the technical problems existing in the prior art. To this end, the utility model proposes a water level detection circuit.

[0004] The purpose of the utility model can be achieved through the following technical solutions:

[0005] A water level detection circuit comprises a main control module, a conversion module, a measurement module and a comparison module;

[0006] The input end of the conversion module is connected to the output end of the main control module, the output end of the conversion module is connected to the input end of the measurement module, and the conversion module is used to receive the control signal of the main control module and convert direct current into alternating current;

[0007] The output end of the measuring module is connected to the input end of the comparing module, and the measuring module is used to measure the water level and generate a measuring signal according to the water level condition;

[0008] The output end of the comparison module is connected to the input end of the main control module. The comparison module is used to compare the measurement signal generated by the measurement module with the standard signal and generate a comparison signal to the main control module.

[0009] A water level detection circuit according to an embodiment of the utility model has at least the following technical effects: direct current is converted into alternating current through a conversion module, and the use of alternating current detection can avoid the problem of scale generation on the detection module due to long-term use, thereby effectively improving the reliability and service life of the product.

[0010] According to some embodiments of the present invention, the main control module is used to transmit a control signal to the conversion module and determine the water level condition according to the comparison signal generated by the comparison module.

[0011] According to some embodiments of the utility model, the conversion module also includes a switching module and a first capacitor, the switching module includes a transistor, the base of the transistor is connected to the output end of the main control module through a second resistor, the collector of the transistor is connected to one end of the first capacitor, the collector of the transistor is also connected to a DC power supply through a first resistor, and the emitter of the transistor is grounded.

[0012] According to some embodiments of the utility model, the transistor is an NPN transistor, the transistor base is grounded through a third resistor, and the voltage of the DC power supply is 25V.

[0013] According to some embodiments of the utility model, the conversion module is connected to the detection module through a fourth resistor, and the detection module includes a fifth resistor, a sixth resistor, a seventh resistor, a first diode and a water level probe, the positive pole of the first diode is connected to one end of the fourth resistor, the negative pole of the first diode is connected to one end of the sixth resistor, and the detection module is connected to the input end of the comparison module through the end of the sixth resistor away from the first diode; one end of the fifth resistor is connected between the fourth resistor and the first diode, and the other end is connected to the water level probe; one end of the water level probe is connected to the fifth resistor, and the other end is arranged in a water container to be detected, and a grounding probe connected to a power ground is arranged in the water container, and the grounding probe is located below the water level probe; one end of the seventh resistor is connected to one end of the sixth resistor away from the first diode, and the other end is grounded.

[0014] According to some embodiments of the utility model, the comparison module includes a voltage comparator, a tenth resistor and an eleventh resistor, the non-inverting input terminal of the voltage comparator is connected to an end of the sixth resistor away from the first diode, the reverse input terminal of the voltage comparator is connected to an end of the eleventh resistor, an end of the eleventh resistor away from the voltage comparator is connected to a reference voltage source, one end of the tenth resistor is connected between the reverse input terminal of the voltage comparator and the eleventh resistor, and an end of the tenth resistor away from the voltage comparator is grounded.

[0015] According to some embodiments of the present invention, the non-inverting input terminal of the voltage comparator is connected to a 5V power supply via a second diode, and the anode of the second diode is located at one end close to the voltage comparator.

[0016] According to some embodiments of the utility model, the output end of the voltage comparator is connected to the positive power supply input end of the voltage comparator through an eighth resistor, the positive power supply input end of the voltage comparator is connected to a 5V power supply, the output end of the voltage comparator is connected to the negative power supply input end of the voltage comparator through a second capacitor, and the negative power supply input end of the voltage comparator is grounded.

[0017] According to some embodiments of the present invention, the output end of the voltage comparator is connected to the input end of the main control module through a ninth resistor.

[0018] According to some embodiments of the present utility model, the main control module includes at least one of an MCU, an ARM processor, a single-chip microcomputer, a DSP processor, a MIPS processor, an FPGA and a PC. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to facilitate understanding by those skilled in the art, the present invention is further described below in conjunction with the accompanying drawings.

[0020] Figure 1 A circuit provided in one embodiment of the utility model;

[0021] Figure 2 A circuit diagram of a conversion module provided in one embodiment of the utility model;

[0022] Figure 3 A circuit diagram of a measurement module provided in one embodiment of the utility model;

[0023] Figure 4 FIG. 4 is a circuit diagram of a comparison module provided in one embodiment of the utility model.

[0024] Figure symbols: T1, water level probe; C1, first capacitor; C2, second capacitor; D1, first diode; D2, second diode; Q1, transistor; U1, main control module; U2, voltage comparator; R1, first resistor; R2, second resistor; R3, third resistor; R4, fourth resistor; R5, fifth resistor; R6, sixth resistor; R7, seventh resistor; R8, eighth resistor; R9, ninth resistor; R10, tenth resistor; R11, eleventh resistor. DETAILED DESCRIPTION

[0025] In order to further explain the technical means and effects adopted by the present invention to achieve the predetermined purpose of the utility model, the specific implementation method, structure, characteristics and effects of the present invention are described in detail below in combination with the accompanying drawings and preferred embodiments.

[0026] Reference Figure 1-4 As shown, a water level detection circuit provided in this embodiment includes a main control module U1, a conversion module, a measurement module and a comparison module;

[0027] The input end of the conversion module is connected to the output end of the main control module U1, and the output end of the conversion module is connected to the input end of the measurement module. The conversion module is used to receive the control signal of the main control module and convert direct current into alternating current;

[0028] The output end of the measuring module is connected to the input end of the comparing module, and the measuring module is used to generate a corresponding measuring signal according to the water level condition;

[0029] The output end of the comparison module is connected to the input end of the main control module U1. The comparison module is used to compare the measurement signal generated by the measurement module with the standard signal and generate a comparison signal to the main control module.

[0030] In this embodiment, direct current is converted into alternating current through a conversion module, and the use of alternating current detection can avoid the problem of scale generation in the detection module due to long-term use, thereby effectively improving the reliability and service life of the product.

[0031] In a further embodiment of the present invention, the main control module U1 is used to transmit a control signal to the conversion module and determine the water level according to the comparison signal generated by the comparison module.

[0032] In a further embodiment of the utility model, the conversion module also includes a switching module and a first capacitor C1, the switching module includes a transistor Q1, the base of the transistor Q1 is connected to the output end of the main control module through the second resistor R2, the collector of the transistor Q1 is connected to one end of the first capacitor C1, the collector of the transistor Q1 is also connected to a DC power supply through the first resistor R1, and the emitter of the transistor Q1 is grounded.

[0033] In a further embodiment of the present invention, the transistor Q1 is an NPN transistor Q1, the base of the transistor Q1 is grounded through a third resistor R3, and the voltage of the DC power supply is 25V.

[0034] In a further embodiment of the utility model, the conversion module is connected to the detection module through a fourth resistor R4, and the detection module includes a fifth resistor R5, a sixth resistor R6, a seventh resistor R7, a first diode D1 and a water level probe T1. The positive electrode of the first diode D1 is connected to one end of the fourth resistor R4, and the negative electrode of the first diode D1 is connected to one end of the sixth resistor R6. The detection module is connected to the input end of the comparison module through the end of the sixth resistor R6 away from the first diode D1; one end of the fifth resistor R5 is connected between the fourth resistor R4 and the first diode D1, and the other end is connected to the water level probe T1; one end of the water level probe T1 is connected to the fifth resistor R5, and the other end is arranged in a water container to be detected, and a grounding probe connected to the power ground is arranged in the water container, and the grounding probe is located below the water level probe T1; one end of the seventh resistor R7 is connected to one end of the sixth resistor R6 away from the first diode D1, and the other end is grounded.

[0035] In this embodiment, the sixth resistor R6 is connected to the comparison module, and the water level probe T1 is connected in parallel with the sixth resistor R6. When the water level in the water container to be detected overflows the water level probe T1, an equivalent resistance is generated between the water level probe T1 and the power ground, and the sixth resistor R6 is shunted, so that the potential of the input end of the comparison module decreases, and then the signal output by the comparison module changes, so that the detection circuit still has a good detection effect when the conductivity of the water is small, thereby expanding the scope of application of the detection circuit.

[0036] In a further embodiment of the utility model, the comparison module includes a voltage comparator U2, a tenth resistor R10 and an eleventh resistor R11, the in-phase input terminal of the voltage comparator U2 is connected to the end of the sixth resistor R6 away from the first diode D1, the reverse input terminal of the voltage comparator U2 is connected to one end of the eleventh resistor R11, the end of the eleventh resistor R11 away from the voltage comparator U2 is connected to a reference voltage source, one end of the tenth resistor R10 is connected between the reverse input terminal of the voltage comparator U2 and the eleventh resistor R11, and the end of the tenth resistor R10 away from the voltage comparator U2 is grounded.

[0037] In this embodiment, the comparison module uses a voltage comparator U2 to compare the voltage of the detection circuit with the reference voltage, and outputs a PWM signal with a certain duty cycle. At the same time, the reference voltage is set to a constant 5V DC voltage source. When the voltage of the detection circuit changes, the duty cycle of the signal output by the voltage comparator U2 will change accordingly. The main control module U1 identifies the water level status by detecting the change in the duty cycle of the signal output by the voltage comparator U2.

[0038] In a further embodiment of the present invention, the non-inverting input terminal of the voltage comparator U2 is connected to the 5V power supply through the second diode D2, and the anode of the second diode D2 is located near one end of the voltage comparator U2.

[0039] In a further embodiment of the utility model, the output end of the voltage comparator is connected to the positive power input end of the voltage comparator U2 through the eighth resistor R8, the positive power input end of the voltage comparator is connected to the 5V power supply, the output end of the voltage comparator is connected to the negative power input end of the voltage comparator through the second capacitor C2, and the negative power input end of the voltage comparator is grounded.

[0040] In a further embodiment of the present invention, the output end of the voltage comparator U2 is connected to the input end of the main control module U1 through a ninth resistor R9.

[0041] In a further embodiment of the present invention, the main control module U1 includes at least one of an MCU, an ARM processor, a single-chip microcomputer, a DSP processor, a MIPS processor, an FPGA and a PC.

[0042] The operating principle of a water level detection circuit provided by the utility model is as follows: the main control module U1 sends a 0-5V PWM test signal with a certain duty cycle, and the test signal is converted by the transistor Q1 of the switch module to charge and discharge the first capacitor C1 to form an alternating current. After the signal passes through the first capacitor C1 and the fourth resistor R4, a shunt diode first diode D1 and a sixth resistor R6 are set to the in-phase input end of the voltage comparator U2, and then pass through the voltage divider resistor seventh resistor R7 to the power ground. After the power comparator compares the voltage at the in-phase input end with the reference voltage at the reverse input end, it outputs a PWM signal with a certain duty cycle to the input end of the main control module U1. At the same time, another shunt resistor fifth resistor R5 is set to the water level probe T1, and the end of the water level probe T1 away from the fifth resistor R5 is set in the water container to be detected. At this time, an AC signal is generated at the water level probe T1. At the same time, the water container is also provided with a probe connected to the power ground and located below the water level probe T1. When the water level exceeds the water level probe T1, an equivalent resistance will be generated between the water level probe T1 and the power ground. The water level probe T1 divides part of the current, causing the potential of the in-phase input terminal of the voltage comparator U2 to drop, further causing the duty cycle of the PWM signal output by the output terminal of the voltage comparator U2 to change. The main control module U1 detects the change in the duty cycle of the PWM signal output by the output terminal of the voltage comparator U2 to identify whether the water level exceeds the water level probe T1.

[0043] Furthermore, the water level detection circuit can be connected to a display device. After the main control module U1 analyzes the current water level status, the current water level status can be intuitively displayed through the display device.

[0044] Furthermore, the water level detection circuit can be connected to a warning device, and the water level probe T1 can be set at the water level warning height. When the circuit detects the water level through the water level probe T1, it means that the water level has reached the warning height, and a warning is issued through the warning device. The warning device can be an alarm device such as a buzzer.

[0045] Furthermore, multiple groups of water level probes T1 and voltage comparators U2 can be set, and the multiple water level probes T1 can be set at different heights. At the same time, the main control module U1 detects the voltage comparator U2 connected to the corresponding water level probe T1, and judges from multiple heights whether the water level is above the water level probe T1 set at the height to obtain the specific height of the water level, thereby improving the accuracy of water level detection.

[0046] The above description is only a preferred embodiment of the present invention and does not constitute any form of limitation to the present invention. Although the present invention has been disclosed as a preferred embodiment as above, it is not intended to limit the present invention. Any technical personnel in this field can make some changes or modify the technical contents disclosed above into equivalent embodiments without departing from the scope of the technical solution of the present invention. However, any brief modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention are still within the scope of the technical solution of the present invention.

Claims

1. A water level detection circuit, characterized in that: It includes a main control module, a conversion module, a measurement module and a comparison module; The input end of the conversion module is connected to the output end of the main control module, the output end of the conversion module is connected to the input end of the measurement module, and the conversion module is used to receive the control signal of the main control module and convert direct current into alternating current; The output end of the measuring module is connected to the input end of the comparing module, and the measuring module is used to generate a measuring signal according to the water level condition; The output end of the comparison module is connected to the input end of the main control module. The comparison module is used to compare the measurement signal generated by the measurement module with the standard signal and generate a comparison signal to the main control module.

2. A water level detection circuit according to claim 1, characterized in that: The main control module is used to transmit a control signal to the conversion module and determine the water level according to the comparison signal generated by the comparison module.

3. A water level detection circuit according to claim 1, characterized in that: The conversion module also includes a switch module and a first capacitor. The switch module includes a transistor. The base of the transistor is connected to the output end of the main control module through a second resistor, the collector of the transistor is connected to one end of the first capacitor, and the collector of the transistor is also connected to a DC power supply through a first resistor. The emitter of the transistor is grounded.

4. A water level detection circuit according to claim 3, characterized in that: The transistor is an NPN transistor, the base of the transistor is grounded through a third resistor, and the voltage of the DC power supply is 25V.

5. A water level detection circuit according to claim 1, characterized in that: The conversion module is connected to the detection module through a fourth resistor, and the detection module includes a fifth resistor, a sixth resistor, a seventh resistor, a first diode and a water level probe, wherein the positive electrode of the first diode is connected to one end of the fourth resistor, and the negative electrode of the first diode is connected to one end of the sixth resistor, and the detection module is connected to the input end of the comparison module through one end of the sixth resistor away from the first diode; one end of the fifth resistor is connected between the fourth resistor and the first diode, and the other end is connected to the water level probe; one end of the water level probe is connected to the fifth resistor, and the other end is arranged in the water container to be detected; a grounding probe connected to the power ground is arranged in the water container, and the grounding probe is located below the water level probe; one end of the seventh resistor is connected between the sixth resistor and the comparison module, and the other end is grounded.

6. A water level detection circuit according to claim 4, characterized in that: The comparison module includes a voltage comparator, a tenth resistor and an eleventh resistor. The non-inverting input terminal of the voltage comparator is connected to an end of the sixth resistor away from the first diode, the reverse input terminal of the voltage comparator is connected to an end of the eleventh resistor, an end of the eleventh resistor away from the voltage comparator is connected to a reference voltage source, an end of the tenth resistor is connected between the reverse input terminal of the voltage comparator and the eleventh resistor, and an end of the tenth resistor away from the voltage comparator is grounded.

7. A water level detection circuit according to claim 6, characterized in that: The non-inverting input terminal of the voltage comparator is also connected to a 5V power supply via a second diode, and the anode of the second diode is located at one end close to the voltage comparator.

8. A water level detection circuit according to claim 6, characterized in that: The output end of the voltage comparator is connected to the positive power input end of the voltage comparator through the eighth resistor, the positive power input end of the voltage comparator is connected to a 5V power supply, the output end of the voltage comparator is connected to the negative power input end of the voltage comparator through the second capacitor, and the negative power input end of the voltage comparator is grounded.

9. According to the water level detection circuit of claim 6, the output end of the voltage comparator is connected to the input end of the main control module through a ninth resistor.

10. A water level detection circuit according to claim 1, characterized in that: The main control module includes at least one of an MCU, an ARM processor, a single-chip microcomputer, a DSP processor, a MIPS processor, an FPGA and a PC.

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