Tea dispenser control and detection circuit

Abstract

The utility model discloses a tea outlet machine control and detection circuit comprising a current detection circuit, an input end of which is connected with a peristaltic pump and an output end of which is connected with an input end of a main control circuit; the input end of the liquid level detection circuit is arranged in the water tank, and the output end is connected with the input end of the main control circuit; the input end of the temperature acquisition circuit is connected with the temperature sensor, and the output end is connected with the input end of the main control circuit; the output end of the main control circuit is connected with the input end of the driving circuit; and the output end of the driving circuit is connected with the current detection circuit. According to the technical scheme, the working current of the peristaltic pump is monitored in real time, so that when the peristaltic pump breaks down, whether the fault is caused by overcurrent or not can be determined in time, and the maintenance efficiency of the tea discharging machine is improved; meanwhile, the temperature and liquid level detection of liquid in the water tank in the tea discharging machine can be clearly displayed to an operator, so that the operator can replenish water or adjust the temperature in time, and the use efficiency of the tea discharging machine is improved.

Description

Technical Field

[0001] The utility model relates to the technical field of tea dispensing machine control, in particular to a tea dispensing machine control and detection circuit. Background Art

[0002] With the improvement of people's living standards, various beverages have emerged. In particular, equipment for making milk tea has occupied an increasingly larger market share. Equipment for making milk tea is called a tea dispenser. A peristaltic pump needs to be provided in the tea dispenser to fully stir different liquids or ingredients to make the milk tea more delicious. In the prior art, the peristaltic pump is an electrical device, and its working current cannot be monitored in real time. As a result, when the peristaltic pump fails, the cause of the failure cannot be found out in time, thereby reducing the maintenance efficiency of the tea dispenser. At the same time, the temperature and liquid level detection of the liquid in the water tank of the tea dispenser cannot be clearly displayed to the operator, resulting in the operator being unable to replenish water or adjust the temperature in time, thereby reducing the use efficiency of the tea dispenser. Utility Model Content

[0003] Based on this, it is necessary to propose a tea dispensing machine control and detection circuit to address the above problems.

[0004] A tea dispensing machine control and detection circuit, comprising:

[0005] A current detection circuit, the input end of which is connected to the peristaltic pump, and the output end of which is connected to the input end of the main control circuit, for collecting the current signal of the peristaltic pump and outputting the current signal to the main control circuit;

[0006] A liquid level detection circuit, the input end of which is placed in the water tank, and the output end of which is connected to the input end of the main control circuit, is used to collect the liquid level signal of the water tank and output the liquid level signal to the main control circuit;

[0007] A temperature acquisition circuit, whose input end is connected to the temperature sensor and whose output end is connected to the input end of the main control circuit, is used to receive the temperature signal acquired by the temperature sensor and output the temperature signal to the main control circuit;

[0008] A main control circuit, whose output end is connected to the input end of the drive circuit, is used to receive the current signal, the liquid level signal and the temperature signal, and output a control signal to the drive circuit;

[0009] The output end of the driving circuit is connected to the current detection circuit, and is used to receive the control signal, and output the control signal to the peristaltic pump through the current detection circuit, and drive the peristaltic pump to operate.

[0010] In one embodiment, the tea dispenser control and detection circuit further includes:

[0011] The first isolation circuit is arranged between the driving circuit and the main control circuit, and is used for isolating the control signal output by the main control circuit and then outputting it to the driving circuit.

[0012] In one embodiment, the tea dispenser control and detection circuit further includes:

[0013] The second isolation circuit is arranged between the liquid level detection circuit and the main control circuit, and is used for isolating the liquid level signal output by the liquid level detection circuit and then outputting it to the main control circuit.

[0014] In one embodiment, the driving circuit includes: a MOS tube, a linear regulator, a first diode, a fuse and an interface;

[0015] The input terminal HIN of the MOS tube is connected to the output terminal of the main control circuit, and the output terminal of the MOS tube is connected to the gate of the linear regulator;

[0016] The source of the linear regulator is grounded, the drain of the linear regulator is connected to the current input terminal of the current detection circuit, the current output terminal of the current detection circuit is connected to the input terminal of the interface, and the output terminal of the interface is connected to the peristaltic pump;

[0017] The anode of the first diode is connected to the current output end of the current detection circuit, and the cathode of the first diode is connected to the external power supply and the input end of the interface;

[0018] One end of the fuse is connected to the external power supply; the other end is connected to the input end of the interface.

[0019] In one embodiment, the current detection circuit includes: a current sensor;

[0020] The current input end of the current sensor is connected to the drain of the linear regulator, and the current output end of the current sensor is connected to the input end of the interface; the current output end of the current sensor is connected to the input end of the main control circuit.

[0021] In one embodiment, the liquid level detection circuit includes: a second diode, a third diode, a fourth diode, a triode, a first resistor, a second resistor, a fourth resistor and a first capacitor;

[0022] One end of the first resistor is connected to the liquid level sensor, and the other end of the first resistor is connected to one end of the second resistor and the anode of the second diode;

[0023] The other end of the second resistor is grounded;

[0024] The cathode of the second diode is connected to an external power supply;

[0025] The first capacitor is connected in parallel with the second resistor;

[0026] The anode of the third diode is connected to the anode of the second diode, and the cathode of the third diode is connected to the anode of the fourth diode;

[0027] The cathode of the fourth diode is grounded;

[0028] One end of the fourth resistor is connected to the anode of the second diode, and the other end is connected to the base of the transistor;

[0029] The collector of the transistor is connected to the external power supply and the input end of the main control circuit, and the emitter of the transistor is grounded.

[0030] In one embodiment, the temperature acquisition circuit includes: a second capacitor, a fifth resistor, a sixth resistor, a seventh resistor, an eighth resistor, a ninth resistor and an operational amplifier;

[0031] One end of the second capacitor is connected to one end of the eighth resistor, one end of the fifth resistor and the positive electrode of the temperature sensor, and the other end of the second capacitor is grounded;

[0032] The other end of the eighth resistor is connected to an external power supply;

[0033] The other end of the fifth resistor is connected to the non-inverting input end of the operational amplifier;

[0034] One end of the seventh resistor is connected to the negative electrode of the temperature sensor and one end of the ninth resistor, and the other end of the seventh resistor is connected to the inverting input end of the operational amplifier;

[0035] The other end of the ninth resistor is grounded;

[0036] The output end of the operational amplifier is connected to the input end of the main control circuit;

[0037] One end of the sixth resistor is connected to an end of the fifth resistor away from the second capacitor, and the other end of the sixth resistor is connected to the output end of the operational amplifier.

[0038] In one embodiment, the tea dispenser control and detection circuit, the temperature acquisition circuit further comprises: a fifth diode;

[0039] An anode of the fifth diode is grounded, and a cathode of the fifth diode is connected to the other end of the second capacitor.

[0040] In one embodiment,

[0041] The main control circuit comprises: a main control chip;

[0042] The first isolation circuit includes: a first isolation chip;

[0043] The input end of the first isolation chip is connected to the first output end of the main control chip, and the output end of the first isolation chip is connected to the input end of the driving circuit;

[0044] The first input terminal of the main control chip is connected to the output terminal of the current detection circuit;

[0045] The second input terminal of the main control chip is connected to the second isolation circuit;

[0046] The third input terminal of the main control chip is connected to the output terminal of the temperature acquisition circuit.

[0047] In one embodiment, the second isolation circuit includes: a second isolation chip;

[0048] The input end of the second isolation chip is connected to the output end of the liquid level detection circuit, and the output end of the second isolation chip is connected to the second output end of the main control chip.

[0049] Implementing the embodiments of the present utility model will have the following beneficial effects:

[0050] The present application collects the current signal of the peristaltic pump through the current detection circuit, and outputs the current signal to the main control circuit; the liquid level detection circuit collects the liquid level signal of the water tank, and outputs the liquid level signal to the main control circuit; the temperature acquisition circuit receives the temperature signal collected by the temperature sensor, and outputs the temperature signal to the main control circuit; the main control circuit receives the current signal, the liquid level signal and the temperature signal, and outputs the control signal to the drive circuit; the drive circuit receives the control signal, and outputs the control signal to the peristaltic pump through the current detection circuit, and drives the peristaltic pump to operate. Real-time monitoring of the current of the peristaltic pump is achieved, so that when the peristaltic pump fails, it can be determined in time whether the cause of the failure is caused by overcurrent, thereby improving the maintenance efficiency of the tea dispenser; at the same time, the temperature and liquid level detection of the liquid in the water tank of the tea dispenser can also be clearly displayed to the operator, so that the operator can replenish water or adjust the temperature in time, thereby improving the use efficiency of the tea dispenser. BRIEF DESCRIPTION OF THE DRAWINGS

[0051] In order to more clearly illustrate the embodiments of the utility model or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the utility model. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0052] in:

[0053] Figure 1 It is a structural block diagram of a tea dispensing machine control and detection circuit in one embodiment;

[0054] Figure 2 It is a structural block diagram of a tea dispensing machine control and detection circuit in another embodiment;

[0055] Figure 3 is a circuit diagram of a driving circuit and a current detection circuit in one embodiment;

[0056] Figure 4 is a circuit diagram of a liquid level detection circuit in one embodiment;

[0057] Figure 5 is a circuit diagram of a temperature acquisition circuit in one embodiment;

[0058] Figure 6 is a circuit diagram of a first isolation circuit in one embodiment;

[0059] Figure 7 is a circuit diagram of a second isolation circuit in one embodiment;

[0060] Figure 8 FIG. 4 is a circuit diagram of a main control circuit in one embodiment. DETAILED DESCRIPTION

[0061] The following will be combined with the drawings in the embodiments of the utility model to clearly and completely describe the technical solutions in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments of the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0062] As people's living standards improve, various beverages have emerged. In particular, equipment for making milk tea has occupied an increasingly larger market share. Equipment for making milk tea is called a tea dispenser. A peristaltic pump needs to be installed in the tea dispenser to fully stir different liquids or ingredients to make the milk tea more delicious. In the prior art, the peristaltic pump is an electrical device, and its working current cannot be monitored in real time. As a result, when the peristaltic pump fails, the cause of the failure cannot be found out in time, reducing the maintenance efficiency of the tea dispenser; at the same time, the temperature and liquid level detection of the liquid in the water tank of the tea dispenser cannot be clearly displayed to the operator, resulting in the operator being unable to replenish water or adjust the temperature in time, reducing the use efficiency of the tea dispenser. In order to solve the above technical problems, the present application provides a tea dispenser control and detection circuit, such as Figure 1As shown, it includes: a current detection circuit 20, a liquid level detection circuit 30, a temperature acquisition circuit 40, a main control circuit 70 and a drive circuit 10; wherein the input end of the current detection circuit 20 is connected to the peristaltic pump, and the output end is connected to the input end of the main control circuit 70, for collecting the current signal of the peristaltic pump and outputting the current signal to the main control circuit 70; the input end of the liquid level detection circuit 30 is placed in the water tank, and the output end is connected to the input end of the main control circuit 70, for collecting the liquid level signal of the water tank and outputting the liquid level signal to the main control circuit 70; the input end of the temperature acquisition circuit 40 It is connected to the temperature sensor, and its output end is connected to the input end of the main control circuit 70, so as to receive the temperature signal collected by the temperature sensor and output the temperature signal to the main control circuit 70; the output end of the main control circuit 70 is connected to the input end of the drive circuit 10, so as to receive the current signal, the liquid level signal and the temperature signal, and output the control signal to the drive circuit 10; the output end of the drive circuit 10 is connected to the current detection circuit 20, so as to receive the control signal, and output the control signal to the peristaltic pump through the current detection circuit 20, and drive the peristaltic pump to operate. The present application collects the current signal of the peristaltic pump through the current detection circuit 20, and outputs the current signal to the main control circuit 70; the liquid level detection circuit 30 collects the liquid level signal of the water tank, and outputs the liquid level signal to the main control circuit 70; the temperature acquisition circuit 40 receives the temperature signal collected by the temperature sensor, and outputs the temperature signal to the main control circuit 70; the main control circuit 70 receives the current signal, the liquid level signal and the temperature signal, and outputs the control signal to the drive circuit 10; the drive circuit 10 receives the control signal, and outputs the control signal to the peristaltic pump through the current detection circuit 20, and drives the peristaltic pump to operate. Real-time monitoring of the current of the peristaltic pump is achieved, so that when the peristaltic pump fails, it can be determined in time whether the cause of the failure is caused by overcurrent, thereby improving the maintenance efficiency of the tea dispenser; at the same time, the temperature and liquid level detection of the liquid in the water tank of the tea dispenser can also be clearly displayed to the operator, so that the operator can replenish water or adjust the temperature in time, thereby improving the use efficiency of the tea dispenser.

[0063] In one embodiment, Figure 2 As shown, the tea dispenser control and detection circuit comprises: a first isolation circuit 50 and a second isolation circuit 60, wherein:

[0064] The first isolation circuit 50 is disposed between the drive circuit 10 and the main control circuit 70, and is used to isolate the control signal output by the main control circuit 70 and output it to the drive circuit 10. The second isolation circuit 60 is disposed between the liquid level detection circuit 30 and the main control circuit 70, and is used to isolate the liquid level signal output by the liquid level detection circuit 30 and output it to the main control circuit 70.

[0065] In one embodiment, Figure 3 As shown, the driving circuit 10 includes: a MOS tube U63, a linear regulator Q25, a first diode D59, a fuse F15 and an interface P16;

[0066] The input terminal HIN of the MOS tube U63 is connected to the output terminal of the main control circuit 70, and the output terminal HO of the MOS tube U63 is connected to the gate of the linear regulator Q25;

[0067] The source of the linear regulator Q25 is grounded, the drain of the linear regulator Q25 is connected to the current input terminal of the current detection circuit 20, the current output terminal of the current detection circuit 20 is connected to the input terminal of the interface P16, and the output terminal of the interface P16 is connected to the peristaltic pump;

[0068] The anode of the first diode D59 is connected to the current output terminal of the current detection circuit 20, and the cathode of the first diode D59 is connected to the external power supply and the input terminal of the interface P16;

[0069] One end of the fuse F15 is connected to the external power supply; the other end is connected to the input end of the interface P16.

[0070] In one embodiment, Figure 3 As shown, the current detection circuit 20 includes: a current sensor U64;

[0071] The current input end of the current sensor U64 is connected to the drain of the linear regulator Q25, and the current output end of the current sensor U64 is connected to the input end of the interface P16; the current output end of the current sensor U64 is connected to the input end of the main control circuit 70.

[0072] In one embodiment, Figure 4 As shown, the liquid level detection circuit 30 includes: a second diode D134, a third diode D139, a fourth diode D144, a transistor Q44, a first resistor R267, a second resistor R277, a fourth resistor R268 and a first capacitor C170;

[0073] One end of the first resistor R267 is connected to the liquid level sensor, and the other end of the first resistor R267 is connected to one end of the second resistor R277 and the anode of the second diode D134;

[0074] The other end of the second resistor R277 is grounded;

[0075] The cathode of the second diode D134 is connected to an external power supply;

[0076] The first capacitor C170 is connected in parallel with the second resistor R277;

[0077] The anode of the third diode D139 is connected to the anode of the second diode D134, and the cathode of the third diode D139 is connected to the anode of the fourth diode D144;

[0078] The cathode of the fourth diode D144 is grounded;

[0079] One end of the fourth resistor R268 is connected to the anode of the second diode D134, and the other end is connected to the base of the transistor Q44;

[0080] The collector of the transistor Q44 is connected to the external power supply and the input end of the main control circuit 70, and the emitter of the transistor Q44 is grounded.

[0081] In one embodiment, Figure 5 As shown, the temperature acquisition circuit 40 includes: a second capacitor C187, a fifth resistor R327, a sixth resistor R323, a seventh resistor R329, an eighth resistor R288, a ninth resistor R333 and an operational amplifier U1;

[0082] One end of the second capacitor C187 is connected to one end of the eighth resistor R288, one end of the fifth resistor R327 and the positive electrode of the temperature sensor, and the other end of the second capacitor C187 is grounded;

[0083] The other end of the eighth resistor R288 is connected to an external power supply;

[0084] The other end of the fifth resistor R327 is connected to the non-inverting input end of the operational amplifier U1;

[0085] One end of the seventh resistor R329 is connected to the negative electrode of the temperature sensor and one end of the ninth resistor R333, and the other end of the seventh resistor R329 is connected to the inverting input end of the operational amplifier U1;

[0086] The other end of the ninth resistor R333 is grounded;

[0087] The output end of the operational amplifier U1 is connected to the input end of the main control circuit 70;

[0088] One end of the sixth resistor R323 is connected to one end of the fifth resistor R327 away from the second capacitor C187, and the other end of the sixth resistor R323 is connected to the output end of the operational amplifier U1.

[0089] In one embodiment, Figure 3 As shown, the temperature acquisition circuit 40 further includes: a fifth diode D32;

[0090] An anode of the fifth diode D32 is grounded, and a cathode of the fifth diode D32 is connected to the other end of the second capacitor C187.

[0091] In one embodiment, Figure 8 As shown, the main control circuit 70 includes: a main control chip U88;

[0092] like Figure 6 As shown, the first isolation circuit 50 includes: a first isolation chip U71;

[0093] The input terminal VIB of the first isolation chip U71 is connected to the first output terminal FE5 of the main control chip U88, and the output terminal VOB of the first isolation chip U71 is connected to the input terminal of the driving circuit 10;

[0094] The first input terminal PA4 of the main control chip U88 is connected to the output terminal of the current detection circuit 20;

[0095] The second input terminal PD1 of the main control chip U88 is connected to the second isolation circuit 60;

[0096] The third input terminal PA5 of the main control chip U88 is connected to the output terminal of the temperature acquisition circuit 40 .

[0097] In one embodiment, Figure 7 As shown, the second isolation circuit 60 includes: a second isolation chip U33;

[0098] The input terminal VIB of the second isolation chip U33 is connected to the output terminal of the liquid level detection circuit 30 , and the output terminal VOB of the second isolation chip U33 is connected to the second output terminal PD1 of the main control chip U88 .

[0099] The present application collects the current signal of the peristaltic pump through the current detection circuit 20, and outputs the current signal to the main control circuit 70; the liquid level detection circuit 30 collects the liquid level signal of the water tank, and outputs the liquid level signal to the main control circuit 70; the temperature acquisition circuit 40 receives the temperature signal collected by the temperature sensor, and outputs the temperature signal to the main control circuit 70; the main control circuit 70 receives the current signal, the liquid level signal and the temperature signal, and outputs the control signal to the drive circuit 10; the drive circuit 10 receives the control signal, and outputs the control signal to the peristaltic pump through the current detection circuit 20, and drives the peristaltic pump to operate. Real-time monitoring of the current of the peristaltic pump is achieved, so that when the peristaltic pump fails, it can be determined in time whether the cause of the failure is caused by overcurrent, thereby improving the maintenance efficiency of the tea dispenser; at the same time, the temperature and liquid level detection of the liquid in the water tank of the tea dispenser can also be clearly displayed to the operator, so that the operator can replenish water or adjust the temperature in time, thereby improving the use efficiency of the tea dispenser.

[0100] The above disclosure is only a preferred embodiment of the present invention, and certainly cannot be used to limit the scope of rights of the present invention. Therefore, equivalent changes made according to the claims of the present invention are still within the scope covered by the present invention.

Claims

1. A tea dispensing machine control and detection circuit, characterized in that: include: A current detection circuit, the input end of which is connected to the peristaltic pump, and the output end of which is connected to the input end of the main control circuit, for collecting the current signal of the peristaltic pump and outputting the current signal to the main control circuit; A liquid level detection circuit, the input end of which is placed in the water tank, and the output end of which is connected to the input end of the main control circuit, is used to collect the liquid level signal of the water tank and output the liquid level signal to the main control circuit; A temperature acquisition circuit, whose input end is connected to the temperature sensor and whose output end is connected to the input end of the main control circuit, is used to receive the temperature signal acquired by the temperature sensor and output the temperature signal to the main control circuit; A main control circuit, whose output end is connected to the input end of the drive circuit, is used to receive the current signal, the liquid level signal and the temperature signal, and output a control signal to the drive circuit; The output end of the driving circuit is connected to the current detection circuit, and is used to receive the control signal, and output the control signal to the peristaltic pump through the current detection circuit, and drive the peristaltic pump to operate.

2. The tea dispensing machine control and detection circuit according to claim 1, characterized in that: Also includes: The first isolation circuit is arranged between the driving circuit and the main control circuit, and is used for isolating the control signal output by the main control circuit and then outputting it to the driving circuit.

3. The tea dispensing machine control and detection circuit according to claim 2, characterized in that: Also includes: The second isolation circuit is arranged between the liquid level detection circuit and the main control circuit, and is used for isolating the liquid level signal output by the liquid level detection circuit and then outputting it to the main control circuit.

4. The tea dispensing machine control and detection circuit according to claim 1, characterized in that: The driving circuit comprises: a MOS tube, a linear regulator, a first diode, a fuse and an interface; The input terminal HIN of the MOS tube is connected to the output terminal of the main control circuit, and the output terminal of the MOS tube is connected to the gate of the linear regulator; The source of the linear regulator is grounded, the drain of the linear regulator is connected to the current input terminal of the current detection circuit, the current output terminal of the current detection circuit is connected to the input terminal of the interface, and the output terminal of the interface is connected to the peristaltic pump; The anode of the first diode is connected to the current output end of the current detection circuit, and the cathode of the first diode is connected to the external power supply and the input end of the interface; One end of the fuse is connected to the external power supply; the other end is connected to the input end of the interface.

5. The tea dispensing machine control and detection circuit according to claim 4, characterized in that: The current detection circuit comprises: a current sensor; The current input end of the current sensor is connected to the drain of the linear regulator, and the current output end of the current sensor is connected to the input end of the interface; the current output end of the current sensor is connected to the input end of the main control circuit.

6. The tea dispensing machine control and detection circuit according to claim 1, characterized in that: The liquid level detection circuit comprises: a second diode, a third diode, a fourth diode, a triode, a first resistor, a second resistor, a fourth resistor and a first capacitor; One end of the first resistor is connected to the liquid level sensor, and the other end of the first resistor is connected to one end of the second resistor and the anode of the second diode; The other end of the second resistor is grounded; The cathode of the second diode is connected to an external power supply; The first capacitor is connected in parallel with the second resistor; The anode of the third diode is connected to the anode of the second diode, and the cathode of the third diode is connected to the anode of the fourth diode; The cathode of the fourth diode is grounded; One end of the fourth resistor is connected to the anode of the second diode, and the other end is connected to the base of the transistor; The collector of the transistor is connected to the external power supply and the input end of the main control circuit, and the emitter of the transistor is grounded.

7. The tea dispensing machine control and detection circuit according to claim 1, characterized in that: The temperature acquisition circuit comprises: a second capacitor, a fifth resistor, a sixth resistor, a seventh resistor, an eighth resistor, a ninth resistor and an operational amplifier; One end of the second capacitor is connected to one end of the eighth resistor, one end of the fifth resistor and the positive electrode of the temperature sensor, and the other end of the second capacitor is grounded; The other end of the eighth resistor is connected to an external power supply; The other end of the fifth resistor is connected to the non-inverting input end of the operational amplifier; One end of the seventh resistor is connected to the negative electrode of the temperature sensor and one end of the ninth resistor, and the other end of the seventh resistor is connected to the inverting input end of the operational amplifier; The other end of the ninth resistor is grounded; The output end of the operational amplifier is connected to the input end of the main control circuit; One end of the sixth resistor is connected to an end of the fifth resistor away from the second capacitor, and the other end of the sixth resistor is connected to the output end of the operational amplifier.

8. The tea dispensing machine control and detection circuit according to claim 7, characterized in that: The temperature acquisition circuit further includes: a fifth diode; An anode of the fifth diode is grounded, and a cathode of the fifth diode is connected to the other end of the second capacitor.

9. The tea dispensing machine control and detection circuit according to claim 3, characterized in that: The main control circuit comprises: a main control chip; The first isolation circuit includes: a first isolation chip; The input end of the first isolation chip is connected to the first output end of the main control chip, and the output end of the first isolation chip is connected to the input end of the driving circuit; The first input terminal of the main control chip is connected to the output terminal of the current detection circuit; The second input terminal of the main control chip is connected to the second isolation circuit; The third input terminal of the main control chip is connected to the output terminal of the temperature acquisition circuit.

10. The tea dispensing machine control and detection circuit according to claim 9, characterized in that: The second isolation circuit includes: a second isolation chip; The input end of the second isolation chip is connected to the output end of the liquid level detection circuit, and the output end of the second isolation chip is connected to the second output end of the main control chip.

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