Contact-type alternating-current water level detection device

Abstract

The utility model relates to the technical field of water level sensors, in particular to a contact type alternating-current water level detection device. Comprising an MCU module, the MCU module is connected with a water pump through a driving circuit, and the driving circuit controls starting or stopping of the water pump; the MCU module is further connected with a detection circuit module and an inverter circuit module, the detection circuit module sends signals to the MCU module, the MCU module controls the inverter circuit module through the signals, and the inverter circuit module is connected with a metal common probe 1 and at least one water level detection probe. The metal common probe 1 and the at least one water level detection probe are connected with the MCU module through the detection circuit module, and the power supply module supplies power to the MCU module and the inverter circuit module. The circuit can be directly transplanted to a water pump control circuit, an external sensor is not needed, switching of use scenes can be rapidly completed, and multi-probe and multi-water-level detection can be achieved through arrangement of probes of different heights.

Description

TECHNICAL FIELD

[0001] The utility model relates to water level sensor technical field, concretely is contact type alternating current water level detection device. BACKGROUND

[0002] With the continuous popularity of water level sensor, more and more devices begin to use water level sensor to replace traditional mechanical structure device. In the circuit control of drainage or water supply, generally adopts the float ball type water level sensor to indirectly control the start or stop of water pump, because of its early origin and cheap price, so the audience is relatively wide, but the float ball type water level switch needs to put the device into the water tank and install complicatedly and is inconvenient to maintain in later period, and the use scene is single. The capacitive water level sensor can detect the water level change in the container through the medium, and although this non-contact water level sensor does not have the problem of later cleaning, it cannot detect the water level change in the container of pure metal material, which also limits its use scene. Therefore, a water level monitoring device for conveniently switching use scene is needed to control the liquid discharge or supply circuit. SUMMARY

[0003] The problem to be solved is to provide a water level monitoring device for conveniently switching use scene to control the liquid discharge or supply circuit.

[0004] To achieve the above purpose, the utility model provides the following technical scheme: contact type alternating current water level detection device, including MCU module, MCU module passes through drive circuit and connects water pump, and drive circuit controls the opening or stop of water pump, MCU module is connected detection circuit module and inverter circuit module still, detection circuit module gives signal to MCU module, and MCU module passes through signal control inverter circuit module, and inverter circuit module is connected with metal public probe and at least one water level detection probe, and metal public probe and at least one water level detection probe all are connected MCU module through detection circuit module, and power module is the power supply for MCU module, inverter circuit module and drive circuit, inverter circuit module adopts full bridge drive circuit, and full bridge drive circuit includes left half bridge and right half bridge, and left half bridge includes the NPN triode Q1 and PNP triode Q3 in series connection, and NPN triode Q1 and PNP triode Q3 are connected in series and are connected with resistance R2 in parallel, and resistance R2 is connected with photoelectric coupler PC1 in series, right half bridge includes the NPN triode Q2 and PNP triode Q4 in series connection, and NPN triode Q2 and PNP triode Q4 are connected in series and are connected with resistance R3 in parallel, and resistance R3 is connected with photoelectric coupler PC2 in series.

[0005] Preferably, the at least one water level detection probe includes a water level probe one, a water level probe two and a water level probe three.

[0006] Preferably, the power module comprises electrolytic capacitor E1, MLCC capacitor C12, electrolytic capacitor E2 and MLCC capacitor C11 connected in parallel, and the electrolytic capacitor E1, the MLCC capacitor C12, the electrolytic capacitor E2 and the MLCC capacitor C11 are connected with the low dropout linear regulator U1 in parallel.

[0007] Preferably, the detection circuit module is connected with the water level probe one, the water level probe two and the water level probe three through an RC filter circuit, and the RC filter circuit comprises resistors R15, R16 and R17, and MLCC capacitors C1, C2 and C3; the resistor R15 is connected with the MLCC capacitor C1 in series through the rectifier diode D8, the resistor R16 is connected with the MLCC capacitor C2 in series through the rectifier diode D9, and the resistor R17 is connected with the MLCC capacitor C3 in series through the rectifier diode D10.

[0008] Preferably, the MCU module adopts a single-chip microcomputer model STM32F030C8Tx, and the pins 10, 11 and 12 of the STM32F030C8Tx are connected with the water level probe one, the water level probe two and the water level probe three respectively, and the pins 42 and 44 of the STM32F030C8Tx are connected with the full-bridge drive circuit of the inverter circuit module.

[0009] Compared with the prior art, the contact type alternating current water level detection device has the following beneficial effects:

[0010] 1. The circuit structure of the device is simple, low in cost and high in reliability; the circuit can be directly transplanted into a water pump control circuit, an external sensor is not needed, and the switching of use scenes can be quickly completed.

[0011] 2. The probe provided by the device supplies an alternating square wave signal, the cathode of a traditional direct current probe is always fixed at one pole, and under the condition of continuously applied current, calcium and magnesium ions in water are prone to form scale at the cathode; the device adopts an alternating current probe, thereby effectively avoiding the problem of scale accumulation caused by the cathode being always fixed, and the device is convenient to maintain in the later period.

[0012] 3. The device can realize multi-probe and multi-water level detection through the setting of water level probes of different heights. BRIEF DESCRIPTION OF DRAWINGS

[0013] Figure 1 Fig. 1 is a structural schematic diagram of the device;

[0014] Figure 2 Fig. 3 is a principle diagram of a power module of the device;

[0015] Figure 3 Fig. 4 is a principle diagram of an inverter circuit module of the device;

[0016] Figure 4 This is a schematic diagram of the detection circuit module of the device of this utility model;

[0017] Figure 5 This is a schematic diagram of the MCU module of the device of this utility model;

[0018] Explanation of the attached diagram labels: 1. Metal common probe; 2. Liquid level probe one; 3. Liquid level probe two; 4. Liquid level probe three. Detailed Implementation

[0019] The technical solutions of the present utility model will now be described with reference to the accompanying drawings in the embodiments of the present utility model:

[0020] To address the problems mentioned in the background art, this utility model proposes a contact-type AC water level detection device, such as... Figure 1 As shown, this utility model's contact-type AC water level detection device includes an MCU module. The MCU module is connected to a water pump via a drive circuit, and the MCU module sends an action signal to the drive circuit, which controls the water pump to start or stop. Simultaneously, the MCU module is connected to a detection circuit module and an inverter circuit module. The MCU module receives signals from the detection circuit module and controls the inverter circuit module via these signals. The inverter circuit module is connected to a metal common probe 1 and at least one water level detection probe. Both the metal common probe 1 and at least one water level detection probe are connected to the MCU module via the detection circuit module. A power supply module provides power to the MCU module, inverter circuit module, and drive circuit. The circuit of this utility model can be ported to a water pump control circuit using the resources on the circuit board, eliminating the need for external sensors and allowing for rapid switching between application scenarios.

[0021] The water tank is typically filled with non-pure water. Taking advantage of the conductivity of non-pure water, a metal common probe 1 and one or more metal water level detection probes are located at the bottom of the tank. Figure 1 The water level detection probes shown include water level probe 1 (2), water level probe 2 (3), and water level probe 3 (4). The power supply module inverts the isolated 24V low-voltage DC power generated by the switching power supply into low-voltage AC power through the inverter circuit module and outputs it to each probe. The metal common probe 1, water level probe 1 (2), water level probe 2 (3), and water level probe 3 (4) are connected to the ADC port of the MCU module through the rectifier and filter circuit in the detection circuit module for signal detection. When the metal common probe 1 and the water level detection probes are simultaneously immersed in water, the conductivity of non-pure water creates a path for the AC power. At this time, the resistor connected in series with the water level detection probe generates a voltage drop due to the current passing through it. This voltage signal is then recognized by the ADC port of the MCU after passing through the rectifier and filter circuit in the detection circuit module, thereby determining the water level and realizing the water level detection function.

[0022] Figure 2The utility model discloses a device power module's schematic diagram, this scheme adopts 24V isolation direct current power supply, E1, E2 is electrolytic capacitor, the main role of E1, E2 is energy storage, C11, C12 is MLCC capacitor, and C11, C12 is responsible for filtering high frequency interference in power supply, U1 is low dropout linear regulator, and electrolytic capacitor E1, MLCC capacitor C12, electrolytic capacitor E2 and MLCC capacitor C11 are connected low dropout linear regulator U1 after parallel, and is responsible for the 24V direct current voltage stabilization 3.3V direct current output supply singlechip use.

[0023] Figure 3 It is the schematic diagram of inverter circuit module, and the inverter circuit module adopts full bridge drive circuit and is inverted into AC through water level detection probe with 24V direct current. Full bridge drive circuit includes left half bridge and right half bridge, and the left half bridge includes the series connection of NPN triode Q1 and PNP triode Q3, and the right half bridge includes the series connection of NPN triode Q2 and PNP triode Q4, Q1, Q2 are NPN triodes, Q3, Q4 are PNP triodes, and the four triodes of NPN triode Q1, NPN triode Q2, PNP triode Q3 and PNP triode Q4 form full bridge drive circuit, and the series connection of NPN triode Q1 and PNP triode Q3 is connected with resistance R2 in parallel, and the series connection of NPN triode Q2 and PNP triode Q4 is connected with resistance R3 in parallel, and resistance R2 and resistance R3 provide bias for left and right half bridges respectively, resistance R2 is connected with photocoupler PC1 in series, resistance R3 is connected with photocoupler PC2 in series, and photocoupler PC1 and photocoupler PC2 are responsible for driving left and right half bridges to output, and the two groups of drive signals are 180 degrees in phase, when WLD_PWML is high level, photocoupler PC1 is turned on, and the base of NPN triode Q1 and PNP triode Q3 is pulled low, at this moment, the upper tube is in cut-off state, and the lower tube is in conduction state, WLD_PWM R is low level, at this moment, the base of NPN triode Q2 and PNP triode Q4 is in high level state, NPN triode Q2 is turned on, PNP triode Q4 is cut off, and the current flows from right half bridge to left half bridge, and when WLD_PWML is low, WLD_PWM R is high, photocoupler PC1 is turned off, photocoupler PC2 is turned on, the base of NPN triode Q1 and PNP triode Q3 is pulled high by biasing resistance, NPN triode Q1 is in conduction state, PNP triode Q3 is in cut-off state, the base of NPN triode Q2 and PNP triode Q4 is pulled low by photocoupler PC2, NPN triode Q2 is cut off, and PNP triode Q4 is turned on, at this moment, the current direction flows from left half bridge to right half bridge, and realizes the commutation of current. Resistance R8 and resistance R1 are responsible for current limiting, prevent the upper and lower tubes of full bridge drive circuit from being turned on simultaneously and causing large current to damage the circuit. The role of D1, D2, D3 and D4 is clamping, prevents the damage of triode due to the peak voltage produced by lead parasitic inductance in commutation process. C17 is responsible for absorbing voltage noise produced in the driving process.

[0024] Figure 4 In order to detect the schematic diagram of the circuit module, TH, TM and TL are water level probe one 2, water level probe two 3 and water level probe three 4 respectively, resistance R9 is connected in series with water level probe one 2, resistance R10 is connected in series with water level probe two 3, resistance R11 is connected in series with water level probe three 4, and the common probe COM is a metal common probe 1. When the common probe COM and the water level monitoring probe TH, TM and TL form a current loop through water, the current passing through the above-mentioned resistances R9, R10 and R11 will produce a voltage drop. Resistances R15, R16 and R17 and MLCC capacitors C1, C2 and C3 constitute an RC filter circuit to filter out high-frequency harmonic components and noise in the loop. D8, D9 and D10 are rectifier diodes, resistance R15 is connected in series with MLCC capacitor C1 through rectifier diode D8, resistance R16 is connected in series with MLCC capacitor C2 through rectifier diode D9, and resistance R17 is connected in series with MLCC capacitor C3 through rectifier diode D10. The reverse blocking characteristics of rectifier diodes D8, D9 and D10 are used to rectify the alternating voltage signal into a unidirectional direct current signal, which facilitates sampling by the MCU module.

[0025] Figure 5 The MCU module is a schematic diagram, IC1 is a single-chip microcomputer, and its model is STM32F030C8Tx. J1 is a program burning port. The MCU module uses 3.3V power supply, and has a built-in 16-bit ADC channel. Pin 10, pin 11 and pin 12 of STM32F030C8Tx correspond to IDH, IDM and IDL respectively. IDH, IDM and IDL are three water level detection signals after rectification, corresponding to water level probe one 2, water level probe two 3 and water level probe three 4 respectively, and are sent to the ADC port of the single-chip microcomputer for sampling. WLD_PWMR and WLD_PWML are a set of complementary drive signals. WLD_PWMR corresponds to pin 42 of STM32F030C8Tx, and WLD_PWML corresponds to pin 45 of STM32F030C8Tx. Pin 42 and pin 44 are connected to the full-bridge drive circuit of the inverter circuit module, which is responsible for driving the full-bridge drive circuit to realize the inversion from direct current to alternating current. C7, C8, C9 and C10 are MLCC capacitors responsible for filtering power supply noise. R14 and C6 are a reset circuit that provides a reset signal to the MCU.

[0026] The utility model discloses a device working process is as follows, power module is responsible for the power supply of MCU module, drive circuit module and inverter circuit module, guarantees its normal work. MCU module carries out corresponding command through the program that has burnt, and MCU module sends drive signal to inverter circuit module, and inverter circuit module according to drive signal to the isolated 24V direct current of power module supply passes through full bridge drive circuit inverter as alternating current and exports to probe part, and detection circuit module is responsible for detecting the voltage signal of each probe, if metal public probe 1 and water level detection probe form a loop through water, then the corresponding resistance that is in series with probe will produce voltage signal, and detection circuit module is responsible for the voltage signal and does rectification filtering processing, and sends into the ADC mouth of MCU module and carries out detection and logic judgment, to this to control drive circuit module signal transmission, to realize the operation or stop of water pump motor, reach the effect that water level detection intelligent control water pump pumping and drainage. The utility model discloses a device uses circuit structure simple, and cost is low and reliability is high;The circuit can be directly transplanted to the water pump control circuit, need not external sensor, can complete the switching of use scene quickly, the utility model discloses the probe supplies for the alternating current square wave signal, effectively avoided the problem that the water scale accumulation caused by cathode always fixed, if need to clean directly take out the probe and clean the probe, and maintenance is convenient.

[0027] The above embodiments are only part of the embodiments of the utility model, rather than all the embodiments. Based on the embodiments in the utility model, all other embodiments obtained by those skilled in the art without creative labor belong to the scope of protection of the utility model.

Claims

1. A contact type AC water level detecting device, characterized by: The MCU module is connected with a driving circuit, a detection circuit module and an inverter circuit module.

2. The contact AC type water level detecting device according to claim 1, wherein: The at least one water level detection probe includes a water level probe one (2), a water level probe two (3) and a water level probe three (4).

3. The contact AC type water level detecting device according to claim 2, wherein: The power module includes electrolytic capacitors E1, MLCC capacitors C12, electrolytic capacitors E2 and MLCC capacitors C11 connected in parallel.

4. The contact AC type water level detecting device according to claim 3, wherein: The detection circuit module is connected with the water level probe one (2), the water level probe two (3) and the water level probe three (4) through an RC filter circuit.

5. The contact AC type water level detecting device according to claim 4, wherein: The MCU module adopts a single-chip microcomputer model STM32F030C8Tx, the pins 10, 11 and 12 of the STM32F030C8Tx are connected with the water level probe one (2), the water level probe two (3) and the water level probe three (4) respectively, and the pins 42 and 44 of the STM32F030C8Tx are connected with the full-bridge driving circuit of the inverter circuit module.

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