A circuit structure for water pump flow measurement

Abstract

The application relates to the technical field of water pump flow measurement, and provides a circuit structure for water pump flow measurement, which comprises a power supply circuit, a single-chip microcomputer circuit and display circuit, 485 circuit, 4G signal transmission circuit, three-phase current voltage acquisition circuit, key circuit and alarm circuit which are simultaneously connected with the power supply circuit and the single-chip microcomputer circuit, the single-chip microcomputer circuit comprises a main control chip, the main control chip adopts an STM32F103VET6 microcontroller, a built-in FLASH memory is used for storing program codes and flow calculation algorithms, and a plurality of general-purpose input and output pins of the main control chip are used for signal interaction. The application can quickly and accurately complete the water pump flow measurement task, effectively solves the problems of insufficient precision, slow response and weak anti-interference ability existing in traditional measurement technology, and provides a more reliable and intelligent solution for water pump flow measurement.

Description

Technical Field

[0001] This application relates to the field of water pump flow measurement technology, and specifically to a circuit structure for water pump flow measurement. Background Technology

[0002] In the current field of water pump flow measurement, traditional measurement methods have certain limitations. For example, mechanical flow meters are easily affected by impurities, leading to wear and blockage, resulting in decreased measurement accuracy and a shorter lifespan. Electromagnetic flow meters are effective for measuring conductive liquids, but are expensive and have poor accuracy for low-conductivity liquids. While ultrasonic flow meters offer the advantage of non-contact measurement, they have strict requirements for the installation environment and lack stability in liquids containing air bubbles or impurities. Furthermore, existing integrated circuit systems used in water pump flow measurement also suffer from weak anti-interference capabilities, complex signal processing, and slow response speeds, making it difficult to meet the demands of modern industrial production for high-precision, fast-response, and stable measurement of water pump flow under complex operating conditions. Utility Model Content

[0003] To help solve the above-mentioned technical problems, this application provides a circuit structure for measuring the flow rate of a water pump, adopting the following technical solution: A circuit structure for measuring the flow rate of a water pump, comprising: The circuit includes a power supply circuit, a microcontroller circuit, a display circuit that connects both the power supply circuit and the microcontroller circuit, a 485 circuit, a 4G signal transmission circuit, a three-phase current and voltage acquisition circuit, a keypad circuit, and an alarm circuit. The microcontroller circuit includes a main control chip, which uses an STM32F103VET6 microcontroller. The built-in FLASH memory is used to store program code and flow calculation algorithms. The main control chip has multiple general-purpose input / output pins for signal interaction. The button circuit includes a DC power supply module, a pull-up resistor array, four independent button switches, an adjustable potentiometer array, a ceramic capacitor array, and a GND grounding network. The DC power supply is connected to the input terminals of the four independent button switches to form a high-level pull-up path. The button output terminal is directly connected to pin 1 of the corresponding potentiometer to form a button signal output channel. The potentiometer pin 2 is connected in parallel with the button output terminal, and pin 3 is grounded through a capacitor to form an RC filter network. The negative terminals of all capacitors are connected to the GND grounding network to form a complete signal conditioning circuit. The alarm circuit includes a power supply module, an NPN transistor, a freewheeling diode, a buzzer, a base bias resistor, and a signal current limiting resistor. The positive terminal of the DC power supply is connected to the anode of the freewheeling diode and the collector of the NPN transistor through a parallel path. The cathode of the freewheeling diode is connected to the collector of the NPN transistor and the positive terminal of the buzzer at the same point to form a freewheeling protection circuit. The base of the NPN transistor receives the control signal output by the microcontroller circuit through the signal current limiting resistor, and is grounded through the base bias resistor to form a voltage divider bias network. The emitter is directly grounded. The negative terminal of the buzzer is connected to the collector of the NPN transistor to form a switch drive path.

[0004] Preferably, the power supply circuit includes an input filter capacitor assembly, a switching regulator, an inductor, an output rectifier assembly, a linear regulator, an output filter capacitor assembly, and a TVS diode. The input filter capacitor assembly is connected to the input terminal of the switching regulator. The output terminal of the switching regulator is connected to the output rectifier assembly via an inductor. The output rectifier assembly is connected to the input terminal of the linear regulator. The output terminal of the linear regulator is connected to the output filter capacitor assembly. A TVS diode is connected in parallel between the power input terminal and ground to form a protection circuit.

[0005] Preferred, The display circuit includes a microcontroller interface pin group, a resistor array, a capacitor array, a connector, and a power supply module. The microcontroller interface pin group is directly connected to the corresponding pins of the connector via a resistor array; The capacitor array is connected in parallel between the DC power module and ground; The connector serves as an external interface for physical connection to the LCD display. The power module provides the operating voltage for the entire circuit.

[0006] Preferred, The 4G signal transmission circuit includes a MINI PCI-E interface circuit, a level conversion circuit, a SIM card circuit, and a power supply filtering auxiliary circuit. The MINI PCI-E interface circuit connects to the external 4G module via physical pins. Its signal pins are directly connected to the input of the level conversion circuit. The output of the level conversion circuit is connected to the SIM card circuit control pins and the subsequent data processing unit to achieve signal level matching. The SIM card circuit is connected to the level conversion circuit and the microcontroller via a dedicated signal line to complete the SIM card communication link. The power filtering auxiliary circuit is connected in parallel to the power input of each circuit, including a filter network and transient suppression components.

[0007] Preferred, The three-phase current and voltage acquisition circuit includes a metering chip, an input connector, an output control connector, a 485 communication transmitting connector, and a receiving connector. The input connector connects to the corresponding analog input pins of the metering chip via differential signal pairs. Simultaneously, the three-phase voltage and neutral wire are connected to the metering chip. The output control connector integrates the digital power supply VCC pin and GND pin, and the serial data TXD pin and RXD pin, which are connected to the corresponding functional pins of the metering chip. The 485 communication transmitting connector connects to the serial transmitting end of the metering chip via the PA2_TX_485 pin, and the receiving connector connects to the serial receiving end of the chip via the PA3_RX_485 pin.

[0008] Preferably, the 485 circuit includes a DC / DC isolation module, an optocoupler isolation chip, a 485 transceiver, a resettable fuse, a TVS diode, and an array of resistor-capacitor auxiliary components. The DC / DC isolation module is connected to a DC 5V power supply and ground on the input side, and a 5V_485 isolated power supply and a GND_485 isolated ground on the output side. The VDD1 of the optocoupler isolation chip is connected to DC3.3, GND1 is grounded, the 485_TXD3 and 485_RXD3 pins are connected to external control signals, VOA and VOB receive the RE and DE pins of the transmitter respectively, VIA and VIB receive the RO and DI pins of the transmitter respectively, VDD2 is connected to 5V_485, and GND2 is connected to GND_485. The VCC of the 485 transceiver is connected to 5V_485, and GND is connected to GND_485. The RO, RE, DE, and DI pins are connected to the corresponding pins of the optocoupler. The A / B pins are connected to the 485 bus via a resettable fuse and a TVS diode. A resettable fuse is connected in series between the transceiver A / B pins and the bus, and a TVS diode is connected in parallel between the bus A / B and GND_485; The array of resistors and capacitors is distributed in the power supply path and signal path.

[0009] Preferred, The microcontroller circuit includes a main control chip, a power network, a JTAG debugging interface, a main crystal oscillator circuit, a power-on reset module, a BOOT0 boot mode selection circuit, a four-way keypad input array, a three-color LED indicator module, an active buzzer driver circuit, an RS-485 communication interface, a USB full-speed interface, and an LCD display interface. The main control chip is connected to a backup power supply via the VBAT pin, VDD_1-VDD_4 and VDDA pins are connected in parallel to the main power supply, and VSS_1-VSS_4 and VSSA pins are grounded to form a power supply loop. The JTAG debugging interface is connected to a debugger via the PA13 / JTMS and PA14 / JTCK pins for online programming and hardware breakpoint debugging. The main crystal oscillator circuit is used to generate the system clock together with the internal phase-locked loop. The power-on reset module is connected to an RC reset circuit via the NRST pin. The BOOT0 pin is grounded through a 10KΩ resistor and configured for system memory boot mode. The keypad input array is used to provide user input functionality, and the active buzzer is driven via the PC10 pin.

[0010] In summary, this application can quickly and accurately complete the task of measuring water pump flow, effectively solving the problems of insufficient accuracy, slow response, and weak anti-interference ability of traditional measurement technologies, and providing a more reliable and intelligent solution for water pump flow measurement. Attached Figure Description

[0011] Figure 1 This is a circuit diagram of the power supply circuit of this application; Figure 2 This is a circuit diagram of the display circuit of this application; Figure 3 This is a circuit diagram of the 485 circuit of this application; Figure 4 This is a circuit diagram of the 4G signal transmission circuit of this application; Figure 5 This is a circuit diagram of the three-phase current and voltage acquisition circuit of this application; Figure 6 This is a circuit diagram of the microcontroller circuit of this application; Figure 7 This is a circuit diagram of the button circuit of this application; Figure 8 This is a circuit diagram of the alarm circuit of this application. Detailed Implementation

[0012] The present application will be further described below with reference to the accompanying drawings. The structure and principle of the present application are very clear to those skilled in the art. It should be understood that the specific embodiments described herein are merely illustrative of the present application and are not intended to limit the present application.

[0013] The circuit structure for measuring water pump flow in this application includes: The circuit includes a power supply circuit, a microcontroller circuit, a display circuit that connects both the power supply circuit and the microcontroller circuit, a 485 circuit, a 4G signal transmission circuit, a three-phase current and voltage acquisition circuit, a keypad circuit, and an alarm circuit. The microcontroller circuit includes a main control chip, which uses an STM32F103VET6 microcontroller. The built-in FLASH memory is used to store program code and flow calculation algorithms. The main control chip has multiple general-purpose input / output pins for signal interaction. The button circuit includes a DC 3.3V power supply module, a 10K pull-up resistor array (R33-R36), four independent push-button switches (KKEY1-KKEY4), an adjustable potentiometer array (W1-W4), a 104 ceramic capacitor array (C52-C55), and a GND grounding network. The DC 3.3V power supply is connected to the input terminals of the KKEY1-KKEY4 buttons through resistors R33-R36, forming a high-level pull-up path. The button output terminals are directly connected to pin 1 of the corresponding potentiometers W1-W4, forming the button signal output channel. The potentiometer pin 2 is connected in parallel with the button output terminal, and pin 3 is grounded through capacitors C52-C55, forming an RC filter network. The negative terminals of all capacitors are connected to the GND grounding network, forming a complete signal conditioning circuit.

[0014] The DC 3.3V power module provides a stable low-voltage power supply for the button circuit, ensuring reliable operation of the digital circuit. A 10K pull-up resistor array maintains a high level when the button is not triggered; when the button is pressed, a low-level signal is generated through resistor division, enabling level detection of the button status. An independent push-button switch serves as the user input trigger element, changing the circuit level through mechanical contact, supporting function selection and parameter setting. An adjustable potentiometer array optimizes the button trigger threshold and debouncing time parameters by adjusting the resistance values ​​between pins, adapting to different operating habits and environmental conditions. A 104 ceramic capacitor array and potentiometers form an RC low-pass filter, filtering out high-frequency noise generated by button mechanical bounce and ensuring signal stability. A GND grounding network provides a stable zero-potential reference point, ensuring potential consistency and anti-interference capabilities for all components.

[0015] This circuit achieves reliable acquisition and anti-interference processing of button signals through a combination of pull-up resistors, potentiometer adjustment, and RC filtering, making it particularly suitable for scenarios in industrial control equipment that require highly reliable user input.

[0016] The alarm circuit includes a DC5V power supply module, a T8050 NPN transistor Q2, an LL4148 freewheeling diode D1, a BELL buzzer, a 2K base bias resistor R30, and a 1K signal current limiting resistor R23.

[0017] The positive terminal of the DC5V power supply is connected in parallel to the anode of diode D1 and the collector of transistor Q2. The cathode of diode D1, the collector of transistor Q2, and the positive terminal of the buzzer are connected at the same point to form a freewheeling protection circuit. The base of transistor Q2 receives the beep control signal through resistor R23 and is grounded through resistor R30 to form a voltage divider bias network. The emitter is directly grounded. The negative terminal of the buzzer is connected to the collector of transistor Q2 to form a switch drive path.

[0018] DC5V power supply module: Provides a stable operating voltage for the alarm circuit, ensuring reliable operation of the buzzer and transistor. T8050 NPN transistor: As an electronic switching device, it controls the on / off state of the buzzer under the control of the beep signal (control signal). It conducts when the base current reaches a threshold, driving the buzzer to sound. LL4148 freewheeling diode: Connected in parallel across the buzzer, it provides a reverse electromotive force discharge path at the moment the transistor turns off, preventing high voltage from damaging the transistor. BELL buzzer: Converts electrical signals into sound wave signals, enabling audio feedback functions such as fault alarms and status prompts. 2K base bias resistor R30: Forms a voltage divider network with R23, providing a suitable base bias voltage for the transistor, ensuring it is in the off state when static. 1K signal current limiting resistor R23: Limits the beep signal input current, preventing overcurrent damage to the transistor and simultaneously achieving signal level matching.

[0019] This circuit achieves a highly reliable and low-power alarm function through a combination of transistor switch driving, diode freewheeling protection, and resistor network design. It is particularly suitable for scenarios in water pump flow measurement systems that require fault alarms and status indications.

[0020] The power supply circuit includes an input filter capacitor assembly, a switching regulator BL8033CB6TR, an inductor, an output rectifier assembly, a linear regulator AMS1117-3.3, an output filter capacitor assembly, and a TVS diode D16.

[0021] The input filter capacitor assembly is connected to the input terminal of the switching regulator BL8033CB6TR; the output terminal of the switching regulator is connected to the output rectifier assembly via an inductor; the output rectifier assembly is connected to the input terminal of the linear regulator AMS1117-3.3; the output terminal of the linear regulator is connected to the output filter capacitor assembly; the TVS diode D16 is connected in parallel between the power input terminal and ground to form a protection circuit.

[0022] The input filter capacitor assembly filters out high-frequency noise and ripple from the input power supply, providing a smooth input voltage. The BL8033CB6TR switching regulator achieves a 12V to 5V step-down conversion through high-frequency switching operation, improving power conversion efficiency. The inductor stores and transfers energy, working with the switching regulator to complete voltage regulation. The output rectifier assembly rectifies the AC voltage output from the inductor into a DC voltage. The AMS1117-3.3 linear regulator further stabilizes the 5V voltage to 3.3V, providing a precise DC output for the system. The output filter capacitor assembly filters out residual ripple in the output voltage, ensuring stable voltage at the load end. The TVS diode D16 suppresses transient voltage surges (such as ESD or voltage spikes), ensuring the circuit's anti-interference capability and operational reliability.

[0023] This circuit achieves efficient conversion from 12V input to a stable 3.3V output through multi-stage voltage conversion and protection design. At the same time, it enhances surge protection capability through TVS diodes, meeting the stable measurement requirements under complex operating conditions.

[0024] The display circuit includes a microcontroller interface pin group, a 33R resistor array, a multi-value capacitor array, a 16×2 connector P2, and a DC3.3V power supply module.

[0025] The microcontroller interface pin group (CS_LCD, RES_LCD, RS_LCD, WR_LCD, RD_LCD and DB0_LCD-DB7_LCD) is directly connected to the corresponding pins of the 16×2 connector P2 via a 33R resistor array; a multi-value capacitor array (C1 / C3 / C4 / C7 / C19 / C21 / C26 / C29 / C33 / C38 / C42, etc.) is connected in parallel between the DC3.3V power supply and ground; the 16×2 connector P2 serves as the external interface and is physically connected to the LCD display; the DC3.3V power supply module provides a stable operating voltage for the entire circuit.

[0026] The microcontroller interface pin group enables communication and control with the LCD. CS_LCD handles device selection, RES_LCD performs hardware reset, RS_LCD switches between instruction and data modes, WR_LCD / RD_LCD controls data read / write, and DB0-DB7 form an 8-bit parallel data bus. A 33R resistor array acts as a current-limiting protection element to prevent damage to the microcontroller interface pins due to overload. A multi-value capacitor array uses different capacitance combinations to achieve wide-band power filtering, suppressing high-frequency noise and voltage fluctuations in the DC3.3V power supply. The 16×2 connector P2 provides a standardized physical interface, enabling reliable electrical connection and signal transmission between the circuit and the LCD display. The DC3.3V power module provides a stable low-voltage power supply to the display circuit and LCD that meets the requirements of the STM32 microcontroller system.

[0027] The 485 circuit includes a DC / DC isolation module B0505S-1W, an optocoupler isolation chip 131U31, a 485 transceiver BL3085, a resettable fuse (1206 200MA 30V 0.2A), a TVS diode SMBJ6.8CA, and an array of resistors and capacitors.

[0028] The DC / DC isolation module's input side is connected to a 5V DC power supply and ground, while the output side provides a 5V 485 isolated power supply and a GND 485 isolated ground. The optocoupler isolation chip's VDD1 is connected to DC 3.3V, GND1 is grounded, and the 485_TXD3 / 485_T / R3 / 485_RXD3 pins are connected to external control signals. The VOA / VOB receiver / transmitter's RE / DE pins and the VIA / VIB receiver / transmitter's RO / DI pins are also connected. VDD2 is connected to 5V 485, and GND2 is connected to GND 485. The 485 receiver... The transceiver's VCC is connected to 5V_485, and GND is connected to GND_485. The RO / RE / DE / DI pins are connected to the corresponding pins of the optocoupler. The A / B pins are connected to the 485 bus via a resettable fuse and a TVS diode. The resettable fuse is connected in series between the transceiver's A / B pins and the bus, and the TVS diode is connected in parallel between the bus A / B and GND_485. The array of resistors and capacitors is distributed in the power path and signal path, including 104 / 102 capacitors for filtering and 4.7K resistors for signal pull-up / pull-down.

[0029] DC / DC isolation module: Achieves power isolation through magnetic isolation, blocking common-mode interference paths and improving the system's anti-interference capability; Optocoupler isolation chip: Achieves electrical isolation between control signals and bus signals, preventing ground loop interference and surge impacts from intruding into the control system; 485 transceiver: Performs bidirectional conversion between TTL level and RS-485 differential signals, supporting multi-point communication and long-distance transmission; Self-resetting fuse: Blows to protect the transceiver during bus overcurrent, automatically restoring conduction after fault clearance, ensuring continuous circuit operation; TVS diode: Clamps transient overvoltages on the bus to a safe range, preventing damage to the transceiver due to surge events such as lightning strikes and static electricity; Resistor and capacitor auxiliary components: Capacitors filter high-frequency noise from the power supply, and resistors set the default signal level, jointly ensuring signal integrity and circuit stability.

[0030] The 4G signal transmission circuit includes a MINI PCI-E interface circuit, a level conversion circuit, a SIM card circuit, and a power supply filtering auxiliary circuit.

[0031] The MINI PCI-E interface circuit connects to the external 4G module via physical pins, and its signal pins are directly connected to the input of the level conversion circuit. The output of the level conversion circuit is connected to the SIM card circuit control pins and subsequent data processing units to achieve signal level matching. The SIM card circuit is connected to the level conversion circuit and the microcontroller via dedicated signal lines (such as SIM_DATA, SIM_CLK, SIM_RST) to complete the SIM card communication link. The power filtering auxiliary circuit is connected in parallel to the power input of each functional module, including a π-type filter network (capacitor + inductor + capacitor) and transient suppression components.

[0032] The three-phase current and voltage acquisition circuit includes an IM3331 metering chip, a Header 4 type input connector J1, an output control connector P4, a 485 communication transmitting connector P5, and a receiving connector P6.

[0033] Input connector J1 is directly connected to the corresponding analog input pin of IM3331 through differential signal pairs (IA± / IB± / IC±), while the three-phase voltages A / B / C and neutral line N are connected to the chip through a voltage divider network. The output control connector P4 integrates digital power supply VCC / GND and serial data TXD / RXD, which are connected one-to-one with the corresponding function pins of the IM3331. The 485 communication transmitter connector P5 is connected to the serial transmitter of the IM3331 via the PA2_TX_485 pin, and the receiver connector P6 is connected to the serial receiver of the chip via the PA3_RX_485 pin, forming a complete 485 communication link.

[0034] The microcontroller circuit includes an STM32F105RCT6 main control chip, a 3.3V power supply network, a JTAG debugging interface, an 8MHz main crystal oscillator circuit, a power-on reset module, a BOOT0 startup mode selection circuit, a four-way key input array, a three-color LED indicator module, an active buzzer driver circuit, an RS-485 communication interface, a USB 2.0 full-speed interface, and an LCD display interface.

[0035] The main control chip is connected to the backup power supply via the VBAT pin. The VDD_1-VDD_4 and VDDA pins are connected in parallel to the 3.3V main power supply. The VSS_1-VSS_4 and VSSA pins are grounded to form a power supply loop. The JTAG debugging interface is connected to the debugger via the PA13 / JTMS and PA14 / JTCK pins, supporting in-circuit programming and hardware breakpoint debugging. The 8MHz main crystal oscillator is connected via the OSC_IN / PD0 and OSC_OUT / PD1 pins, working with the internal PLL to generate a 72MHz system clock. The power-on reset module is connected to the RC reset circuit via the NRST pin to ensure reliable reset upon system power-on. The BOOT0 pin is grounded via a 10KΩ resistor and configured for system memory boot mode. The key input array is connected via PB2 / BOOT1, PB3 / JTDO, and PC. Pins 24 / KEY4 and PC25 / KEY3 are connected to enable user input. The tri-color LED module is driven through pins PC13 / TAMPER-RTC, PC14 / OSC32_IN, and PC15 / OSC32_OUT, supporting RGB status indication. The active buzzer is driven through pin PC10, working with a transistor to achieve audible and visual alarm functions. The RS-485 communication interface is connected through pins PA2 / 485_TXD1, PA3 / 485_RXD1, and PA4 / 485_T / R1, supporting half-duplex communication protocol. The USB 2.0 interface is connected through pins PA11 / USBD+ and PA12 / USBD-, supporting full-speed data transmission. The LCD display interface is connected through pins PB5-PB9, enabling parallel data transmission and control signal interaction.

[0036] This overall circuit system uses the STM32F105RCT6 microcontroller as its core and achieves water pump flow measurement and intelligent management through multi-module collaboration.

[0037] The power supply circuit provides a dual-channel regulated DC 3.3V / 5V power supply. After input filtering, switching regulation, and multi-stage capacitor filtering, it provides low-noise power to each module. The three-phase current and voltage acquisition circuit uses the IM3331 metering chip to synchronously acquire three-phase power frequency signals. After conversion by the built-in ADC, it communicates with the microcontroller through the SPI interface. The display circuit drives the LCD screen through control pins such as CS_LCD / RS_LCD to visualize parameters such as flow rate and pressure in real time. The 485 communication circuit integrates a DC / DC isolation module and an optocoupler isolation chip, and works with the BL3085 transceiver to achieve long-distance differential signal transmission, supporting the Modbus protocol. The 4G signal transmission circuit connects to external modules through the MINI PCI-E interface, and after level conversion by the TXS0108, it is connected to the SIM card circuit to achieve wireless remote data transmission. The button circuit uses a 10K pull-up resistor array and an RC filter network to support four independent button inputs and debouncing. The alarm circuit uses the microcontroller I / O port to drive the T8050 transistor to control the buzzer to sound, and works with the LL4148 freewheeling diode to suppress the reverse electromotive force. The system processes the collected data in real time through a microcontroller. When it detects excessive flow, abnormal parameters, or hardware failure, it triggers an alarm circuit with audible and visual prompts. At the same time, it uploads data to the cloud platform through the 485 / 4G interface, realizing fault self-diagnosis, remote monitoring, and intelligent decision-making, forming a closed-loop control system for the entire process, which meets the high precision and high reliability requirements of industrial-grade water pump flow measurement.

Claims

1. A circuit structure for measuring the flow rate of a water pump, characterized in that, include: The circuit includes a power supply circuit, a microcontroller circuit, a display circuit that connects both the power supply circuit and the microcontroller circuit, a 485 circuit, a 4G signal transmission circuit, a three-phase current and voltage acquisition circuit, a keypad circuit, and an alarm circuit. The microcontroller circuit includes a main control chip, which uses an STM32F103VET6 microcontroller. The built-in FLASH memory is used to store program code and flow calculation algorithms. The main control chip has multiple general-purpose input / output pins for signal interaction. The button circuit includes a DC power supply module, a pull-up resistor array, four independent button switches, an adjustable potentiometer array, a ceramic capacitor array, and a GND grounding network. The DC power supply is connected to the input terminals of the four independent button switches to form a high-level pull-up path. The button output terminal is directly connected to pin 1 of the corresponding potentiometer to form a button signal output channel. The potentiometer pin 2 is connected in parallel with the button output terminal, and pin 3 is grounded through a capacitor to form an RC filter network. The negative terminals of all capacitors are connected to the GND grounding network to form a complete signal conditioning circuit. The alarm circuit includes a power supply module, an NPN transistor, a freewheeling diode, a buzzer, a base bias resistor, and a signal current limiting resistor. The positive terminal of the DC power supply is connected to the anode of the freewheeling diode and the collector of the NPN transistor through a parallel path. The cathode of the freewheeling diode is connected to the collector of the NPN transistor and the positive terminal of the buzzer at the same point to form a freewheeling protection circuit. The base of the NPN transistor receives the control signal output by the microcontroller circuit through the signal current limiting resistor, and is grounded through the base bias resistor to form a voltage divider bias network. The emitter is directly grounded. The negative terminal of the buzzer is connected to the collector of the NPN transistor to form a switch drive path.

2. The circuit structure for measuring water pump flow rate according to claim 1, characterized in that, The power supply circuit includes an input filter capacitor assembly, a switching regulator, an inductor, an output rectifier assembly, a linear regulator, an output filter capacitor assembly, and a TVS diode. The input filter capacitor assembly is connected to the input terminal of the switching regulator. The output terminal of the switching regulator is connected to the output rectifier assembly via an inductor. The output rectifier assembly is connected to the input terminal of the linear regulator. The output terminal of the linear regulator is connected to the output filter capacitor assembly. A TVS diode is connected in parallel between the power input terminal and ground to form a protection circuit.

3. The circuit structure for measuring water pump flow rate according to claim 1, characterized in that, The display circuit includes a microcontroller interface pin group, a resistor array, a capacitor array, a connector, and a power supply module. The microcontroller interface pin group is directly connected to the corresponding pins of the connector via a resistor array; The capacitor array is connected in parallel between the DC power module and ground; The connector serves as an external interface for physical connection to the LCD display. The power module provides the operating voltage for the entire circuit.

4. The circuit structure for measuring water pump flow rate according to claim 1, characterized in that, The 4G signal transmission circuit includes a MINI PCI-E interface circuit, a level conversion circuit, a SIM card circuit, and a power supply filtering auxiliary circuit. The MINI PCI-E interface circuit connects to the external 4G module via physical pins. Its signal pins are directly connected to the input of the level conversion circuit. The output of the level conversion circuit is connected to the SIM card circuit control pins and the subsequent data processing unit to achieve signal level matching. The SIM card circuit is connected to the level conversion circuit and the microcontroller via a dedicated signal line to complete the SIM card communication link. The power filtering auxiliary circuit is connected in parallel to the power input of each circuit, including a filter network and transient suppression components.

5. The circuit structure for measuring water pump flow rate according to claim 1, characterized in that, The three-phase current and voltage acquisition circuit includes a metering chip, an input connector, an output control connector, a 485 communication transmitting connector, and a receiving connector. The input connector connects to the corresponding analog input pins of the metering chip via differential signal pairs. Simultaneously, the three-phase voltage and neutral wire are connected to the metering chip. The output control connector integrates the digital power supply VCC pin and GND pin, and the serial data TXD pin and RXD pin, which are connected to the corresponding functional pins of the metering chip. The 485 communication transmitting connector connects to the serial transmitting end of the metering chip via the PA2_TX_485 pin, and the receiving connector connects to the serial receiving end of the chip via the PA3_RX_485 pin.

6. The circuit structure for measuring water pump flow rate according to claim 1, characterized in that, The 485 circuit includes a DC / DC isolation module, an optocoupler isolation chip, a 485 transceiver, a resettable fuse, TVS diodes, and an array of resistors and capacitors. The DC / DC isolation module is connected to a DC 5V power supply and ground on the input side, and a 5V_485 isolated power supply and a GND_485 isolated ground on the output side. The VDD1 of the optocoupler isolation chip is connected to DC3.3, GND1 is grounded, the 485_TXD3 and 485_RXD3 pins are connected to external control signals, VOA and VOB receive the RE and DE pins of the transmitter respectively, VIA and VIB receive the RO and DI pins of the transmitter respectively, VDD2 is connected to 5V_485, and GND2 is connected to GND_485. The VCC of the 485 transceiver is connected to 5V_485, and GND is connected to GND_485. The RO, RE, DE, and DI pins are connected to the corresponding pins of the optocoupler. The A / B pins are connected to the 485 bus via a resettable fuse and a TVS diode. A resettable fuse is connected in series between the transceiver A / B pins and the bus, and a TVS diode is connected in parallel between the bus A / B and GND_485; The array of resistors and capacitors is distributed in the power supply path and signal path.

7. The circuit structure for measuring the flow rate of a water pump according to claim 1, characterized in that, The microcontroller circuit includes a main control chip, a power network, a JTAG debugging interface, a main crystal oscillator circuit, a power-on reset module, a BOOT0 boot mode selection circuit, a four-way keypad input array, a three-color LED indicator module, an active buzzer driver circuit, an RS-485 communication interface, a USB full-speed interface, and an LCD display interface. The main control chip is connected to a backup power supply via the VBAT pin, VDD_1-VDD_4 and VDDA pins are connected in parallel to the main power supply, and VSS_1-VSS_4 and VSSA pins are grounded to form a power supply loop. The JTAG debugging interface is connected to a debugger via the PA13 / JTMS and PA14 / JTCK pins for online programming and hardware breakpoint debugging. The main crystal oscillator circuit is used to generate the system clock together with the internal phase-locked loop. The power-on reset module is connected to an RC reset circuit via the NRST pin. The BOOT0 pin is grounded through a 10KΩ resistor and configured for system memory boot mode. The keypad input array is used to provide user input functionality, and the active buzzer is driven via the PC10 pin.

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