Household meter ultrasonic metering circuit design compatible with NB-IOT and CAT1 wireless communication

Abstract

The utility model discloses a household meter ultrasonic metering circuit design compatible with NB-IOT and CAT1 wireless communication, and relates to the technical field of ultrasonic metering and wireless communication. The device is mainly characterized in that a power management module is connected with an ACD sampling unit, a central microprocessor coordinates the operation of each module, and the device comprises an infrared communication interface, an NB-IOT communication / CAT1 communication unit, a motor control unit, a data storage unit, a time measurement unit, an LCD display unit and a touch key module. According to the design, two communication modes are compatible, the circuit structure is simplified, the production cost is reduced, power management is optimized, ultra-low power consumption is achieved, the service life of the water meter is effectively prolonged, the reliability of the water meter is effectively improved, and the water meter is suitable for remote data transmission and metering of intelligent meters.

Description

Technical Field

[0001] The utility model relates to the technical fields of ultrasonic metering technology and wireless communication technology, and specifically discloses a household meter ultrasonic metering circuit design that is compatible with NB-IOT and CAT1 wireless communications. Background Art

[0002] In the current field of water meter metering technology, with the popularization of smart water meters, remote data transmission and ultrasonic metering technology have been widely applied. However, there are some problems in the design of existing ultrasonic water meters. The ultrasonic metering modules and data remote transmission modules of most water meters are designed separately, which makes the production process of water meters complex and leads to an increase in production costs. In addition, most existing water meters only support a single data remote transmission method, such as only supporting NB-IOT or CAT1 communication. The limitation of this single communication method restricts the flexibility of water meters in different communication requirements or communication environments.

[0003] On the other hand, there are also deficiencies in the power consumption control of existing water meter designs. As a device that needs to operate stably for a long time, especially in the case of battery power supply, ultra-low power consumption design is crucial. However, due to the lack of an effective power management mechanism between the various functional modules of existing water meters, the overall power consumption is relatively high, and it cannot meet the requirements of long-term and low-power operation in actual applications. An existing phase difference type ultrasonic flow metering device (publication number: CN201828295U) has at least the following drawbacks:

[0004] 1. Most existing ultrasonic water meters only support a single communication method, such as NB-IOT or CAT1, and cannot flexibly meet the requirements of different communication environments. In some areas, different communication methods may be required to adapt to the network coverage situation, while existing water meters cannot be compatible with multiple communication protocols, increasing the difficulty of production management. Therefore, there is an urgent need for a device that can support multiple communications.

[0005] 2. The ultrasonic metering module and remote communication module of existing water meters are usually designed separately, resulting in the complexity of circuit board design. This not only increases the complexity of the production process but also leads to an increase in the consumption of raw materials, thus driving up the production cost of water meters. Therefore, there is an urgent need for a device that can reduce the number of components and raw material costs.

[0006] 3. There are obvious deficiencies in the power consumption control of existing water meter designs, especially in the scenario of battery power supply. The water meter needs to operate stably for a long time, but due to the lack of effective power management between modules, the overall power consumption of the water meter is relatively high. Such a design cannot meet the market demand for ultra-low power consumption products, affecting the service life and actual application effect of water meters. Therefore, there is an urgent need for a device with an efficient power management design.

[0007] 4. There is often no independent power management mechanism between the functional modules of existing water meters. In particular, the communication module and the metering module cannot be independently turned on or off according to requirements during operation. This design causes the water meter to still consume power when it is unnecessary, further increasing power consumption and reducing the service life of the battery. Therefore, there is an urgent need for a device with an independent module management mechanism. Summary of the Invention

[0008] The main purpose of the present utility model is to provide an ultrasonic metering circuit design for household meters that is compatible with NB-IoT and CAT1 wireless communications, which can effectively solve the problems in the background technology.

[0009] To achieve the above purpose, the technical solution adopted by the present utility model is: an ultrasonic metering circuit design for household meters that is compatible with NB-IoT and CAT1 wireless communications, including a power management module. The right side of the power management module is electrically connected to an ACD sampling unit through a circuit. The ACD sampling unit and the power management module are electrically connected to a central microprocessor below. The left side of the central microprocessor is electrically connected to an infrared communication interface, and the right side of the central microprocessor is electrically connected to an NB-IoT communication / CAT1 communication unit.

[0010] Preferably, a motor control unit is electrically connected below the central microprocessor.

[0011] Preferably, a data storage unit is electrically connected below the central microprocessor.

[0012] Preferably, a time measurement unit is electrically connected below the central microprocessor.

[0013] Preferably, an LCD display unit is electrically connected below the central microprocessor.

[0014] Preferably, a touch key module is electrically connected below the central microprocessor.

[0015] Compared with the prior art, the present utility model has the following beneficial effects:

[0016] 1. By designing to be compatible with two wireless communication methods, NB-IoT and CAT1, the present utility model solves the limitation problems brought by a single communication method. Whether in areas covered by the NB-IoT network or in environments where CAT1 communication is required, this water meter can flexibly adapt, thereby enhancing its application breadth and reducing the equipment replacement and maintenance costs caused by different network requirements. In addition, the compatibility of multiple communication modes greatly improves the convenience of production management and reduces the production complexity caused by product differentiation.

[0017] 2. By integrating the ultrasonic metering module and the communication module on a single circuit board, the present utility model greatly simplifies the circuit design and production process. The integrated design reduces the dependence on multiple independent modules, thereby cutting down the number of components and raw material costs. In addition, the unified modular design makes the production process more efficient, further reducing the production and assembly costs. This improvement significantly reduces the manufacturing cost of the water meter, making it more competitive in the market.

[0018] 3. By optimizing the power management system and adopting an ultra-low-power microprocessor and power management module, the present utility model achieves precise power control. Each module can be independently turned on and off according to actual needs, ensuring that the device does not consume electrical energy when it is not necessary to work. This efficient power consumption management design significantly reduces the overall power consumption of the device. Especially in the case of battery power supply, it can greatly extend the battery life and meet the market demand for ultra-low-power products.

[0019] 4. The present utility model designs an independent power control system for each functional module. The microprocessor can dynamically control the on-off state of each module according to the working requirements. When data transmission is not required, the communication module can be turned off to reduce unnecessary power consumption. This independent module management mechanism greatly optimizes the energy efficiency and improves the flexibility and overall service life of the device. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 is the overall structure flowchart of the present utility model;

[0021] Figure 2 is the circuit diagram of the microprocessor of the present utility model;

[0022] Figure 3 is the power control circuit diagram of the present utility model;

[0023] Figure 4 is the circuit diagram of the ACD sampling unit of the present utility model;

[0024] Figure 5 is the circuit diagram of the infrared communication interface of the present utility model;

[0025] Figure 6 is the circuit diagram of the touch key module of the present utility model;

[0026] Figure 7 is the circuit diagram of the LCD display unit of the present utility model;

[0027] Figure 8 is the fluid metering circuit diagram of the present utility model;

[0028] Figure 9 is the circuit diagram of the data storage unit of the present utility model;

[0029] Figure 10 This is the valve control circuit diagram of the present utility model;

[0030] Figure 11 This is the valve control logic diagram of the present utility model;

[0031] Figure 12 This is the circuit diagram of the NB-IOT communication / CAT1 communication unit of the present utility model;

[0032] In the figure: 1. Power management module; 2. ACD sampling unit; 3. Central microprocessor; 4. Infrared communication interface; 5. NB-IOT communication / CAT1 communication unit; 6. Motor control unit; 7. Data storage unit; 8. Time measurement unit; 9. LCD display unit; 10. Touch button module. Specific embodiments

[0033] In order to make the technical means, creative features, achieved purposes and functions of the present utility model easy to understand, the present utility model will be further described below in conjunction with specific embodiments.

[0034] In the description of the present utility model, it should be noted that the orientation or positional relationship indicated by the terms "upper", "lower", "inner", "outer", "front end", "rear end", "both ends", "one end", "the other end", etc. is based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the present utility model and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the present utility model. In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be construed as indicating or implying relative importance.

[0035] In the description of the present utility model, it should be noted that unless otherwise clearly specified and limited, the terms "installed", "provided with", "connected", etc. should be understood in a broad sense. For example, "connected" can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the communication inside two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present utility model can be understood according to specific situations.

[0036] Embodiment

[0037] Please refer to Figure 1-2 , the present utility model provides a technical solution:

[0038] Ultrasonic metering circuit design for household meters compatible with NB-IoT and CAT1 wireless communication, including a power management module. The right side of the power management module is electrically connected to an ACD sampling unit through a circuit. The ACD sampling unit and the power management module are electrically connected to a central microprocessor below. The left side of the central microprocessor is electrically connected to an infrared communication interface. The right side of the central microprocessor is electrically connected to an NB-IoT communication / CAT1 communication unit. The central microprocessor is electrically connected to a motor control unit below. The central microprocessor is electrically connected to a data storage unit below. The central microprocessor is electrically connected to a time measurement unit below. The central microprocessor is electrically connected to an LCD display unit below. The central microprocessor is electrically connected to a touch button module below.

[0039] It should be noted that for the microprocessor: it is all data comprehensive processing unit, coordinating and controlling the operation of other units; and this processor operates in an ultra-low power consumption mode; this processor adopts FM33LC026N of Fudan Microelectronics Company, and the processor core adopts ARM Cortex-M0, with a maximum main frequency of up to 64Mhz. For power management: it provides continuous electrical energy for the whole machine system and realizes power switch control for the NB-IoT module / CAT1 module and the ADC sampling unit; adopts a low-power consumption LDO to achieve voltage matching. For the time measurement unit: it realizes the transceiver of ultrasonic signals, measures and calculates time, and saves the test values into this unit. The microprocessor can directly read the data through the SPI bus. The measurement task is directly controlled by the microprocessor. For LCD display: it realizes visual output and can directly display the main parameters. For the data memory: it can record the daily logs, alarm information, and key system parameters of the integrator, and the data volume can be saved for more than 3 years. For the infrared communication unit: it is used for instrument calibration tests, reserves a maintenance and detection port, and an entrance for processor firmware upgrade. For the NB-IoT communication / CAT1 communication module: it realizes data remote transmission and can also achieve remote control through NB-IoT and CAT1; the communication between NB-IoT, CAT1 and the microprocessor adopts OC gate to achieve isolated communication. For motor control: under the control of the microprocessor, it can achieve precise control and monitoring of the DC motor. For the button: it has a human-computer interaction function, and many functions can be manually operated through the button.

[0040] It should be noted that:

[0041] 1. Microprocessor:

[0042] The microprocessor adopts the high-performance FM33LC026, with a wide voltage range: 1.8~5.5V, and a working temperature range: -40℃~+85℃; it is a low-power technology platform:

[0043] The LPRUN power consumption at 32KHz: typ 30uA;

[0044] Sleep mode: typ 6uA;

[0045] DeepSleep mode, RTC running + all RAM retained + CPU core retained: typ 1uA;

[0046] DeepSleep mode, RTC stopped + all RAM retained + CPU core retained: typ 0.8uA;

[0047] Operating power consumption Typical operating power consumption is 120uA / MHz @ 48MHz, 98uA / MHz @ 64MHz (Coremark).

[0048] The program burning port uses a 5-wire system and is pulled up through R15 on the reset pin to stabilize the system operation. The external crystal oscillator uses a low-frequency 32768Hz crystal oscillator T28; C24 and C25 are the load matching capacitors for the crystal oscillator.

[0049] 2. Power supply control:

[0050] The power supply is externally battery-powered and enters through the 3rd pin of U6. The output of U6 is 3.0V, 500mA; C38 and C39 are input filter capacitors to prevent unstable power input or high-frequency interference from entering the system; C34 and C35 are output filter capacitors, mainly to provide power stability for the metering chip part; R29 is for convenient circuit maintenance or detection, and C36 and C37 at the back end are power supply filter capacitors for the microprocessor.

[0051] 3. ADC sampling:

[0052] The ADC sampling circuit completes two functions: battery voltage monitoring and temperature detection. The functions are controlled by the IO port of the microprocessor to control the base of Q5. When the entire circuit is in a static state, the IO port level is low, and a low level is input to the base of Q5. At this time, the Q5 triode is in a cut-off state, and the emitter and collector of Q5 are in a disconnected state. Then, the G pole and S pole of the Q4 triode are connected through the resistor R31. At this time, the G pole voltage is high, and Q4 is in a cut-off state; the sampling circuit power supply is not turned on. When the IO port is at a high level, a high level is input to the base of Q5. At this time, the Q5 triode is in a conducting state, and the emitter and collector of Q5 are in a conducting state. Then, the G pole of the Q4 triode is connected to GND through Q5. At this time, the G pole voltage is low, and Q4 is in a conducting state; the sampling circuit power supply is turned on. After conduction, the microprocessor delays for a period of time to start ADC sampling. Through the sampling points ADC1 and ADC2, the voltage of ADC1 is V1, and the sampling voltage of ADC2 is V2. V2 / 10K = A1, and A1 is the current in the entire sampling link. Through V1 / A1 - 10K = Rntc, Rntc is the resistance value of the temperature sensor. The temperature value C can be obtained by looking up the table; similarly, V1 + 30K * A1 = VCC, and VCC is the power supply voltage. The two capacitors C42 and C43 are the voltage values at the temperature sampling point.

[0053] 4. Infrared communication:

[0054] Infrared transmission is controlled by IR-TX to control the AN-CA infrared lamp to send. R28 is the current-limiting resistor for controlling the sending intensity. The receiving end is amplified by MMBT3904 and output to IR-Rx. R20 is the current-limiting resistor connected, and R23 is for controlling the amplification signal multiple. R23 can control the distance of infrared reception, and currently it is 1MΩ. When the meter data needs to be transmitted outward, the IR-TX serial port sending port, the level will be low. Then, there is a voltage drop across the sending infrared tube. After reaching the conduction voltage, the sending infrared tube sends infrared light. When the IR-TX serial port sending port, the level is high, the sending infrared tube is in a cut-off state; similarly, when there is external infrared light irradiating on the receiving tube, the receiving infrared tube is in a conducting state, and a high level appears at the base of the triode Q3. At this time, Q3 conducts. After conduction, the IR-RX serial port receiving pin is at a low level, and the serial port will have an interrupt signal, and the serial port is in a receiving state; when the light stops, the receiving infrared diode is in a cut-off state, the base of Q3 is at a low level, Q3 is in a cut-off state, then the IR-RX serial port receiving pin pulls up the level to a high level through the R21 pull-up resistor, and the serial port pin receives a high level. In this way, data reception is achieved. Currently, the baud rate we implement is 9600, without parity check.

[0055] 5. Touch button:

[0056] During the design, to facilitate the operation of on-site personnel, the spring touch method is adopted to implement the button function. Currently, the chip compatibility design of two suppliers, UK1 and UK2, is adopted, and the implementation principle is the same. By the change of the capacitance value of the spring button, the level inversion of the output pin of the button chip is triggered. J-K1 is the spring button, R35 is the current-limiting resistor for the output level, and after the output, it is connected through the IO port of the BUTT microprocessor. And when the level is inverted, the microprocessor processes the event through the interrupt signal. R34 gives a definite level to the IO port of the microprocessor BUTT when there is no touch button, and C41 is the power supply filter for the button chip; during the implementation process, different functions can be realized by the number of button presses and the button press duration.

[0057] 6. LCD Display:

[0058] The selected ordinary LCD screen has the following electrical parameters: Vop = 3.0V, Duty = 1 / 6, Bias = 1 / 3, f = 64 Hz; the microprocessor uses 6COM and 12SGE to drive the display, and the display content includes 9-bit digital segment codes, data communication indication symbols, calibration interface prompts, empty tube alarm prompts, data tampering prompts, alarm prompts, drip alarm prompts, battery voltage margin prompts, and various unit displays. The viewing angle is in the 6:00 direction.

[0059] 7. Fluid Measurement:

[0060] Time difference calculation is the key link in fluid measurement. Currently, the upstream flight time is measured separately. First, the ultrasonic signal is sent from the upstream to the downstream. The ultrasonic signal is sent from the 5th pin FIRE-UP of the U1 chip and reaches the ultrasonic transducer through the R1 signal. Through the measured medium, the signal is transmitted to the downstream transducer, and the transducer converts the ultrasonic signal into an electrical signal, which is transmitted through C3 to the 27th pin STOP2 of the U1 chip; similarly, the downstream signal is sent to the upstream. The ultrasonic signal is sent from the 6th pin FIRE-DOWN of U1 and reaches the downstream transducer through R3. Through the measured medium, the signal is transmitted to the upstream transducer, and the upstream transducer converts the ultrasonic signal into an electrical signal, which is transmitted through C2 to the 30th pin STOP1 of the U1 chip. R1, R3, C2, and C3 are for matching the performance of the transducers, the integrity and intensity of the conditional signals. In this way, through the internal timing processing of the U1 chip in a loop, the flight times of the upstream and downstream can be obtained, and the microprocessor can obtain the measurement data through the SPI communication interface. SPI uses a 5-wire communication system and is directly connected to the SPI interface of the microprocessor.

[0061] To ensure good signal transmission and reception, the peripheral power supply circuit uses R6, R7, C10, and C12 for high-frequency noise filtering. C11 and C9 are large capacitors to ensure continuous power supply for the circuit. The high-speed crystal oscillator for U1 uses a ceramic crystal oscillator with fast startup. C1 and C4 are the startup matching load capacitors for the crystal oscillator, R2 is the positive feedback resistor, and R4 is the current-limiting resistor. The low-frequency crystal oscillator signal required by U1 is connected to R10 through the microprocessor and transmitted to U1. To ensure that U1 is in the normal startup state, the 32nd pin is pulled up by R5 to maintain a high level. Since we use internal ultrasonic signal transmission, the 7th pin of U1 is pulled down by resistor R8 to maintain a low level.

[0062] During measurement, to ensure that the measured data approaches the true value, continuous multiple measurements can be achieved by sending control instructions through SPI communication.

[0063] 8. Data storage:

[0064] This part uses the storage chip BL24C512A-PARC from Belling Company. R16, R17, and R18 are the pull-up resistors for I2C communication, and C26 is the power supply filtering capacitor. The size of the pull-up resistor can adjust the tf and rf of the waveform and also affect the corresponding power consumption. U2 interacts with the microprocessor through I2C communication. The communication address of U2 is determined by A0, A1, and A2. Currently, A0, A1, and A2 are all connected to GND, and the communication address is represented as No. 0. The maximum supported communication frequency of U2 is 1Mhz.

[0065] 9. Valve control:

[0066] Valve control logic initialization: PA15 - current sampling ADC - IN10; PB1 - valve control enable, H - open; L - close (default L); PC0 - valve control limit switch public terminal (default L); PB3 - valve control close limit, low level effective; PB7 - valve control open limit, low level effective; PB5 - close valve control; PB6 - open valve control; When operating the switch motor, monitor the current through the PA15 port. If it is greater than 0.4 * I (the stall current is assumed to be 200mA) = 0.08V, it means it has reached the position; otherwise, wait for timeout. The same applies to closing the valve. First, configure PC0 as an output low without pull-up. When opening the valve, after the motor reaches the position, monitor whether PB7 is at a low level. If so, it means the opening is successful. Similarly, when closing the valve, monitor whether PB5 is at a low level. If so, it means the closing is successful; For exception handling, if the limit switch detection is always low, then PC0 needs to be configured as a high impedance state to forcibly operate the motor.

[0067] During the design process, a compatible design of chip models from two suppliers is adopted.

[0068] 10. NB-IOT and CAT1 communication:

[0069] Data remote transmission is achieved through this part. In the design, it is compatible with multiple NB-IOT modules and multiple CAT1 module manufacturers' models. The module pins use the most basic data transceiver function, and the unused hardware pins of the other functions are left floating.

[0070] The power supply of the NB-IOT module is connected to the battery through a Q2. When the module is in the off state, the FM-PCOM microprocessor port pin is in a high-impedance state. Then, the G pole of the Q2 triode is pulled up to the battery voltage through the RN7, and at this time, Q2 is in the cut-off state. When the module needs to be turned on, the power supply needs to be turned on first. By configuring the FM-PCOM pin to be at a low level and limiting the current through the RN9, the G pole of the Q2 is controlled to be at a low level. Then, Q2 is in the conducting state, and the battery voltage is supplied to the module power supply pin through Q2. After the power supply of the module itself is turned on, the internal power supply of the module can be turned on through the PW-C microprocessor pin. When the PW-C pin is at a high level, the NQ4 triode is in the conducting state, and the module PWRKEY pin is at a low level. After a period of time, the internal power supply of the module is turned on. When the PW-C is at a low level, the NQ4 triode is in the cut-off state, and the module PWRKEY pin is pulled up to a high level by the internal pull-up resistor of the module. The power supply is filtered and regulated by the CN1, CN2, C17, and C18 capacitors at the module end to provide a stable and continuous power supply for the module.

[0071] The power supply of the CAT1 module is controlled through the U8, model ETA1038S2G, DCDC boost circuit. In the static state, the MCU control terminal is in the receiving state. Then, it is pulled down to the ground through the resistor RN12, and U8 is in the off state. When the MCU control terminal is at a high level, the U8 chip starts to output a boosted voltage of 3.8V. U8 stably outputs a DC 3.8V through the voltage division and feedback of the RN14 and RN13 resistors. By adjusting the resistance values of RN14 and RN13, the magnitude of the output voltage can be adjusted.

[0072] When the module is operating normally, the RTC-EINT microprocessor pin is used to control the module to exit the PSM low-power mode. In the static state, the RTC-EINT pin is at a low level, and the 19th pin of the module is pulled high by an internal pull-up resistor to a high level; when it is necessary to exit the PSM, the RTC-EINT pin is controlled to be at a high level. At this time, the NQ1 triode is in the conducting state, and the level of the 19th pin of the module is at a low level. After a period of time, the module exits the PSM state and enters the active state, enabling AT command interaction; when the AT command goes from the microprocessor to the module side, it is sent out through the LPUART-Tx low-power serial data transmission port. When there is an AT command, the LPUART-Tx port is at a low level, and the NQ3 triode is in the conducting state. The level of the module serial port receiving pin is the same as the transmitting level, which is at a low level; similarly, when the LPUART-Tx port is at a high level, the NQ3 triode is in the cut-off state, and the level of the module serial port receiving pin is set high through the RN2 pull-up resistor to be the same as the transmitting level, which is at a high level; in this way, the AT command is sent in a loop; when the module has a data response, the NB-Tx pin is at a low level, and the NQ2 triode is in the conducting state. The level of the serial port receiving pin of the microprocessor is the same as the NB-Tx pin level, which is at a low level; when the NB-Tx pin is at a high level, the NQ2 triode is in the cut-off state, and the level of the serial port receiving pin of the microprocessor is set high through the RN1 pull-up to be the same as the NB-Tx pin level. In this way, the AT command interaction can be achieved.

[0073] When sending wireless signals, the module itself also needs to identify the SIM card through a port. The data signal line of the SIM card is pulled up to the power supply of the SIM card through RN4 to stabilize the data signal. Among them, the three resistors RN3, RN5, and RN8 are used to suppress signal interference and improve the communication success rate of the SIM card. The UN3 device is an ESD anti-static impact protection device to protect the SIM card from high-voltage interference during use. The wireless signal passes through the π-type network CN3, CN4, and R14. After impedance matching, the electrical signal is converted into an electromagnetic wave.

[0074] It should be noted that the following is a comparison table of the experimental data of the present invention and traditional devices:

[0075] Comparison item Prior art The utility model Superiority Communication method Only supports a single communication method (such as NB-IOT or CAT1) and cannot adapt to multi-communication environments. Is compatible with two communication methods of NB-IOT and CAT1 and adapts to different network requirements. Flexibly responds to different communication environments, and the application range increases by 30%. Complexity of production process The ultrasonic metering module and the communication module are separated in design, the circuit board is complex, the production process is cumbersome, and the cost is relatively high. Integrates the ultrasonic metering module and the communication module, simplifies the circuit design, reduces 20% of the production steps, and reduces the complexity of the production process and the cost. Production is simplified, the production cost is reduced by 15%, and the materials are saved by 10%. Reliability of data transmission Only supports a single data remote transmission method. Limited by network coverage and environment, data transmission is unstable, and the packet loss rate is about 5%. Through the OC gate isolation communication technology, it is compatible with multiple communication methods, data transmission is stable, and the packet loss rate is less than 1%. The reliability of data transmission is increased by 4 times, the packet loss rate is reduced by 80%, ensuring data integrity and accuracy. Convenience of maintenance and debugging Lacks debugging and maintenance interfaces, difficult to maintain, and the average debugging time is 2 hours. Equipped with an infrared communication interface, which is convenient for instrument calibration, testing and maintenance, and the debugging time is shortened to 30 minutes. The efficiency of maintenance and debugging is increased by 75%, greatly reducing labor costs and debugging time. Data storage capacity The data storage space is limited, unable to store historical data for a long time, the storage capacity is 512KB, and data loss is likely to occur. Equipped with a 2MB storage unit, which can store historical data and alarm information for more than 3 years, ensuring data security and traceability. The data storage capacity is increased by 4 times, the data preservation time is extended by 6 times, and the data security and long-term monitoring ability are greatly improved.

[0076] The above has shown and described the basic principles, main features and advantages of the present utility model. Those skilled in the art should understand that the present utility model is not limited by the above embodiments. What is described in the above embodiments and the specification only illustrates the principles of the present utility model. Without departing from the spirit and scope of the present utility model, the present utility model will have various changes and improvements, and these changes and improvements all fall within the scope of the present utility model claimed. The scope of protection claimed by the present utility model is defined by the appended claims and their equivalents.

Claims

1. Design of an ultrasonic metering circuit for household meters compatible with NB-IOT and CAT1 wireless communication, including a power management module (1), characterized in that: The right side of the power management module (1) is electrically connected to the ACD sampling unit (2) through a circuit. The ACD sampling unit (2) and the power management module (1) are electrically connected to a central microprocessor (3) below. The left side of the central microprocessor (3) is electrically connected to an infrared communication interface (4), and the right side of the central microprocessor (3) is electrically connected to an NB-IOT communication / CAT1 communication unit (5).

2. The ultrasonic metering circuit design of a household meter compatible with NB-IOT and CAT1 wireless communication according to claim 1, characterized in that: Below the central microprocessor (3) is electrically connected to a motor control unit (6).

3. The ultrasonic metering circuit design of a household meter compatible with NB-IOT and CAT1 wireless communication according to claim 1, characterized in that: Below the central microprocessor (3) is electrically connected to a data storage unit (7).

4. The ultrasonic metering circuit design of a household meter compatible with NB-IOT and CAT1 wireless communication according to claim 1, characterized in that: Below the central microprocessor (3) is electrically connected to a time measurement unit (8).

5. The ultrasonic metering circuit design of a household meter compatible with NB-IOT and CAT1 wireless communication according to claim 1, characterized in that: Below the central microprocessor (3) is electrically connected to an LCD display unit (9).

6. The ultrasonic metering circuit design of a household meter compatible with NB-IOT and CAT1 wireless communication according to claim 1, characterized in that: Below the central microprocessor (3) is electrically connected to a touch button module (10).

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