Vibration detection circuit for low-power-consumption ultrasonic intelligent gas meter

Abstract

The utility model relates to a vibration detection circuit of a low-power-consumption ultrasonic intelligent gas meter. The vibration detection circuit is used for converting the vibration amplitude into an electric signal by adopting an electromagnetic induction omnidirectional vibration sensor; the two-stage operational amplifier processing circuit comprises a first-stage operational amplifier circuit and a second-stage operational amplifier circuit and is used for filtering, decoupling and amplifying weak current signals output by the omnidirectional vibration sensor; the magnetic interference detection circuit adopts a magnetoresistive sensor to detect the change of an environment magnetic field and outputs a magnetic interference signal; and the output signal detection and judgment circuit converts the amplified signal into a high-low level signal through a triode, and a main control chip of the ultrasonic intelligent gas meter can combine the magnetic interference signal and the high-low level signal output by the triode to carry out dual verification so as to judge whether the vibration is effective vibration or not. According to the utility model, through collaborative optimization of electromagnetic sensing and a multi-stage circuit, detection reliability, omnidirectional response capability and intrinsic safety characteristics are considered, and the active safety protection efficiency of a gas circuit is remarkably improved.

Description

Technical Field

[0001] This utility model relates to a low-power ultrasonic smart gas meter vibration detection circuit. Background Technology

[0002] With the development of electronic technology, ultrasonic measurement technology has been widely used in the field of gas metering due to its advantages such as no mechanical parts, no pressure loss, and wide measurement range. Ultrasonic smart gas meters are characterized by high accuracy, long lifespan, and low maintenance, and are suitable for residential and industrial / commercial gas metering.

[0003] However, in practical applications, environmental vibrations (such as earthquakes, mechanical shocks, or equipment vibrations) pose a significant challenge to the metering performance of ultrasonic smart gas meters. Meter vibration has multiple impacts on ultrasonic smart gas meter measurement: In terms of measurement accuracy, vibration causes micro-displacement of the transducer, resulting in changes in sound path, leading to calculation errors, and exacerbating waveform distortion. Regarding measurement stability, vibration may cause the transducer to generate false signals. Long-term vibration can also reduce the durability of the equipment. In terms of measurement range, noise from vibration reduces the resolution of ultrasonic signals passing through low-velocity fluids, thus affecting the measurement performance of ultrasonic smart gas meters.

[0004] Currently, to reduce the impact of meter vibration on ultrasonic smart gas meter measurement, physical vibration reduction measures are generally adopted to optimize the installation environment and improve the equipment's vibration resistance. Existing solutions can effectively monitor whether vibration occurs in the environment surrounding the ultrasonic smart gas meter; however, the electromagnetic induction omnidirectional vibration sensor used in these solutions is susceptible to magnetic interference, leading to false readings. Furthermore, to avoid signal loss due to insufficient vibration signals to activate the transistor, the bias voltage of the inverting operational amplifier is raised to the transistor's activation voltage, causing the operational amplifier circuit to operate in an abnormal mode, resulting in significant power consumption. Existing solutions are reliable and practical in environments with AC power (ignoring power consumption) and minimal magnetic field interference, but they still have shortcomings in vibration resistance and power consumption. We optimize the vibration detection circuit of the ultrasonic gas meter through a two-stage operational amplifier signal processing circuit, further reducing power consumption while ensuring reliability. Utility Model Content

[0005] To address the problems existing in the prior art, the purpose of this utility model is to provide a technical solution for a low-power ultrasonic smart gas meter vibration detection circuit.

[0006] The low-power ultrasonic smart gas meter vibration detection circuit is characterized by comprising:

[0007] Vibration detection circuit: It adopts an electromagnetic induction omnidirectional vibration sensor to convert the vibration amplitude into an electrical signal;

[0008] Two-stage operational amplifier processing circuit: including a first-stage operational amplifier circuit and a second-stage operational amplifier circuit, which filters, decouples and amplifies the weak current signal output by the omnidirectional vibration sensor;

[0009] Magnetic interference detection circuit: Uses a magnetoresistive sensor to detect changes in the ambient magnetic field and outputs a magnetic interference signal;

[0010] Output signal detection and judgment circuit: The amplified signal is converted into high and low level signals through a transistor. The main control chip of the ultrasonic smart gas meter can perform dual verification by combining the magnetic interference signal and the high and low level signals output by the transistor to determine whether it is a valid vibration.

[0011] The vibration detection circuit for a low-power ultrasonic smart gas meter is characterized in that the vibration detection circuit uses an omnidirectional vibration sensor L1. The output signal of the omnidirectional vibration sensor L1 is filtered by capacitor C2 and decoupled by capacitor C4, and then input to the inverting input terminal of operational amplifier U1A through resistor R3.

[0012] The low-power ultrasonic smart gas meter vibration detection circuit is characterized by its two-stage operational amplifier processing circuit: the inverting input terminal of operational amplifier U1A receives a signal through resistor R3; feedback resistor R1 and capacitor C1 are connected in parallel to form a low-pass filter network to suppress high-frequency noise; the signal processed by operational amplifier U1A is input to the non-inverting input terminal of operational amplifier U1B; the closed-loop gain of operational amplifier U1B is determined by the resistance ratio of feedback resistor R6 to input resistor R5; resistor R6 and capacitor C7 are connected in parallel to form an RC feedback network; the RC combination realizes frequency response control; the output signal after the second-stage amplification is further filtered by the RC low-pass filter composed of resistor R4 and capacitor C5 before being input to the base of transistor Q1.

[0013] The vibration detection circuit for a low-power ultrasonic smart gas meter is characterized in that the output signal detection and judgment circuit has the collector of transistor Q1 connected to power supply VDD and the emitter of transistor Q1 grounded; when no vibration is detected, transistor Q1 is cut off and outputs a high level; when vibration is detected, transistor Q1 is turned on and outputs a low level.

[0014] This invention utilizes an electromagnetically inductive omnidirectional vibration sensor for vibration detection. The sensor generates a current upon the occurrence of a minor vibration. After filtering and decoupling, the current is input to a two-stage operational amplifier circuit, where it is amplified and output as a voltage. This voltage is then detected and judged by an output signal detection and judgment circuit. The ultrasonic smart gas meter determines whether vibration has occurred in real time by detecting high and low voltage levels. Simultaneously, this design incorporates a magnetoresistive sensor to detect magnetic interference signals. A dual verification process, using both the magnetic interference signal and the high and low voltage signals output by the transistor, is performed to determine whether the vibration is valid. This ensures the detection of minute vibration changes, exhibits high sensitivity, and provides a timely response to vibration signals.

[0015] 1. Employing an electromagnetic induction vibration sensor and signal processing circuitry, combined with filtering, decoupling, and operational amplifier amplification technologies, it can accurately capture weak vibration signals from the gas meter and its surrounding environment (such as illegal prying or disassembly). This ensures the detection of minute vibration changes, exhibits high sensitivity, and can respond promptly to vibration signals. Subsequently, data can be recorded using an ultrasonic smart gas meter controller for subsequent accident investigation and analysis. For example, an audible and visual alarm module can alert users to take appropriate measures, and the data can be transmitted in real-time to the gas company's back-end system. The gas company can then monitor the gas meter's operating status remotely through a platform, promptly detect and handle abnormalities, and provide users with more convenient and efficient services.

[0016] 2. Employing a magnetoresistive sensor as the magnetic field detection unit provides excellent anti-interference capabilities. By detecting changes in the ambient magnetic field in real time, it outputs a magnetic interference signal. This design not only effectively prevents false alarms caused by external magnetic field interference but also identifies malicious magnetic attack behavior and triggers the corresponding safety protection mechanism of the gas meter, greatly improving the reliability and safety of the system in complex electromagnetic environments.

[0017] 3. A two-stage operational amplifier processing circuit is adopted to address the shortcomings of long-term high power consumption operation of operational amplifiers in traditional detection schemes. Optimization is achieved through a hierarchical signal processing mechanism. Under the condition of maintaining the reference bias voltage, this design significantly reduces the ineffective power consumption under static conditions while expanding the dynamic range of weak signal detection through a segmented signal processing mode, thus avoiding the continuous energy loss problem caused by the fixed high-voltage bias in traditional schemes. Attached Figure Description

[0018] Figure 1 Block diagram of vibration detection circuit module for low-power ultrasonic smart gas meter;

[0019] Figure 2 For vibration detection circuit;

[0020] Figure 3 This is a magnetic interference detection circuit. Detailed Implementation

[0021] The present invention will be further described below with reference to the accompanying drawings:

[0022] The purpose of this application is to provide a low-power ultrasonic smart gas meter vibration detection circuit. To provide a basic understanding of some aspects of the disclosed embodiments, a brief summary is given below. This summary is not intended as a general description, nor is it intended to identify key / important components or to describe the scope of protection of these embodiments. Its sole purpose is to present some concepts in a simple form as a prelude to the detailed description that follows.

[0023] A low-power ultrasonic smart gas meter vibration detection circuit includes:

[0024] Vibration detection circuit: It adopts an electromagnetic induction omnidirectional vibration sensor to convert the vibration amplitude into an electrical signal;

[0025] Two-stage operational amplifier processing circuit: including a first-stage operational amplifier circuit and a second-stage operational amplifier circuit, which filters, decouples and amplifies the weak current signal output by the omnidirectional vibration sensor;

[0026] Magnetic interference detection circuit: Uses a magnetoresistive sensor to detect changes in the ambient magnetic field and outputs a magnetic interference signal;

[0027] Output signal detection and judgment circuit: The amplified signal is converted into high and low level signals through a transistor. The main control chip of the ultrasonic smart gas meter can perform dual verification by combining the magnetic interference signal and the high and low level signals output by the transistor to determine whether it is a valid vibration.

[0028] like Figure 2 As shown: One end of vibration sensor L1 is grounded, and the other end of vibration sensor L1 is connected to the first end of capacitor C2 and capacitor C4. The other end of capacitor C4 is grounded, and the other end of capacitor C2 is connected to one end of resistor R3.

[0029] In this solution, the vibration detection stage prioritizes omnidirectional vibration sensors with electromagnetic induction as the core detection component. Specifically, in the implementation plan, the L1 omnidirectional vibration sensor, model BL-8001, is used. The BL-8001 employs non-contact electromagnetic induction technology, utilizing Faraday's law of electromagnetic induction to directly convert vibration amplitude and frequency into electrical signals, eliminating the need for mechanical contacts and avoiding wear.

[0030] The weak current generated by the omnidirectional vibration sensor L1 after being vibrated is filtered by capacitor C2 and decoupled by capacitor C4, and then input to the operational amplifier U1A through resistor R3. The filtering by capacitor C2 can filter out high-frequency noise and eliminate signal distortion caused by high-frequency instability of the amplifier. The decoupling by capacitor C4 helps to eliminate self-excited oscillation, enabling the amplifier to work stably, and can reduce coupling interference between components and improve the electromagnetic compatibility of the circuit.

[0031] The other end of resistor R3 is connected to the inverting input terminal VIN1- of operational amplifier U1A. One end of capacitor C1 and one end of resistor R1 are connected to the inverting input terminal VIN1- of operational amplifier U1A respectively. The other ends of capacitor C1 and resistor R1 are both connected to the output terminal VOUT1 of operational amplifier U1A. One end of capacitor C3 is grounded, and the other end of capacitor C3 is connected to the power supply VDD and the positive power supply V+ of operational amplifier U1A. The non-inverting input terminal and the negative power supply V- of operational amplifier U1A are both grounded.

[0032] Operational amplifier U1A is a single-stage inverting operational amplifier. Its virtual short characteristic forces VIN1- to remain grounded; its virtual open characteristic means that all input current flows through external resistor R1 and capacitor C1. The input current enters the inverting input of operational amplifier U1A through resistor R3, and then flows to the output through feedback resistor R1. The closed-loop gain of operational amplifier U1A is directly determined by the ratio of the resistances of resistors R1 and R3. Simultaneously, resistor R1 and capacitor C1, connected in parallel, form part of the feedback network and also achieve frequency response control through an RC combination. Capacitor C3 filters out high-frequency noise on the power supply VDD, preventing noise from coupling to the positive power supply V+ of operational amplifier U1A through the power line.

[0033] The output terminal of operational amplifier U1A is connected to the non-inverting input terminal of operational amplifier U1B. One end of resistor R5 is grounded, and the other end of resistor R5 is connected to one end of resistor R6, one end of capacitor C7, and the inverting input terminal of operational amplifier U1B. The output terminal of operational amplifier U1B, the other end of resistor R6, and the other end of capacitor C7 are each connected to one end of resistor R4.

[0034] Operational amplifier U1B, acting as the second-stage inverting operational amplifier, utilizes a virtual short characteristic that forces the potential of its inverting input (VIN2-) to approximately follow that of its non-inverting input (VIN2+). Its virtual open characteristic ensures that input current cannot flow into the amplifier's internal circuitry; the signal current flows entirely through the feedback network composed of external resistor R5, resistor R6, and capacitor C7. After being amplified by the preceding operational amplifier U1A, the input signal is input to the non-inverting input of operational amplifier U1B. The closed-loop gain is determined by the ratio of the feedback resistor R6 to the input resistor R5. Resistor R6 and capacitor C7 are connected in parallel to form the feedback network, and this RC combination achieves frequency response control. The current after the second-stage amplification flows to the output of operational amplifier U1B.

[0035] This invention utilizes a two-stage operational amplifier to amplify the weak signal generated by the omnidirectional vibration sensor L1 after vibration. Optimization is achieved through a hierarchical signal processing mechanism, expanding the dynamic range of weak signal detection without raising the reference voltage, ensuring the system always operates in a normal environment. This design, through a segmented signal processing mode, expands the dynamic range of weak signal detection while maintaining the reference bias voltage, significantly reducing ineffective power consumption under static conditions and avoiding the continuous energy loss problem caused by the fixed high-voltage bias in traditional solutions.

[0036] The signal at the output terminal VOUT2 of operational amplifier U1B passes through a first-order RC low-pass filter composed of resistor R4 and capacitor C5, allowing low-frequency signals to pass through while attenuating high-frequency noise and ensuring signal purity. Through the synergistic effect of resistor R4 and capacitor C5, the circuit achieves filtering and adaptation of the op-amp output signal, ensuring that the base of transistor Q1 receives a stable, low-noise drive signal.

[0037] The collector of transistor Q1 is connected to the power supply VDD, the emitter of transistor Q1 is grounded at one end of capacitor C5, and the base of transistor Q1 is connected to the other end of resistor R4 and the other end of capacitor C5. When no vibration is detected, the voltage at the output of operational amplifier U1B is lower than the reference voltage of transistor Q1, insufficient to turn on transistor Q1. The output signal volt_CHECK is connected to the power supply VDD through pull-up resistor R2, thus remaining at a high level (close to VDD). If vibration occurs, after amplification and filtering, the voltage at the output of operational amplifier U1B is higher than the reference voltage of transistor Q1, transistor Q1 enters the conducting state, and the output signal volt_CHECK is pulled down to ground (GND) through the conducting transistor Q1, thus becoming a low level.

[0038] A high-performance magnetoresistive sensor U2 is required in the magnetic interference detection circuit to detect changes in magnetic field strength or direction. In this implementation, we used the S-5716ACDL.2-M3TIG magnetoresistive sensor U2. The VDD power input pin (pin 1) of the magnetoresistive sensor U2 is connected to the power supply VDD and one end of capacitor C6, with the other end of capacitor C6 grounded. The GND ground pin (pin 3) of the magnetoresistive sensor U2 is grounded, and the OUT signal output pin (pin 2) of the magnetoresistive sensor U2 outputs a WAKE_UP signal. The magnetoresistive sensor U2 can reliably detect the presence of magnetic interference in the current environment. When magnetic interference is present, the WAKE_UP output pin outputs a high-level signal; when there is no magnetic interference, the WAKE_UP output pin outputs a low-level signal. The main control chip of the ultrasonic smart gas meter can determine the presence of magnetic interference by receiving the WAKE_UP signal, avoiding misjudgments of vibration detection due to magnetic interference and improving the reliability of vibration detection in the smart gas meter.

[0039] The presence of vibration in the circuit can be determined by checking whether the output signal volt_CHECK of transistor Q1 is low. Utilizing the switching characteristics of transistor Q1, it converts the vibration signal into a digital level output signal volt_CHECK, with a low level indicating vibration. The magnetic interference detection circuit outputs a WAKE_UP signal; a high level indicates the presence of magnetic interference. The main control chip of the ultrasonic smart gas meter can first verify the WAKE_UP signal output by the magnetic interference detection circuit. If it is high, it is determined to be magnetic interference; if it is low, the high or low level of the volt_CHECK signal output by the vibration circuit confirms whether vibration has occurred. This design effectively distinguishes between real vibration and magnetic interference through dual signal verification, improving detection reliability. It is also simple in structure, low in cost, and has a fast response, making it suitable for scenarios requiring real-time vibration monitoring. A well-designed filter network can significantly improve the circuit's reliability and anti-interference capability.

[0040] The specific circuit connection relationship of this utility model is as follows:

[0041] One end of the omnidirectional vibration sensor L1 is connected to ground. The other end of L1 is connected to one end of capacitor C2 and one end of capacitor C4. The other end of capacitor C4 is grounded. The other end of capacitor C2 is connected to one end of resistor R3. The other end of resistor R3 is connected to the inverting input terminal VIN1- of operational amplifier U1A, one end of resistor R1 and one end of capacitor C1, and the other ends of resistor R1 and capacitor C1 are connected to the output terminal VOUT1 of operational amplifier U1A. The non-inverting input terminal VIN1+ of operational amplifier U1A is connected to ground via its negative power supply V-. The positive power supply V+ of operational amplifier U1A is connected to power supply VDD and one end of capacitor C3. The other end of capacitor C3 is grounded. The output terminal VOUT1 of amplifier U1A is connected to the non-inverting input terminal VIN2+ of operational amplifier U1B. The inverting input terminal VIN2+ of operational amplifier U1B is connected to one end of resistor R5, one end of resistor R6, and one end of capacitor C7. The other end of resistor R5 is grounded. The other end of resistor R6 and the other end of capacitor C7 are connected to the output terminal VOUT2 of operational amplifier U1B. The output terminal VOUT2 of operational amplifier U1B is connected to one end of capacitor C5 and the base of transistor Q1 through resistor R4. The other end of capacitor C5 is grounded to the emitter of transistor Q1. The collector of transistor Q1 is connected to the power supply VDD through resistor R2. The collector of transistor Q1 is the output signal volt_CHECK.

[0042] The VDD power input pin (pin 1) of the magnetoresistive sensor U2 is connected to the power supply VDD and one end of the capacitor C6. The other end of the capacitor C6 is grounded. The GND ground pin (pin 3) of the magnetoresistive sensor U2 is grounded. The OUT signal output pin (pin 2) of the magnetoresistive sensor U2 outputs the WAKE_UP signal.

[0043] This invention utilizes a vibration detection circuit, a two-stage operational amplifier processing circuit, a magnetic interference detection circuit, and an output signal detection and judgment circuit. External vibrations generate a current through the vibration detection circuit. This current then passes through a first-stage and a second-stage operational amplifier circuit to generate an amplified electrical signal, which flows to the output signal detection and judgment circuit. The output signal detection and judgment circuit can output high and low levels. The high and low level signals received by the ultrasonic gas meter are used to determine whether the meter has vibrated (see...). Figure 1 ).

[0044] This invention captures minute vibration signals using an electromagnetic omnidirectional vibration sensor. After filtering, decoupling, and amplification by two stages of operational amplifiers, the signals are converted into recognizable voltage signals. A transistor level is used to determine the vibration state in real time, and a magnetoresistive sensor is combined to monitor environmental magnetic field interference, achieving dual anti-interference protection. The circuit can operate stably for extended periods in low-power mode, making it suitable for various complex scenarios, balancing accurate response with adaptability to complex environments.

[0045] The circuit of this invention can be used to detect vibrations in the gas meter and its surrounding environment in real time, and to trigger the gas meter to perform safety protection actions. In the event of earthquakes or strong vibrations, the ultrasonic smart gas meter, by acquiring the level signal output by this invention, controls the gas meter to automatically close the gas valve, preventing gas leaks and reducing the risk of gas accidents. It can also simultaneously trigger an audible and visual alarm to warn the user. Furthermore, the ultrasonic smart gas meter can record the time and related parameters of vibration occurrence, and store the vibration time, frequency, and intensity parameters in non-volatile memory, providing data support for accident tracing. This invention, through the coordinated optimization of electromagnetic sensing and multi-level circuitry, balances detection reliability, omnidirectional response capability, and intrinsic safety characteristics, significantly improving the active safety protection effectiveness of gas circuits.

Claims

1. A low-power ultrasonic intelligent gas meter vibration detection circuit, characterized in that The application relates to an ultrasonic intelligent gas meter, which comprises the following parts: a vibration detection circuit: an omnidirectional vibration sensor is adopted to convert vibration amplitude into an electric signal through electromagnetic induction; a two-stage operational amplifier processing circuit: a weak current signal output by the omnidirectional vibration sensor is filtered, decoupled and amplified through a one-stage operational amplifier circuit and a two-stage operational amplifier circuit; a magnetic interference detection circuit: a magnetic resistance sensor is adopted to detect environmental magnetic field changes and output a magnetic interference signal; an output signal detection and judgment circuit: a transistor is adopted to convert the amplified signal into a high or low level signal; the main control chip of the ultrasonic intelligent gas meter can combine the magnetic interference signal and the high or low level signal output by the transistor to carry out double verification and judge whether the vibration is effective.

2. The low-power consumption ultrasonic intelligent gas meter vibration detection circuit according to claim 1, characterized in that The vibration detection circuit adopts an omnidirectional vibration sensor L1; the output signal of the omnidirectional vibration sensor L1 is filtered through a capacitor C2 and decoupled through a capacitor C4, and then input into the inverting input end of an operational amplifier U1A through a resistor R3.

3. The low-power consumption ultrasonic intelligent gas meter vibration detection circuit according to claim 1, characterized in that The two-stage operational amplifier processing circuit: the inverting input end of the operational amplifier U1A receives signals through the resistor R3; a feedback resistor R1 and a capacitor C1 are connected in parallel to form a low-pass filter network to inhibit high-frequency noise; the signal processed by the operational amplifier U1A is input into the non-inverting input end of an operational amplifier U1B; the closed-loop gain of the operational amplifier U1B is determined by the resistance ratio of a feedback resistor R6 and an input resistor R5; the resistor R6 and a capacitor C7 are connected in parallel to form an RC feedback network; the RC combination realizes frequency response control; the output signal after the two-stage amplification is further filtered through an RC low-pass filter composed of a resistor R4 and a capacitor C5 and then input into the base of a transistor Q1.

4. The low-power consumption ultrasonic intelligent gas meter vibration detection circuit according to claim 1, characterized in that The output signal detection and judgment circuit: the collector of the transistor Q1 is connected to a power supply VDD and the emitter of the transistor Q1 is connected to the ground; when no vibration is detected, the transistor Q1 is cut off and high level is output; when vibration is detected, the transistor Q1 is turned on and low level is output.

Images