An ultrasonic water meter transducer on-line self-checking system and method

Abstract

The application discloses an ultrasonic water meter transducer online self-checking system, which comprises a main control MCU and an acoustic channel selection switching analog switch K1, a signal emission / reception switching analog switch K2, a signal amplification filtering module, a signal amplitude sampling circuit, a TDC module, an ultrasonic signal emission module and a short circuit detection module connected with the main control MCU; one end of the acoustic channel selection switching analog switch K1 is connected with a plurality of ultrasonic transducers; the other end of the acoustic channel selection switching analog switch K1 is connected with one end of the signal emission / reception switching analog switch K2; the other end of the signal emission / reception switching analog switch K2 is connected with the signal amplification filtering module, the ultrasonic signal emission module and the short circuit detection module; the system increases the short circuit detection module and the matched control time sequence on the basis of the existing ultrasonic water meter, realizes the functions of ultrasonic transducer short circuit detection, open circuit damage detection and signal strength detection, and solves the problem of ultrasonic water meter sensor performance monitoring.

Description

Technical Field

[0001] This invention relates to the field of water meter testing technology, specifically to an online self-testing system and method for ultrasonic water meter transducers. Background Technology

[0002] In water flow measurement applications, ultrasonic water meters, as an emerging intelligent flow meter, are often used to replace mechanical water meters. Their working principle is based on the time-difference method, which analyzes and calculates the flow velocity by detecting the time difference generated when ultrasonic waves propagate downstream and upstream in water, thereby further calculating the instantaneous and cumulative flow rates. Compared with mechanical water meters, they have advantages such as high accuracy, low starting flow rate, no pressure loss, wide rangeability, long service life, and no moving parts. To achieve time-difference flow measurement, ultrasonic water meter sensors, except for straight pipe sections, are usually equipped with one or more pairs of ultrasonic transducers for transmitting and receiving ultrasonic signals. The commonly used sensor structure is the direct-fire type, such as... Figure 1 The diagram shows the structure of a single-channel ultrasonic water meter sensor. Multi-channel ultrasonic water meter sensors can be expanded based on this basic configuration.

[0003] The ultrasonic transducer is a crucial component of an ultrasonic water meter. Its internal piezoelectric element converts electrical energy into mechanical energy, enabling the ultrasonic water meter to acquire and measure water flow signals. The signal quality of the ultrasonic transducer directly affects the metering performance of the ultrasonic water meter. In practical use, due to varying operating conditions, the transducer may malfunction, typically due to the following: ① Scaling of the transducer, causing signal attenuation; ② Impact to the transducer's contact surface, leading to ceramic breakage or short circuits between the positive and negative electrodes, resulting in signal loss; ③ Use beyond the permissible temperature range, causing the piezoelectric element to detach, resulting in signal attenuation or loss; ④ Open circuit in the signal line, leading to signal loss. These faults can cause measurement problems in one or more channels, resulting in inaccurate or non-existent flow measurement.

[0004] Ultrasonic water meters are typically installed in road manholes, transmitting data wirelessly. They are rarely monitored until significant flow deviations or failure to measure occur, at which point the problem is investigated. By then, the erroneous data has already caused considerable disruption, and repairs become urgent, necessitating unplanned flow interruptions and disassembly. Therefore, early detection, location, and resolution of problems are crucial for users. Currently, many ultrasonic water meters only have signal strength detection capabilities, typically involving excitation from one transducer and reception from the other. The amplitude of the received signal is used to determine if the channel is functioning correctly. This method relies on the transmission or reception signal from the other transducer for testing one transducer. For example... Figure 2As shown, the signal emitted by the first ultrasonic transducer 1 arrives at the second ultrasonic transducer 2 after time t1. After receiving the signal, the second ultrasonic transducer 2 enters the circuit to calculate the signal amplitude, obtaining A1. Conversely, the signal emitted by the second ultrasonic transducer 2 arrives at the first ultrasonic transducer 1 after time t2. After receiving the signal, the first ultrasonic transducer 1 enters the circuit to calculate the signal amplitude, obtaining A2. Since two transducers are used in one detection process, from the overall effect of transmission and reception, the amplitudes A1 and A2 obtained by this method are basically the same, and the matching difference between the two transducers cannot be determined. Summary of the Invention

[0005] To address the common faults of ultrasonic water meter transducers and the inability of existing ultrasonic water meter signal strength detection functions to determine the matching differences between two transducers in the same channel, this invention provides an online self-testing system for ultrasonic water meter transducers. The system includes a main control MCU and connected to the MCU a channel selection switching analog switch K1, a signal transmission / reception switching analog switch K2, a signal amplification and filtering module, a signal amplitude sampling circuit, a TDC module, an ultrasonic signal transmission module, and a short-circuit detection module. One end of the channel selection switching analog switch K1 is connected to several ultrasonic transducers, and the other end of K1 is connected to one end of the signal transmission / reception switching analog switch K2. The other end of K2 is connected to the signal amplification and filtering module, the ultrasonic signal transmission module, and the short-circuit detection module. Based on existing ultrasonic water meters, this system adds a short-circuit detection module and corresponding control timing, enabling short-circuit detection, open-circuit damage detection, and signal strength detection functions for ultrasonic transducers. This solves the problem of performance monitoring of ultrasonic water meter sensors during field use.

[0006] A further objective of this invention is to propose a method where a first ultrasonic transducer transmits a signal to a second ultrasonic transducer, and the signal is reflected back to the first ultrasonic transducer after being reflected by the surface of the second ultrasonic transducer. The surface of the ultrasonic transducer is typically made of corrosion-resistant and smooth stainless steel, thus enabling the ultrasonic transducer to transmit and receive signals independently.

[0007] To achieve the above objectives, the present invention adopts the following technical solution:

[0008] An online self-testing system for ultrasonic water meter transducers includes a main control MCU. The main control MCU is connected to a channel selection switching analog switch K1 and a signal transmission / reception switching analog switch K2. One end of the channel selection switching analog switch K1 is connected to several ultrasonic transducers, and the other end of the channel selection switching analog switch K1 is connected to one end of the signal transmission / reception switching analog switch K2. The other end of the signal transmission / reception switching analog switch K2 is connected to a signal amplification and filtering module, an ultrasonic signal transmission module, and a short-circuit detection module. The short-circuit detection module is connected to the main control MCU. This invention adds an ultrasonic transducer short-circuit detection module and corresponding control timing to the existing ultrasonic water meter, realizing short-circuit detection, open-circuit damage detection, and signal strength detection functions for the ultrasonic transducer. This invention features a simple circuit structure, requiring only the addition of a short-circuit detection module. It measures whether the positive and negative terminals of each ultrasonic transducer are short-circuited by switching an analog switch. During self-testing, the ultrasonic transducer employs a special operating timing sequence, utilizing the wake wave generated by the transducer's residual vibration effect to determine if the transmitted signal successfully excites the transducer. If no wake wave signal is acquired within the wake wave time window, the transducer is considered open-circuited or damaged, thus achieving open-circuit or damaged transducer detection. After eliminating the aforementioned short-circuit or open-circuit faults, the transducer acquires the amplitude of its own reflected signal during self-testing, independent of the performance of the transducer at the other end of the channel. The reflected signal reception time is twice that of normal unidirectional transmission. Simply acquiring the signal amplitude within the reflection reception time window t yields the transducer's own transmission and reception performance. By comparing the current transducer performance with its factory standard value or that of the transducer at the other end of the channel, it is determined whether the transducer can continue to operate stably, i.e., whether the transducer is normal and whether it is matched with the transducer at the other end of the channel.

[0009] Preferably, the signal amplification and filtering module is connected to the main control MCU after being connected to the signal amplitude sampling circuit. The signal amplification and filtering module is used to amplify and filter the signal, and the signal amplitude sampling circuit is used to acquire the signal strength (signal amplitude).

[0010] Preferably, the signal amplification and filtering module is connected to the TDC module and then to the main control MCU. The TDC module is used to control the timing.

[0011] Preferably, the TDC module is connected to the ultrasonic signal transmitting module.

[0012] Preferably, the short-circuit detection module includes a short-circuit detection switching analog switch K3, resistors R1, R2, R3, and R4. The short-circuit detection switching analog switch K3 has a control signal input port IN, a first signal port COM1, a second signal port COM2, a first gear port NC, and a second gear port NO. The control signal input port IN of the short-circuit detection switching analog switch K3 is connected to the main control MCU. One end of resistor R1 is connected to VCC, and the other end of resistor R1 is connected to one end of resistor R2 and the first signal port COM1 of the short-circuit detection switching analog switch K3. The other end of resistor R2 is grounded. One end of resistor R3 is connected to VCC, and the other end of resistor R3 is connected to one end of resistor R4 and the second signal port COM2 of the short-circuit detection switching analog switch K3. The other end of resistor R4 is grounded. In addition to signal amplitude calculation, compared to conventional methods, this invention adds a short-circuit detection module and a special self-test control timing sequence, which can accurately locate a single ultrasonic transducer and determine whether its positive and negative terminals are short-circuited, whether the signal line is open-circuited, or whether the signal is abnormal.

[0013] Preferably, the short-circuit detection module further includes line a and line b. One end of line a is connected to the first position port NC of the short-circuit detection switching analog switch K3, and the other end of line a is connected to the signal transmission / reception switching analog switch K2. One end of line b is connected to the second position port NO of the short-circuit detection switching analog switch K3, and the other end of line b is connected to the signal transmission / reception switching analog switch K2. Initially, lines a and b are connected to the floating pins of the short-circuit detection switching analog switch K3. This invention achieves short-circuit detection of the ultrasonic transducer by measuring the voltage between lines a and b of the short-circuit detection module.

[0014] An online self-testing method for an ultrasonic water meter transducer, applicable to the aforementioned online self-testing system for an ultrasonic water meter transducer, includes the following steps:

[0015] Step S1: Short circuit detection of the positive and negative electrodes of the ultrasonic transducer;

[0016] Step S2: Detection of open circuit damage in ultrasonic transducers;

[0017] Step S3: Detection of abnormal ultrasonic transducer signals;

[0018] This invention achieves short-circuit detection by measuring the voltage between the two lines of the short-circuit detection module. During the self-test, it controls the entire information chain of each ultrasonic transducer's signal transmission, resonant wake wave, signal reflection, and signal reception. This enables the signal self-test function to locate a single ultrasonic transducer and its signal path, determining whether its positive and negative terminals are short-circuited, whether the signal line is open-circuited, or whether the signal is abnormal. It covers common fault phenomena in the practical application of ultrasonic water meters and solves the problem of performance monitoring of ultrasonic water meter sensors in the field.

[0019] Preferably, the first ultrasonic transducer performs a self-test. The specific process of step S1 includes the following steps:

[0020] Step S11: The main control MCU switches the channel selection switching analog switch K1 to the first ultrasonic transducer. At this time, the positive and negative terminals of the first ultrasonic transducer are connected to the signal transmission / reception switching analog switch K2.

[0021] Step S12: The main control MCU switches the signal transmission / reception switching analog switch K2 to the ultrasonic signal transmission module. At this time, the positive and negative terminals of the first ultrasonic transducer are connected to the ultrasonic signal transmission module and the short circuit detection module.

[0022] Step S13: The main control MCU applies a control signal to the short-circuit detection switching analog switch K3, so that the first signal port COM1 is connected to the first gear port NC, and the second signal port COM2 is connected to the second gear port NO;

[0023] Step S14: The main control MCU collects the output voltage amplitudes Ua and Ub of line a and line b, compares Ua and Ub. If Ua = Ub, then the positive and negative terminals of the first ultrasonic transducer are short-circuited; if Ua ≠ Ub, then the positive and negative terminals of the first ultrasonic transducer are not short-circuited.

[0024] Step S15: After the short circuit detection is completed, the main control MCU sends a control signal to the short circuit detection switching analog switch K3 to return line a and line b to the floating state.

[0025] Preferably, the first ultrasonic transducer performs a self-test. The specific process of step S2 includes the following steps:

[0026] Step S21: The main control MCU maintains the state of the channel selection switching analog switch K1 and the signal transmission / reception switching analog switch K2, and the positive and negative terminals of the first ultrasonic transducer are connected to the ultrasonic signal transmission module; the main control MCU controls the TDC module to open the receiving window for the period after the transmission excitation segment ends;

[0027] Step S22: The main control MCU sends a command to emit an ultrasonic excitation signal through the TDC module and the ultrasonic signal transmitting module;

[0028] Step S23: After the transmission excitation phase ends, the main control MCU quickly switches the signal transmission / reception switching analog switch K2 to the signal amplification and filtering module. At this time, the positive and negative terminals of the first ultrasonic transducer are connected to the signal amplification and filtering module.

[0029] Step S24: The main control MCU acquires several wake wave times t from the TDC module. n t n+1 t n+2 …t n+mCalculate the time interval between the aforementioned wake waves:

[0030] Δt n =t n+1 -t n

[0031] Δt n+1 =t n+2 -t n+1

[0032] Δt n+m-1 =t n+m -t n+m-1

[0033] Step S25: Determine whether the wake frequency is consistent with the transmitted signal frequency based on the time interval. If they are consistent, the signal line of the first ultrasonic transducer is intact and the first ultrasonic transducer can resonate normally. Otherwise, the first ultrasonic transducer may be in an open circuit or damaged state.

[0034] Preferably, the first and second ultrasonic transducers in the same channel perform self-tests. The specific process of step S3 includes the following steps:

[0035] Step S31: The main control MCU maintains the state of the channel selection switching analog switch K1 and the signal transmission / reception switching analog switch K2, and the positive and negative terminals of the first ultrasonic transducer are connected to the signal amplification and filtering module;

[0036] Step S32: The main control MCU obtains the intensity S1 of the reflected signal from the first ultrasonic transducer through the signal amplification and filtering module and the signal amplitude sampling circuit;

[0037] Step S33: The main control MCU switches the channel selection switching analog switch K1 to the second ultrasonic transducer, repeats steps S12-S32, and obtains the intensity S2 of the reflected signal from the second ultrasonic transducer.

[0038] Step S34: Compare S1 and S2 with the standard intensity S of the reflected signal of the ultrasonic water meter transducer. If S1 and S2 are significantly smaller than S, the surfaces of the first and second ultrasonic transducers may be scaled or their performance may be aging.

[0039] Step S35: Compare S1 and S2. If the difference between S1 and S2 is large, it means that the two ultrasonic transducers in this channel are mismatched.

[0040] The signal strength detection (signal anomaly detection or signal attenuation detection) provided by this invention utilizes a self-transmitting and self-receiving ultrasonic transducer. The first ultrasonic transducer transmits a signal to the second ultrasonic transducer. After reflection from the surface of the second ultrasonic transducer, the signal returns to the first ultrasonic transducer. Upon receiving the transmitted signal, the first ultrasonic transducer calculates the signal amplitude to obtain S1. Similarly, the second ultrasonic transducer transmits a signal to the first ultrasonic transducer. After reflection from the surface of the first ultrasonic transducer, the signal returns to the second ultrasonic transducer. Upon receiving the transmitted signal, the second ultrasonic transducer calculates the signal amplitude to obtain S2. The surface of the ultrasonic transducers is typically made of corrosion-resistant and smooth stainless steel, ensuring strong reflected signal strength. The obtained S1 and S2 depend solely on the transmission and reception capabilities of the first and second ultrasonic transducers. If one of the ultrasonic transducers malfunctions, the difference between the amplitudes of S1 and S2 will significantly increase, thus determining whether the two ultrasonic transducers can continue to match and operate normally.

[0041] Therefore, the advantages of the present invention are:

[0042] (1) The circuit structure is simple. Only a short circuit detection module needs to be added. The positive and negative poles of each ultrasonic transducer are short-circuited by switching the analog switch.

[0043] (2) When the ultrasonic transducer is self-tested, a special working sequence is adopted. The tail wave generated by the residual vibration effect of the ultrasonic transducer is used to determine whether the transmitted signal successfully excites the ultrasonic transducer. If the tail wave signal is not collected in the tail wave time window, it is considered that the ultrasonic transducer is open circuit or damaged, thus realizing the detection of open circuit or damage of ultrasonic transducer.

[0044] (3) After eliminating the above-mentioned faults such as short circuit or open circuit, the ultrasonic transducer collects the amplitude of its own reflected signal during self-test. It does not depend on the performance of the ultrasonic transducer at the other end of the channel. The reflected signal reception time is twice that of normal unidirectional transmission. It is only necessary to collect the signal amplitude within the window of the reflection reception time t to obtain the transmission and reception performance of the ultrasonic transducer itself. The current performance of the ultrasonic transducer is compared with its factory standard value or the ultrasonic transducer at the other end of the channel to determine whether the ultrasonic transducer can continue to work stably. Attached Figure Description

[0045] Figure 1 This is a schematic diagram of the structure of a mono-channel ultrasonic water meter sensor in the background technology of this invention.

[0046] Figure 2 This is a schematic diagram of the circuit structure of an existing ultrasonic water meter with signal strength detection function in the background art of this invention.

[0047] Figure 3This is a schematic diagram of the self-test signal flow of a single-channel ultrasonic transducer in an embodiment of the present invention.

[0048] Figure 4 This is a schematic diagram of the structure of an online self-testing system for an ultrasonic water meter transducer according to an embodiment of the present invention.

[0049] Figure 5 This is a schematic diagram of the residual vibration tailwave of the ultrasonic transducer in an embodiment of the present invention.

[0050] Figure 6 This is a schematic diagram of an ultrasonic transducer receiving reflected signals in an embodiment of the present invention.

[0051] Figure 7 This is a schematic diagram of the short-circuit detection module in an embodiment of the present invention.

[0052] Figure 8 This is a flowchart of an online self-testing method for an ultrasonic water meter transducer according to an embodiment of the present invention.

[0053] 1. First ultrasonic transducer; 2. Second ultrasonic transducer; 3. Main control MCU; 4. Signal amplitude sampling circuit; 5. Signal amplification and filtering module; 6. Ultrasonic signal transmission module; 7. TDC module; 8. Multiplex analog switch; 9. Short circuit detection module. Detailed Implementation

[0054] The present invention will now be further described with reference to the accompanying drawings and specific embodiments.

[0055] Example 1:

[0056] An online self-testing system for ultrasonic water meter transducers, such as Figure 4As shown, the system includes a main control MCU3, a channel selection switching analog switch K1, a signal transmission / reception switching analog switch K2, a signal amplification and filtering module 5, a signal amplitude sampling circuit 4, a TDC module 7, an ultrasonic signal transmission module 6, and a short-circuit detection module 9. The channel selection switching analog switch K1 has a control signal input port, multiple position ports, and a signal output port. The control signal input port is connected to the main control MCU3; the multiple position ports are connected to several ultrasonic transducers respectively. The signal transmission / reception switching analog switch K2 has a control signal input port, a signal input port, a first position port, and a second position port. The control signal input port is connected to the main control MCU3; the signal input port is connected to the signal output port of the channel selection switching analog switch K1; the first position port is connected to the signal amplification and filtering module 5; and the second position port is connected to the ultrasonic signal transmission module 6 and the short-circuit detection module 9. The signal amplification and filtering module 5 is connected to the signal amplitude sampling circuit 4 and the TDC module 7, and then connected to the main control MCU3. The TDC module 7 is connected to the ultrasonic signal transmission module 6. The short-circuit detection module 9 is connected to the main control MCU3. This embodiment adds an ultrasonic transducer short-circuit detection module and a matching control timing sequence to the existing ultrasonic water meter, realizing the functions of ultrasonic transducer short-circuit detection, open-circuit damage detection, and signal strength detection.

[0057] The structure of the short-circuit detection module 9 is not unique; this embodiment provides one configuration, such as... Figure 7 As shown, the short-circuit detection module 9 includes a short-circuit detection switching analog switch K3, resistors R1, R2, R3, and R4. The short-circuit detection switching analog switch K3 has a control signal input port IN, a first signal port COM1, a second signal port COM2, a first gear port NC, and a second gear port NO. The control signal input port IN of the short-circuit detection switching analog switch K3 is connected to the main control MCU3. One end of resistor R1 is connected to VCC, and the other end of resistor R1 is connected to one end of resistor R2 and the first signal port COM1 of the short-circuit detection switching analog switch K3. The other end of resistor R2 is grounded. One end of resistor R3 is connected to VCC, and the other end of resistor R3 is connected to one end of resistor R4 and the second signal port COM2 of the short-circuit detection switching analog switch K3. The other end of resistor R4 is grounded. The short-circuit detection module 9 also includes line a and line b. One end of line a is connected to the first position port NC of the short-circuit detection switching analog switch K3, and the other end of line a is connected to the signal transmission / reception switching analog switch K2. One end of line b is connected to the second position port NO of the short-circuit detection switching analog switch K3, and the other end of line b is connected to the signal transmission / reception switching analog switch K2. In the initial state, lines a and b are connected to the floating pins of the short-circuit detection switching analog switch K3. In this embodiment, short-circuit detection of the ultrasonic transducer is achieved by measuring the voltage between lines a and b of the short-circuit detection module.

[0058] Example 2:

[0059] An online self-testing method for ultrasonic water meter transducers, such as Figure 8 As shown, an online self-testing system for an ultrasonic water meter transducer, applicable to the above, includes the following steps:

[0060] Step S1: Short circuit detection of the positive and negative electrodes of the ultrasonic transducer;

[0061] Step S2: Detection of open circuit damage in ultrasonic transducers;

[0062] Step S3: Detection of abnormal ultrasonic transducer signals;

[0063] This embodiment achieves short circuit detection by measuring the voltage between the two lines of the short circuit detection module. During the self-test, it controls the entire information chain of each ultrasonic transducer's signal transmission, resonant tail wave, signal reflection, and signal reception. This enables the signal self-test function to locate a single ultrasonic transducer and its signal path, and to determine whether its positive and negative terminals are short-circuited, whether the signal line is open-circuited, or whether the signal is abnormal.

[0064] The self-test for the first ultrasonic transducer, step S1, includes the following steps:

[0065] Step S11: The main control MCU switches the channel selection switching analog switch K1 to the first ultrasonic transducer. At this time, the positive and negative terminals of the first ultrasonic transducer are connected to the signal transmission / reception switching analog switch K2.

[0066] Step S12: The main control MCU switches the signal transmission / reception switching analog switch K2 to the ultrasonic signal transmission module. At this time, the positive and negative terminals of the first ultrasonic transducer are connected to the ultrasonic signal transmission module and the short circuit detection module.

[0067] Step S13: The main control MCU applies a control signal to the short-circuit detection switching analog switch K3, so that the first signal port COM1 is connected to the first gear port NC, and the second signal port COM2 is connected to the second gear port NO;

[0068] Step S14: The main control MCU collects the output voltage amplitudes Ua and Ub of line a and line b, compares Ua and Ub. If Ua = Ub, then the positive and negative terminals of the first ultrasonic transducer are short-circuited; if Ua ≠ Ub, then the positive and negative terminals of the first ultrasonic transducer are not short-circuited.

[0069] Step S15: After the short circuit detection is completed, the main control MCU sends a control signal to the short circuit detection switching analog switch K3 to return line a and line b to the floating state.

[0070] The self-test for the first ultrasonic transducer, step S2, includes the following steps:

[0071] Step S21: The main control MCU maintains the state of the channel selection switching analog switch K1 and the signal transmission / reception switching analog switch K2, and the positive and negative terminals of the first ultrasonic transducer are connected to the ultrasonic signal transmission module; the main control MCU controls the TDC module to open the receiving window for the period after the transmission excitation segment ends;

[0072] Step S22: The main control MCU sends a command to emit an ultrasonic excitation signal through the TDC module and the ultrasonic signal transmitting module;

[0073] Step S23: After the transmission excitation phase ends, the main control MCU quickly switches the signal transmission / reception switching analog switch K2 to the signal amplification and filtering module. At this time, the positive and negative terminals of the first ultrasonic transducer are connected to the signal amplification and filtering module.

[0074] Step S24: The main control MCU acquires several wake wave times t from the TDC module. n t n+1 t n+2 …t n+m Calculate the time interval between several wake wave times:

[0075] Δt n =t n+1 -t n

[0076] Δt n+1 =t n+2 -t n+1

[0077] Δt n+m-1 =t n+m -t n+n-1

[0078] Step S25: Determine whether the wake frequency is consistent with the transmitted signal frequency based on the time interval. If they are consistent, the signal line of the first ultrasonic transducer is intact and the first ultrasonic transducer can resonate normally. Otherwise, the first ultrasonic transducer may be in an open circuit or damaged state.

[0079] The self-test for the first and second ultrasonic transducers in the same channel, step S3, includes the following steps:

[0080] Step S31: The main control MCU maintains the state of the channel selection switching analog switch K1 and the signal transmission / reception switching analog switch K2, and the positive and negative terminals of the first ultrasonic transducer are connected to the signal amplification and filtering module;

[0081] Step S32: The main control MCU obtains the intensity S1 of the reflected signal from the first ultrasonic transducer through the signal amplification and filtering module and the signal amplitude sampling circuit;

[0082] Step S33: The main control MCU switches the channel selection switching analog switch K1 to the second ultrasonic transducer, repeats steps S12-S32, and obtains the intensity S2 of the reflected signal from the second ultrasonic transducer.

[0083] Step S34: Compare S1 and S2 with the standard intensity S of the reflected signal of the ultrasonic water meter transducer. If S1 and S2 are significantly smaller than S, the surfaces of the first and second ultrasonic transducers may be scaled or their performance may be aging.

[0084] Step S35: Compare S1 and S2. If the difference between S1 and S2 is large, it means that the two ultrasonic transducers in this channel are mismatched.

[0085] The signal strength detection (signal anomaly detection or signal attenuation detection) provided in this embodiment is achieved by a self-transmitting and self-receiving ultrasonic transducer at one end, such as... Figure 3 As shown, the first ultrasonic transducer 1 transmits a signal to the second ultrasonic transducer 2. The signal is reflected back to the first ultrasonic transducer 1 after being reflected from the surface of the second ultrasonic transducer 2. Upon receiving the transmitted signal, the first ultrasonic transducer 1 enters the circuit to calculate the signal amplitude, obtaining S1. Similarly, the second ultrasonic transducer 2 transmits a signal to the first ultrasonic transducer 1. The signal is reflected back to the second ultrasonic transducer 2 after being reflected from the surface of the first ultrasonic transducer 1. Upon receiving the transmitted signal, the second ultrasonic transducer 2 enters the circuit to calculate the signal amplitude, obtaining S2. The surfaces of the ultrasonic transducers are typically made of corrosion-resistant and smooth stainless steel, ensuring the strength of the reflected signal. The S1 and S2 obtained here depend solely on the transmission and reception capabilities of the first and second ultrasonic transducers 1 and 2. If one of the ultrasonic transducers malfunctions, the difference between the amplitudes of S1 and S2 will significantly increase, thus determining whether the two ultrasonic transducers can continue to match and operate normally.

[0086] Example 3:

[0087] The specific implementation process is as follows:

[0088] 1) such as Figure 4 As shown, taking the self-test operation of the first ultrasonic transducer 1 as an example, the main control MCU3 switches the channel selection switching analog switch K1 to the first ultrasonic transducer 1. At this time, the positive and negative terminals of the first ultrasonic transducer 1 are connected to the signal transmission / reception switching analog switch K2. The main control MCU3 then switches the signal transmission / reception switching analog switch K2 to the ultrasonic signal transmission module 6. At this time, the positive and negative terminals of the first ultrasonic transducer 1 are connected to the ultrasonic signal transmission module 6 and the short circuit detection module 9, that is, line a and line b are connected to the positive and negative terminals of the first ultrasonic transducer 1.

[0089] 2) such as Figure 7As shown, the short-circuit detection module 9 can obtain different voltage values ​​U1 and U2 by voltage division using two resistors (the short-circuit detection module scheme is not unique). The main control MCU3 applies a control signal to the short-circuit detection switching analog switch K3, so that U1 is connected to line a and U2 is connected to line b (initially, lines a and b are connected to the floating pins of K3). Lines a and b are simultaneously input to the ADC module of the main control MCU3. When the positive and negative poles of the first ultrasonic transducer 1 are short-circuited, the voltage amplitudes of lines a and b will be equal, i.e., Ua = Ub; otherwise, lines a and b will acquire voltages U1 and U2 respectively, i.e., Ua ≠ Ub. After the short-circuit detection is completed, the main control MCU3 sends a control signal to K3 to return lines a and b to the floating state.

[0090] 3) such as Figure 5 As shown, under normal conditions, the positive and negative signals of the ultrasonic transducer consist of the transmission excitation segment and the residual tailwave segment. If the ultrasonic transducer is open-circuited or damaged, there will be no residual tailwave signal. Therefore, the main control MCU3 maintains the K1 and K2 states, that is, the positive and negative terminals of the first ultrasonic transducer 1 are connected to the ultrasonic signal transmission module 6, and the time receiving window of the TDC module 7 is set to open after the transmission excitation segment ends. At this time, the main control MCU3 sends a command to emit an ultrasonic excitation signal through the TDC module 7 and the ultrasonic signal transmission module 6.

[0091] 4) After the transmission excitation phase ends, K2 quickly switches to the signal amplification and filtering module 5. The frequency of the residual oscillation wake wave is basically the same as the transmission excitation frequency. After amplification and filtering, it is captured by the TDC module 7. The main control MCU3 obtains several wake wave timest from the TDC module 7. n t n+1 t n+2 t n+3 Calculate the intervals between these times:

[0092] Δt n =t n+1 -t n

[0093] Δt n+1 =t n+2 -t n+1

[0094] Δt n+2 =t n+3 -t n+2

[0095] Based on these signal time intervals, it can be determined whether the tailwave frequency is consistent with the transmitted signal frequency. If they are consistent, it can be considered that the signal line of the first ultrasonic transducer 1 is intact and the first ultrasonic transducer 1 can resonate normally. Otherwise, the first ultrasonic transducer 1 may be in an open circuit or damaged state.

[0096] 5) After the first ultrasonic transducer 1 emits an excitation signal in the above steps, the ultrasonic signal is transmitted in the medium in the pipe. After reaching another ultrasonic transducer (i.e., the second ultrasonic transducer 2) in the same channel, it is reflected back to the first ultrasonic transducer 1 through its surface. At this time, the positive and negative poles of the first ultrasonic transducer 1 and the signal amplification and filtering module 5 remain unobstructed.

[0097] 6) After time t after the signal is transmitted, the reflected signal is amplified and filtered and enters the signal amplitude sampling circuit 4. The main control MCU3 can obtain the signal strength S1 of the reflected signal of the first ultrasonic transducer 1 being tested.

[0098] 7) Replace the first ultrasonic transducer 1 with the second ultrasonic transducer 2 (i.e., the main control MCU3 switches the channel selection switching analog switch K1 to the second ultrasonic transducer 2), repeat the above steps 1-6, and obtain the short circuit, open circuit and other status information of the second ultrasonic transducer 2, and also obtain the reflected signal intensity S2.

[0099] 8) Based on the standard performance of ultrasonic transducers and the pipe diameter, ultrasonic water meters are set with a standard intensity S for the reflected signal of ultrasonic transducers. All ultrasonic transducers must meet this standard to be allowed to leave the factory. Therefore, the signal intensities S1 and S2 are compared with the standard intensity S. If there is a significant attenuation (S1 and S2 are significantly less than the standard intensity S), the surface of the ultrasonic transducer may be scaled or its performance may be aging. Continued use may cause measurement failure. On the other hand, if the difference between the signal intensities S1 and S2 is large, it indicates that the two ultrasonic transducers in this channel (the first ultrasonic transducer 1 and the second ultrasonic transducer 2) are mismatched. Continued use may also cause measurement failure.

[0100] The ultrasonic transducers of all channels are tested using the above steps. When phenomena such as short circuit, open circuit, or mismatch of reflected signal intensity occur, the ultrasonic water meter can display an alarm on the LCD panel or transmit the alarm remotely to remind users of potential risks. This allows users to take early on-site measures and avoid metering accidents.

[0101] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. An online self-testing system for ultrasonic water meter transducers, characterized in that, The system includes a main control MCU, which is connected to a channel selection switching analog switch K1 and a signal transmission / reception switching analog switch K2. One end of the channel selection switching analog switch K1 is connected to several ultrasonic transducers, and the other end of the channel selection switching analog switch K1 is connected to one end of the signal transmission / reception switching analog switch K2. The other end of the signal transmission / reception switching analog switch K2 is connected to a signal amplification and filtering module, an ultrasonic signal transmission module, and a short-circuit detection module. The short-circuit detection module is connected to the main control MCU. The signal transmit / receive switching analog switch K2 has a control signal input port, a signal input port, a first position port, and a second position port. The first position port is connected to the signal amplification and filtering module; the second position port is connected to the ultrasonic signal transmit module and the short circuit detection module. The short-circuit detection module also includes line a and line b. One end of line a is connected to the first position port of the short-circuit detection switching analog switch K3, and the other end of line a is connected to the signal transmission / reception switching analog switch K2. One end of line b is connected to the second position port NO of the short-circuit detection switching analog switch K3, and the other end of line b is connected to the signal transmission / reception switching analog switch K2. In the initial state, lines a and b are connected to the floating pins of the short-circuit detection switching analog switch K3. The control signal input port is connected to the main control MCU3; the signal input port is connected to the signal output port of the channel selection switching analog switch K1.

2. The online self-testing system for ultrasonic water meter transducers according to claim 1, characterized in that, The signal amplification and filtering module is connected to the signal amplitude sampling circuit and then to the main control MCU.

3. An online self-testing system for ultrasonic water meter transducers according to claim 1 or 2, characterized in that, The signal amplification and filtering module is connected to the TDC module and then to the main control MCU.

4. The online self-testing system for ultrasonic water meter transducers according to claim 3, characterized in that, The TDC module is connected to the ultrasonic signal transmitting module.

5. The online self-testing system for ultrasonic water meter transducers according to claim 1, characterized in that, The channel selection switching analog switch K1 has a control signal input port, multiple gear ports and a signal output port. The control signal input port is connected to the main control MCU3; the multiple gear ports are respectively connected to several ultrasonic transducers.

6. The online self-testing system for ultrasonic water meter transducers according to claim 1, characterized in that, The short-circuit detection module includes a short-circuit detection switching analog switch K3, resistors R1, R2, R3, and R4. The short-circuit detection switching analog switch K3 has a control signal input port IN, a first signal port COM1, a second signal port COM2, a first gear port NC, and a second gear port NO. The control signal input port IN of the short-circuit detection switching analog switch K3 is connected to the main control MCU. One end of resistor R1 is connected to VCC, and the other end of resistor R1 is connected to one end of resistor R2 and the first signal port COM1 of the short-circuit detection switching analog switch K3. The other end of resistor R2 is grounded. One end of resistor R3 is connected to VCC, and the other end of resistor R3 is connected to one end of resistor R4 and the second signal port COM2 of the short-circuit detection switching analog switch K3. The other end of resistor R4 is grounded.

7. An online self-testing method for an ultrasonic water meter transducer, applicable to the online self-testing system for an ultrasonic water meter transducer as described in any one of claims 1-6, characterized in that, Includes the following steps: Step S1: Short circuit detection of the positive and negative electrodes of the ultrasonic transducer; Step S2: Detection of open circuit damage in ultrasonic transducers; Step S3: Detection of abnormal ultrasonic transducer signals.

8. The online self-testing method for an ultrasonic water meter transducer according to claim 7, characterized in that, The first ultrasonic transducer performs a self-test. The specific process of step S1 includes the following steps: Step S11: The main control MCU switches the channel selection switching analog switch K1 to the first ultrasonic transducer. At this time, the positive and negative terminals of the first ultrasonic transducer are connected to the signal transmission / reception switching analog switch K2. Step S12: The main control MCU switches the signal transmission / reception switching analog switch K2 to the ultrasonic signal transmission module. At this time, the positive and negative terminals of the first ultrasonic transducer are connected to the ultrasonic signal transmission module and the short circuit detection module. Step S13: The main control MCU applies a control signal to the short-circuit detection switching analog switch K3, so that the first signal port COM1 is connected to the first gear port NC, and the second signal port COM2 is connected to the second gear port NO; Step S14: The main control MCU acquires the output voltage amplitudes Ua and Ub of lines a and b, compares Ua and Ub, and if... If the positive and negative terminals of the first ultrasonic transducer are short-circuited; if Then there is no short circuit between the positive and negative terminals of the first ultrasonic transducer; Step S15: After the short circuit detection is completed, the main control MCU sends a control signal to the short circuit detection switching analog switch K3 to return line a and line b to the floating state.

9. The online self-testing method for an ultrasonic water meter transducer according to claim 8, characterized in that, The first ultrasonic transducer performs a self-test. The specific process of step S2 includes the following steps: Step S21: The main control MCU maintains the state of the channel selection switching analog switch K1 and the signal transmission / reception switching analog switch K2, and the positive and negative terminals of the first ultrasonic transducer are connected to the ultrasonic signal transmission module; the main control MCU controls the TDC module to open the receiving window for the period after the transmission excitation segment ends; Step S22: The main control MCU sends a command to emit an ultrasonic excitation signal through the TDC module and the ultrasonic signal transmitting module; Step S23: After the transmission excitation phase ends, the main control MCU quickly switches the signal transmission / reception switching analog switch K2 to the signal amplification and filtering module. At this time, the positive and negative terminals of the first ultrasonic transducer are connected to the signal amplification and filtering module. Step S24: The main control MCU acquires several wake wave times from the TDC module. Calculate the time interval between the aforementioned wake waves: Step S25: Determine whether the wake frequency is consistent with the transmitted signal frequency based on the time interval. If they are consistent, the signal line of the first ultrasonic transducer is intact and the first ultrasonic transducer can resonate normally. Otherwise, the first ultrasonic transducer is in an open circuit or damaged state.

10. The online self-testing method for an ultrasonic water meter transducer according to claim 8, characterized in that, The first and second ultrasonic transducers of the same channel perform self-tests. The specific process of step S3 includes the following steps: Step S31: The main control MCU maintains the state of the channel selection switching analog switch K1 and the signal transmission / reception switching analog switch K2, and the positive and negative terminals of the first ultrasonic transducer are connected to the signal amplification and filtering module; Step S32: The main control MCU obtains the intensity of the reflected signal from the first ultrasonic transducer through the signal amplification and filtering module and the signal amplitude sampling circuit. ; Step S33: The main control MCU switches the channel selection switching analog switch K1 to the second ultrasonic transducer, and repeats steps S12-S32 to obtain the intensity of the reflected signal from the second ultrasonic transducer. ; Step S34: and Standard intensity of reflected signal from ultrasonic water meter transducer If a comparison is made, and Significantly smaller If the first and second ultrasonic transducers are scaled or their performance is aged, then the surface of the first and second ultrasonic transducers will be scaled or their performance will be aged. Step S35: Comparison and ,like and If the difference is large, it means that the two ultrasonic transducers in that channel are mismatched.

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