Self-diagnosis alarm circuit for eliminating environmental interference of liquid turbine flowmeter

By designing a self-diagnostic alarm circuit in a liquid turbine flowmeter to automatically identify and eliminate electromagnetic interference, the problem of measurement error of the flowmeter in harsh environments is solved, and more accurate flow measurement and simplified installation process is achieved.

CN222965734UActive Publication Date: 2025-06-10NANJING UNIV OF AERONAUTICS & ASTRONAUTICS
View PDF 0 Cites 0 Cited by

Patent Information

Application Number
CN202422103788.0
Authority / Receiving Office
CN · China
Patent Type
Utility models(China)
Current Assignee / Owner
Filing Date
2024-08-29
Publication Date
2025-06-10
Estimated Expiration
2034-08-29

AI Technical Summary

Technical Problem

Liquid turbine flowmeters are susceptible to strong electromagnetic interference in harsh environments, resulting in measurement errors, and the prior art is difficult to automatically detect and eliminate interference, resulting in difficulty in selecting installation locations and wasting manpower and material resources.

Method used

A self-diagnosis alarm circuit for liquid turbine flowmeter is designed, including an impeller rotation acquisition circuit module, an interference signal acquisition module, an alarm output circuit module, a signal switching module and a CPU module. By automatically identifying the interference signal and switching signal acquisition, the self-diagnosis and elimination of the interference signal is realized.

Benefits of technology

It realizes the self-diagnosis and alarm functions of the liquid turbine flowmeter in an electromagnetic interference environment, which can automatically eliminate interference, improve the measurement accuracy of the flowmeter, reduce waste of manpower and material resources, and simplify the selection of installation locations.

✦ Generated by Eureka AI based on patent content.

Smart Images

  • Figure CN222965734U_ABST
    Figure CN222965734U_ABST
Patent Text Reader

Abstract

The utility model discloses a self-diagnosis alarm circuit for eliminating environmental interference of a liquid turbine flowmeter. The self-diagnosis alarm circuit comprises an impeller rotation acquisition circuit module, an interference signal circuit acquisition module, an alarm output circuit module, a signal switching module, a CPU module, a liquid turbine flowmeter signal detector and an interference signal detector, space electromagnetic interference is amplified through the interference signal acquisition circuit module, then signals are latched through the alarm output circuit module, alarm output is compared, and the magnitude of field interference can be recognized through the on-off state of a light-emitting diode. And meanwhile, the CPU module acquires an output signal of the alarm output circuit module, automatically switches and acquires a signal of the interference signal acquisition module, and eliminates an interference signal in a normal measurement signal through a frequency spectrum, so that a correct interference-free flow signal is obtained through conversion, and self-diagnosis alarm output of space electromagnetic interference is realized. And the interference influence can be automatically eliminated.
Need to check novelty before this filing date? Find Prior Art

Description

Technical Field

[0001] The utility model relates to the technical field of turbine flowmeters, in particular to a self-diagnosis alarm circuit for eliminating environmental interference of a liquid turbine flowmeter. Background Technique

[0002] A liquid turbine flowmeter is a velocity flowmeter, which mainly consists of components such as a turbine, a flow straightener, a signal detector, and a converter. Its working principle is that when the measured liquid flows through the sensor, it drives the turbine to rotate, and the rotation speed of the turbine is proportional to the flow velocity of the liquid. The signal detector converts the rotation speed of the turbine into an electrical pulse signal, which is amplified by an amplifier and then sent to a display instrument for display and cumulative calculation. The liquid turbine flowmeter has the advantages of high accuracy, good repeatability, wide measurement range, and fast response speed. It is widely used in industrial fields such as petroleum, chemical industry, metallurgy, food, and pharmaceuticals to measure and control the flow of various liquid media.

[0003] Since the signal detector of the liquid turbine usually consists of an inductance coil with 1000 - 2000 turns around a permanent magnet, and the turbine blades are made of a magnetically conductive material. When the turbine blades rotate, they will periodically approach and leave the signal detector, resulting in electromagnetic induction in the inductance coil and generating an electromotive force with a periodic waveform at both ends of the coil. The converter then calculates its periodic frequency by amplifying and shaping the electromotive force, and obtains an accurate flow value through frequency calculation.

[0004] However, in some harsh installation environments, the most common one is an environment with strong electromagnetic interference. According to the principle of electromagnetic induction, strong electromagnetic interference will also cause a periodic electromotive force to be generated at both ends of the coil of the signal detector. The converter cannot distinguish whether this electromotive force is the electromotive force of electromagnetic interference or the electromotive force generated by the rotation of the impeller, resulting in a large error in the measurement of the turbine flowmeter. Usually, this kind of interference can only be discovered after the flowmeter is installed. At the same time, since electromagnetic interference belongs to low-frequency interference, it is very difficult to remove it by means of shielding and grounding, and only the installation location can be changed. And when choosing the installation location, it is still impossible to determine whether there is an impact of electromagnetic interference, and it can only be judged by experience. Usually, multiple site selections are required to find a suitable installation location, resulting in a waste of a large amount of manpower and material resources. Therefore, there is an urgent need for a method and functional circuit for a turbine flowmeter to automatically detect and diagnose the amplitude of on-site electromagnetic interference, alarm and eliminate the interference, so as to conveniently and quickly find a suitable installation location that does not affect the measurement on-site and eliminate the interference to measure the correct flow rate.

[0005] Therefore, the utility model provides a self-diagnosis alarm circuit for eliminating environmental interference of a liquid turbine flowmeter to solve the above problems. Content of the Utility Model

[0006] In view of the deficiencies of the prior art, the utility model provides a self-diagnosis alarm circuit for eliminating environmental interference of a liquid turbine flowmeter, which solves the above problems.

[0007] To achieve the above objectives, the utility model is realized through the following technical solutions: A self-diagnosis alarm circuit for eliminating environmental interference of a liquid turbine flowmeter includes an impeller rotation acquisition circuit module, an interference signal circuit acquisition module, an alarm output circuit module, a signal switching module, a CPU module, a liquid turbine flowmeter signal detector, and an interference signal detector;

[0008] The output ends of the impeller rotation acquisition circuit module and the interference signal circuit acquisition module are respectively electrically connected to the input ends of the signal switching module, and the input end of the impeller rotation acquisition circuit module is electrically connected to the output end of the liquid turbine flowmeter signal detector;

[0009] The output end of the interference signal circuit acquisition module is electrically connected to the input end of the alarm output circuit module;

[0010] The output ends of the alarm output circuit module and the signal switching module are respectively electrically connected to the input ends of the CPU module;

[0011] The output end of the CPU module is electrically connected to the control pin of the signal switching module.

[0012] Preferably, the CPU module adopts a microcontroller, including GPIO input, output, and AD conversion modules.

[0013] Preferably, the impeller rotation acquisition circuit module includes resistor R12, resistor R13, resistor R14, capacitor C3, and operational amplifier U5;

[0014] The input signal of the impeller rotation acquisition circuit module is the two output pins of the liquid turbine flowmeter signal detector. The two output pins of the liquid turbine flowmeter signal detector are respectively defined as SIG_C and SIG_D. The liquid turbine flowmeter signal detector is composed of an inductor coil with 1000 - 2000 turns around a permanent magnet steel. The liquid turbine flowmeter signal detector is fixedly connected to the pipe body of the liquid turbine flowmeter. The output pin SIG_C of the liquid turbine flowmeter signal detector is respectively electrically connected to one ends of resistor R13 and resistor R14. The output pin SIG_D of the liquid turbine flowmeter signal detector is connected to the other end of resistor R14 and the ground wire;

[0015] The other end of the resistor R13 is connected to pin 4 of the operational amplifier U5 (pin 4 of the operational amplifier U5 is its inverting input terminal), and the other end of the resistor R13 is simultaneously connected to one end of the resistor R12 and the capacitor C3. Pin 3 of the operational amplifier U5 is grounded (pin 3 of the operational amplifier U5 is its non-inverting input terminal);

[0016] Pin 5 of the operational amplifier U5 is connected to the power supply VCC (pin 5 of the operational amplifier U5 is its power supply pin);

[0017] Pin 2 of the operational amplifier U5 is connected to ground (pin 2 of the operational amplifier U5 is its ground pin);

[0018] The other ends of the resistor R12 and the capacitor C3 are connected to pin 1 of the operational amplifier U5 (pin 1 of the operational amplifier U5 is its output terminal), and at the same time, it is the output of the impeller rotation acquisition circuit module. The output of the impeller rotation acquisition circuit module is defined as SIG_F.

[0019] Preferably, the interference signal circuit acquisition module includes a resistor R9, a resistor R10, a resistor R11, a capacitor C1, and an operational amplifier U3;

[0020] The input signal of the interference signal acquisition circuit module is the two output pins of the interference signal detector. The two output pins of the interference signal detector are respectively defined as SIG_A and SIG_B;

[0021] The interference signal detector is usually composed of an inductance coil with 1000 - 2000 turns around a permanent magnet. The interference signal detector is placed in the same direction as the liquid turbine flowmeter signal detector but is not connected to the pipe body of the liquid turbine flowmeter;

[0022] The output pin SIG_A of the interference signal detector is respectively electrically connected to one end of the resistor R10 and the resistor R11;

[0023] The output pin SIG_B of the interference signal detector is respectively connected to the other end of the resistor R11 and the ground wire;

[0024] The other end of the resistor R10 is connected to pin 4 of the operational amplifier U3 (pin 4 of the operational amplifier U3 is its inverting input terminal), and the other end of the resistor R10 is simultaneously connected to one end of the resistor R9 and the capacitor C1;

[0025] Pin 3 of the operational amplifier U3 is grounded (pin 3 of the operational amplifier U3 is its non-inverting input terminal);

[0026] Pin 5 of the operational amplifier U3 is connected to the power supply VCC (pin 5 of the operational amplifier U3 is its power supply pin);

[0027] Pin 2 of the operational amplifier U3 is connected to ground (Pin 2 of the operational amplifier U3 is its ground pin);

[0028] The other ends of the resistor R10 and the capacitor C1 are connected to Pin 1 of the operational amplifier U3 (Pin 1 of the operational amplifier U3 is its output terminal), and at the same time, it is the output of the interference signal acquisition circuit module. The output of the interference signal acquisition circuit module is defined as SIG_E.

[0029] Preferably, the alarm output circuit module includes a diode D1, resistors R1, R2, R3, R4, R5, R6, R7, R8, a capacitor C2, comparators U1, U2, U4, light-emitting diodes LED1, LED2, and LED3;

[0030] The output SIG_E of the interference signal acquisition circuit module is connected to the positive electrode of the diode D1;

[0031] The negative electrode of the diode D1 is respectively connected to one end of the capacitor C2, one end of the resistor R8, Pin 3 of the comparator U1, Pin 3 of the comparator U2, and Pin 3 of the comparator U4 (Pin 3 of the comparator U1, Pin 3 of the comparator U2, and Pin 3 of the comparator U4 are all the non-inverting terminals of the comparator);

[0032] Pin 2 of the comparator U1, Pin 2 of the comparator U2, and Pin 2 of the comparator U4 are all grounded (Pin 2 of the comparator U1, Pin 2 of the comparator U2, and Pin 2 of the comparator U4 are all the ground pins of the comparator),

[0033] Pin 5 of the comparator U1, Pin 5 of the comparator U2, and Pin 5 of the comparator U4 are all connected to the power supply VCC (Pin 5 of the comparator U1, Pin 5 of the comparator U2, and Pin 5 of the comparator U4 are all the power supply pins of the comparator);

[0034] The other end of the capacitor C2 is connected to the other end of the resistor R8, and at the same time, the other end of the capacitor C2 is grounded;

[0035] Pin 4 of the comparator U1 is respectively connected to one end of the resistor R5 and one end of the resistor R6 (Pin 4 of the comparator U1 is its inverting terminal);

[0036] The other end of the resistor R6 is grounded;

[0037] The other end of the resistor R5 is connected to one end of the resistor R4, and at the same time, the other end of the resistor R5 is connected to Pin 4 of the comparator U2 (Pin 4 of the comparator U2 is its inverting terminal);

[0038] The other end of the resistor R4 is connected to one end of the resistor R3, and at the same time, the other end of the resistor R4 is connected to Pin 4 of the comparator U4 (Pin 4 of the comparator U4 is its inverting terminal);

[0039] The other end of resistor R3 is connected to the power supply VCC;

[0040] Pin 1 of comparator U1 is connected to resistor R1. At the same time, pin 1 of comparator U1 is connected to the input pin CPU_IO_1 of the CPU module (pin 1 of comparator U1 is its output terminal);

[0041] The other end of resistor R1 is connected to the positive electrode of light-emitting diode LED1;

[0042] The negative electrode of light-emitting diode LED1 is grounded;

[0043] Pin 1 of comparator U2 is connected to resistor R2. At the same time, pin 1 of comparator U2 is connected to the input pin CPU_IO_2 of the CPU module (pin 1 of comparator U2 is its output terminal);

[0044] The other end of resistor R2 is connected to the positive electrode of light-emitting diode LED2;

[0045] The negative electrode of light-emitting diode LED2 is grounded;

[0046] Pin 1 of comparator U4 is connected to resistor R7. At the same time, pin 1 of comparator U4 is connected to the input pin CPU_IO_3 in the CPU module (pin 1 of comparator U4 is its output terminal);

[0047] The other end of resistor R7 is connected to the positive electrode of light-emitting diode LED3;

[0048] The negative electrode of light-emitting diode LED3 is grounded.

[0049] Preferably, the signal switching circuit is composed of an electronic analog switch U6;

[0050] The output SIG_F of the impeller rotation acquisition circuit module is connected to pin 1 of the electronic analog switch U6 (pin 1 of the electronic analog switch U6 is its input pin);

[0051] The output SIG_E of the interference signal acquisition circuit module is connected to pin 3 of the electronic analog switch U6 (pin 3 of the electronic analog switch U6 is its input pin);

[0052] Pin 2 of the electronic analog switch U6 is connected to the AD conversion input pin CPU_AD in the CPU module (pin 2 of the electronic analog switch U6 is its output pin);

[0053] Pin 4 of the electronic analog switch U6 is connected to the output pin CPU_IO_4 in the CPU module (pin 4 of the electronic analog switch U6 is its control pin).

[0054] Beneficial effects

[0055] The utility model provides a self-diagnosis alarm circuit for eliminating environmental interference of a liquid turbine flowmeter. Compared with the prior art, the following beneficial effects are achieved:

[0056] The spatial electromagnetic interference is amplified by the interference signal acquisition circuit module, and then the signal is latched and compared for alarm output through the alarm output circuit module. The magnitude of the on-site interference can be identified by the on-off state of the light-emitting diode. At the same time, the CPU module collects the output signal of the alarm output circuit module, automatically switches to collect the signal of the interference signal acquisition module, and eliminates the interference signal in the normal measurement signal through spectrum, so as to convert and obtain the correct interference-free flow signal, realizing the self-diagnosis alarm output of the spatial electromagnetic interference and automatically eliminating the influence of the interference. Description of the Drawings

[0057] Figure 1 is the circuit principle block diagram of the utility model;

[0058] Figure 2 is the circuit schematic diagram of the utility model. Specific Embodiments

[0059] The following will clearly and completely describe the technical solutions in the embodiments of the utility model with reference to the accompanying drawings in the embodiments of the utility model. Obviously, the described embodiments are only a part of the embodiments of the utility model, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the utility model without creative efforts shall fall within the protection scope of the utility model.

[0060] Please refer to Figure 1 and Figure 2 , a self-diagnosis alarm circuit for eliminating environmental interference of a liquid turbine flowmeter, including an impeller rotation acquisition circuit module, an interference signal circuit acquisition module, an alarm output circuit module, a signal switching module, a CPU module, a liquid turbine flowmeter signal detector and an interference signal detector;

[0061] The output ends of the impeller rotation acquisition circuit module and the interference signal circuit acquisition module are respectively electrically connected to the input end of the signal switching module, and the input end of the impeller rotation acquisition circuit module is electrically connected to the output end of the liquid turbine flowmeter signal detector;

[0062] The output end of the interference signal circuit acquisition module is electrically connected to the input end of the alarm output circuit module;

[0063] The output end of the alarm output circuit module and the output end of the signal switching module are respectively electrically connected to the input end of the CPU module;

[0064] The output end of the CPU module is electrically connected to the control pin of the signal switching module;

[0065] The CPU module uses a microcontroller, including GPIO input, output, and AD conversion modules;

[0066] The impeller rotation acquisition circuit module includes resistor R12, resistor R13, resistor R14, capacitor C3, and operational amplifier U5;

[0067] The input signals of the impeller rotation acquisition circuit module are the two output pins of the liquid turbine flowmeter signal detector. The two output pins of the liquid turbine flowmeter signal detector are respectively defined as SIG_C and SIG_D. The liquid turbine flowmeter signal detector consists of an inductance coil with 1000 - 2000 turns around a permanent magnet. The liquid turbine flowmeter signal detector is fixedly connected to the pipe body of the liquid turbine flowmeter. The output pin SIG_C of the liquid turbine flowmeter signal detector is electrically connected to one end of resistor R13 and resistor R14 respectively. The output pin SIG_D of the liquid turbine flowmeter signal detector is connected to the other end of resistor R14 and the ground wire;

[0068] The other end of resistor R13 is connected to pin 4 of operational amplifier U5 (pin 4 of operational amplifier U5 is its inverting input terminal), and the other end of resistor R13 is simultaneously connected to one end of resistor R12 and capacitor C3. Pin 3 of operational amplifier U5 is grounded (pin 3 of operational amplifier U5 is its non-inverting input terminal);

[0069] Pin 5 of operational amplifier U5 is connected to power supply VCC (pin 5 of operational amplifier U5 is its power supply pin);

[0070] Pin 2 of operational amplifier U5 is connected to the ground (pin 2 of operational amplifier U5 is its grounding pin);

[0071] The other ends of resistor R12 and capacitor C3 are connected to pin 1 of operational amplifier U5 (pin 1 of operational amplifier U5 is its output terminal), and at the same time, it is the output of the impeller rotation acquisition circuit module. The output of the impeller rotation acquisition circuit module is defined as SIG_F.

[0072] The interference signal circuit acquisition module includes resistor R9, resistor R10, resistor R11, capacitor C1, and operational amplifier U3;

[0073] The input signals of the interference signal acquisition circuit module are the two output pins of the interference signal detector. The two output pins of the interference signal detector are respectively defined as SIG_A and SIG_B;

[0074] The interference signal detector usually consists of an inductance coil with 1000 - 2000 turns around a permanent magnet steel, and the interference signal detector is placed in the same direction as the signal detector of the liquid turbine flowmeter but not connected to the pipe body of the liquid turbine flowmeter;

[0075] The output pin SIG_A of the interference signal detector is electrically connected to one end of resistor R10 and resistor R11 respectively;

[0076] The output pin SIG_B of the interference signal detector is connected to the other end of resistor R11 and the ground wire respectively;

[0077] The other end of resistor R10 is connected to pin 4 of operational amplifier U3 (pin 4 of operational amplifier U3 is its inverting input terminal), and the other end of resistor R10 is simultaneously connected to one end of resistor R9 and capacitor C1;

[0078] Pin 3 of operational amplifier U3 is grounded (pin 3 of operational amplifier U3 is its non-inverting input terminal);

[0079] Pin 5 of operational amplifier U3 is connected to power supply VCC (pin 5 of operational amplifier U3 is its power supply pin);

[0080] Pin 2 of operational amplifier U3 is connected to the ground (pin 2 of operational amplifier U3 is its grounding pin);

[0081] The other ends of resistor R10 and capacitor C1 are connected to pin 1 of operational amplifier U3 (pin 1 of operational amplifier U3 is its output terminal), and at the same time, it is the output of the interference signal acquisition circuit module. The output of the interference signal acquisition circuit module is defined as SIG_E.

[0082] The alarm output circuit module includes diode D1, resistor R1, resistor R2, resistor R3, resistor R4, resistor R5, resistor R6, resistor R7, resistor R8, capacitor C2, comparator U1, comparator U2, comparator U4, light-emitting diode LED1, light-emitting diode LED2, and light-emitting diode LED3;

[0083] The output SIG_E of the interference signal acquisition circuit module is connected to the positive pole of diode D1;

[0084] The negative pole of diode D1 is connected to one end of capacitor C2, one end of resistor R8, pin 3 of comparator U1, pin 3 of comparator U2, and pin 3 of comparator U4 respectively (pin 3 of comparator U1, pin 3 of comparator U2, and pin 3 of comparator U4 are all the non-inverting terminals of the comparator);

[0085] Pin 2 of comparator U1, pin 2 of comparator U2, and pin 2 of comparator U4 are all grounded (pin 2 of comparator U1, pin 2 of comparator U2, and pin 2 of comparator U4 are all the ground pins of the comparator).

[0086] Pin 5 of comparator U1, pin 5 of comparator U2, and pin 5 of comparator U4 are all connected to power supply VCC (pin 5 of comparator U1, pin 5 of comparator U2, and pin 5 of comparator U4 are all the power supply pins of the comparator);

[0087] The other end of capacitor C2 is connected to the other end of resistor R8, and at the same time, the other end of capacitor C2 is grounded;

[0088] Pin 4 of comparator U1 is respectively connected to one end of resistor R5 and one end of resistor R6 (pin 4 of comparator U1 is its inverting input terminal);

[0089] The other end of resistor R6 is grounded;

[0090] The other end of resistor R5 is connected to one end of resistor R4, and at the same time, the other end of resistor R5 is connected to pin 4 of comparator U2 (pin 4 of comparator U2 is its inverting input terminal);

[0091] The other end of resistor R4 is connected to one end of resistor R3, and at the same time, the other end of resistor R4 is connected to pin 4 of comparator U4 (pin 4 of comparator U4 is its inverting input terminal);

[0092] The other end of resistor R3 is connected to power supply VCC;

[0093] Pin 1 of comparator U1 is connected to resistor R1, and at the same time, pin 1 of comparator U1 is connected to the input pin CPU_IO_1 of the CPU module (pin 1 of comparator U1 is its output terminal);

[0094] The other end of resistor R1 is connected to the positive electrode of light-emitting diode LED1;

[0095] The negative electrode of light-emitting diode LED1 is grounded;

[0096] Pin 1 of comparator U2 is connected to resistor R2, and at the same time, pin 1 of comparator U2 is connected to the input pin CPU_IO_2 of the CPU module (pin 1 of comparator U2 is its output terminal);

[0097] The other end of resistor R2 is connected to the positive electrode of light-emitting diode LED2;

[0098] The negative electrode of light-emitting diode LED2 is grounded;

[0099] Pin 1 of comparator U4 is connected to resistor R7, and at the same time, pin 1 of comparator U4 is connected to the input pin CPU_IO_3 in the CPU module (pin 1 of comparator U4 is its output terminal);

[0100] The other end of the resistor R7 is connected to the positive electrode of the light-emitting diode LED3;

[0101] The negative electrode of the light-emitting diode LED3 is grounded.

[0102] The signal switching circuit is composed of an electronic analog switch U6;

[0103] The output SIG_F of the impeller rotation acquisition circuit module is connected to pin 1 of the electronic analog switch U6 (pin 1 of the electronic analog switch U6 is its input pin);

[0104] The output SIG_E of the interference signal acquisition circuit module is connected to pin 3 of the electronic analog switch U6 (pin 3 of the electronic analog switch U6 is its input pin);

[0105] Pin 2 of the electronic analog switch U6 is connected to the AD conversion input pin CPU_AD in the CPU module (pin 2 of the electronic analog switch U6 is its output pin);

[0106] Pin 4 of the electronic analog switch U6 is connected to the output pin CPU_IO_4 in the CPU module (pin 4 of the electronic analog switch U6 is its control pin);

[0107] The impeller rotation acquisition circuit module acquires the impeller rotation signal of the turbine flowmeter, but the spatial electromagnetic interference will also be acquired. The interference signal acquisition circuit module only acquires the spatial electromagnetic interference signal and does not acquire the impeller rotation signal. When the electromagnetic interference is large, the alarm output circuit module will latch the interference signal and output it through comparison for alarm.

[0108] After the interference signal is amplified by the interference signal acquisition circuit, the peak value is latched in the alarm output circuit module and compared with the three fixed voltage thresholds generated by the resistors R3, R4, R5, and R6. When the amplified signal is greater than the voltage threshold, the comparator outputs a high level, otherwise it outputs a low level;

[0109] Therefore, the magnitude of the interference signal can be determined by the output of the comparator. The three comparators correspond to three levels of interference signal intensity, corresponding to the on and off states of three LED lights, with a total of four states: all of LED1, LED2, and LED3 are off; LED1 is on; LED1 and LED2 are on; LED1, LED2, and LED3 are all on. When applied on-site, the magnitude of the on-site interference can be determined by the states of the three LED lights, and the flowmeter can be installed at a position with less interference to avoid the influence of interference.

[0110] When the interference is small, all alarm output circuit modules output a low level. The CPU module directly collects the signals of the impeller rotation acquisition circuit, and converts the signals into impeller rotation spectrum signals through FFT operation (FFT operation, that is, fast Fourier transform, is an algorithm used to convert time-domain signals into frequency-domain signals. In this technical solution, FFT operation is used to convert the signals collected by the impeller rotation acquisition circuit module and the interference signal acquisition circuit module into impeller rotation spectrum signals and interference spectrum signals. By analyzing and processing these spectrum signals, the elimination of interference signals can be achieved, so as to obtain the correct flow signal. FFT operation has the characteristics of high efficiency and speed, which can greatly reduce the amount of calculation and enable fast spectrum analysis in real-time signal processing), and then converts them into flow display. When the interference is large, the alarm output circuit module outputs a high level, and the three output signals represent different interference signal levels. When the single-chip microcomputer collects that the alarm output signal is high level or the alarm level changes, it switches to collect the signals of the interference signal acquisition circuit module, and converts the signals into interference spectrum signals through FFT operation; the CPU module subtracts and eliminates the interference spectrum in the impeller rotation spectrum signal, and then the interference-free impeller signal spectrum can be obtained, so as to be converted into the correct flow signal and eliminate the influence of electromagnetic interference.

[0111] By amplifying the spatial electromagnetic interference through the interference signal acquisition circuit module, and then locking and comparing the alarm output of the signal through the alarm output circuit module, the size of the on-site interference can be identified through the on-off state of the light-emitting diode; at the same time, the CPU module collects the output signal of the alarm output circuit module, automatically switches to collect the signals of the interference signal acquisition module, and eliminates the interference signals in the normal measurement signals through spectrum, so as to convert and obtain the correct interference-free flow signal. The utility model realizes the self-diagnosis alarm output of spatial electromagnetic interference, can automatically eliminate the interference influence, can guide the installation of the flowmeter at the position with small interference on site, and can also automatically eliminate the interference influence within a certain range.

[0112] At the same time, the content not described in detail in this specification belongs to the prior art well-known to those skilled in the art.

[0113] It should be noted that in this article, relational terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the term "comprising", "including" or any other variant thereof is intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements not only includes those elements, but also includes other elements not expressly listed, or elements inherent to such process, method, article or device.

[0114] Although embodiments of the present utility model have been shown and described, those of ordinary skill in the art can understand that various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principle and spirit of the present utility model. The scope of the present utility model is defined by the appended claims and their equivalents.

Claims

1. A self-diagnosis alarm circuit for eliminating environmental interference in a liquid turbine flowmeter, characterized in that: It includes an impeller rotation acquisition circuit module, an interference signal circuit acquisition module, an alarm output circuit module, a signal switching module, a CPU module, a liquid turbine flowmeter signal detector and an interference signal detector; The output end of the impeller rotation acquisition circuit module and the output end of the interference signal circuit acquisition module are electrically connected to the input end of the signal switching module respectively, and the input end of the impeller rotation acquisition circuit module is electrically connected to the output end of the liquid turbine flowmeter signal detector; The output end of the interference signal circuit acquisition module is electrically connected to the input end of the alarm output circuit module; The output end of the alarm output circuit module and the output end of the signal switching module are electrically connected to the input end of the CPU module respectively; The output end of the CPU module is electrically connected to the control pin of the signal switching module.

2. The self-diagnosis alarm circuit for eliminating environmental interference of a liquid turbine flowmeter according to claim 1, characterized in that: The CPU module adopts a microcontroller, including GPIO input, output and AD conversion modules.

3. A self-diagnosis alarm circuit for eliminating environmental interference in a liquid turbine flowmeter according to claim 2, characterized in that: The impeller rotation collection circuit module includes a resistor R12, a resistor R13, a resistor R14, a capacitor C3 and an operational amplifier U5; The input signal of the impeller rotation acquisition circuit module is the two output pins of the liquid turbine flowmeter signal detector, the two output pins of the liquid turbine flowmeter signal detector are defined as SIG_C and SIG_D respectively, the liquid turbine flowmeter signal detector is composed of a 1000-2000 turn inductor coil surrounding a permanent magnetic steel, the liquid turbine flowmeter signal detector is fixedly connected to the pipe body of the liquid turbine flowmeter, the output pin SIG_C of the liquid turbine flowmeter signal detector is electrically connected to one end of the resistor R13 and the resistor R14 respectively, and the output pin SIG_D of the liquid turbine flowmeter signal detector is connected to the other end of the resistor R14 and the ground wire; The other end of the resistor R13 is connected to the 4th pin of the operational amplifier U5, and the other end of the resistor R13 is also connected to the resistor R12 and one end of the capacitor C3, and the 3rd pin of the operational amplifier U5 is grounded; Pin 5 of the operational amplifier U5 is connected to the power supply VCC; Pin 2 of the operational amplifier U5 is connected to the ground; The other ends of the resistor R12 and the capacitor C3 are connected to the pin 1 of the operational amplifier U5 and are the outputs of the impeller rotation acquisition circuit module. The output of the impeller rotation acquisition circuit module is defined as SIG_F.

4. A self-diagnosis alarm circuit for eliminating environmental interference in a liquid turbine flowmeter according to claim 3, characterized in that: The interference signal circuit acquisition module includes a resistor R9, a resistor R10, a resistor R11, a capacitor C1 and an operational amplifier U3; The input signal of the interference signal acquisition circuit module is the two output pins of the interference signal detector, and the two output pins of the interference signal detector are defined as SIG_A and SIG_B respectively; The interference signal detector is composed of an inductor coil with 1000-2000 turns surrounding a permanent magnetic steel. The interference signal detector is placed in the same direction as the liquid turbine flowmeter signal detector but is not connected to the tube body of the liquid turbine flowmeter. The output pin SIG_A of the interference signal detector is electrically connected to one end of the resistor R10 and one end of the resistor R11 respectively; The output pin SIG_B of the interference signal detector is respectively connected to the other end of the resistor R11 and the ground wire; The other end of the resistor R10 is connected to the pin 4 of the operational amplifier U3, and the other end of the resistor R10 is also connected to the resistor R9 and one end of the capacitor C1; Pin 3 of the operational amplifier U3 is grounded; Pin 5 of the operational amplifier U3 is connected to the power supply VCC; Pin 2 of the operational amplifier U3 is connected to the ground; The other ends of the resistor R10 and the capacitor C1 are connected to the pin 1 of the operational amplifier U3 and are the outputs of the interference signal acquisition circuit module. The output of the interference signal acquisition circuit module is defined as SIG_E.

5. A self-diagnosis alarm circuit for eliminating environmental interference in a liquid turbine flowmeter according to claim 4, characterized in that: The alarm output circuit module includes a diode D1, a resistor R1, a resistor R2, a resistor R3, a resistor R4, a resistor R5, a resistor R6, a resistor R7, a resistor R8, a capacitor C2, a comparator U1, a comparator U2, a comparator U4, a light emitting diode LED1, a light emitting diode LED2 and a light emitting diode LED3; The output SIG_E of the interference signal acquisition circuit module is connected to the anode of the diode D1; The cathode of the diode D1 is respectively connected to one end of the capacitor C2, one end of the resistor R8, pin 3 of the comparator U1, pin 3 of the comparator U2 and pin 3 of the comparator U4; Pin 2 of comparator U1, pin 2 of comparator U2 and pin 2 of comparator U4 are all grounded; Pin 5 of comparator U1, pin 5 of comparator U2 and pin 5 of comparator U4 are all connected to power supply VCC; The other end of the capacitor C2 is connected to the other end of the resistor R8, and the other end of the capacitor C2 is grounded; Pin 4 of the comparator U1 is connected to one end of the resistor R5 and one end of the resistor R6 respectively; The other end of the resistor R6 is grounded; The other end of the resistor R5 is connected to one end of the resistor R4, and the other end of the resistor R5 is connected to the 4th pin of the comparator U2; The other end of the resistor R4 is connected to one end of the resistor R3, and the other end of the resistor R4 is connected to the 4th pin of the comparator U4; The other end of the resistor R3 is connected to the power supply VCC; Pin 1 of the comparator U1 is connected to the resistor R1, and pin 1 of the comparator U1 is connected to the input pin CPU_IO_1 of the CPU module; The other end of the resistor R1 is connected to the positive electrode of the light emitting diode LED1; The cathode of the light emitting diode LED1 is grounded; Pin 1 of the comparator U2 is connected to the resistor R2, and at the same time, pin 1 of the comparator U2 is connected to the input pin CPU_IO_2 of the CPU module; The other end of the resistor R2 is connected to the positive electrode of the light emitting diode LED2; The cathode of the light emitting diode LED2 is grounded; Pin 1 of the comparator U4 is connected to the resistor R7, and pin 1 of the comparator U4 is connected to the input pin CPU_IO_3 in the CPU module; The other end of the resistor R7 is connected to the positive electrode of the light emitting diode LED3; The cathode of the light emitting diode LED3 is grounded.

6. A self-diagnosis alarm circuit for eliminating environmental interference in a liquid turbine flowmeter according to claim 4, characterized in that: The signal switching circuit is composed of an electronic analog switch U6; The output SIG_F of the impeller rotation acquisition circuit module is connected to pin 1 of the electronic analog switch U6; The output SIG_E of the interference signal acquisition circuit module is connected to pin 3 of the electronic analog switch U6; Pin 2 of the electronic analog switch U6 is connected to the AD conversion input pin CPU_AD in the CPU module; Pin 4 of the electronic analog switch U6 is connected to the output pin CPU_IO_4 in the CPU module.