CN211147811U - Excitation self-diagnosis circuit of electromagnetic flowmeter - Google Patents

Abstract

The embodiment of the utility model provides an electromagnetic flowmeter excitation self-diagnosis circuit, electromagnetic flowmeter excitation self-diagnosis circuit includes: the constant-current excitation circuit module, the voltage comparison circuit module and the processor are arranged in the circuit; the constant current excitation circuit module comprises an excitation generating circuit and a constant current source generating circuit; the input end of the voltage comparison circuit module is electrically connected with the excitation generating circuit and the public connecting end of the constant current source generating circuit, the output end of the voltage comparison circuit module is electrically connected with the processor, the voltage comparison circuit module is used for outputting whether the excitation generating circuit is abnormal or not according to the voltage input by the input end, so that the real-time diagnosis of the excitation circuit is realized, the automatic alarm is realized when the excitation is abnormal, the short circuit or the open circuit of the excitation coil is simultaneously distinguished, and the convenience is provided for the judgment and the maintenance of faults.

Description

Excitation self-diagnosis circuit of electromagnetic flowmeter

Technical Field

The embodiment of the utility model provides a relate to electromagnetic flowmeter self-diagnosis technique, especially relate to electromagnetic flowmeter excitation self-diagnosis circuit.

Background

An electromagnetic flow meter is a meter for measuring the flow of an electrically conductive fluid. The magnetic field is generated by applying a signal to the exciting coil, and the fluid generates induced electromotive force by cutting the magnetic induction lines, so that the flow rate of the fluid is calculated. The flow meter cannot measure accurately or cannot measure due to improper excitation, which is usually caused by damage (short circuit or open circuit) of the excitation coil or poor contact or short circuit between the sensor and the excitation circuit.

The common self-checking method of the electromagnetic flowmeter can only judge whether the coil part circuit of the electromagnetic flowmeter works abnormally, cannot specifically judge whether the coil part circuit is caused by short circuit or open circuit, has not clear judgment on faults, and is not beneficial to maintenance and subsequent improvement.

SUMMERY OF THE UTILITY MODEL

The embodiment of the utility model provides an electromagnetic flowmeter excitation self-diagnosis circuit diagnoses excitation circuit in real time, distinguishes simultaneously that excitation coil short circuit still opens circuit and causes, provides convenience for the judgement and the maintenance of trouble.

In a first aspect, the embodiment of the utility model provides an electromagnetic flowmeter excitation self-diagnosis circuit, electromagnetic flowmeter excitation self-diagnosis circuit includes:

the constant-current excitation circuit module, the voltage comparison circuit module and the processor are arranged in the circuit; the constant current excitation circuit module comprises an excitation generating circuit and a constant current source generating circuit; the excitation generating circuit is electrically connected with the constant current source generating circuit; the input end of the voltage comparison circuit module is electrically connected with the common connecting end of the excitation generating circuit and the constant current source generating circuit, the output end of the voltage comparison circuit module is electrically connected with the processor, and the voltage comparison circuit module is used for outputting a signal whether the excitation generating circuit is abnormal or not according to the voltage input by the input end.

Further, the voltage comparison circuit module includes a first voltage comparator, a second voltage comparator, a first voltage dividing resistor and a second voltage dividing resistor.

Furthermore, a first end of the first divider resistor is electrically connected with a common connection end of the constant current source generating circuit and the excitation generating circuit, a second end of the first divider resistor is electrically connected with a first end of the second divider resistor, and a second end of the second divider resistor is grounded; the second end of the first voltage dividing resistor is connected to the negative input end of the first voltage comparator and the positive input end of the second voltage comparator.

Further, the processor is electrically connected to the output of the first voltage comparator and the output of the second voltage comparator.

Further, the voltage comparison circuit module further comprises a third voltage dividing resistor and a fourth voltage dividing resistor; the first end of the third voltage dividing resistor is connected with a constant direct current power supply; the second end of the third voltage dividing resistor is electrically connected with the first end of the fourth voltage dividing resistor; the second end of the fourth voltage-dividing resistor is grounded; the second end of the third voltage dividing resistor is connected to the positive input end of the first voltage comparator.

Furthermore, the voltage comparison circuit module further comprises a fifth voltage-dividing resistor and a sixth voltage-dividing resistor; a first end of the fifth voltage-dividing resistor is connected with a constant direct-current power supply; the second end of the fifth voltage-dividing resistor is electrically connected with the first end of the sixth voltage-dividing resistor; the second end of the sixth divider resistor is grounded; and the second end of the fifth voltage-dividing resistor is connected to the negative input end of the second voltage comparator.

Furthermore, the excitation generating circuit comprises an excitation voltage input end, at least two excitation coils, a first P-type field effect tube, a second P-type field effect tube, a first N-type field effect tube and a second N-type field effect tube; the source electrode of the first P-type field effect transistor and the source electrode of the second P-type field effect transistor are electrically connected with the excitation voltage input end; the drain electrode of the first P-type field effect transistor is electrically connected with the drain electrode of the first N-type field effect transistor, and the drain electrode of the second P-type field effect transistor is electrically connected with the drain electrode of the second N-type field effect transistor; the source electrode of the first N-type field effect transistor and the source electrode of the second N-type field effect transistor are connected to a constant current source generating circuit; the at least two excitation coils are electrically connected end to end in sequence, the first end of each excitation coil is electrically connected with the connecting part of the first P-type field effect transistor and the second N-type field effect transistor, and the second end of each excitation coil is electrically connected with the connecting part of the second P-type field effect transistor and the second N-type field effect transistor; the grid of the first P-type field effect tube is connected with a first I/O port of the chip, the grid of the second P-type field effect tube is connected with a fourth I/O port of the chip, the grid of the first N-type field effect tube is connected with a second I/O port of the chip, and the grid of the second N-type field effect tube is connected with a third I/O port of the chip and used for controlling the opening and closing of the first P-type field effect tube, the second P-type field effect tube, the first N-type field effect tube and the second N-type field effect tube.

Further, the constant current source generating circuit comprises a third voltage comparator, a third N-type field effect transistor and a resistor; the drain electrode of the third N-type field effect transistor is electrically connected with the excitation generating circuit, and the source electrode is grounded through a resistor; the positive input end of the third voltage comparator is connected with a constant direct-current power supply, the negative input end of the third voltage comparator is electrically connected with the source electrode of the third N-type field effect transistor, and the output end of the third voltage comparator is electrically connected with the grid electrode of the third N-type field effect transistor.

Further, the first voltage comparator outputs a high level, and then the excitation coil in the excitation generating circuit is open-circuited; the second voltage comparator outputs high level, and then the excitation coil in the excitation generating circuit is short-circuited; and the first voltage comparator and the second voltage comparator both output low level, so that the excitation generating circuit is normal.

Furthermore, the device also comprises an alarm module which is electrically connected with the processor; the output end of the first voltage comparator is electrically connected with the fifth I/O port of the chip and used for acquiring the output level of the first voltage comparator by the processor; and if the first voltage comparator outputs a high level, controlling the alarm module to alarm.

Furthermore, the device also comprises an alarm module which is electrically connected with the processor; the output end of the second voltage comparator is electrically connected with the sixth I/O port of the chip and used for acquiring the output level of the second voltage comparator by the processor; and if the second voltage comparator outputs a high level, controlling the alarm module to alarm.

In a second aspect, the embodiment of the present invention provides an electromagnetic flowmeter excitation self-diagnosis method, which can be applied to the utility model discloses the electromagnetic flowmeter excitation self-diagnosis circuit that the arbitrary embodiment provides, electromagnetic flowmeter excitation self-diagnosis method include following step:

1) the first voltage comparator judges the normal state and the open circuit of the excitation coil by comparing the reference voltage input to the negative input end of the first voltage comparator with the first comparison voltage input to the positive input end of the first voltage comparator, when the excitation coil is open circuit, the first voltage comparator outputs high level, otherwise, the second voltage comparator outputs low level;

2) the second voltage comparator compares a reference voltage input to a positive input terminal of the second voltage comparator with a second comparison voltage input to a negative input terminal of the second voltage comparator, and outputs a high level when the at least one of the field coils is short-circuited, or outputs a low level when the at least one of the field coils is short-circuited.

The embodiment of the utility model provides an electromagnetic flow meter excitation self-diagnosis circuit, electromagnetic flow meter excitation self-diagnosis circuit includes: the constant-current excitation circuit module, the voltage comparison circuit module and the processor are arranged in the circuit; the constant current excitation circuit module comprises an excitation generating circuit and a constant current source generating circuit; the excitation generating circuit is electrically connected with the constant current source generating circuit; the input end of the voltage comparison circuit module is electrically connected with the common connecting end of the excitation generating circuit and the constant current source generating circuit, the output end of the voltage comparison circuit module is electrically connected with the processor, and the voltage comparison circuit module is used for outputting a signal whether the excitation generating circuit is abnormal or not according to the voltage input by the input end; the first voltage comparator judges the normal state and the open circuit of the excitation coil by comparing the reference voltage input to the negative input end of the first voltage comparator with the first comparison voltage input to the positive input end of the first voltage comparator, when the excitation coil is open circuit, the first voltage comparator outputs high level, otherwise, the second voltage comparator outputs low level; the second voltage comparator compares a reference voltage input to a positive input terminal of the second voltage comparator with a second comparison voltage input to a negative input terminal of the second voltage comparator, and outputs a high level when the at least one of the field coils is short-circuited, or outputs a low level when the at least one of the field coils is short-circuited. The excitation circuit is diagnosed in real time, an alarm is automatically given when the excitation is abnormal, and whether the excitation coil is short-circuited or open-circuited is distinguished, so that convenience is provided for fault judgment and maintenance.

Drawings

Fig. 1 is a schematic diagram of an excitation self-diagnosis circuit of an electromagnetic flowmeter according to an embodiment of the present invention;

fig. 2 is a schematic circuit diagram of a voltage comparison circuit module according to an embodiment of the present invention;

fig. 3 is a schematic diagram of an excitation generating circuit according to an embodiment of the present invention;

fig. 4 is a schematic circuit diagram of an excitation self-diagnosis circuit of an electromagnetic flowmeter according to an embodiment of the present invention;

fig. 5 is a schematic diagram illustrating a connection between a voltage comparator, a processor and an alarm module according to an embodiment of the present invention;

fig. 6 is a flowchart of an electromagnetic flowmeter excitation self-diagnosis method provided by the embodiment of the present invention.

Detailed Description

The present invention will be described in further detail with reference to the accompanying drawings and examples. It is to be understood that the specific embodiments described herein are merely illustrative of the invention and are not limiting of the invention. It should be further noted that, for the convenience of description, only some of the structures related to the present invention are shown in the drawings, not all of the structures.

Example one

Based on current electromagnetic flow meter self-checking method, can only simply judge that the excitation is unusual, can not specifically judge because what kind of reason caused the damage, be unfavorable for the judgement and the maintenance of trouble, and follow-up equipment modified problem, the embodiment of the utility model provides an electromagnetic flow meter excitation self-diagnosis circuit, it is exemplary, refer to fig. 1, fig. 1 is the utility model provides an electromagnetic flow meter excitation self-diagnosis circuit schematic diagram, electromagnetic flow meter excitation self-diagnosis circuit includes: the constant current excitation circuit module 10, the voltage comparison circuit module 20 and the processor 30; the constant current excitation circuit module 10 comprises an excitation generating circuit 11 and a constant current source generating circuit 12; the excitation generating circuit 11 is electrically connected with the constant current source generating circuit 12; the input end of the voltage comparison circuit module 20 is electrically connected with the common connection end of the excitation generating circuit 11 and the constant current source generating circuit 12, the output end of the voltage comparison circuit module 20 is electrically connected with the processor 30, and the voltage comparison circuit module 20 is used for outputting a signal indicating whether the excitation generating circuit 11 is abnormal or not according to the voltage input by the input end; the processor 30 comprises a chip. The excitation generating circuit 11 is open, no voltage signal is input to the input end of the voltage comparator circuit module 20, and the processor 30 receives a signal that the high level signal output by the output end of the voltage comparator circuit module 20 is abnormal; the excitation generating circuit 11 is short-circuited, the voltage signal input by the input terminal of the voltage comparator circuit module 20 is greater than the voltage signal input by the input terminal of the voltage comparator circuit module 20 when the excitation generating circuit 11 is normal, and the processor 30 receives a signal that the high level signal output by the output terminal of the voltage comparator circuit module 20 is abnormal.

Further, referring to fig. 2, fig. 2 is a circuit schematic diagram of a voltage comparison circuit module according to an embodiment of the present invention, and the voltage comparison circuit module 20 includes a first voltage comparator 21, a second voltage comparator 22, a first voltage-dividing resistor R1 and a second voltage-dividing resistor R2.

A first end of the first divider resistor R1 is electrically connected to the common connection end of the constant current source generation circuit 12 and the excitation generation circuit 11, a second end of the first divider resistor R1 is electrically connected to a first end of the second divider resistor R2, and a second end of the second divider resistor R2 is grounded; a second end of the first voltage dividing resistor R1 is connected to the negative input terminal of the first voltage comparator 21 and the positive input terminal of the second voltage comparator 22.

Specifically, the first voltage dividing resistor R1 and the second voltage dividing resistor R2 divide the voltage to obtain a reference voltage, and the reference voltage is input to the negative input terminal of the first voltage comparator 21, and is input to the positive input terminal of the second voltage comparator 22.

Specifically, the processor 30 is electrically connected to the output terminal of the first voltage comparator 21 and the output terminal of the second voltage comparator 22.

The voltage comparison circuit module 20 further includes a third voltage dividing resistor R3 and a fourth voltage dividing resistor R4; the first end of the third voltage dividing resistor R3 is connected with a constant direct current power supply U1; a second end of the third voltage dividing resistor R3 is electrically connected with the fourth voltage dividing resistor R4; the second end of the fourth voltage-dividing resistor R4 is grounded; a second end of the third voltage dividing resistor R3 is connected to the positive input end of the first voltage comparator 21.

Specifically, the third voltage dividing resistor R3 and the fourth voltage dividing resistor R4 divide the voltage to obtain a first comparison voltage, and the first comparison voltage is connected to the positive input end of the first voltage comparator 21

The voltage comparison circuit module 20 further includes a fifth voltage-dividing resistor R5 and a sixth voltage-dividing resistor R6; the first end of a fifth voltage-dividing resistor R5 is connected with a constant direct-current power supply U2; a second end of the fifth voltage-dividing resistor R5 is electrically connected with the sixth voltage-dividing resistor R6; a second end of the sixth voltage-dividing resistor R6 is grounded; a second terminal of the fifth voltage-dividing resistor R5 is connected to the negative input terminal of the second voltage comparator 22.

Specifically, the fifth voltage-dividing resistor R5 and the sixth voltage-dividing resistor R6 divide the voltage to obtain a second comparison voltage, and the second comparison voltage is connected to the negative input terminal of the second voltage comparator 22.

Further, referring to fig. 3, fig. 3 is a schematic circuit diagram of an excitation generating circuit according to an embodiment of the present invention, the excitation generating circuit 11 includes an excitation voltage input terminal 116, at least two excitation coils 115, a first P-type fet 111, a second P-type fet 114, a first N-type fet 112, and a second N-type fet 113; the source electrode of the first P-type field effect transistor 111 and the source electrode of the second P-type field effect transistor 114 are electrically connected with an excitation voltage input end 116; the drain of the first P-type field effect transistor 111 is electrically connected with the drain of the first N-type field effect transistor 112, and the drain of the second P-type field effect transistor 114 is electrically connected with the drain of the second N-type field effect transistor 113; the source electrode of the first N-type field effect transistor 112 and the source electrode of the second N-type field effect transistor 113 are connected to the constant current source generating circuit 12; the at least two excitation coils 115 are electrically connected end to end in sequence, the first end of each excitation coil is electrically connected with the connecting part of the first P-type field effect transistor 111 and the second N-type field effect transistor 112, and the second end of each excitation coil is electrically connected with the connecting part of the second P-type field effect transistor 114 and the second N-type field effect transistor 113; the grid of the first P-type field effect transistor 111 is connected to the first I/O port 41 of the chip, the grid of the second P-type field effect transistor 114 is connected to the fourth I/O port 44 of the chip, the grid of the first N-type field effect transistor 112 is connected to the second I/O port 42 of the chip, and the grid of the second N-type field effect transistor 113 is connected to the third I/O port 43 of the chip, and is used for controlling the opening and closing of the first P-type field effect transistor 111, the second P-type field effect transistor 114, the first N-type field effect transistor 112 and the second N-type field effect transistor 113.

Specifically, an excitation generating circuit 10 composed of an excitation voltage input end 116, at least two excitation coils 115, a first P-type field effect transistor 111, a second P-type field effect transistor 114, a first N-type field effect transistor 112, and a second N-type field effect transistor 113 is in an "H" shape, and may be referred to as an H-bridge circuit, and the H-bridge circuit is used for generating a flow detection magnetic field;

preferably, according to the actual working requirement of the electromagnetic flowmeter, the excitation coil 115 is conducted to generate magnetic fields in opposite directions by simultaneously conducting the first P-type field effect transistor 111 and the second N-type field effect transistor 113 or simultaneously conducting the second P-type field effect transistor 114 and the first N-type field effect transistor 113;

further, referring to fig. 4, fig. 4 is a schematic diagram of an excitation self-diagnostic circuit of an electromagnetic flowmeter according to an embodiment of the present invention, the constant current source generating circuit 12 includes a third voltage comparator 121, a third N-type fet 122, and a resistor R; the drain of the third N-type fet 122 is electrically connected to the excitation generating circuit 12, and the source is grounded via a resistor R; the positive input end of the third voltage comparator 121 is connected to the constant dc power supply U3, the negative input end is electrically connected to the source of the third N-type fet 122, and the output end is electrically connected to the gate of the third N-type fet 122;

specifically, the constant current source generating circuit 12 is configured to supply a stable constant current to the excitation generating circuit 11.

Alternatively, when the first voltage comparator 21 outputs a high level, the exciting coil 115 in the excitation generating circuit 11 is disconnected; the second voltage comparator 22 outputs a high level, the exciting coil 115 in the excitation generating circuit 11 is short-circuited; the first voltage comparator 21 and the second voltage comparator 22 both output a low level, and the excitation generating circuit 11 is normal.

Specifically, the voltage comparison circuit module 20 outputs a high level, and the circuit is in a fault state.

Specifically, the voltage at the connection end between the constant current source generating circuit 12 and the excitation generating circuit 11 is divided by the first voltage dividing resistor R1 and the second voltage dividing resistor R2 to obtain a reference voltage, and the reference voltage is connected to the negative input end of the first voltage comparator 21 circuit, for example, the excitation voltage is input to the excitation voltage input end 116 and is 24V, the excitation current is 250mA, the resistance of the excitation coil 115 is 40 Ω, the voltage on the excitation coil 115 is 250mA x40 Ω -10V, the voltage at the connection end between the constant current source generating circuit 12 and the excitation generating circuit 11 is 24V-10V-14V, and the first voltage dividing resistor R1 and the second voltage dividing resistor R2 are connected by the resistor 1: 20 partial pressures, giving a reference voltage of 0.67V. That is, when the exciting coil 115 is normal, the negative-side input voltage of the first voltage comparator 21 circuit is 0.67V; when the exciting coil 115 is turned off, the constant current source generating circuit is not turned on, and the input voltage of the negative terminal of the first voltage comparator 21 circuit is 0V; a first comparison voltage obtained by dividing the constant direct current power supply U1 by the third voltage dividing resistor R3 and the fourth voltage dividing resistor R4 is connected to a positive input end of the first voltage comparator 21 circuit, illustratively, the constant direct current power supply U1 is 3.3V, and the third voltage dividing resistor R3 and the fourth voltage dividing resistor R4 divide the voltage by 1:10, so that the first comparison voltage is 0.3V. When the exciting coil 115 is normal, 0.67V >0.3V, the first voltage comparator 21 outputs a low level, and when the exciting coil 115 is disconnected or the sensor is in poor contact with the exciting circuit or is not connected, 0V <0.3V, the first voltage comparator 21 outputs a high level;

specifically, the voltage at the connection end between the constant current source generating circuit 12 and the excitation generating circuit 11 is divided by the first voltage dividing resistor R1 and the second voltage dividing resistor R2 to obtain a reference voltage, and the reference voltage is connected to the positive input end of the second voltage comparator 22 circuit. Illustratively, the excitation voltage input end 116 inputs an excitation voltage of 24V, an excitation current of 250mA, and a resistance of the excitation coil 115 is 40 Ω, assuming that the number of the excitation coils 115 is two, when one coil is short-circuited, the resistance of the excitation coil 115 is 20 Ω, the voltage consumed by the excitation coil 115 is 250mA × 20 Ω -5V, and the voltage at the connection end between the constant current source generating circuit 12 and the excitation generating circuit 11 is 24V-5V-19V; when both the excitation coils are short-circuited, the voltage is 24V, that is, when the excitation coils are short-circuited, the voltage range of the input voltage comparison module 20 is 19V to 24V. Illustratively, the first divider resistor R1 and the second divider resistor R2 are implemented as resistors 1: the reference voltage range is 0.9V to 1.14V through 20 voltage division, and when the excitation coil 115 is normal, the input voltage at the positive terminal of the circuit of the second voltage comparator 22 is 0.67V, so that a second comparison voltage obtained by dividing the constant direct current power supply U2 through the fifth voltage dividing resistor R5 and the sixth voltage dividing resistor R6 is connected to the negative input terminal of the circuit of the second voltage comparator 22, and is larger than 0.67V and smaller than 0.9V, for example, the constant direct current power supply U2 is 3.3V, and the fifth voltage dividing resistor and the sixth voltage dividing resistor are 1: 3.3, the second contrast voltage is 0.77V. When the excitation is normal, 0.67<0.77, the second voltage comparator 22 outputs a low level; when the exciting coil is short-circuited, the reference voltage is greater than 0.77V, and the second voltage comparator 22 outputs a high level.

Optionally, referring to fig. 5, fig. 5 is a schematic diagram illustrating connection between a voltage comparator, a processor and an alarm module according to an embodiment of the present invention, and further includes an alarm module 50, where the alarm module 50 is electrically connected to the processor 30; the output end of the first voltage comparator 21 is electrically connected with the fifth I/O port 45 of the chip, and is used for acquiring the output level of the first voltage comparator 21 by the processor 30; if the first voltage comparator 21 outputs a high level, the alarm module 50 is controlled to alarm; optionally, the alarm module 50 may use an indicator light to flash and/or a display screen to display error alarm words.

Optionally, the system further comprises an alarm module 50, wherein the alarm module 50 is electrically connected with the processor 30; the output end of the second voltage comparator 22 is electrically connected with the chip sixth I/O port 46, and is used for the processor 30 to collect the output level of the second voltage comparator 22; if the second voltage comparator outputs high level, the alarm module 50 is controlled to alarm; optionally, the alarm module 50 may use an indicator light to flash and/or a display screen to display error alarm words.

The embodiment of the utility model provides a pair of electromagnetic flow meter excitation self-diagnosis circuit, electromagnetic flow meter excitation self-diagnosis circuit includes: the constant-current excitation circuit module, the voltage comparison circuit module and the processor are arranged in the circuit; the constant current excitation circuit module comprises an excitation generating circuit and a constant current source generating circuit; the excitation generating circuit is electrically connected with the constant current source generating circuit; the input end of the voltage comparison circuit module is electrically connected with the common connecting end of the excitation generating circuit and the constant current source generating circuit, the output end of the voltage comparison circuit module is electrically connected with the processor, and the voltage comparison circuit module is used for outputting a signal indicating whether the excitation generating circuit is abnormal or not according to the voltage input by the input end, so that the excitation circuit is diagnosed in real time, and circuit faults caused by short circuit or open circuit of the excitation coil are distinguished.

Example two

The embodiment of the utility model provides a still provide an electromagnetic flow meter excitation self-diagnosis method, can be applied to the utility model discloses the electromagnetic flow meter excitation self-diagnosis circuit that arbitrary embodiment provided, refer to fig. 6, fig. 6 is the embodiment of the utility model provides a pair of electromagnetic flow meter excitation self-diagnosis method flow chart, electromagnetic flow meter excitation self-diagnosis method includes following step:

s1: the first voltage comparator 21 outputs a corresponding level by comparing a reference voltage input to a negative input terminal of the first voltage comparator 21 with a first comparison voltage input to a positive input terminal of the first voltage comparator 21;

s2: the second voltage comparator 22 outputs a corresponding level by comparing the reference voltage input to the positive input terminal of the second voltage comparator 22 with the second comparison voltage input to the negative input terminal of the second voltage comparator 22;

s3: the processor 30 collects the output levels of the first voltage comparator 21 and the second voltage comparator 22;

s4: and judging the normality of the circuit, the disconnection of the excitation coil and the short circuit of the excitation coil. Judging the circuit condition: if the first voltage comparator 21 outputs a high level, the exciting coil 115 is open-circuited; if the second voltage comparator 22 outputs a high level, at least one of the exciting coils 115 is short-circuited;

s5: and the alarm module 50 gives an alarm according to the judgment result to realize the excitation self-diagnosis of the electromagnetic flowmeter.

The embodiment of the utility model provides a pair of electromagnetic flowmeter excitation self-diagnosis method possesses and the utility model provides a corresponding beneficial effect of circuit structure, voltage comparison circuit module is through the comparison to reference voltage and contrast voltage, and whether unusual signal of output excitation production circuit is received and is judged output signal by the treater, realizes the excitation circuit real-time diagnosis, and the differentiation is excitation coil short circuit or opens circuit simultaneously and causes, provides convenience for the judgement and the maintenance of trouble.

It should be noted that the foregoing is only a preferred embodiment of the present invention and the technical principles applied. It will be understood by those skilled in the art that the present invention is not limited to the particular embodiments described herein, but is capable of various obvious changes, rearrangements and substitutions as will now become apparent to those skilled in the art without departing from the scope of the invention. Therefore, although the present invention has been described in greater detail with reference to the above embodiments, the present invention is not limited to the above embodiments, and may include other equivalent embodiments without departing from the scope of the present invention.

Claims (9)

1. An electromagnetic flowmeter excitation self-diagnosis circuit, characterized in that the electromagnetic flowmeter excitation self-diagnosis circuit comprises:

the constant-current excitation circuit module, the voltage comparison circuit module and the processor are arranged in the circuit;

the constant current excitation circuit module comprises an excitation generating circuit and a constant current source generating circuit; the excitation generating circuit is electrically connected with the constant current source generating circuit; the input end of the voltage comparison circuit module is electrically connected with the common connecting end of the excitation generating circuit and the constant current source generating circuit, the output end of the voltage comparison circuit module is electrically connected with the processor, and the voltage comparison circuit module is used for outputting a signal whether the excitation generating circuit is abnormal or not according to the voltage input by the input end.

2. The electromagnetic flow meter excitation self-diagnostic circuit of claim 1, wherein the voltage comparison circuit module comprises a first voltage comparator, a second voltage comparator, a first voltage dividing resistor and a second voltage dividing resistor;

a first end of the first divider resistor is electrically connected with a common connection end of the constant current source generating circuit and the excitation generating circuit, a second end of the first divider resistor is electrically connected with a first end of the second divider resistor, and a second end of the second divider resistor is grounded; a second end of the first voltage dividing resistor is connected to a negative input end of the first voltage comparator and a positive input end of the second voltage comparator;

the processor is electrically connected with the output end of the first voltage comparator and the output end of the second voltage comparator.

3. The electromagnetic flow meter excitation self-diagnostic circuit of claim 2, wherein the voltage comparison circuit module further comprises a third voltage dividing resistor and a fourth voltage dividing resistor; a first end of the third voltage dividing resistor is connected with a constant direct current power supply; the second end of the third voltage dividing resistor is electrically connected with the first end of the fourth voltage dividing resistor; the second end of the fourth voltage-dividing resistor is grounded; a second end of the third voltage dividing resistor is connected to a positive input end of the first voltage comparator.

4. The electromagnetic flowmeter excitation self-diagnostic circuit of claim 2, wherein the voltage comparison circuit module further comprises a fifth voltage-dividing resistor and a sixth voltage-dividing resistor; a first end of the fifth voltage-dividing resistor is connected to a constant direct-current power supply; the second end of the fifth voltage-dividing resistor is electrically connected with the first end of the sixth voltage-dividing resistor; the second end of the sixth divider resistor is grounded; and the second end of the fifth voltage-dividing resistor is connected to the negative input end of the second voltage comparator.

5. The electromagnetic flow meter excitation self-diagnostic circuit of claim 1, wherein the excitation generating circuit comprises an excitation voltage input, at least two excitation coils, a first P-type field effect transistor, a second P-type field effect transistor, a first N-type field effect transistor, a second N-type field effect transistor; the source electrode of the first P-type field effect transistor and the source electrode of the second P-type field effect transistor are electrically connected with an excitation voltage input end; the drain electrode of the first P-type field effect transistor is electrically connected with the drain electrode of the first N-type field effect transistor, and the drain electrode of the second P-type field effect transistor is electrically connected with the drain electrode of the second N-type field effect transistor; the source electrode of the first N-type field effect transistor and the source electrode of the second N-type field effect transistor are connected to the constant current source generating circuit; the at least two excitation coils are electrically connected end to end in sequence, a first end of each excitation coil is electrically connected with a connecting part of the first P-type field effect transistor and the second N-type field effect transistor, and a second end of each excitation coil is electrically connected with a connecting part of the second P-type field effect transistor and the second N-type field effect transistor; the grid of the first P type field effect tube is connected with a first I/O port of a chip, the grid of the second P type field effect tube is connected with a fourth I/O port of the chip, the grid of the first N type field effect tube is connected with a second I/O port of the chip, and the grid of the second N type field effect tube is connected with a third I/O port of the chip and used for controlling the opening and closing of the first P type field effect tube, the second P type field effect tube, the first N type field effect tube and the second N type field effect tube.

6. The electromagnetic flow meter excitation self-diagnosis circuit according to claim 1, wherein the constant current source generating circuit comprises a third voltage comparator, a third N-type field effect transistor, a resistor; the drain electrode of the third N-type field effect transistor is electrically connected with the excitation generating circuit, and the source electrode of the third N-type field effect transistor is grounded through the resistor; and the positive input end of the third voltage comparator is connected with a constant direct-current power supply, the negative input end of the third voltage comparator is electrically connected with the source electrode of the third N-type field effect transistor, and the output end of the third voltage comparator is electrically connected with the grid electrode of the third N-type field effect transistor.

7. The electromagnetic flowmeter excitation self-diagnostic circuit of claim 2, wherein the first voltage comparator outputs a high level, and the excitation coil in the excitation generation circuit is open-circuited; when the second voltage comparator outputs a high level, the excitation coil in the excitation generating circuit is short-circuited; and the first voltage comparator and the second voltage comparator both output low levels, so that the excitation generating circuit is normal.

8. The electromagnetic flow meter excitation self-diagnostic circuit of claim 7, further comprising an alarm module, the alarm module being electrically connected to the processor; the output end of the first voltage comparator is electrically connected with a fifth I/O port of the chip and used for acquiring the output level of the first voltage comparator by the processor; and if the first voltage comparator outputs a high level, controlling the alarm module to alarm.

9. The electromagnetic flow meter excitation self-diagnostic circuit according to claim 8, wherein an output terminal of the second voltage comparator is electrically connected to a sixth I/O port of a chip, and is used for the processor to acquire an output level of the second voltage comparator; and if the second voltage comparator outputs a high level, controlling the alarm module to alarm.

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