CN203719712U - Exciter circuit for electromagnetic flowmeter based on magnetic field measurement - Google Patents
Exciter circuit for electromagnetic flowmeter based on magnetic field measurement Download PDFInfo
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- CN203719712U CN203719712U CN201420063847.XU CN201420063847U CN203719712U CN 203719712 U CN203719712 U CN 203719712U CN 201420063847 U CN201420063847 U CN 201420063847U CN 203719712 U CN203719712 U CN 203719712U
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- 238000005259 measurement Methods 0.000 title claims abstract description 12
- 238000010586 diagram Methods 0.000 description 4
- 238000005516 engineering process Methods 0.000 description 4
- 239000012530 fluid Substances 0.000 description 2
- 238000005070 sampling Methods 0.000 description 2
- 230000007547 defect Effects 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 230000006698 induction Effects 0.000 description 1
- 239000004065 semiconductor Substances 0.000 description 1
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Abstract
The utility model provides an exciter circuit for an electromagnetic flowmeter based on magnetic field measurement and relates to the technical field of the electromagnetic flowmeter. The technical problem of increasing the measuring precision is solved. The exciter circuit comprises a sensing coil, a constant flow source generating loop, an H bridge and an H bridge control loop, wherein the two ends of the sensing coil are respectively connected with two output ends of the H bridge; the constant flow source generating loop comprises a power tube, an amplifier, a comparator and a Hall element; an in-phase input end of the amplifier is connected with the output end of the Hall element; an inverted input end of the amplifier is grounded through an input resistor; the output end of the amplifier is connected with the inverted input end of the amplifier through a feedback resistor; the in-phase input end of the comparator is connected with a reference voltage; the inverted input end of the comparator is connected with the output end of the amplifier; the output end of the comparator is connected with a grid of the power tube; an output electrode of the power tube is connected with the H bridge. The exciter circuit provided by the utility model can adjust the exciting current according to the change of the magnetic field.
Description
Technical field
The utility model relates to electromagnetic flowmeter technology, particularly relates to a kind of technology of the electromagnetic flowmeter field circuit based on magnetic-field measurement.
Background technology
Electromagnetic flowmeter is a kind of for measuring the instrument of fluid flow.Field circuit is the indispensable important component part of electromagnetic flowmeter, and its effect is to produce size and the controlled exciting current of sequential, carrys out stimulus sensor, thereby produces magnetic field.Fluid is done cutting magnetic line in pipeline, produces induced voltage at signal electrode two ends, and the size of induced voltage, is all directly proportional to magnetic induction density, flow velocity.
Existing electromagnetic flowmeter is all realized and is kept magnetic field intensity constant by control exciting current, the existing typical field circuit that electromagnetic flowmeter adopts all comprises that power supply, constant current source produce loop, and for controlling H bridge and the relevant supporting loop thereof of direction of current.
Fig. 3 is a kind of existing typical field circuit that electromagnetic flowmeter adopts, in this circuit, S31 is power supply, B31 is H bridge, U31 is H bridge control loop, L31 is sensing coil, amplifier A31, comparer A32, power tube Q31 and sampling resistor R31 form constant current source and produce loop, and the constant current source in this field circuit produces loop and is arranged on low limit.
Fig. 4 is the existing typical field circuit of another kind that electromagnetic flowmeter adopts, in this circuit, S41 is power supply, B41 is H bridge, U41 is H bridge control loop, L41 is sensing coil, amplifier A41, comparer A42, power tube Q41 and sampling resistor R41 form constant current source and produce loop, and the constant current source in this field circuit produces loop and is arranged on flash.
There is the shortcoming that can not monitor magnetic field size in the field circuit that existing electromagnetic flowmeter adopts (such as above-mentioned two kinds of circuit), while producing the faults such as turn-to-turn short circuit when sensing coil, can cause the constant and problem that magnetic field diminishes of exciting current, thereby have influence on the measuring accuracy of electromagnetic flowmeter.
Utility model content
For the defect existing in above-mentioned prior art, technical problem to be solved in the utility model is to provide a kind ofly can adjust exciting current according to changes of magnetic field, thereby guarantees the electromagnetic flowmeter field circuit based on magnetic-field measurement of electromagnetic flowmeter survey precision.
In order to solve the problems of the technologies described above, a kind of electromagnetic flowmeter field circuit based on magnetic-field measurement provided by the utility model, comprise that sensing coil, constant current source produce loop, and for controlling the H bridge of sensing coil direction of current, for controlling the H bridge control loop of H bridge work;
Each control signal output terminal of described H bridge control loop is received respectively each control end of H bridge, and two output terminals of H bridge are received respectively at the two ends of described sensing coil;
It is characterized in that: described constant current source produces loop and comprises power tube, amplifier, comparer, Hall element;
The low limit input end of H bridge is received in described power tube or drain electrode, source electrode receive ground, or drain electrode receive positive supply, source electrode is received the flash input end of H bridge;
The in-phase input end of described amplifier connects the output terminal of Hall element, and the inverting input of amplifier is received ground through an input resistance, and the output terminal of amplifier is received the inverting input of amplifier through a feedback resistance;
The in-phase input end of described comparer is received reference voltage, the output terminal of the anti-phase input termination amplifier of comparer, and the output terminal of comparer is received the grid of power tube.
The electromagnetic flowmeter field circuit based on magnetic-field measurement that the utility model provides, the characteristic of utilizing the output meeting of Hall element to change according to changes of magnetic field, monitor the magnetic field that sensing coil produces, can adjust exciting current according to changes of magnetic field, thereby guarantee electromagnetic flowmeter survey precision.
Accompanying drawing explanation
Fig. 1 is the electrical block diagram of the electromagnetic flowmeter field circuit based on magnetic-field measurement of the utility model the first embodiment;
Fig. 2 is the electrical block diagram of the electromagnetic flowmeter field circuit based on magnetic-field measurement of the utility model the second embodiment;
Fig. 3 is the electrical block diagram of a kind of existing typical field circuit of adopting of electromagnetic flowmeter;
Fig. 4 is the electrical block diagram of the existing typical field circuit of another kind that adopts of electromagnetic flowmeter.
Embodiment
Below in conjunction with accompanying drawing explanation, embodiment of the present utility model is described in further detail, but the present embodiment is not limited to the utility model, every employing analog structure of the present utility model and similar variation thereof, all should list protection domain of the present utility model in.
As shown in Figure 1, a kind of electromagnetic flowmeter field circuit based on magnetic-field measurement that the utility model the first embodiment provides, comprise that sensing coil L11, constant current source produce loop, and for controlling the H bridge B11 of sensing coil direction of current, for controlling the H bridge control loop U11 of H bridge work, for the power supply S11 to the power supply of H bridge;
Each control signal output terminal of described H bridge control loop U11 is received respectively each control end of H bridge B11, and two output terminals of H bridge B11 are received respectively at the two ends of described sensing coil L11;
It is characterized in that: described constant current source produces loop and comprises power tube Q11, amplifier A11, comparer A12, Hall element H11;
The low limit input end of H bridge B11 is received in the drain electrode of described power tube Q11, and the source electrode of power tube Q11 is received ground;
The in-phase input end of described amplifier A11 connects the output terminal of Hall element H11, and the inverting input of amplifier A11 is received ground through an input resistance R11, and the output terminal of amplifier A11 is received the inverting input of amplifier A11 through a feedback resistance R12;
The in-phase input end of described comparer A12 is received reference voltage V ref11, the output terminal of the anti-phase input termination amplifier A11 of comparer A12, and the output terminal of comparer A12 is received the grid of power tube Q11.
In the utility model the first embodiment, described H bridge and H bridge control loop are prior art.
In the utility model the first embodiment, the output gain signal of described amplifier A11 is 1 times, the value of reference voltage V ref11 is 3V, and what amplifier A11 and comparer A12 adopted is that model is the amplifier chip of OPA2209, and what power tube Q11 adopted is that model is the metal-oxide-semiconductor of IRF3607PBF.
In the utility model the first embodiment, what described Hall element adopted is that model is the Hall element of SS496A1, the service area of this sensor is 4.5V～10.5V, typical operating voltage is 5.0V, under 5V supply voltage, the magnetic field intensity scope that can measure is-0.8mT～0.8mT that corresponding output voltage is 0.5V～4.5V.
The principle of work of the utility model the first embodiment is as follows:
Hall element H11 is placed on certain ad-hoc location of mozzle inside surface of electromagnetic flowmeter, utilize Hall element H11 to measure the magnetic field intensity of specified point in mozzle, when the magnetic field intensity of specified point diminishes, the output voltage of Hall element H11 also can diminish, the grid voltage of power tube Q11 can increase, exciting current in sensing coil L11 is increased, it is large that the magnetic field intensity of specified point also becomes thereupon, when the magnetic field intensity of specified point becomes large, it is large that the output voltage of Hall element H11 also can become, the grid voltage of power tube Q11 can reduce, exciting current in sensing coil L11 is reduced, the magnetic field intensity of specified point also diminishes thereupon, this negative feedback regulative mode makes the magnetic field energy of sensing coil keep constant.
As shown in Figure 2, a kind of electromagnetic flowmeter field circuit based on magnetic-field measurement that the utility model the second embodiment provides, comprise that sensing coil L21, constant current source produce loop, and for controlling the H bridge B21 of sensing coil direction of current, for controlling the H bridge control loop U21 of H bridge work, for the power supply S21 to the power supply of H bridge;
Each control signal output terminal of described H bridge control loop U21 is received respectively each control end of H bridge B21, and two output terminals of H bridge B21 are received respectively at the two ends of described sensing coil L21;
It is characterized in that: described constant current source produces loop and comprises power tube Q21, amplifier A21, comparer A22, Hall element H21;
The low limit input end of H bridge B21 is received in the drain electrode of described power tube Q21, and the source electrode of power tube Q21 is received ground;
The in-phase input end of described amplifier A21 connects the output terminal of Hall element H21, and the inverting input of amplifier A21 is received ground through an input resistance R21, and the output terminal of amplifier A21 is received the inverting input of amplifier A21 through a feedback resistance R22;
The in-phase input end of described comparer A22 is received reference voltage V ref21, the output terminal of the anti-phase input termination amplifier A21 of comparer A22, and the output terminal of comparer A22 is received the grid of power tube Q21.
The utility model the second embodiment and the utility model the first embodiment difference are: the constant current source of the utility model the first embodiment produces the low limit that loop is arranged on H bridge, and the constant current source of the utility model the second embodiment produces the flash that loop is arranged on H bridge, other structure is basic identical, and principle of work is also similar.
Claims (1)
1. the electromagnetic flowmeter field circuit based on magnetic-field measurement, comprises that sensing coil, constant current source produce loop, and for controlling the H bridge of sensing coil direction of current, for controlling the H bridge control loop of H bridge work;
Each control signal output terminal of described H bridge control loop is received respectively each control end of H bridge, and two output terminals of H bridge are received respectively at the two ends of described sensing coil;
It is characterized in that: described constant current source produces loop and comprises power tube, amplifier, comparer, Hall element;
The low limit input end of H bridge is received in described power tube or drain electrode, source electrode receive ground, or drain electrode receive positive supply, source electrode is received the flash input end of H bridge;
The in-phase input end of described amplifier connects the output terminal of Hall element, and the inverting input of amplifier is received ground through an input resistance, and the output terminal of amplifier is received the inverting input of amplifier through a feedback resistance;
The in-phase input end of described comparer is received reference voltage, the output terminal of the anti-phase input termination amplifier of comparer, and the output terminal of comparer is received the grid of power tube.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201420063847.XU CN203719712U (en) | 2014-02-13 | 2014-02-13 | Exciter circuit for electromagnetic flowmeter based on magnetic field measurement |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201420063847.XU CN203719712U (en) | 2014-02-13 | 2014-02-13 | Exciter circuit for electromagnetic flowmeter based on magnetic field measurement |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN203719712U true CN203719712U (en) | 2014-07-16 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201420063847.XU Expired - Lifetime CN203719712U (en) | 2014-02-13 | 2014-02-13 | Exciter circuit for electromagnetic flowmeter based on magnetic field measurement |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN203719712U (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103791955A (en) * | 2014-02-13 | 2014-05-14 | 上海肯特仪表股份有限公司 | Electromagnetic flowmeter energizing circuit based on magnetic field measurement |
-
2014
- 2014-02-13 CN CN201420063847.XU patent/CN203719712U/en not_active Expired - Lifetime
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103791955A (en) * | 2014-02-13 | 2014-05-14 | 上海肯特仪表股份有限公司 | Electromagnetic flowmeter energizing circuit based on magnetic field measurement |
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| Date | Code | Title | Description |
|---|---|---|---|
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| CX01 | Expiry of patent term |
Granted publication date: 20140716 |
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| CX01 | Expiry of patent term |