CN201548272U - Current source for electromagnetic flow meter - Google Patents
Current source for electromagnetic flow meter Download PDFInfo
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- CN201548272U CN201548272U CN2009200999797U CN200920099979U CN201548272U CN 201548272 U CN201548272 U CN 201548272U CN 2009200999797 U CN2009200999797 U CN 2009200999797U CN 200920099979 U CN200920099979 U CN 200920099979U CN 201548272 U CN201548272 U CN 201548272U
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- circuit
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- electromagnetic flowmeter
- current
- flow meter
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Abstract
The utility model relates to a current source for an electromagnetic flow meter. With the development of modern industries, the higher demand of the property index of a flow meter is required. In the known electromagnetic flow meter, the amplification for a flow signal is performed by using a peak sampling signal maintaining regulating technique, a broadband signal amplifying circuit of which amplifies the flow signal together with various interference noises so the signal to noise ratio is low and the resolution ratio is inferior. The current source for the electromagnetic flow meter comprises a transformation circuit (1), a rectification filter circuit (2), a power tube (3), a reference circuit (4), a comparison amplifier (5) and a sampling circuit (6), and is characterized in that the transformation circuit (1) is connected with the rectification filter circuit (2), and the power tube (3), the reference circuit (4) and the sampling circuit (6) are respectively connected with the comparison amplifier (5). The product is used as an excitation current source for the electromagnetic flow meter.
Description
Technical field:
The utility model relates to a kind of current source, particularly a kind of excitation current source that is used for electromagnetic flowmeter.
Background technology:
Along with development of modern industry, the performance index of flowmeter are had higher requirement.In known electromagnetic flowmeter, peak sampling and holding signal conditioning technology is generally adopted in the amplification of flow signal, its broadband signal amplifying circuit together amplifies multiple interference noise with flow signal, cause signal to noise ratio (S/N ratio) low, differentiate rate variance.
Summary of the invention:
The purpose of this utility model provide a kind of can be in each cycle of flow signal the constant constant mean value excitation current source of current average, produce and satisfy the required permanent average magnetic field of narrow-band filtering conditioning technology, and then the performance index of raising electromagnetic flowmeter.
For realizing that purpose described in the utility model is achieved in that
The electromagnetic flowmeter current source comprises: transforming circuit (1), current rectifying and wave filtering circuit (2), power tube (3), reference circuit (4), comparison amplifier (5) and sample circuit (6), described transforming circuit (1) is connected with current rectifying and wave filtering circuit (2), and described power tube (3), reference circuit (4), sample circuit (6) are connected with comparison amplifier (5) respectively.
Described electromagnetic flowmeter current source, described comparison amplifier (5) is an integrating amplifier, described integrating amplifier is made up of operational amplifier U2, integrating resistor R5 and integrating capacitor C2.
Described electromagnetic flowmeter current source, described power tube (3) is a NPN transistor, have base stage, emitter and collector, described base stage is connected with comparison amplifier (5) output terminal, described collector is connected with current rectifying and wave filtering circuit (2) output terminal, and described emitter is the positive output end of current source.
Described electromagnetic flowmeter current source, described reference circuit (4) comprising: reference source U1, current-limiting resistance R1, divider resistance R2 and divider resistance R3.
Described electromagnetic flowmeter current source, described sample circuit (6) is serially connected on the output current loop.
Beneficial effect:
1, this product is according to the requirement of narrow-band filtering signal condition technology to the excitation power supply in generation magnetic field, make the electric current of output can be in each cycle of flow signal mean value constant, consequent alternating magnetic field keeps mean value constant in each cycle of flow signal, meet narrow-band filtering conditioning Technology Need, improve the performance index of electromagnetic flowmeter.
2, this product drives the magnetizing coil generation alternating magnetic field of electromagnetic flowmeter.The working environment of electromagnetic flowmeter is complicated and changeable, and wherein Temperature Influence is particularly evident.Because there is temperature coefficient in the equivalent internal resistance R of magnetizing coil,, thereby influence the stable of alternating magnetic field so temperature variation will directly cause the variation of exciting curent.Adopting permanent average current source technology is that electromagnetic flowmeter is excitatory, can make the temperature stability of alternating magnetic field improve an order of magnitude.
3, the power supply of this product is from transformation, the rectification of AC network, adopt the permanent average current source shown in the accompanying drawing 2, can effectively suppress the fluctuation that line voltage produces, when line voltage changes in-17%～+ 10% scope, exciting curent mean value in each cycle of flow signal remains stable, and the intensity that produces alternating magnetic field also is permanent all value stabilizations.
4. the desired magnetic field intensity of narrow-band filtering signal condition technology has constant mean value in each cycle of flow signal, this obviously has special requirement to the excitation current source that produces magnetic field, after finding this specific character, we provide a kind of in each cycle of flow signal the constant constant mean value excitation current source of current average.The utility model and excitatory the comparing of constant voltage of generally adopting, permanent average current excitation technology can effectively suppress the influence to the alternating magnetic field of electromagnetic flowmeter of temperature change and voltage ripple of power network.
Permanent excitatory technology of average of electromagnetic flowmeter more of the present utility model and the excitatory technology of existing electromagnetic flowmeter, current source of the present utility model, the electric current of output can be in each cycle of flow signal mean value constant, and then the permanent average alternating magnetic field that the magnetizing coil that drives electromagnetic flowmeter produces keeps constant in each cycle of flow signal, meet narrow-band filtering conditioning Technology Need, can make the temperature stability of the alternating magnetic field of electromagnetic flowmeter improve an order of magnitude, and effectively suppress line voltage and in-17%～+ 10% scope, fluctuate to the influence of permanent average alternating magnetic field, improve the performance index of electromagnetic flowmeter.
Description of drawings:
Accompanying drawing 1 is the theory diagram of this product.
Accompanying drawing 2 is circuit theory diagrams of this product.
Accompanying drawing 3 is working waveform figures of this product.
Accompanying drawing 4 is a kind of structural representations of this product.
Specific embodiments:
With reference to accompanying drawing, be described in detail the preferred specific embodiment of the utility model.
Embodiment 1:
In accompanying drawing 1, constant mean value excitation current source of electromagnetic flowmeter comprises: transforming circuit 1, current rectifying and wave filtering circuit 2, power tube 3, reference circuit 4, comparison amplifier 5 and sample circuit 6.Described transforming circuit 1 is connected with current rectifying and wave filtering circuit 2, and described power tube 3, reference circuit 4, sample circuit 6 are connected with comparison amplifier 5 respectively.
Described constant mean value excitation current source of electromagnetic flowmeter, described power tube is a NPN transistor, has base stage, emitter and collector.Described reference circuit is made up of reference source U1, current-limiting resistance R1, divider resistance R2 and R3.
Described constant mean value excitation current source of electromagnetic flowmeter, described comparison amplifier is an integrating amplifier.Form by operational amplifier U2, integrating resistor R5 and integrating capacitor C2.
Described constant mean value excitation current source of electromagnetic flowmeter, described sample circuit is serially connected in output current loop.
In this circuit structure, the positive pole of reference source U1 connects the output terminal of current rectifying and wave filtering circuit through current-limiting resistance R1, the minus earth of reference source U1, the output of reference source U1 is connected with the in-phase input end of R2 dividing potential drop with amplifier U2 through resistance R 1, for permanent average current source provides reference voltage.The inverting input of amplifier U2 is connected with sampling resistor Rn through integrating resistor R5, obtain the comparative voltage of permanent average current source, the output of reference source U1 simultaneously provides the charge or discharge electric current through resistance R 4 to integration capacitor C 2, the other end of integrating capacitor C2 is connected with the output terminal of amplifier U2 and the base stage of power tube Q, the collector of power tube Q connects the output terminal of current rectifying and wave filtering circuit, the positive output end of the very permanent average current source of the emission of power tube Q.
Describe the constant mean value excitation current source course of work of the present utility model in detail with reference to accompanying drawing 2:
1) when i (t) is constant, sampled voltage U
0Constant, the A point has I
1=I
2, Ic=0, integrating capacitor C2 do not have the charge or discharge process, and the output voltage of integrating amplifier U2, power tube Q remains unchanged, and circuit is in the current stabilization output state;
2) change I as i (t)
1≠ I
2, Ic (≠ 0) carries out charge or discharge to integration C2, regulates output voltage U through integrating amplifier U2
b, the output voltage Ec of change power tube Q, the current stabilization of realization i (t).
When i (t) increase, have:
If i (t) reduces, then:
Constant mean value excitation current source of the present utility model is regulated by taking a sample, relatively realize close-loop feedback, and the electric current of being exported mean value in each cycle of flow signal is constant.
Claims (8)
1. electromagnetic flowmeter current source, comprise: transforming circuit, current rectifying and wave filtering circuit, power tube, reference circuit, comparison amplifier and sample circuit, it is characterized in that: described transforming circuit is connected with current rectifying and wave filtering circuit, and described power tube, reference circuit, sample circuit are connected with comparison amplifier respectively.
2. electromagnetic flowmeter current source according to claim 1 is characterized in that: described comparison amplifier is an integrating amplifier, and described integrating amplifier is made up of operational amplifier U2, integrating resistor R5 and integrating capacitor C2.
3. electromagnetic flowmeter current source according to claim 1 and 2, it is characterized in that: described power tube is a NPN transistor, have base stage, emitter and collector, described base stage is connected with the comparison amplifier output terminal, described collector is connected with rectification filter circuit output end, and described emitter is the positive output end of current source.
4. electromagnetic flowmeter current source according to claim 1 and 2 is characterized in that: described reference circuit comprises: reference source U1, current-limiting resistance R1, divider resistance R2 and divider resistance R3.
5. electromagnetic flowmeter current source according to claim 3 is characterized in that: described reference circuit comprises: reference source U1, current-limiting resistance R1, divider resistance R2 and divider resistance R3.
6. according to claim 1 or 2 or 5 described constant mean value excitation current source of electromagnetic flowmeter, it is characterized in that: described sample circuit is serially connected on the output current loop.
7. electromagnetic flowmeter current source according to claim 3 is characterized in that: described sample circuit is serially connected on the output current loop.
8. electromagnetic flowmeter current source according to claim 4 is characterized in that: described sample circuit is serially connected on the output current loop.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2009200999797U CN201548272U (en) | 2009-05-26 | 2009-05-26 | Current source for electromagnetic flow meter |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2009200999797U CN201548272U (en) | 2009-05-26 | 2009-05-26 | Current source for electromagnetic flow meter |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN201548272U true CN201548272U (en) | 2010-08-11 |
Family
ID=42603447
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN2009200999797U Expired - Fee Related CN201548272U (en) | 2009-05-26 | 2009-05-26 | Current source for electromagnetic flow meter |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN201548272U (en) |
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102109366A (en) * | 2010-12-13 | 2011-06-29 | 浦瑞斯仪表（上海）有限公司 | Multi-frequency pulse digital width adjustment constant current source for electromagnetic flow meter |
| CN101900587B (en) * | 2009-05-26 | 2012-08-08 | 哈尔滨理工大学 | Constant mean value excitation current source of electromagnetic flowmeter |
| CN104048711A (en) * | 2014-07-04 | 2014-09-17 | 威海市天罡仪表股份有限公司 | Electromagnetic field multi-level strength switching circuit and electromagnetic field multi-level strength switching calculation method |
| CN104660026A (en) * | 2015-03-13 | 2015-05-27 | 上海华测导航技术股份有限公司 | Circuit structure capable of achieving soft start of DCDC rear-end heavy-load module |
| CN105571662A (en) * | 2015-12-31 | 2016-05-11 | 深圳万讯自控股份有限公司 | Signal processing method and device for electromagnetic flowmeter |
-
2009
- 2009-05-26 CN CN2009200999797U patent/CN201548272U/en not_active Expired - Fee Related
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101900587B (en) * | 2009-05-26 | 2012-08-08 | 哈尔滨理工大学 | Constant mean value excitation current source of electromagnetic flowmeter |
| CN102109366A (en) * | 2010-12-13 | 2011-06-29 | 浦瑞斯仪表（上海）有限公司 | Multi-frequency pulse digital width adjustment constant current source for electromagnetic flow meter |
| CN104048711A (en) * | 2014-07-04 | 2014-09-17 | 威海市天罡仪表股份有限公司 | Electromagnetic field multi-level strength switching circuit and electromagnetic field multi-level strength switching calculation method |
| CN104048711B (en) * | 2014-07-04 | 2017-07-18 | 威海市天罡仪表股份有限公司 | Electromagnetic field multi-level intensity switching circuit and its switching computational methods |
| CN104660026A (en) * | 2015-03-13 | 2015-05-27 | 上海华测导航技术股份有限公司 | Circuit structure capable of achieving soft start of DCDC rear-end heavy-load module |
| CN105571662A (en) * | 2015-12-31 | 2016-05-11 | 深圳万讯自控股份有限公司 | Signal processing method and device for electromagnetic flowmeter |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| C17 | Cessation of patent right | ||
| CF01 | Termination of patent right due to non-payment of annual fee |
Granted publication date: 20100811 Termination date: 20120526 |