CN208282876U - A kind of measuring device of the Electromagnetic Flow of low noise - Google Patents
A kind of measuring device of the Electromagnetic Flow of low noise Download PDFInfo
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- CN208282876U CN208282876U CN201820815490.4U CN201820815490U CN208282876U CN 208282876 U CN208282876 U CN 208282876U CN 201820815490 U CN201820815490 U CN 201820815490U CN 208282876 U CN208282876 U CN 208282876U
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Abstract
The utility model provides a kind of measuring device of the Electromagnetic Flow of low noise, shell, and it is set to the power supply unit interconnected in shell and measuring unit, the measuring unit is internally provided with excitation circuit, the first filter module for once filtering is provided between the magnet exciting coil of the excitation signal of the excitation circuit, the magnet exciting coil of excitation signal is respectively arranged to the second filter module of secondary filtering；It can simplify IC design in the utility model, increase substantially measuring system signal-to-noise ratio, the anti-interference ability for enhancing measurement, can adapt to the measurement under various environment, guarantee the stability of measurement, also allow for the required precision for meeting small signaling traffic point, apparent for inhibiting the signal noise in all kinds of environment to have the effect of, so that water meter signal-to-noise ratio enhances, range ratio becomes larger, precision can cover, and water meter can be enable more more accurately to be measured.
Description
Technical field
The utility model relates to electronic field more particularly to a kind of measuring devices of the Electromagnetic Flow of low noise.
Background technique
Electromagnetism water meter is the measuring instrument that specially designs for the requirement of water supply used water enterprise practical, with the height of science and technology
Speed development is constantly progressive with measurement technology, and electromagnetism water meter has been more and more widely used in urban water supply metering.With biography
System mechanical water meter is compared, and electromagnetism water meter has broader measurement range, does not move or convex portion, does not generate parasitic pressure drop,
It is corrosion-resistant without abrasion, accurate measurement, steady performance, at the same electromagnetism water meter can in-line power, avoid accidental power failure from making
At measurement error.
The measurement performance of electromagnetism water meter is codetermined by the performance of sensor and converter, for converter, electricity
Extremely collected induced electromotive force signal signal-to-noise ratio is stronger, and the metering of electromagnetism water meter is more accurate, and sensitivity is higher.
It is ubiquitous for the interference of signal but since electromagnetism water meter must be applied among various environment.
Currently, the source of noise is broadly divided into inside and outside two kinds, internal noise mainly due to circuit design, manufacturing process etc. because
Element is generated by instrument itself.And external noise is as the electronic environment and physicochemical environment (natural environment) where equipment
Caused, external noise commonly known as " interferes ", and this interference may be electromagnetic interference, it is also possible to which mechanical oscillation are dry
It disturbs, it is also possible to the interference from temperature change.Currently, most of electromagnetism water meter product leads to noise due to the interference of noise
Than being affected, range ratio is not generally high, also, not high for the flow measurement precision of small-range.
Utility model content
In view of the foregoing deficiencies of prior art, the utility model provides a kind of measurement dress of the Electromagnetic Flow of low noise
It sets, to solve the above technical problems.
The measuring device of the Electromagnetic Flow of low noise provided by the utility model, comprising: shell, and be set in shell
The power supply unit and measuring unit of interconnection, the measuring unit are internally provided with excitation circuit, and the excitation circuit is encouraged
The first filter module for once filtering is provided between the magnet exciting coil of magnetic signal, the magnet exciting coil of excitation signal is set respectively
Set the second filter module for secondary filtering.
Further, the power supply unit includes band gap reference, error amplifier, adjustment pipe and point for being divided
Piezoresistance network, the output end of the band gap reference are connected with shunt capacitance, the resistor voltage divider network and error amplifier
Input terminal connection, the adjustment manages and connect with the output end of error amplifier.
Further, the measuring unit further include for acquire in pipeline the feedback module of fluid flow signal and for into
The analog-to-digital conversion module of row analog-to-digital conversion, the output end of the feedback module and the input terminal of analog-to-digital conversion module connect.
Further, the measuring unit is additionally provided with comparator, be previously provided with inside the comparator it is multiple for
The fragmentation threshold that detected value is compared.
Further, the shell uses metal material, and the enclosure interior is provided with the total place for single-point grounding.
Further, the power supply unit uses linear voltage regulator.
Further, first filter module is RC filter circuit, and second filter module is LRC filter circuit.
It further, further include screen unit for shielding external electromagnetic field interference signal, the screen unit is copper foil
Material.
The utility model has the beneficial effects that the measuring device of the Electromagnetic Flow of the low noise in the utility model, Ke Yijian
Change IC design, increases substantially measuring system signal-to-noise ratio, enhance the anti-interference ability of measurement, can adapt to various environment
Under measurement, guarantee the stability of measurement, also allow for the required precision for meeting small signaling traffic point, for inhibiting all kinds of rings
Signal noise in border has the effect of apparent, so that water meter signal-to-noise ratio enhances, range ratio becomes larger, and precision can cover, energy
Water meter is enough set more more accurately to be measured.
Detailed description of the invention
Fig. 1 is the noise model circuit diagram of the measuring device of the Electromagnetic Flow of low noise in the utility model embodiment.
Fig. 2 is the electric discharge absorption circuit circuit of the measuring device of the Electromagnetic Flow of low noise in the utility model embodiment
Figure.
Fig. 3 is the single-point earth signal of the measuring device of the Electromagnetic Flow of low noise in the utility model embodiment
Figure.
Fig. 4 is that the electric field shielding mode of the measuring device of the Electromagnetic Flow of low noise in the utility model embodiment is illustrated
Figure.
Specific embodiment
Illustrate the embodiments of the present invention below by way of specific specific example, those skilled in the art can be by this theory
Content disclosed by bright book understands other advantages and effect of the utility model easily.The utility model can also be by addition
Different specific embodiments are embodied or practiced, and the various details in this specification can also be based on different viewpoints and answer
With carrying out various modifications or alterations under the spirit without departing from the utility model.It should be noted that the case where not conflicting
Under, the feature in following embodiment and embodiment can be combined with each other.
It should be noted that diagram provided in following embodiment only illustrates the basic of the utility model in a schematic way
Conception, only shown in schema then with related component in the utility model rather than component count when according to actual implementation, shape
And size is drawn, when actual implementation kenel, quantity and the ratio of each component can arbitrarily change for one kind, and its assembly layout
Kenel may also be increasingly complex.
The measuring device of the Electromagnetic Flow of low noise in the present embodiment includes mainly shell, and is set in shell
The power supply unit and measuring unit of interconnection, the measuring unit are internally provided with excitation circuit, and the excitation circuit is encouraged
The first filter module for once filtering, the magnet exciting coil point of each excitation signal are provided between the magnet exciting coil of magnetic signal
The second filter module of secondary filtering She Zhi be used for.
Power supply noise is one kind of electromagnetic interference, and especially transient noise is interfered, the rate of climb is fast, the duration is short,
Voltage amplitude amplitude is high, randomness is strong, is also easy to produce severe jamming to microcomputer and digital circuit.The output noise of integrated circuit derives from
In device electronic noise and due to the external environmental noise that integrated circuit inputs signal and introduces, wherein in device electricity
Sub- noise mainly has thermal noise, G-R noise, shot noise and the big classification of 1/f noise 4, as shown in Fig. 2, in the present embodiment, electricity
Source unit includes band gap reference, error amplifier EA, adjustment pipe and the resistor voltage divider network for being divided, band-gap reference
The output end of source EA is connected with shunt capacitance C0, the input terminal connection of the resistor voltage divider network and error amplifier, the tune
Homogeneous tube is connect with the output end of error amplifier EA, and resistor voltage divider network is made of R1 and R2.Preferably, the electricity in the present embodiment
Source unit is a kind of low pressure difference linear voltage regulator using linear voltage regulator LDO (low dropout regulator), using at it
The transistor or field-effect tube (FET) run in linear region, subtracts the voltage of excess from the input voltage of application, generates warp
The output voltage overregulated.As shown in Figure 1, noise constitutes output equivalent noise mainly including band gap referenceError
The equivalent input noise of amplifierThe output voltage noise of resistance R1, R2WithIt is former according to noise power superposition
Reason, shown in the output voltage integrated noise such as formula (1) in LDO frequency range of interest:
From formula (1) as can be seen that LDO output noise mainly by the ratio of resistance R1 and R2, band gap reference it is defeated
Equivalent noise and the input equivalent noise of error amplifier influence out.Its main noise source is band gap reference, this implementation
Example adds a biggish shunt capacitance to filter most of noise in the output end of band gap reference, another noise in LDO
Source is resistor voltage divider network, and since resistor voltage divider network is connected to the input terminal of error amplifier, the noise generated will
Amplified by control loop, the resistance of the resistor voltage divider network in the present embodiment is prevented small as far as possible such to reduce by control resistance
Noise.Low pressure difference linear voltage regulator in the present embodiment, output voltage noise: 10 μ VRMS of <, internal noise are all by inside
Single order low pass R/C filters are reduced before it.It is transmitted to output buffer stage, the cutoff frequency of the low pass R/C filters is about
0.1Hz.Linear voltage regulator in the present embodiment output+3.3v and+2.5v respectively.+ 3.3v is that cpu individually powers.+ 2.5v is mould
Conversion module power supply.External capacitive is connected to the pin to filter the noise generated by internal band gap.
In the present embodiment, it when the flow to conductive fluid measures, needs to supply to magnet exciting coil
The exciting current of alternating polarity switching, detection generate a pair of magnetic field orthotropic and configuration in measurement pipe with from magnet exciting coil
The electromotive force generated between electrode is handled after the electromotive force generated between the electrode amplification by sampled signal.This existing
Have in technology, due to the counter electromotive force of magnet exciting coil L, can be produced between the control terminal side that excitation signal CD1, CD2 are entered
Raw high voltage differential forms spike interference.It can also be produced in the polarity switching of exciting current I, while between the H bridge terminal of rear end
Raw high counter electromotive force, moment potential difference can change very greatly, or even all be higher by much than the supply voltage of excitation circuit.It may damage
The component of bad circuit, while being also the reason of generating noise.Circuit structure in through this embodiment can eliminate exchange and encourage
Counter electromotive force brought by magnet exciting coil when magnetic avoids the damage of the circuit as caused by high voltage, simultaneously effective reduces excitation
The counter electromotive force of coil L reduces noise.Make the stabilization of exciting current.As shown in Fig. 2, in excitation signal CD1 and CD2 excitation wire
It is connected between circle using the first filter module, C77 capacitor absorbs energy when spike arrives, and is released energy by R21 and R23
Amount, can significantly cut down spike, add the second filter module later and continue to filter out noise jamming, it is preferable that the present embodiment
In the first filter module be RC filter circuit, be made of resistance R22 and capacitor C77, the second filter module be LRC filtered electrical
Road, wherein LRC filtered electrical routing resistance R24, capacitor C78 and inductance the L2 composition being connect with excitation signal CD1, with excitation signal
LRC filtered electrical routing resistance R25, the capacitor C79 and inductance L1 of CD2 connection are formed.
In the present embodiment, electromagnetic flowmeter is handled after the electromotive force generated between electrode amplification by sampled signal,
The flow for flowing through the fluid in measurement pipe measures.Traditional electromagnetic flowmeter is when measuring liquid not full packages in pipeline
It waits, for the collected signal of CPU by processing meeting one air-control signal of feedback to signal circuit, the blank pipe network of signal processing can be straight
It connects and is connected with CPU pin.Since signal circuit is directly connected with sensor, many common mode interferences are had, DM EMI etc. is made an uproar
Sound, it is likely that be coupled among CPU, the calculating of CPU is interfered, measurement accuracy is influenced.The present embodiment is provided with collection tube
The feedback module of fluid flow signal is connected with the analog-to-digital conversion module for carrying out analog-to-digital conversion in road, and sensor can energy band
The common mode interference come, DM EMI can be isolated by analog-to-digital conversion module, then by analog-to-digital conversion module that signal is anti-
It is fed to CPU, evades such interference and coupling to CPU.Do not pass through CPU using air-control signal and directly walk signal circuit, but passes through AD
Chip arrives signal again, can evade the various noise jammings of IC interior in this way.
In the present embodiment, measuring unit is additionally provided with comparator, and multiple be used for and inspection is previously provided with inside comparator
The fragmentation threshold that measured value is compared.By comparing measured value and each fragmentation threshold, to realize control to different range using not
Same sample frequency completes measurement using the excitation mode of transient field, such as: according to three measurement point Q1, Q2, Q3 are divided
Section selects 5Hz sample frequency, excitation width 220ms, exciting current 120mA, excitation frequency 1/ when being lower than Q1*120%
15Hz；When being lower than Q2*120%, 100Hz sample frequency, excitation width 20ms, exciting current are selected when being higher than Q1*150%
100mA, excitation frequency 1/4Hz；When being lower than Q3*120%, 400Hz sample frequency, excitation width are selected when being higher than Q2*150%
12.5ms, exciting current 60mA, excitation frequency 1Hz.
In the present embodiment, the circuit ground low for working frequency is using single-point grounding formula (i.e. entire circuit system
In a system point regard ground connection reference point as, it is all to connect on this point of being all connected to over the ground, and a safety ground spiral shell is set
Bolt), the circuit coupling of impedance altogether is generated to prevent two points ground fault.The single-point grounding of multiple circuits is divided into series winding and parallel connection two again
Kind, the circuit coupling of total ground impedance due to series connection is generated, in the present embodiment, low-frequency channel is preferably with list in parallel
Point grounding type, as shown in Figure 3.
In the present embodiment, further include screen unit for shielding external electromagnetic field interference signal, realize to external
The shielding processing of electromagnetic interference, the present embodiment select the material of high permeability, but should prevent time saturation；It is long to shorten magnetic circuit as far as possible
Degree, increases the sectional area of shield；Electric field shielding is the capacitive couplings interference between preventing two equipment (original part, component).?
The reflection loss of incidence surface；Enter the decaying that the electromagnetic wave of shield is absorbed by material not by reflection；Inside shield
Multiple attenuation (only in attenuation by absorption < 15dB just significant).The present embodiment is due to requiring shielding material magnetic resistance
Small, magnetic conductivity is higher, and absorption loss is bigger；Conductivity is higher, and absorption loss is bigger；Frequency is higher, and absorption loss is bigger.It is preferred that
Ground, using copper foil as the material of the signal shielding interference of electromagnetic field, correspondingly, the shell of measuring device uses metal material,
As shown in Figure 4.
The above embodiments are only illustrative of the principle and efficacy of the utility model, and not for limitation, this is practical new
Type.Any person skilled in the art can all carry out above-described embodiment under the spirit and scope without prejudice to the utility model
Modifications and changes.Therefore, such as those of ordinary skill in the art without departing from the revealed essence of the utility model
All equivalent modifications or change completed under mind and technical idea, should be covered by the claim of the utility model.
Claims (8)
1. a kind of measuring device of the Electromagnetic Flow of low noise characterized by comprising shell, and be set in shell mutually
The power supply unit and measuring unit being connected, the measuring unit are internally provided with excitation circuit, the excitation of the excitation circuit
The first filter module for once filtering, the magnet exciting coil difference of each excitation signal are provided between the magnet exciting coil of signal
The second filter module for secondary filtering is set.
2. the measuring device of the Electromagnetic Flow of low noise according to claim 1, it is characterised in that: the power supply unit packet
Include band gap reference, error amplifier, adjustment pipe and the resistor voltage divider network for being divided, the band gap reference it is defeated
Outlet is connected with shunt capacitance, the input terminal connection of the resistor voltage divider network and error amplifier, the adjustment pipe and error
The output end of amplifier connects.
3. the measuring device of the Electromagnetic Flow of low noise according to claim 1, it is characterised in that: the measuring unit is also
It is described including the analog-to-digital conversion module for acquiring the feedback module of fluid flow signal in pipeline and for carrying out analog-to-digital conversion
The output end of feedback module and the input terminal of analog-to-digital conversion module connect.
4. the measuring device of the Electromagnetic Flow of low noise according to claim 1, it is characterised in that: the measuring unit is also
It is provided with comparator, multiple fragmentation thresholds for being compared with detected value are previously provided with inside the comparator.
5. the measuring device of the Electromagnetic Flow of low noise according to claim 1, it is characterised in that: the shell is using gold
Belong to material, the enclosure interior is provided with the total place for single-point grounding.
6. the measuring device of the Electromagnetic Flow of low noise according to claim 2, it is characterised in that: the power supply unit is adopted
Use linear voltage regulator.
7. the measuring device of the Electromagnetic Flow of low noise according to claim 2, it is characterised in that: the first filtering mould
Block is RC filter circuit, and second filter module is LRC filter circuit.
8. the measuring device of the Electromagnetic Flow of low noise according to claim 1, it is characterised in that: further include for shielding
The screen unit of external electromagnetic field interference signal, the screen unit are copper foil material.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201820815490.4U CN208282876U (en) | 2018-05-30 | 2018-05-30 | A kind of measuring device of the Electromagnetic Flow of low noise |
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| Application Number | Priority Date | Filing Date | Title |
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| CN201820815490.4U CN208282876U (en) | 2018-05-30 | 2018-05-30 | A kind of measuring device of the Electromagnetic Flow of low noise |
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| CN208282876U true CN208282876U (en) | 2018-12-25 |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN108489561A (en) * | 2018-05-30 | 2018-09-04 | 重庆川仪自动化股份有限公司 | A kind of measuring device of the Electromagnetic Flow of low noise |
| WO2020155456A1 (en) * | 2019-01-28 | 2020-08-06 | 深圳市鸿远微思电子有限公司 | Application apparatus combining led dimmer and reactor |
-
2018
- 2018-05-30 CN CN201820815490.4U patent/CN208282876U/en active Active
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN108489561A (en) * | 2018-05-30 | 2018-09-04 | 重庆川仪自动化股份有限公司 | A kind of measuring device of the Electromagnetic Flow of low noise |
| CN108489561B (en) * | 2018-05-30 | 2024-06-28 | 重庆川仪自动化股份有限公司 | Low-noise electromagnetic flow measuring device |
| WO2020155456A1 (en) * | 2019-01-28 | 2020-08-06 | 深圳市鸿远微思电子有限公司 | Application apparatus combining led dimmer and reactor |
| US11337281B2 (en) | 2019-01-28 | 2022-05-17 | Shenzhen Hontech-Wins Electronics Co., Ltd | Application apparatus combining LED dimmer and reactor |
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