CN202648715U - Low conductivity electromagnetic flowmeter - Google Patents
Low conductivity electromagnetic flowmeter Download PDFInfo
- Publication number
- CN202648715U CN202648715U CN 201220006072 CN201220006072U CN202648715U CN 202648715 U CN202648715 U CN 202648715U CN 201220006072 CN201220006072 CN 201220006072 CN 201220006072 U CN201220006072 U CN 201220006072U CN 202648715 U CN202648715 U CN 202648715U
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- electromagnetic flowmeter
- low conductivity
- amplifier
- signal
- noise
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Abstract
A low conductivity electromagnetic flowmeter is a novel electromagnetic flowmeter measuring a low conductivity liquid. The low conductivity electromagnetic flowmeter is characterized in that, a closed loop control circuit provided with an integration controller and eliminating noise and interference signals is adopted, and a high performance microprocessor is adopted to perform digital signal processing of flow signals, and the noise and interference signals obtained through processing goes through a program control amplifier of a simulation feedback loop to superpose digit filtering signals to feedback signals. Digit and simulation dual noise signal feedback is adopted, further improving signal to noise ratio of the electromagnetic flowmeter, making the electromagnetic flowmeter measure a liquid with low conductivity in high precision, and enlarging application scope of the electromagnetic flowmeter in industrial production.
Description
Technical field
The utility model relates to a kind of electromagnetic flowmeter, particularly relates to a kind of intelligent electromagnetic flowmeter of measuring Liquid for Low Conductance.
Background technology
Electromagnetic flowmeter has vital impact having a wide range of applications aspect water, sewage, mud, ore pulp, acid, alkali, salt liquid and the measurement of food slurries to industrial manufacture process.The ultimate principle of electromagnetic flowmeter (EMF) is Faraday's electromagnetic induction law, and namely conductor produces induction electromotive force at its two ends during cutting magnetic line movement in magnetic field.Measuring tube is equipped with up and down magnetizing coil, produces magnetic field behind the logical exciting curent and passes measuring tube, and electrode is contained in the measuring tube inwall and contacts with liquid, draws induced potential, delivers to converter.
Based on above measuring principle, electromagnetic flowmeter generally all adopts the excitation technology of positive-negative polarity for fear of the polarization of electrode phenomenon, yet when measuring the low conductivity fluid flow, waving appears in the output of instrument, exports unstablely, causes and can't use.The reason that produces this phenomenon is that the electrochemical potential of electrode regularly changes when measuring low conductivity fluid, produces the noise signal that amplitude and excitation frequency are inversely proportional to, both hydrodynamic noise.Simultaneously, when measuring Liquid for Low Conductance, because the direct impedance of liquid is very large, and flow signal is very little, therefore is very easy to be disturbed by the power frequency component of industry spot, and further causes the error of measurement of flow signal very large.
The utility model content
The purpose of this novel practical has been to provide the high-accuracy electromagnetic flowmeter that can a kind ofly measure Liquid for Low Conductance, solve because the measurement liquid electric conductivity is crossed when hanging down, the drawback that the traditional electrical magnetic flowmeter can't normally use, thereby the application of the electromagnetic flowmeter that enlarges.
The technical scheme that the utility model adopts is as follows:
The low conductivity electromagnetic flowmeter, comprise microprocessor (1), sensor (2), input amplifier (3), comparer (4), programmed switch formula storer (5), bandpass filter (7), controlled accurate detuner (8), integral controller (9), low-pass filter amplifier (10), clock circuit (11), programmable amplifier (12), voltage modulator (13), numerically-controlled precise excitation current source (14), analog voltage signal revolution word signal ADC (15), liquid crystal (16), output interface (17), 4-20mA exports (18), 485 communications (19), frequency/pulse output (20) forms.Have with the closed control circuit of integral controller its by input amplifier (3), comparer (4), programmed switch formula storer (5), bandpass filter (7), controlled accurate detuner (8), integral controller (9), low-pass filter amplifier (10), clock circuit (11), programmable amplifier (12), voltage modulator (13) form.Microprocessor (1) links to each other with programmable amplifier (12), clock circuit (11) links to each other with controlled accurate detuner (8) with programmed switch formula storer (5), and comparer (4) is connected with programmed switch formula storer (5) with voltage modulator (13).
Produce exciting current by numerically-controlled precise excitation current source (14) and offer sensor, then the direct ratio that sensor is produced and the voltage signal of flow are amplified by input amplifier (3), by clock circuit (11) and microprocessor (1) control, make it when exciting current is stablized, it is deducted the voltage signal that is produced by voltage detuner (13), the voltage that accurately is proportional to noise signal of the voltage signal of this feedback for finally obtaining via microprocessor (1) computing.Therefore can suppress by the voltage signal of flow noise and the undesired signal that changes with respect to the exciting current cycle, simultaneously also can the civil power interference voltage of sensor or stube cable coupling generation is suppressed too.
In order to remove the Noise and Interference signal that superposes in the real traffic signal, this novel practical has adopted way that analog feedback and digital signal processing dual mode combine to carry out: eliminate circuit by input amplifier (3) at analogue noise, comparer (4), programmed switch formula storer (5), bandpass filter (7), controlled accurate detuner (8), integral controller (9), low-pass filter amplifier (10), clock circuit (11), programmable amplifier (12), voltage modulator (13) forms the closed control circuit with integral controller.The input voltage of control circuit is to be transfused to the flow signal that amplifier (3) has amplified, in comparative degree, feedback voltage and signal voltage compare, if flow is constant, its steady state (SS) is, the output of comparer is constant, if fluctuations in discharge, then between the voltage of the voltage signal that has amplified and feedback, produce difference, feed back to programmed switch formula storer (5).Then in programmed switch formula storer (5), will reduce accurately the Noise and Interference signal that is superimposed upon on the flow signal.And carry out filtering by bandpass filter (7), further noise decrease and undesired signal.
Through filtered flow signal, after through the filtering and signal processing of passing through again low-pass filter amplifier (10), signal is amplified in the scope that analog voltage signal revolution word signal ADC (15) can sample, and microprocessor just can obtain the size of real flow signal by sampling.At microprocessor internal, adopted bandwidth only for the logical Finite Impulse Response filter of band of 1Hz simultaneously, flow signal has further been processed, the Noise and Interference signal has further been separated.Data before and after microprocessor (1) is processed according to the logical Finite Impulse Response filter of inside band are subtracted each other, obtain a numerical value that is directly proportional with Noise and Interference, microprocessor is according to the amplification of the size control programmable amplifier (12) of this numerical value, the Noise and Interference signal feedback that will be obtained by digital signal processing is in the analog signal processing backfeed loop, so that can be with when low conductivity be measured, the Noise and Interference signal that liquid produces is inhibited greatly, thereby has realized the high-acruracy survey to Liquid for Low Conductance.
Simultaneously, this novel practical adopts various output interface 4-20mA outputs (18), 485 communication (19), the frequency/pulse outputs (20) that also have general electromagnetic flowmeter, and the flow signal that microprocessor obtains the most at last offers the user by liquid crystal display and output interface and uses.
The beneficial effects of the utility model:
The utility model adopts and can accurately measure the fluid flow of low conductivity, has overcome the deficiency of current flux meter in low conductivity measurement application, has enlarged the range of application of electromagnetic flowmeter in commercial production.Simultaneously, when improving the signal to noise ratio (S/N ratio) of sensor, when also further having reduced the ready-made application of instrument, the ready-made power frequency of environment has improved measuring accuracy to the impact of flow signal.
Description of drawings
Embodiment
Below by specific embodiment, and by reference to the accompanying drawings 1, the technical solution of the utility model is further specified.
Embodiment: low conductivity electromagnetic flowmeter (referring to accompanying drawing 1), comprise microprocessor (1), sensor (2), input amplifier (3), comparer (4), programmed switch formula storer (5), bandpass filter (7), controlled accurate detuner (8), integral controller (9), low-pass filter amplifier (10), clock circuit (11), programmable amplifier (12), voltage modulator (13), numerically-controlled precise excitation current source (14), analog voltage signal revolution word signal ADC (15), liquid crystal (16), output interface (17), 4-20mA exports (18), 485 communications (19), frequency/pulse output (20) forms.Microprocessor (1) links to each other with programmable amplifier (12), clock circuit (11) links to each other with controlled accurate detuner (8) with programmed switch formula storer (5), and comparer (4) is connected with programmed switch formula storer (5) with voltage modulator (13).
In accompanying drawing 1, produce the constant current exciting current by numerically-controlled precise excitation current source (14) and offer sensor, then the direct ratio that sensor is produced and the voltage signal of flow are amplified by input amplifier (3), this signal is subtracted each other with the Noise and Interference signal of circuit feedback in comparer (4), then by bandpass filter (7), controlled accurate detuner (8), integral controller (9) flow signal is carried out filtering, modulation.After processing through the filtering of low-pass filter amplifier (10) and signal, signal is amplified in the scope that analog voltage signal revolution word signal ADC (15) can sample, carried out the sampling of flow signal by microprocessor.Microprocessor carries out digital filter to the data that its sampling obtains, the amplification of microprocessor control programmable amplifier (12), the Noise and Interference signal feedback that will be obtained by digital signal processing is in the analog signal processing backfeed loop, the Noise and Interference signal that liquid is produced is inhibited greatly, thereby has realized the high-acruracy survey to Liquid for Low Conductance.
Claims (3)
1. low conductivity electromagnetic flowmeter, comprise microprocessor (1), sensor (2), input amplifier (3), comparer (4), programmed switch formula storer (5), bandpass filter (7), controlled accurate detuner (8), integral controller (8), post-amplifier (9), low-pass filter amplifier (10), clock circuit (11), programmable amplifier (12), voltage modulator (13), numerically-controlled precise excitation current source (14), analog voltage signal revolution word signal ADC (15), liquid crystal (16), output interface (17), 4-20mA exports (18), 485 communications (19), frequency/pulse output (20) forms.
2. low conductivity electromagnetic flowmeter according to claim 1, it is characterized in that: have with the closed control circuit of integral controller its by input amplifier (3), comparer (4), programmed switch formula storer (5), bandpass filter (7), controlled accurate detuner (8), integral controller (9), low-pass filter amplifier (10), clock circuit (11), programmable amplifier (12), voltage modulator (13) form.
3. low conductivity electromagnetic flowmeter according to claim 1, it is characterized in that: microprocessor (1) links to each other with programmable amplifier (12), clock circuit (11) links to each other with controlled accurate detuner (8) with programmed switch formula storer (5), and comparer (4) is connected with programmed switch formula storer (5) with voltage modulator (13).
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 201220006072 CN202648715U (en) | 2012-01-09 | 2012-01-09 | Low conductivity electromagnetic flowmeter |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 201220006072 CN202648715U (en) | 2012-01-09 | 2012-01-09 | Low conductivity electromagnetic flowmeter |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN202648715U true CN202648715U (en) | 2013-01-02 |
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN 201220006072 Expired - Fee Related CN202648715U (en) | 2012-01-09 | 2012-01-09 | Low conductivity electromagnetic flowmeter |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN202648715U (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN111238586A (en) * | 2020-03-27 | 2020-06-05 | 上海市计量测试技术研究院 | Electromagnetic flowmeter for measuring low conductivity and rate measuring method thereof |
-
2012
- 2012-01-09 CN CN 201220006072 patent/CN202648715U/en not_active Expired - Fee Related
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN111238586A (en) * | 2020-03-27 | 2020-06-05 | 上海市计量测试技术研究院 | Electromagnetic flowmeter for measuring low conductivity and rate measuring method thereof |
| CN111238586B (en) * | 2020-03-27 | 2021-08-20 | 上海市计量测试技术研究院 | Electromagnetic flowmeter for measuring low conductivity and rate measuring method thereof |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| DD01 | Delivery of document by public notice |
Addressee: Suzhou Sixiang Electronic Science and Technology Co., Ltd. Document name: Notification of Termination of Patent Right |
|
| CF01 | Termination of patent right due to non-payment of annual fee |
Granted publication date: 20130102 Termination date: 20140109 |