CN106053347A - Turbidity measuring circuit - Google Patents
Turbidity measuring circuit Download PDFInfo
- Publication number
- CN106053347A CN106053347A CN201610671027.2A CN201610671027A CN106053347A CN 106053347 A CN106053347 A CN 106053347A CN 201610671027 A CN201610671027 A CN 201610671027A CN 106053347 A CN106053347 A CN 106053347A
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
- G01N21/01—Arrangements or apparatus for facilitating the optical investigation
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
- G01N21/17—Systems in which incident light is modified in accordance with the properties of the material investigated
- G01N21/47—Scattering, i.e. diffuse reflection
- G01N21/49—Scattering, i.e. diffuse reflection within a body or fluid
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- Health & Medical Sciences (AREA)
- Life Sciences & Earth Sciences (AREA)
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- General Physics & Mathematics (AREA)
- Immunology (AREA)
- Pathology (AREA)
- Investigating Or Analysing Materials By Optical Means (AREA)
Abstract
The invention discloses a turbidity measuring circuit which comprises a central processor; the central processor is electrically connected to a constant current control module; the constant current control module is electrically connected to a white LED lamp; the white LED lamp acts on a signal receiving module through an optical structure; the signal receiving module is coupled to a current/voltage conversion module; a signal converted by the current/voltage conversion module passes through a signal amplification module and then is delivered to the central processor. The turbidity measuring circuit adopts the white LED lamp as a light source and a first-level silicon photodiode as a signal receiving unit, the white LED lamp is controlled to generate stable brightness through the constant current control module, a differential amplifying circuit is adopted after the signal is received, and interference is suppressed; a circuit land is used as a reference for AD sampling, PGA inside an AD chip is used for controlling gain to achieve high resolution ratio and stable effect, and influence of zero drift and unstable measurement under low turbidity is effectively inhibited.
Description
Technical field
The present invention relates to transmissometer technical field, a kind of turbidity measuring circuit for transmissometer.
Background technology
In field of measuring technique, there is a kind of turbidimetry being specifically designed for liquid, to obtain fluid characteristics parameter.
And existing transmissometer light source on the market typically uses tungsten lamp and LED two schemes, in processing of circuit, often
Because it is big to process null offset that is the most proper and then that show, needing frequently zeroing, resolution is low, and in low turbidity situation
Lower extreme is unstable.Therefore, market is needed badly a kind of measure low turbidity and stablizes, the turbidimetry system that null offset is little.
Summary of the invention
It is an object of the invention to provide a kind of turbidity measuring circuit, which solve current turbidity measuring circuit null offset
Greatly, low turbidity measures unstable technical problem.
For reaching above-mentioned purpose, technical scheme proposed by the invention is:
A kind of turbidity measuring circuit of the present invention, comprising: central processing unit, described central processing unit is electrically connected to constant current
Control module, described constant-current control module is electrically connected to white LED lamp, and described white LED lamp acts on through an optical texture
One signal receiving module, described signal receiving module is coupled in current/voltage-converted module, described current/voltage-converted module
Signal after conversion is delivered to described central processing unit after a signal amplification module；Described central processing unit controls described constant current
Control module provides stable electric current for described white LED lamp, and the light of described white LED lamp is through on described optical texture
Scatter to signal receiving module after solution to be measured, described signal receiving module receive after the optical signal of scattering through described electric current/
Change into the signal of telecommunication after voltage transformation module, signal amplification module and be delivered to central processing unit, described central processing unit calculate
Turbidity value.
Wherein, described described signal receiving module is that silicon photo diode receives circuit.
Wherein, described signal amplification module includes: one-level amplifying circuit and be coupled in described one-level amplifying circuit
Second amplifying circuit, described second amplifying circuit includes a digital regulation resistance being controlled by described central processing unit.
Wherein, described one-level amplifying circuit uses differential amplifier circuit.
Wherein, described central processing unit also includes what working power, described working power included powering for central processing unit
Digital power, and the analog power powered for described white LED lamp；Between wherein said digital power and analog power and ground
All it is in series with for being electrically connected with the inductance for isolation between anti-interference capacitor, digital power and analog power.
Wherein, described constant-current control module includes: the Zener diode being series between power supply and ground and the first resistance,
Described Zener diode two ends are parallel with an electric capacity, and the negative electrode of described Zener diode is also in series with one second resistance, and described
The outfan of two resistance is coupled in an operational amplifier and makes constant output current so that the short void of void that utilizes described operational amplifier is disconnected.
Wherein, the outfan of described operational amplifier is also electrically connected with switch three pole being controlled by central processing unit
Pipe.
Wherein, described silicon photo diode receives circuit and includes: silicon photo diode, the anode of described silicon photo diode and the moon
Pole is electrically connected to the input of a difference amplifier respectively, and the input of described difference amplifier and outfan are also parallel with electric capacity
And resistance.
Wherein, the optical texture of this turbidity measuring circuit application is a smooth noise reduction scatterometry mechanism, and described smooth noise reduction dissipates
Penetrating measuring mechanism to include: annular body, the annular sidewall of described annular body is provided with for injecting the white of white LED lamp white light
Optical channel, for installing the sense channel of silicon photo diode, and for suppressing the noise reducing mechanism of optical noise；The most above-mentioned white light
Differing 90 degree of central angles between passage with sense channel, described noise reducing mechanism is positioned at the dead ahead of white light passage.
Compared with prior art, the turbidity measuring circuit of the present invention, it uses white LED lamp as light source, one-level silicon light
Diode, as signal receiving unit, controls white LED lamp by constant-current control module and makes it produce stable brightness, at signal
Take differential amplifier circuit, suppression interference after reception, then carry out AD sampling with circuit for reference, utilize within A/D chip
PGA is controlled gain and reaches the effect that resolution is high and stable, effectively inhibits and measures under null offset and low turbidity
Unstable impact.
Accompanying drawing explanation
Fig. 1 is the functional block diagram of the turbidity measuring circuit of the present invention.
Fig. 2 is the central processor section circuit diagram of the turbidity measuring circuit of the present invention.
Fig. 3 is the power supply partial circuit diagram of the turbidity measuring circuit of the present invention.
Fig. 4 is the constant-current control module partial circuit diagram of the turbidity measuring circuit of the present invention.
Fig. 5 is the silicon photo diode circuit part circuit diagram of the turbidity measuring circuit of the present invention.
Fig. 6 is the signal amplification module partial circuit diagram of the turbidity measuring circuit of the present invention.
Fig. 7 is the light noise reduction scatterometry mechanism structure signal that the turbidity measuring circuit of the present invention is applied to turbidimetry
Figure.
Detailed description of the invention
Below with reference to accompanying drawing, the present invention is given elaboration further.
Referring to accompanying drawing 1 to accompanying drawing 6, in the present embodiment, this turbidity measuring circuit includes: central processing unit 1, above-mentioned in
Central processor 1 is electrically connected to constant-current control module 2, and above-mentioned constant-current control module 2 is electrically connected to white LED lamp 3, above-mentioned white light
LED 3 acts on a signal receiving module 5 through an optical texture 4, and above-mentioned signal receiving module 5 is coupled in current/voltage and turns
Die change block 6, the signal after the conversion of above-mentioned current/voltage-converted module 6 is delivered to above-mentioned centre after a signal amplification module 7
Reason device 1, is wherein positioned over optical texture 4 for solution to be detected, is scattered.Above-mentioned central processing unit 1 controls above-mentioned
Constant-current control module 2 provides stable electric current for above-mentioned white LED lamp 3, and the light of above-mentioned white LED lamp 3 passes through above-mentioned optics
Signal receiving module 5 is scattered to, after above-mentioned signal receiving module 5 receives the optical signal of scattering after solution to be measured in structure 4
After above-mentioned current/voltage-converted module 6, signal amplification module 7, change into the signal of telecommunication be delivered to central processing unit 1, in above-mentioned
Central processor 1 calculates turbidity value according to turbidity algorithm.
Referring to accompanying drawing 2 and accompanying drawing 3, above-mentioned central processing unit 1 also includes that working power, above-mentioned working power include
The digital power powered for central processing unit, this digital power forms with inductance L1 left part circuit, and is above-mentioned white light
The analog power of LED 3 power supply, this analog power forms with the right part circuit of inductance L1.The most above-mentioned digital power and
All it is in series with between analog power and ground for anti-interference capacitor C5 and electric capacity C6, is electrically connected between digital power and analog power
It is connected to the inductance L1 for isolation.Power supply inputs, and through inductance, isolation digital power and analog power, is then passed through U5, produces
More stable analog power.So can greatly reduce the interference of digital power, improve power source performance, source reduces circuit
Noise.Equally, analog portion ground wire is isolated with numerical portion ground wire, reduces circuit noise.
Referring to accompanying drawing 4, above-mentioned constant-current control module 2 includes: voltage stabilizing two pole being series between power supply and ground
Pipe U17 and the first resistance R41, above-mentioned Zener diode U17 two ends are parallel with an electric capacity C18, the moon of above-mentioned Zener diode U17
Pole is also in series with one second resistance R42, and the outfan of above-mentioned second resistance R42 is coupled in an operational amplifier U4 in order to above-mentioned
The short void of void of operational amplifier is disconnected makes constant output current.Zener diode U17 is source of stable pressure, and operational amplifier U4, second
Resistance R42, produces mu balanced circuit jointly.Due to the effect of operational amplifier U4, the source of stable pressure of Zener diode U17, conversion
Becoming output at the constant-current source of diode D13, the electric current in circuit is together decided on by the second resistance R42, Zener diode U17.This
The continuous current of sample, is input on diode D13 white LED lamp 3, and the energy of white LED lamp 3 is more stable, and light beats is less.
Wherein, the outfan of above-mentioned operational amplifier U4 is also electrically connected with switch three pole being controlled by central processing unit
Pipe Q1, this switch triode is controlled by central processing unit 1 and automatically controls the opening and closing of white LED lamp.
More specifically, referring to accompanying drawing 5, above-mentioned signal receiving module is that silicon photo diode receives circuit.Wherein, above-mentioned
Silicon photo diode receive circuit and include: silicon photo diode D16, the anode of above-mentioned silicon photo diode D16 and negative electrode Electricity Federation respectively
Being connected to the input of a difference amplifier U2-A, input and the outfan of above-mentioned difference amplifier U2-A are also parallel with electric capacity
C32 and resistance R49.Receiving terminal is received optical signal by silicon photo diode D16, and by difference amplifier U2-A differential amplification, difference is put
Big circuit has good noise suppression feature, and therefore noise jamming is less.
Referring to accompanying drawing 6, above-mentioned signal amplification module 7 includes: one-level amplifying circuit and be coupled in above-mentioned
The second amplifying circuit of level amplifying circuit, above-mentioned stage circuit includes that difference amplifier U2-B, above-mentioned second amplifying circuit include
The one digital regulation resistance U11 being controlled by above-mentioned central processing unit 1, the amplification of this digital regulation resistance U11 is by central processing unit 1
Control, so that its signal reaches to amplify requirement.Wherein, above-mentioned one-level amplifying circuit uses differential amplifier circuit.Put by one-level
The signal of big output, through resistance R50, is input to the adjustable amplification in the second level, and same employing differential amplification mode suppresses noise, then
ADC sampling A/D chip is exported through VPD.Such circuit, light path is more stable, and noise jamming is little, therefore the drift of turbidimetry zero point
Move little, stable performance, particularly show especially prominent in the case of low turbidity.
Referring to accompanying drawing 7, it is the structural representation of light noise reduction scatterometry mechanism of turbidity measuring circuit application.This light
Noise reduction scatterometry mechanism includes that annular body 40, the annular sidewall of annular body 40 are provided with for injecting white LED lamp white
The white light passage 42 of light, for installing the sense channel 41 of silicon photo diode, and for suppressing the noise reducing mechanism 43 of optical noise,
Differing 90 degree of central angles between the most above-mentioned white light passage 42 and sense channel 41, described noise reducing mechanism 43 is positioned at white light passage 42
Dead ahead.
Foregoing, only presently preferred embodiments of the present invention, be not intended to limit embodiment of the present invention, and this area is general
Logical technical staff, according to the central scope of the present invention and spirit, can carry out corresponding flexible or amendment very easily, therefore this
The protection domain of invention should be as the criterion with the protection domain required by claims.
Claims (9)
1. a turbidity measuring circuit, it is characterised in that including: central processing unit, described central processing unit is electrically connected to constant current
Control module, described constant-current control module is electrically connected to white LED lamp, and described white LED lamp acts on through an optical texture
One signal receiving module, described signal receiving module is coupled in current/voltage-converted module, described current/voltage-converted module
Signal after conversion is delivered to described central processing unit after a signal amplification module；Described central processing unit controls described constant current
Control module provides stable electric current for described white LED lamp, and the light of described white LED lamp is through on described optical texture
Scatter to signal receiving module after solution to be measured, described signal receiving module receive after the optical signal of scattering through described electric current/
Change into the signal of telecommunication after voltage transformation module, signal amplification module and be delivered to central processing unit, described central processing unit calculate
Turbidity value.
2. turbidity measuring circuit as claimed in claim 1, it is characterised in that described described signal receiving module is silicon light
Diode receives circuit.
3. turbidity measuring circuit as claimed in claim 1, it is characterised in that described signal amplification module includes: one-level is put
Big circuit and be coupled in the second amplifying circuit of described one-level amplifying circuit, described second amplifying circuit includes that one is controlled by institute
State the digital regulation resistance of central processing unit.
4. turbidity measuring circuit as claimed in claim 3, it is characterised in that described one-level amplifying circuit uses differential amplification
Circuit.
5. turbidity measuring circuit as claimed in claim 1, it is characterised in that described central processing unit also includes working power,
Described working power includes the digital power powered for central processing unit, and the analog power powered for described white LED lamp；
All it is in series with for anti-interference capacitor, digital power and analog power between wherein said digital power and analog power and ground
Between be electrically connected with for isolation inductance.
6. turbidity measuring circuit as claimed in claim 1, it is characterised in that described constant-current control module includes: be series at
Zener diode between power supply and ground and the first resistance, described Zener diode two ends are parallel with an electric capacity, described voltage stabilizing two
The negative electrode of pole pipe is also in series with one second resistance, and it is described to utilize that the outfan of described second resistance is coupled in an operational amplifier
The short void of void of operational amplifier is disconnected makes constant output current.
7. turbidity measuring circuit as claimed in claim 6, it is characterised in that the outfan of described operational amplifier is also electrically connected
It is connected to a switch triode being controlled by central processing unit.
8. turbidity measuring circuit as claimed in claim 2, it is characterised in that described silicon photo diode receives circuit and includes:
Silicon photo diode, the anode of described silicon photo diode and negative electrode are electrically connected to the input of a difference amplifier, described difference respectively
The input and the outfan that divide amplifier are also parallel with electric capacity and resistance.
9. turbidity measuring circuit as claimed in claim 1, it is characterised in that the optical texture of application is that a smooth noise reduction scattering is surveyed
Measuring mechanism, described smooth noise reduction scatterometry mechanism includes: annular body, the annular sidewall of described annular body is provided with for penetrating
Enter the white light passage of white LED lamp white light, for installing the sense channel of silicon photo diode, and for suppressing the fall of optical noise
Make an uproar mechanism；Differing 90 degree of central angles between the most above-mentioned white light passage and sense channel, described noise reducing mechanism is positioned at white light passage
Dead ahead.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201610671027.2A CN106053347A (en) | 2016-08-15 | 2016-08-15 | Turbidity measuring circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201610671027.2A CN106053347A (en) | 2016-08-15 | 2016-08-15 | Turbidity measuring circuit |
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| Publication Number | Publication Date |
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| CN106053347A true CN106053347A (en) | 2016-10-26 |
Family
ID=57480694
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201610671027.2A Pending CN106053347A (en) | 2016-08-15 | 2016-08-15 | Turbidity measuring circuit |
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| CN (1) | CN106053347A (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106770046A (en) * | 2016-12-02 | 2017-05-31 | 北京师范大学 | A kind of farmland ditch TOC or turbidity monitoring device |
| CN109696385A (en) * | 2018-12-19 | 2019-04-30 | 骆杨斌 | The design method of sensor and sensor |
| CN111600562A (en) * | 2020-05-19 | 2020-08-28 | 浙江威星智能仪表股份有限公司 | Control circuit with continuously adjustable amplification gain |
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| US5424843A (en) * | 1992-12-23 | 1995-06-13 | The Regents Of The University Of California | Apparatus and method for qualitative and quantitative measurements of optical properties of turbid media using frequency-domain photon migration |
| CN1851424A (en) * | 2006-05-23 | 2006-10-25 | 渤海船舶重工有限责任公司 | Multi-path output resistance signal generator |
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2016
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106770046A (en) * | 2016-12-02 | 2017-05-31 | 北京师范大学 | A kind of farmland ditch TOC or turbidity monitoring device |
| CN109696385A (en) * | 2018-12-19 | 2019-04-30 | 骆杨斌 | The design method of sensor and sensor |
| CN111600562A (en) * | 2020-05-19 | 2020-08-28 | 浙江威星智能仪表股份有限公司 | Control circuit with continuously adjustable amplification gain |
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