KR20170071319A - Adjustable sensitivity optical dust sensor and method fot adjustable sensitivity - Google Patents

Adjustable sensitivity optical dust sensor and method fot adjustable sensitivity Download PDF

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KR20170071319A
KR20170071319A KR1020150179518A KR20150179518A KR20170071319A KR 20170071319 A KR20170071319 A KR 20170071319A KR 1020150179518 A KR1020150179518 A KR 1020150179518A KR 20150179518 A KR20150179518 A KR 20150179518A KR 20170071319 A KR20170071319 A KR 20170071319A
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current
sensitivity
signal
dust
sensor
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KR1020150179518A
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Korean (ko)
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KR101755368B1 (en
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김선정
황학인
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(주)엔아이디에스
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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N15/00—Investigating characteristics of particles; Investigating permeability, pore-volume or surface-area of porous materials
    • G01N15/06—Investigating concentration of particle suspensions
    • 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
    • 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
    • G01N2015/0693—
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N2201/00—Features of devices classified in G01N21/00
    • G01N2201/12—Circuits of general importance; Signal processing
    • G01N2201/124—Sensitivity
    • G01N2201/1241—Multirange
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N2201/00—Features of devices classified in G01N21/00
    • G01N2201/12—Circuits of general importance; Signal processing
    • G01N2201/125—Digital circuitry
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N2201/00—Features of devices classified in G01N21/00
    • G01N2201/12—Circuits of general importance; Signal processing
    • G01N2201/126—Microprocessor processing

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  • Physics & Mathematics (AREA)
  • Health & Medical Sciences (AREA)
  • Life Sciences & Earth Sciences (AREA)
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  • General Health & Medical Sciences (AREA)
  • General Physics & Mathematics (AREA)
  • Immunology (AREA)
  • Pathology (AREA)
  • Dispersion Chemistry (AREA)
  • Investigating Or Analysing Materials By Optical Means (AREA)

Abstract

The present invention relates to a method for varying sensitivity of an optical dust sensor and an optical dust sensor capable of varying the sensitivity of each concentration by concentration and includes a current supply unit 20 for supplying a current set to the light source unit 30, A light receiving sensor 40 for receiving the scattered light scattered by the dust and outputting an analog signal corresponding thereto, an amplifier 50 for amplifying and outputting the analog signal of the light receiving sensor 40, An analog-to-digital converter 60 for converting an output signal of the amplifier 50 into a digital signal; an analog / digital converter 60 for receiving an output signal of the analog / digital converter 60 and outputting a PLO (Loop Occupancy, A microcomputer 10 for controlling the current supply unit 20 to increase the driving current in a stepwise manner by checking whether the sensitivity of the currently detected dust concentration is equal to or higher than the reference sensitivity, One 0), and a sensor output unit 70 for outputting an output signal according to the dust concentration.

Description

TECHNICAL FIELD [0001] The present invention relates to an optical dust sensor and a method for adjusting the sensitivity of an optical dust sensor,

[0001] The present invention relates to an optical dust sensor and a method for varying the sensitivity of an optical sensor capable of varying sensitivity by density, and more particularly, The present invention relates to an optical dust sensor and a variable sensitivity detection method for each concentration.

In general, the optical dust sensor has a structure for irradiating light of a light source to a region to be dust-detected and detecting the amount of light scattered by the dust at the light-receiving portion to determine the dust concentration.

Such an optical dust sensor can be applied to electronic devices such as air conditioners and air purifiers, and it can also be installed in an automobile to detect indoor dust concentration. Also, it can be applied to an indoor space in which a dust concentration such as a clean room must be managed.

Such an optical dust sensor is disclosed in Japanese Patent Application Laid-Open No. 10-2015-0113575 (MCU type dust sensor, published October 8, 2015). The dust sensor described in the above patent includes a light emitting portion for generating light, a condensing lens for condensing the light scattered by floating dust, a light receiving portion for detecting the condensed light, an amplifying portion for amplifying the light receiving portion signal of the light receiving portion, And an MCU for receiving a signal amplified by the amplifying unit and outputting a pulse width modulation signal, wherein the MCU includes a reference signal generator for performing a function of generating a reference signal, .

However, the reference voltage can be determined by knowing the output value of the initial pollution concentration of the sensor. However, there is a problem that the reference voltage can not be applied without the comparative reference measuring device.

In addition, prior to the above-mentioned Japanese Patent Laid-Open No. 10-2015-0113575, the patent application No. 10-0539310 (registered trademark of Optical Dust Sensor having a self-sensitivity correction function and sensitivity deviation control function, registered on December 21, 2005) A technology for adjusting the sensitivity and controlling the sensitivity deviation using a microcomputer is disclosed.

When there is a reason that the intensity of light entering the light receiving sensor for detecting scattered light changes, that is, when the intensity of the LED light is fluctuating or the lens is contaminated and the sensitivity is lowered, .

However, the conventional techniques can not be applied equally to a single product having a large concentration variation of dust, and it is necessary to detect the average dust concentration in the application field in advance and set the product with a sensitivity matching the dust concentration Therefore, it is necessary to sufficiently calibrate the sensitivity to be applied to a new field. Therefore, it is not easy to apply to a new field, and there is a problem that it takes much time.

If the sensitivity of dust concentration detection is set high in an environment where the concentration of dust is 3,000,000 / ft 3 with a single product, if the product is used in an environment with a concentration of 1,000 pieces / ft 3 , There is a problem that it is necessary to set the sensitivity depending on the concentration because it is difficult to accurately detect the concentration.

According to an aspect of the present invention, there is provided an optical dust sensor which can automatically determine a dust concentration range in an installed environment, And a method for varying the star detection sensitivity.

The present invention also provides an optical dust sensor capable of diagnosing an abnormality of the sensor itself and varying the sensitivity according to the concentration that can notify the abnormality when the abnormality is diagnosed, and a method of varying the sensitivity of detection by concentration.

According to an aspect of the present invention, there is provided an optical dust sensor capable of varying the sensitivity according to the concentration of the present invention. The optical dust sensor includes a current supply unit supplying current to the light source unit, An amplification unit 50 for amplifying and outputting an analog signal of the light receiving sensor 40, and an amplifying unit 50 for amplifying the analog signal of the light receiving sensor 40. The amplifying unit 50 amplifies the analog signal of the light receiving sensor 40, An analog-to-digital converter 60 for converting an output signal into a digital signal, and an analog-to-digital converter 60 for receiving the output signal of the analog-to-digital converter 60 to calculate PLO (Lo Pulse Occupancy, A microcomputer 10 for controlling the current supply unit 20 to increase the driving current in a stepwise manner if it is determined that the sensitivity to the detected dust concentration is not less than the reference sensitivity, Depend on concentration And a sensor output unit 70 for outputting an output signal.

The microcomputer 10 can control to supply the drive current in a stepwise manner from the drive current of the set minimum value to the drive current of the maximum value.

The current supply unit 20 may include a plurality of current paths to supply the driving current of different current values to the light source unit 30 for each current path.

The current supply unit 20 may include a plurality of current paths to supply a sum of currents flowing through the current paths to the light source unit 30 as a driving current.

The microcomputer 10 can output a failure signal through the sensor output unit 70 when the sensitivity to the currently detected dust concentration is less than the reference sensitivity even in a state in which the drive current of the maximum value is supplied.

The failure signal is an LPO signal, which is 0.001 to 0.1 times the normal output signal 70 of the sensor output 70 so that it can be distinguished from the normal output signal of the sensor output 70.

The method for varying the detection sensitivity of each optical density sensor according to the present invention includes the steps of: a) supplying a set minimum driving current (i 0 ) to the light source section 30; and b) C) calculating an LPO graph for the concentration of dust due to the supply of the driving current (i 0 ), wherein the current LPO and confirming that the reference sensitivity over, d) step c) is the step determined that the above sensitivity, the current LPO reference current and maintaining the drive current (i 0), e) wherein c) the step determined that the current LPO Determining whether the current drive current (i 0 ) is a set maximum drive current if it is less than the reference sensitivity; and f) determining a drive current (i 1 ) whose current value is one step higher than the maximum drive current To the light source unit 30, and returning to the step b) Can.

The method may further include generating a fault signal if the maximum driving current is determined as a result of step e).

The failure signal may be 0.001 to 0.1 times the normal sensor output signal.

The optical dust sensor and the method for varying the sensitivity of the concentration according to the present invention are capable of varying the sensitivity according to the concentration of the present invention. In this method, the driving current for driving the light source is gradually increased from a low value to a high value, Is output above the reference sensitivity, it is possible to automatically set the most suitable sensitivity in the currently installed dust concentration environment.

Therefore, there is an effect that it is possible to reduce the inconvenience of setting the sensitivity in advance in consideration of the field to be applied in production of the product.

Further, according to the present invention, even if dusts are not detected even after sequentially inputting from the set minimum drive current to the maximum drive current, it is possible to diagnose and inform the user of abnormality, There is an effect that it is easy to check whether it is in the wiring.

1 is a block diagram of an optical dust sensor capable of varying sensitivity according to a preferred embodiment of the present invention.
2 is a graph for explaining the operation of the present invention.
Fig. 3 is a configuration diagram of the current supply unit in Fig. 1. Fig.
4 is a flowchart of a method for varying detection sensitivity by concentration according to a preferred embodiment of the present invention.

An optical dust sensor capable of varying the sensitivity according to the concentration of the present invention and a method for varying the sensitivity of detection according to concentration will be described in detail with reference to the accompanying drawings.

1 is a block diagram of an optical dust sensor capable of varying sensitivity according to a preferred embodiment of the present invention.

Referring to FIG. 1, an optical dust sensor capable of varying sensitivity according to a preferred embodiment of the present invention includes a current supply unit 20 for supplying a current set to the light source unit 30, A light receiving sensor 40 for receiving scattered light scattered in dust and outputting an analog signal corresponding to the scattered light, an amplifying unit 50 for amplifying and outputting the analog signal of the light receiving sensor 40, An analog-to-digital converter 60 for converting the output signal of the analog-to-digital converter 50 into a digital signal and an output signal of the analog-to-digital converter 60 to calculate an LPO (Lo Pulse Occupancy, A microcomputer 10 for checking whether the sensitivity for the currently detected dust concentration is equal to or higher than the reference sensitivity and for increasing the driving current by controlling the current supply unit 20 if the sensitivity is not higher than the reference sensitivity, Calculated dust It is configured to include the sensor output section 70 for outputting an output signal according to Fig.

Hereinafter, the construction and operation of the optical dust sensor capable of varying the sensitivity according to the concentration according to the preferred embodiment of the present invention will be described in detail.

FIG. 2 is a graph for explaining the operation of the present invention, and shows an output value with respect to a dust concentration according to a difference in driving current.

When the driving current is minimum i 0 , the range of detectable dust concentration becomes large. However, when the driving current is below a certain dust concentration, the output value is low and the slope is gentle and the desired sensitivity can not be obtained.

Also, when the driving current is i 1 , which is the medium value, the range of detectable dust concentration is narrower than i 0 , but it can be confirmed that it is appropriate at the portion of 100,000 ft 3 .

In Fig. 2, the density of dust / ft 3 is used, but mg / ft 3 can be used.

In the case of i 2 , which is the maximum value of the driving current, the detectable dust concentration range is very narrow, but it can be confirmed that the sensitivity is relatively good in the low concentration range.

The dust concentration detection area is divided according to the value of the driving current. In the present invention, the sensitivity can be automatically changed by selecting a driving current most suitable for the current installation environment.

Specifically, in the initial state, the microcomputer 10 controls the current supply unit 20 to supply the driving current i 0 having the lowest value among the set driving currents to the light source unit 30. The light source unit 30 may be an LED, and the light source unit 30 may be applied regardless of the type of the light source that differs in output light amount according to the driving current.

The light source unit 30 generates a light amount of light corresponding to the driving current i 0 by applying the driving current i 0 . This light is scattered in the dust presently installed, and the scattered light is received by the light receiving sensor 40.

The light receiving sensor 40 outputs an emitter signal, which is an analog signal according to the amount of the scattered light received. The emitter signal is amplified through the amplifying unit 50, Signal.

The high signal and the low signal at the output of the A / D converter 60 may indicate that there is no dust and dust, respectively. Depending on the setting, there may be dust and no dust. In the microcomputer 10, It is possible to calculate and output the LPO (%) which is the duration of the Low signal throughout the output of the converter 60.

At this time, the LPO value is substituted into FIG. 2 to calculate the dust concentration, and the dust concentration is calculated considering that the currently detected LPO is the result of supplying the driving current (i 0 ) to the light source unit 30. If the LPO value is less than the set reference sensitivity (or the reference output), it is determined that the dust concentration of the current installation environment is not suitable to supply the driving current i 0 to the light source unit 30, If it is more than the sensitivity, it is determined that it is appropriate and the current driving current (i 0 ) setting is maintained.

When judged that the above is not suitable for the supply of the driving current (i 0), the microcomputer 10 increases one step the driving current supplied to the light source 30 to control the current supply 20.

3 is a diagram showing an embodiment of the current supply unit 20. The current supply unit 20 may include current paths 21, 22 and 23 connected in parallel with resistors R0, R1 and R2, (I 0 , i 1 , i 2 ) can be selectively supplied through the first , Or the sum of the currents supplied through the current paths 21, 22, and 23 may be expressed by the driving currents (i 0 , i 1 , i 2 ).

The specific configuration of the current supply unit 20 is only one example and can be applied irrespective of the configuration as long as it can supply the drive current set in accordance with the control of the microcomputer 10 step by step.

The current supply unit 20 cuts off the driving current i 0 supplied through the current path 21 and supplies the driving current i 1 to the light source unit 30 through the current path 22 under the control of the microcomputer 10 .

The light amount of the light source unit 30 is increased by the supply of the driving current i 1 and the scattered light is received by the light receiving sensor 40 and the analog signal of the light receiving sensor 40 is amplified by the amplifying unit 50, And is converted into a digital signal by the digital-to-analog converter 60. [

The microcomputer 10 receiving the digital signal calculates the LPO of the digital signal and refers the LPO to the graph based on the driving current i 1 in the table of FIG. Is suitable for detecting the concentration of dust in the air.

It is judged that the present LPO is appropriate when the current LPO when the driving current i 1 is supplied is larger than the reference sensitivity (or the reference output) in the table of FIG. 2, and it is judged that it is not suitable if it is less than the reference sensitivity (or reference output).

At this time, if it is judged to be appropriate, the driving current i 1 is supplied to the light source unit 30, and if it is judged that it is not proper, the driving current i 2 which further increases the current value of the driving current .

That is, in FIG. 3, the driving current i 1 supplied through the current path 22 is cut off, and the driving current i 2 is supplied to the light source unit 30 through the current path 23.

The amount of light of the light source unit 30 is further increased as the driving current i 2 is supplied to the light source unit 30 and the signal obtained by amplifying the analog signal of the light receiving sensor 40 receiving the scattered light by the amplifying unit 50 And converted into a digital signal by the analog / digital converter 60 and outputted.

The microcomputer 10 receiving the digital signal again calculates the LPO and checks whether the LPO of the dust concentration currently detected in the output characteristic when the driving current i 2 is supplied is equal to or higher than the reference sensitivity.

In this case, even when the drive current (i 2 ) having the largest current value is supplied as the drive current, the microcomputer 10 detects an abnormality in the light receiving sensor 40 or the like when the currently detected dust concentration based LPO is below the reference sensitivity It is possible to output a failure signal through the sensor output unit 70.

The failure signal is a signal of the LPO that is distinctly distinguished from the normal output of the normal sensor output 70. For example, the fault signal may be 0.001 to 0.01 times the normal output signal 70 of the sensor output section 70 to make it clear whether the signal output from the sensor output section 70 is a malfunction signal or a normal dust concentration signal.

This difference corresponds to about 100 dust particles.

Since the abnormality of the optical dust sensor itself can be easily confirmed from the outside according to the generation of the failure signal, the maintenance becomes easy.

In the above description, whether or not the failure signal is generated is described based on the set maximum driving current (i 2 ). However, a separate criterion can be added in order to check the failure.

4 is a flowchart of a method for varying detection sensitivity by concentration according to a preferred embodiment of the present invention.

1 and 3 described above, the method of varying the sensitivity of each concentration according to the present invention includes the steps of: (S10) supplying a set minimum driving current (i 0 ) to the light source unit 30; the supply of the step (S20), and the driving current (i 0) for processing and calculating the LPO from the microcomputer 10, the output signal of the light receiving the scattered scattered light receiving portion 30 by the light dust of 30) in LPO graph for the dust concentration in accordance with steps (S30) to determine whether more than the current sensitivity LPO the reference, when the judgment result of the S30 step or later sensitivity is currently LPO reference maintaining a current drive current (i 0) (S40) If it is determined in operation S30 that the current drive current i 0 is a set maximum drive current, if the current LPO is less than the reference sensitivity, (S60); and, as a result of the determination in step S50, Or the current flow is supplied to a one-step larger drive current (i 1) to the light source unit 30, and a step (S70), which returns to the aforementioned step S20.

Such a process is a process of automatically setting the driving current or optical output most suitable for detecting the dust concentration of the present installation environment while gradually increasing the value of the driving current. Since the specific operation has been described above in detail, It is omitted.

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit and scope of the invention will be.

10: Microcomputer 20: Current supply unit
30: Light source part 40: Light receiving sensor
50: amplification unit 60: analog / digital conversion unit
70: Sensor output section

Claims (9)

A current supply unit 20 for supplying a current set to the light source unit 30,
A light receiving sensor 40 for receiving scattered light scattered by dust emitted from the light source 30 and outputting an analog signal corresponding to the scattered light,
An amplification unit 50 for amplifying and outputting the analog signal of the light receiving sensor 40,
An analog / digital converter 60 for converting an output signal of the amplifier 50 into a digital signal,
The output signal of the A / D converter 60 is received to calculate the LPO (Lo Pulse Occupancy, duration of the low signal) to determine whether the sensitivity of the currently detected dust concentration is equal to or greater than the reference sensitivity, A microcomputer 10 for controlling the current supply unit 20 to gradually increase the driving current,
And a sensor output unit (70) for outputting an output signal according to the dust concentration calculated by the microcomputer (10).
The method according to claim 1,
The microcomputer (10)
Wherein the control unit controls so as to supply the driving current in a stepwise manner from the set minimum driving current to the maximum driving current.
3. The method of claim 2,
The current supply unit 20,
Wherein the driving current is supplied to the light source part (30) with different current values flowing in each current path, including a plurality of current paths.
3. The method of claim 2,
The current supply unit 20,
Wherein a sum of currents flowing through each current path including a plurality of current paths is supplied to the light source unit (30) as a driving current.
3. The method of claim 2,
When the sensitivity to the currently detected dust concentration is less than the reference sensitivity even in the state in which the drive current of the maximum value is supplied,
Wherein the microcomputer (10) outputs a failure signal through the sensor output unit (70).
6. The method of claim 5,
Wherein the failure signal is an LPO signal and is 0.001 to 0.1 times the normal output signal LPO of the sensor output section 70 so as to be distinguishable from the normal output signal of the sensor output section 70. [ The optical dust sensor can be varied.
a) supplying the set minimum driving current (i 0 ) to the light source unit (30);
b) processing the output signal of the light-receiving unit 30, which has received scattered light scattered by the dust of the light source unit 30, and calculating the LPO in the microcomputer 10;
c) checking whether the current LPO is equal to or higher than the reference sensitivity in the LPO graph of the dust concentration according to the supply of the driving current (i 0 );
d) maintaining a current drive current (i 0) is the c) step of the determination result over the sensitivity, the current standard LPO;
e) determining whether the c) if the determination result of the step is less than the current reference sensitivity LPO maximum drive current, the current drive current (i 0) is set; And
f) supplying a driving current (i 1 ) having a current value one step higher than the maximum driving current to the light source unit (30) as a result of the determination in the step (e), and returning to the step b) Of the detection sensitivity of the optical dust sensor according to the concentration.
8. The method of claim 7,
Further comprising the step of generating a failure signal if the maximum driving current is determined as a result of step e).
9. The method of claim 8,
The fault signal may be,
Wherein the sensor output signal is 0.001 to 0.1 times the normal sensor output signal.
KR1020150179518A 2015-12-15 2015-12-15 Adjustable sensitivity optical dust sensor and method fot adjustable sensitivity KR101755368B1 (en)

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Cited By (4)

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KR20190000995A (en) * 2017-06-26 2019-01-04 엘지전자 주식회사 Dust detecting device and method for controlling the same
KR20190065874A (en) * 2017-12-04 2019-06-12 (주) 테크로스 Method for measuring of total residual oxidant having light-source calibrating function
KR102225665B1 (en) * 2019-10-10 2021-03-10 국방과학연구소 A Method for Detecting Biological Particles
KR20230055857A (en) * 2021-10-19 2023-04-26 관악아날로그 주식회사 Dust sensor

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CN108956892A (en) * 2018-08-06 2018-12-07 佛山市甜慕链客科技有限公司 The device and method of air in a kind of monitoring building

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Publication number Priority date Publication date Assignee Title
KR20190000995A (en) * 2017-06-26 2019-01-04 엘지전자 주식회사 Dust detecting device and method for controlling the same
KR20190065874A (en) * 2017-12-04 2019-06-12 (주) 테크로스 Method for measuring of total residual oxidant having light-source calibrating function
KR102225665B1 (en) * 2019-10-10 2021-03-10 국방과학연구소 A Method for Detecting Biological Particles
KR20230055857A (en) * 2021-10-19 2023-04-26 관악아날로그 주식회사 Dust sensor

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