CN104792729A - Handheld laser gas concentration monitor and control method thereof - Google Patents
Handheld laser gas concentration monitor and control method thereof Download PDFInfo
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- CN104792729A CN104792729A CN201510152780.6A CN201510152780A CN104792729A CN 104792729 A CN104792729 A CN 104792729A CN 201510152780 A CN201510152780 A CN 201510152780A CN 104792729 A CN104792729 A CN 104792729A
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- VNWKTOKETHGBQD-UHFFFAOYSA-N methane Chemical compound C VNWKTOKETHGBQD-UHFFFAOYSA-N 0.000 description 4
- 238000000041 tunable diode laser absorption spectroscopy Methods 0.000 description 4
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- RWSOTUBLDIXVET-UHFFFAOYSA-N Dihydrogen sulfide Chemical compound S RWSOTUBLDIXVET-UHFFFAOYSA-N 0.000 description 1
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Abstract
The invention provides a handheld laser gas concentration monitor and a control method thereof. The monitor comprises a handheld main unit, a gas chamber and a gas chamber connecting rod, wherein the handheld main unit is connected with the gas chamber through the gas chamber connecting rod and comprises a laser light source, a signal acquisition module, a signal processing module, a laser light source current control module, a first temperature sensor, a second temperature sensor, a temperature compensation module and a display module; the signal acquisition module is connected with the gas chamber; the signal processing module is connected with the signal acquisition module; the laser light source current control module is positioned between the laser light source and the signal processing module; the first temperature sensor, the second temperature sensor and the temperature compensation module are connected with the signal processing module respectively; the first temperature sensor and the temperature compensation module are positioned in the laser light source; the second temperature sensor is fixed to the handheld main unit. The gas concentration is measured on the basis of a tunable semiconductor laser absorption spectrum technology, and meanwhile, the laser light source is subjected to temperature compensation; the wavelength of the output laser is stabilized, the current environment temperature participates in gas concentration operation, and the gas concentration can be accurately measured.
Description
Technical field
The invention belongs to laser gas sensor field, relate to a kind of hand-held laser gas concentration monitor and control method thereof.
Background technology
In modern production, life, along with the raising of people's living standard, the requirement that the mankind purify ecologic environment is also more and more higher, and the real-time detection therefore for the harmful gas in air seems particularly important.Especially as the field such as coal and chemical industry, be problem demanding prompt solution to monitoring and prediction that is poisonous in air, harmful gas.And the application of laser gas sensor in this field and research just flourish.
Laser Modulation absorption spectroscopy techniques sensor occurs, its advantage comprises that measuring accuracy is high, fast response time etc., gradually in each monitoring field application.
This sensor utilizes based on gas near-infrared absorption spectrum technology, has screened gas absorption spectra, have employed distributed feedback laser as light source, and PIN photodiode is for receiving.Photodiode is translated into electric signal and carries out signal transacting, by the change through laser intensity before and after air chamber, extrapolate the concentration of gas after receiving the laser signal exported from air chamber, final output gas concentration data.And in prior art, laser instrument is in the process of work, temperature can change, and causes the drift of Output of laser wavelength, and usually chooses the calculating that normal temperature participates in gas concentration, brings error to result of calculation.
Summary of the invention
Given this, the invention provides a kind of hand-held laser gas concentration monitor and control method thereof, object is stable Output of laser wavelength, and current environmental temperature participates in gas concentration computing, realizes the accurate measurement to gas concentration.
For achieving the above object, the present invention adopts following technical scheme:
On the one hand, the hand-held laser gas concentration monitor of the one that the embodiment of the present invention provides, comprises handheld main machine, air chamber and air chamber connecting link; Described handheld main machine is connected by described air chamber connecting link with air chamber; Described handheld main machine comprises LASER Light Source, the signal acquisition module be connected with described air chamber, the signal processing module be connected with described signal acquisition module, LASER Light Source current control module between described LASER Light Source and signal processing module, the first temperature sensor be connected with described signal processing module respectively, the second temperature sensor and temperature compensation module, and display module; Described first temperature sensor and temperature compensation module are positioned at LASER Light Source, and the second temperature sensor is fixed in handheld main machine.
Further, described handheld main machine also comprises proportional-integral derivative controller, carries out accurate temperature compensation for controlling described temperature compensation module to LASER Light Source.
Further, described LASER Light Source current control module comprises triangular current generator and sine-wave current generator, the triangular current that described triangular current generator produces and the sine-wave current that sine-wave current generator produces are input to described LASER Light Source through totalizer, described triangular current is for scanning absorption line, and described sine-wave current is used for carrying out high frequency modulated.
Further, described signal acquisition module comprises the photodetector be connected with described air chamber, for laser signal is converted to electric signal;
The prime amplifier be connected with described photodetector, for amplifying faint electric signal;
The filter capacitor be connected with described prime amplifier, for isolated DC signal and filtering low-frequency noise;
The bandpass filter be connected with described filter capacitor, for filter out-band external noise;
Analog to digital converter between described bandpass filter and signal processing module;
Lock-in amplifier between described prime amplifier and analog to digital converter, for providing second harmonic signal; And
The filter inductance that one end is connected with described bandpass filter and analog to digital converter, for further filtering low-frequency noise.
Further, described handheld main machine also comprises rechargeable battery, for giving each module for power supply in described handheld main machine.
Further, described air chamber is light optically-coupled air chamber, the light flange comprising air chamber outer tube, be arranged on the optical fiber collimator at air chamber outer tube two ends and be arranged on optical fiber collimator; Described air chamber outer tube wall has air hole.
On the other hand, the control method of a kind of hand-held laser gas concentration monitor that the embodiment of the present invention provides, comprises the steps:
Signal processing module, by the temperature of the first temperature sensor measurement LASER Light Source, after being compared by measured temperature, is heated up or cooling to LASER Light Source by temperature compensation module with preset temperature, and by the second temperature sensor measurement current environmental temperature;
Signal processing module carries out Laser Modulation length scanning by LASER Light Source current control module driving laser light source;
Signal acquisition module receives the laser signal exported from air chamber, carries out signals collecting to it;
The signal that signal processing module Received signal strength acquisition module gathers, carries out gas concentration calculating;
Gas concentration is calculated result by display module and shows by signal processing module.
Further, described signal acquisition module receives the laser signal exported from air chamber, carries out signals collecting comprise it:
The laser signal that photoelectric detector exports from air chamber, is converted into electric signal;
Prime amplifier amplifies faint electric signal;
Direct current signal in filter capacitor isolation amplification signal and filtering low-frequency noise;
Out-of-band noise in bandpass filter filtering amplification signal;
Low-frequency noise in the further filtering amplification signal of filter inductance;
Lock-in amplifier produces second harmonic signal;
Analog to digital converter carries out analog to digital conversion to the electric signal after filtering noise and second harmonic signal.
Further, described in carry out gas concentration calculating before, also comprise:
The frequency of signal processing module Automatic-searching absorption peak, and the transmissivity of laser under calculating this frequency.
Further, also comprise:
When exceeding the hand-held laser gas concentration monitor of Preset Time without operation, signal processing module is by rechargeable battery power-off.
Compared with prior art, the advantage of technical solution of the present invention is:
The hand-held laser gas concentration monitor of one provided by the invention and control method thereof, based on tunable diode laser absorption spectroscopy commercial measurement gas concentration, measuring accuracy is high, fast response time, by temperature compensation module, temperature compensation is carried out to LASER Light Source simultaneously, stabilize Output of laser wavelength, current environmental temperature participates in gas concentration computing, achieves the accurate measurement to gas concentration.
Accompanying drawing explanation
Exemplary embodiment of the present invention will be described in detail by referring to accompanying drawing below, the person of ordinary skill in the art is more clear that above-mentioned and other feature and advantage of the present invention, in accompanying drawing:
The structured flowchart of the hand-held laser gas concentration monitor that Fig. 1 provides for the embodiment of the present invention one;
The structural representation of the hand-held laser gas concentration monitor that Fig. 2 provides for the embodiment of the present invention one;
The structural representation of the hand-held laser gas concentration monitor that Fig. 3 provides for the embodiment of the present invention two;
The process flow diagram of the control method of the hand-held laser gas concentration monitor that Fig. 4 provides for the embodiment of the present invention three.
Embodiment
For making the object, technical solutions and advantages of the present invention clearly, hereinafter with reference to the accompanying drawing in the embodiment of the present invention, by embodiment, technical scheme of the present invention is described clearly and completely, obviously, described embodiment is the present invention's part embodiment, instead of whole embodiments.Based on the embodiment in the present invention, those of ordinary skill in the art, not making the every other embodiment obtained under creative work prerequisite, belong to the scope of protection of the invention.
Embodiment one
Fig. 1 gives the structured flowchart of the hand-held laser gas concentration monitor that the embodiment of the present invention one provides; Fig. 2 gives the structural representation of the hand-held laser gas concentration monitor that the embodiment of the present invention one provides, the present embodiment can be used for monitoring the gas concentration of subsurface environment, is applicable to the detection to multiple gases such as steam, methane, carbon monoxide, carbon dioxide, sulfuretted hydrogen, ammonias.As shown in Figure 1 and Figure 2, this hand-held laser gas concentration monitor comprises handheld main machine 10, air chamber 12 and air chamber connecting link 11; Handheld main machine 10 is connected by air chamber connecting link 11 with air chamber 12; Handheld main machine 10 comprises LASER Light Source 20, the signal acquisition module 21 be connected with air chamber 12, the signal processing module 22 be connected with signal acquisition module 21, LASER Light Source current control module 23 between LASER Light Source 20 and signal processing module 22, the first temperature sensor 24, second temperature sensor 25 and the temperature compensation module 27 be connected with signal processing module 22 respectively, and display module 27; First temperature sensor 24 and temperature compensation module 27 are positioned at LASER Light Source 20, and the second temperature sensor 25 is fixed in handheld main machine.
Wherein, air chamber 12 carries out spectral absorption for gas to be measured to laser, and this air chamber 12 hangs over the front end of longer air chamber connecting link 11, has ensured the safety of instrument and personnel; Signal acquisition module 21, for receiving the laser signal exported from air chamber, carries out signals collecting to it; Signal processing module 22 changes the control electric current of LASER Light Source 20 for controlling LASER Light Source current control module 23, process the temperature signal of the first temperature sensor 24, second temperature sensor 25 and the gas concentration signal of signal acquisition module 21 output, and pass through internal algorithm, calculate gas concentration, finally gas concentration data are outputted to display module 27; Temperature compensation module 27 heats up for giving LASER Light Source 20 or lowers the temperature; First temperature sensor 24 is for the temperature of laser light source 20, and the second temperature sensor 25 is for measuring current environmental temperature.
Wherein, LASER Light Source 20 can adopt semiconductor laser, fiber laser etc.Exemplary, the present embodiment, for absorption spectra of methane, adopts the distributed feed-back butterfly laser instrument of wavelength near 1653nm as LASER Light Source 20.Have panel outside handheld main machine 10, embedded display module 27 and switch key on panel, wherein display module 27 can use segment encode liquid crystal display, and this liquid crystal display is connected with signal processing module 22 by winding displacement, adopts M3 pin to drive or MSP430 driving; The present embodiment can adopt the liquid crystal display back side to place signal processing module 22 and interface, by signal processing module 22, data is sent to segment encode liquid crystal display by interface, is shown by segment encode liquid crystal display, and wherein interface can use the interface of band clamp to install; The content of this segment encode liquid crystal display display comprises: gas concentration, environment temperature and abnormality, signal processing module 22 pre-set gas concentration abnormality numerical value, if occur abnormal, then light "abnormal" part, all the other do not show.Also have rechargeable battery in handheld main machine 10, this rechargeable battery is to each module for power supply holding laser gas concentration monitor.
In addition, handheld main machine 10 there are three joints: one is light source out splice going splice, light source out splice going splice can connect settles light flange, light flange exports two tail optical fiber joints and is respectively output light joint and receives light joint, FC/APC fibre-optical splice can be used to connect air chamber connecting link 11, optical fiber is positioned at air chamber connecting link 11, and other end is connected with air chamber 12 by mounting flange; On main frame, second joint is charging connector, and the 3rd joint is switch contacts.
Exemplary, the signal processing module 22 of the present embodiment can adopt ARM microprocessor; First temperature sensor 24, second temperature sensor 25 can adopt PT100 thermistor; Temperature compensation module 27 can adopt TEC (Thermoelectric Cooler, thermoelectric refrigerating unit) chip, and the present embodiment employing model is the TEC chip of max1978, in order to control deviation signal.
The hand-held laser gas concentration monitor that the embodiment of the present invention one provides, based on tunable diode laser absorption spectroscopy commercial measurement gas concentration, measuring accuracy is high, fast response time, by temperature compensation module, temperature compensation is carried out to LASER Light Source simultaneously, stabilize Output of laser wavelength, current environmental temperature participates in gas concentration computing, achieves the accurate measurement to gas concentration.
Embodiment two
Fig. 3 gives the structural representation of the hand-held laser gas concentration monitor that the embodiment of the present invention two provides, as shown in Figure 3, different with the embodiment of the present invention one:
Handheld main machine also comprises proportional-integral derivative controller 30, carries out accurate temperature compensation for control temperature compensating module 27 pairs of LASER Light Source 20.
Particularly, proportional-integral derivative controller 30, according to set-point V+ and output valve V-formation control deviation △, forms controlled quentity controlled variable the ratio P of deviation, integration I and differential D by linear combination, controls controlled device.
In addition, in the present embodiment, LASER Light Source current control module comprises triangular current generator 31 and sine-wave current generator 32, the triangular current that triangular current generator 31 produces and the sine-wave current that sine-wave current generator 32 produces are input to LASER Light Source through totalizer 33, wherein, triangular current is used for driving laser light source, and make laser frequency be scanned across absorption line, sine-wave current is used for carrying out high frequency modulated.Now, the change of LASER Light Source working current can change laser intensity and laser frequency simultaneously, can measure gas concentration according to the input laser intensity at absorption peak respective frequencies place and transmission laser light intensity and temperature.
In the present embodiment, signal acquisition module comprises the photodetector 34 be connected with air chamber 12, for laser signal is converted to electric signal;
The prime amplifier 35 be connected with photodetector 34, for amplifying faint electric signal;
The filter capacitor 36 be connected with prime amplifier 35, for isolated DC signal and filtering low-frequency noise;
The bandpass filter 37 be connected with filter capacitor 36, for filter out-band external noise;
Analog to digital converter 38 between bandpass filter 37 and signal processing module 22;
Lock-in amplifier 40 between described prime amplifier 35 and analog to digital converter 38, for providing second harmonic signal; And
The filter inductance 39 that one end is connected with bandpass filter 37 and analog to digital converter 38, for further filtering low-frequency noise.
In the present embodiment, the signal exported through prime amplifier 35 is divided into two-way, lock-in amplifier 40 of leading up to produces second harmonic signal, second harmonic signal is received by signal processing module 22 after analog to digital conversion, signal processing module 22 extracts the gas concentration information of carrying in second harmonic signal, calculates gas concentration, wherein, the reference signal of lock-in amplifier 40 is provided by sine-wave current generator 32, and is 2 times of actual gas concentration by the gas concentration that second harmonic signal calculates; Another road signal electric capacity 36, bandpass filter 37 and filter inductance 39 after filtering successively, filtering low-frequency noise, then received by signal processing module 22 after analog to digital conversion, signal processing module 22 extracts the gas concentration information of carrying in signal, directly calculates gas concentration.
Exemplary, air chamber 12 adopts light optically-coupled air chamber, the light flange that this light optically-coupled air chamber comprises air chamber outer tube, is arranged on the optical fiber collimator at air chamber outer tube two ends and is arranged on optical fiber collimator; Air chamber outer tube wall has air hole.PIN photodiode selected by photodetector 34, wavelength response range 1200 ~ 1700nm.
The present embodiment is in conjunction with various filters, and final detection high-frequency absorption signal, significantly reduces the self-noise impact of laser instrument, photodetector, improve the sensitivity of detection.
Identical all with the embodiment of the present invention one of other structures of the present embodiment, repeats no more herein.
The hand-held laser gas concentration monitor that the embodiment of the present invention two provides, based on tunable diode laser absorption spectroscopy commercial measurement gas concentration, measuring accuracy is high, fast response time, by temperature compensation module, temperature compensation is carried out to LASER Light Source simultaneously, stabilize Output of laser wavelength, current environmental temperature participates in gas concentration computing, achieve the accurate measurement to gas concentration, finally by filter capacitor, bandpass filter and filter inductance with the use of, only detect high-frequency absorption signal, significantly reduce laser instrument, the self-noise impact of photodetector, improve the sensitivity of detection.
Embodiment three
Fig. 4 gives the process flow diagram of the control method of the hand-held laser gas concentration monitor that the embodiment of the present invention three provides, and as shown in Figure 4, the method comprises the steps:
101, signal processing module is by the temperature of the first temperature sensor measurement LASER Light Source, after being compared by measured temperature, is heated up or cooling to LASER Light Source by temperature compensation module with preset temperature, and by the second temperature sensor measurement current environmental temperature.
The change of temperature can cause the change of LASER Light Source output wavelength, affects measuring accuracy.In this step, first temperature sensor is placed on the emitting semiconductor in LASER Light Source, signal processing module realizes the real-time measurement to LASER Light Source temperature by the first temperature sensor, measured temperature is compared with preset temperature simultaneously, heated up or cooling to LASER Light Source by temperature compensation module, make LASER Light Source accurate work on preset wavelength; Second temperature sensor is fixed in handheld main machine, and signal processing module realizes the real-time measurement to current environmental temperature by the second temperature sensor.
Signal processing module from continuous acquisition environment temperature the second temperature sensor, and participates in the computing of atmospheric concentration by bridge diagram.
102, signal processing module carries out Laser Modulation length scanning by LASER Light Source current control module driving laser light source.
In this step, signal processing module can export DA control signal by RS232 interface to LASER Light Source current control module, makes its driving laser light source export the laser of respective wavelength.
103, signal acquisition module receives the laser signal exported from air chamber, carries out signals collecting to it.
Signal acquisition module receives the laser signal exported from air chamber, after converting thereof into electric signal, carries out amplification filtering process to it, finally converts the collection of digital signal settling signal to.
104, the signal of signal processing module Received signal strength acquisition module collection, carries out gas concentration calculating.
Wherein, after the signal that signal processing module Received signal strength acquisition module gathers, according to the temperature data of process, gas concentration is calculated.
105, gas concentration is calculated result by display module and shows by signal processing module.
In this step, signal processing module can connect display module display result of calculation by RS-232 interface.
In the present embodiment, signal acquisition module receives the laser signal exported from air chamber, carries out signals collecting comprise step 1041 ~ 1047 to it:
1041, the laser signal that exports from air chamber of photoelectric detector, is converted into electric signal;
1042, prime amplifier amplifies faint electric signal;
1043, the direct current signal in filter capacitor isolation amplification signal and filtering low-frequency noise;
1044, the out-of-band noise in bandpass filter filtering amplification signal;
1045, the low-frequency noise in the further filtering amplification signal of filter inductance;
1046, lock-in amplifier produces second harmonic signal;
1047, analog to digital converter carries out analog to digital conversion to the electric signal after filtering noise and second harmonic signal.
In addition, before carrying out gas concentration calculating, also comprise:
The frequency of signal processing module Automatic-searching absorption peak, and the transmissivity of laser under calculating this frequency.
When gas concentration to be measured is lower, signal processing module directly processes the signal through bandpass filter, directly calculates gas concentration.When gas concentration to be measured is higher, the present embodiment adopts direct method and Harmonic Method to combine calculating gas concentration; Particularly, the second harmonic signal that signal processing module real-time reception lock-in amplifier produces, calculate fitted signal, draw out the curve of fitted signal, real-time reception is through the signal of bandpass filter simultaneously, calculate direct measuring-signal, draw out the curve of direct measuring-signal, a new curve is obtained by comparing two curves, output frequency corresponding to this curve maximum is the centre frequency of absorption spectrum, according to the change of light intensity before and after laser light air chamber, calculate the transmissivity of laser under this frequency.This step eliminates the impact that power changes with bias current.
Finally, signal processing module also achieves the power-off protection function to rechargeable battery.Exceed Preset Time, if hand-held laser gas concentration monitor is without any operation, signal processing module, by rechargeable battery power-off, makes monitor be in dormant state.
The embodiment of the present invention three is embodiment of the method, and the inventive method embodiment and product embodiments belong to same design, the detail content of not detailed description in embodiment of the method, can with reference to the said goods embodiment.
The control method of the hand-held laser gas concentration monitor that the embodiment of the present invention three provides, based on tunable diode laser absorption spectroscopy commercial measurement gas concentration, measuring accuracy is high, fast response time, by temperature compensation module, temperature compensation is carried out to LASER Light Source simultaneously, stabilize Output of laser wavelength, current environmental temperature participates in gas concentration computing, achieve the accurate measurement to gas concentration, finally by filter capacitor, bandpass filter and filter inductance with the use of, only detect high-frequency absorption signal, significantly reduce laser instrument, the self-noise impact of photodetector, improve the sensitivity of detection.
Above-mentionedly only the specific embodiment in the present invention to be illustrated; but can not as protection scope of the present invention; every according to the change of the equivalence done by design spirit in the present invention or to modify or equal proportion zooms in or out, all should think and fall into protection scope of the present invention.
Claims (10)
1. a hand-held laser gas concentration monitor, is characterized in that, comprises handheld main machine, air chamber and air chamber connecting link; Described handheld main machine is connected by described air chamber connecting link with air chamber; Described handheld main machine comprises LASER Light Source, the signal acquisition module be connected with described air chamber, the signal processing module be connected with described signal acquisition module, LASER Light Source current control module between described LASER Light Source and signal processing module, the first temperature sensor be connected with described signal processing module respectively, the second temperature sensor and temperature compensation module, and display module; Described first temperature sensor and temperature compensation module are positioned at LASER Light Source, and described second temperature sensor is fixed in described handheld main machine.
2. hand-held laser gas concentration monitor according to claim 1, it is characterized in that, described handheld main machine also comprises proportional-integral derivative controller, carries out accurate temperature compensation for controlling described temperature compensation module to LASER Light Source.
3. hand-held laser gas concentration monitor according to claim 2, it is characterized in that, described LASER Light Source current control module comprises triangular current generator and sine-wave current generator, the triangular current that described triangular current generator produces and the sine-wave current that sine-wave current generator produces are input to described LASER Light Source through totalizer, described triangular current is for scanning absorption line, and described sine-wave current is used for carrying out high frequency modulated.
4. hand-held laser gas concentration monitor according to claim 3, is characterized in that, described signal acquisition module comprises the photodetector be connected with described air chamber, for laser signal is converted to electric signal;
The prime amplifier be connected with described photodetector, for amplifying faint electric signal;
The filter capacitor be connected with described prime amplifier, for isolated DC signal and filtering low-frequency noise;
The bandpass filter be connected with described filter capacitor, for filter out-band external noise;
Analog to digital converter between described bandpass filter and signal processing module;
Lock-in amplifier between described prime amplifier and analog to digital converter, for providing second harmonic signal; And
The filter inductance that one end is connected with described bandpass filter and analog to digital converter, for further filtering low-frequency noise.
5. hand-held laser gas concentration monitor according to claim 4, it is characterized in that, described handheld main machine also comprises rechargeable battery, for giving each module for power supply in described handheld main machine.
6., according to the arbitrary described hand-held laser gas concentration monitor of claim 1-5, it is characterized in that, described air chamber is light optically-coupled air chamber, the light flange comprising air chamber outer tube, be arranged on the optical fiber collimator at air chamber outer tube two ends and be arranged on optical fiber collimator; Described air chamber outer tube wall has air hole.
7. a control method for hand-held laser gas concentration monitor, is characterized in that, comprise the steps:
Signal processing module, by the temperature of the first temperature sensor measurement LASER Light Source, after being compared by measured temperature, is heated up or cooling to LASER Light Source by temperature compensation module with preset temperature, and by the second temperature sensor measurement current environmental temperature;
Signal processing module carries out Laser Modulation length scanning by LASER Light Source current control module driving laser light source;
Signal acquisition module receives the laser signal exported from air chamber, carries out signals collecting to it;
The signal that signal processing module Received signal strength acquisition module gathers, carries out gas concentration calculating;
Gas concentration is calculated result by display module and shows by signal processing module.
8. the control method of hand-held laser gas concentration monitor according to claim 7, is characterized in that, described signal acquisition module receives the laser signal exported from air chamber, carries out signals collecting comprise it:
The laser signal that photoelectric detector exports from air chamber, is converted into electric signal;
Prime amplifier amplifies faint electric signal;
Direct current signal in filter capacitor isolation amplification signal and filtering low-frequency noise;
Out-of-band noise in bandpass filter filtering amplification signal;
Low-frequency noise in the further filtering amplification signal of filter inductance;
Lock-in amplifier produces second harmonic signal;
Analog to digital converter carries out analog to digital conversion to the electric signal after filtering noise and second harmonic signal.
9. the control method of hand-held laser gas concentration monitor according to claim 8, is characterized in that, described in carry out gas concentration calculating before, also comprise:
The frequency of signal processing module Automatic-searching absorption peak, and the transmissivity of laser under calculating this frequency.
10. the control method of hand-held laser gas concentration monitor according to claim 9, is characterized in that, also comprise:
When exceeding the hand-held laser gas concentration monitor of Preset Time without operation, signal processing module is by rechargeable battery power-off.
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| CN106370623A (en) * | 2016-10-21 | 2017-02-01 | 中国矿业大学(北京) | Environment gas remote sensing equipment for mine after disaster |
| CN107145096A (en) * | 2017-03-24 | 2017-09-08 | 江苏舒茨测控设备股份有限公司 | Dual processor sensor signal processing module |
| CN110118580A (en) * | 2019-05-24 | 2019-08-13 | 无锡佶达德光电子技术有限公司 | Laser detection system with environmental factor compensation |
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| CN113484268A (en) * | 2021-07-29 | 2021-10-08 | 天地（常州）自动化股份有限公司 | Infrared carbon dioxide sensor measuring system and temperature compensation method thereof |
| CN113702332A (en) * | 2021-08-23 | 2021-11-26 | 贵州电网有限责任公司 | SF6 electrical equipment fault component CO2Concentration detection device and method |
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| CN104535531A (en) | 2015-04-22 |
| CN104792729B (en) | 2018-09-14 |
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