CN201707750U - Gaseous spectrum absorption box and temperature control grating and combined fiber grating fire hazard warning system - Google Patents
Gaseous spectrum absorption box and temperature control grating and combined fiber grating fire hazard warning system Download PDFInfo
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Abstract
The utility model relates to a gaseous spectrum absorption box and temperature control grating and combined fiber grating fire hazard warning system for real-time wave length correction wide-range temperature monitoring and fire hazard warning in various places, which consists of a wideband light source, an adjustable F-P wave filter, a sensing grating, fiber couplers, a gas absorption box, a reference grating, a photoelectric detector and a signal processor DSP system, wherein the wideband light source is connected with the adjustable F-P wave filter connected with scanning voltage signals, after the output of the adjustable F-P wave filter is connected with the fiber coupler, one path is connected with the sensing grating, reflecting light of the sensing grating is connected with the photoelectric detector after passing through the fiber coupler, after the other path passes through the other fiber coupler, one path is connected with the gas absorption box, in addition, the output of the gas absorption box is connected with the photoelectric detector, the other path is connected with the reference grating, reflecting light of the reference grating is connected with the photoelectric detector after passing through the fiber coupler, and the output of the photoelectric detector is connected with the signal processor DSP system. The utility model enlarges the accurate demodulation range of the wave length, and has high measuring precision and stable performance.
Description
Technical field
The utility model is a kind of gas characteristic spectral absorption box and temperature control grating associating fiber grating fire alarm system that is used for all kinds of places real-time wavelength calibration wide range temperature monitoring and fire alarm, relates to measurement, fire prevention and the alarm technique field of temperature.
Background technology
Fire has constituted great threat as the disaster that a kind of out of control burning on space-time caused to human life's property and social safety.The serious accident of Yin Faing can be found everywhere thus, so the human way of seeking to stop and reduce fire always.In addition, along with the continuous increase of energy demand, the generation of fire preventing ensures the No.1 safety problem that oil gas safety in production becoming especially oil movement and storage, Petrochemical Enterprises face.
Fire detector commonly used at present can be divided into according to detected object: heat detector, sensitive detector, smoke detector and combustible gas probe etc.And the temp sensing type detection is the method for a kind of fire early detection and forecast, and this method real-time follow-up environment temperature gives a forecast when environment temperature ANOMALOUS VARIATIONS or temperature are higher than the fire alarm threshold value.So fire detector is many based on heat detector at present.And wherein, advantages such as essence explosion-proof, anti-strong electromagnetic, electrical insulating property are good, anti-lightning strike because optical fiber has, high precision, so fiber optic temperature fire detector performance is better, range of application is wider, particularly can be applicable to special dimensions such as oil, chemical industry, military project.
The fiber optic temperature fire detector mainly contains two kinds: one is based on the fiber optic temperature fire detector of Raman scattering, the 2nd, Fiber Bragg Grating Temperature fire detector.Fiber optic temperature fire detector based on Raman scattering need adopt the Detection of Weak Signals technology because of its temperature sensing principle has determined system, and the signal processing means complexity can not satisfy requirement to fire forecast well to the response time of temperature variation.
Optical fiber Bragg raster has good temperature-sensing property, as heat detector, adopts the full raster technology to carry out detection with optical fiber Bragg raster, and its signal is strong, and is highly sensitive, and signal Processing is simple, lays flexibly.But because fiber grating is a type sensor, in fire alarm system, need a large amount of fiber gratings, and the scope of existing optical fiber and grating sensing temperature technology acceptance of the bid standing wave length is all very little, and effective demodulation interval of corresponding accurately wavelength is also very narrow, is unfavorable for expanding detector quantity.As temperature control master grating calibration technique, light comb filter calibration technique etc.
The utility model content
The purpose of this utility model provides a kind of stable performance, measuring accuracy height, have sizable wavelength band can increase the usage quantity of fiber grating, obviously improve the gas characteristic spectral absorption box and the temperature control grating associating optical fiber grating temperature fire alarm system of fire alarm system detector capacity.
The principle of work of fiber optic temperature fire alarm system is to adopt fibre optic temperature sensor, monitors the temperature of a plurality of specified points, in case that certain some temperature rises so high is too fast, system just sends corresponding warning, reaches fire-proof and explosion-proof purpose with this.Specifically be, native system adopts fiber grating as temperature sensor, the perception ambient temperature changes, pass perception data back system terminal by optical cable, (DSP) carries out signal Processing through the internal system processor, demodulate the real-time wavelength of thermometric grating, utilize the wavelength of grating itself and the corresponding relation between the temperature again, calculate the real time temperature value of this grating site.Pass through analysis and judgement at last, send corresponding warning message real time temperature.
Wavelength calibration technical solution of the present utility model is as follows:
Native system utilizes the scanning voltage of F-P wave filter and the corresponding relation of its transmission peaks wavelength to demarcate.Here the reference grating of selecting gas absorption box and a plurality of constant temperature for use is as the media of seeking scanning voltage and wavelength corresponding relation.Spectrum gas absorption box can absorb the light wave of specific wavelength, the light wave scope that native system uses is 1525-1545nm, total several absorption peaks, wherein on behalf of the light wave of a specific wavelength (being the device index of absorption cell, known wavelength), each absorption peak be absorbed; Simultaneously, the master grating centre wavelength under the constant temperature is evenly distributed between the 1545-1565nm, and with the gas absorption cassette in series in same built-in channel.And the system wavelength calibration principle is exactly to look for its corresponding scanning voltage value according to the reflection peak of these absorption peaks and master grating, again according to these wavelength-voltage datas to the scanning voltage that simulates the F-P wave filter and the corresponding relation of its transmission peaks wavelength, be according to coming demodulation respectively to measure the real-time wavelength value of FB6 by this wavelength-voltage relationship afterwards.Also just thus, the utility model can 1525-1565nm on a large scale within demodulation sensing grating wavelength, and precision height is measured accurate.
The optical fiber grating temperature-measuring theory diagram as shown in Figure 1, it is by wideband light source, adjustable F-P wave filter, sensing grating, fiber coupler, gas absorption box, form with reference to grating, photodetector and signal processor dsp system; Wideband light source links to each other with the adjustable F-P wave filter that is connected with the scanning voltage signal, after adjustable F-P wave filter output connects fiber coupler, one the tunnel connects sensing grating, the sensing grating reflected light connects photodetector behind fiber coupler, one the tunnel connects the gas absorption box behind another fiber coupler of another Lu Zaijing, and the output of gas absorption box connects photodetector, also have one the tunnel to connect with reference to grating, connect photodetector with reference to the grating reflected light behind another fiber coupler, photodetector output connects the signal processor dsp system.
The light that wideband light source sends goes out to penetrate narrow band light and is added to sensing grating by fiber coupler through adjustable F-P wave filter, and the sensing grating reflected light is transferred to photodetector through fiber coupler; The narrow band light of adjustable F-P wave filter outgoing simultaneously is through gas absorption box transmitted light, also be transferred to photodetector respectively with reference to the light of optical grating reflection; After being converted to electric signal by photodetector, last entering signal processor dsp system is finished Wavelength demodulation and is scaled temperature variation, realizes temperature survey.
Setting up this system requirements meets the following conditions:
(1) adjustable F-P wave filter emergent light can scan each grating in the system successively;
(2) the Bragg centre wavelength of each sensing grating is different in the system, for effective wavelength coding, requires sensing grating FBG1 under the equivalent environment to the Bragg centre wavelength of sensing grating FBGn increasing or decreasing successively;
When (3) requiring grating to be subjected to the outer signals modulation down wave length shift to take place, the centre wavelength non-overlapping copies of optical grating reflection that is to say that each grating will take the band of one section special use, the band non-overlapping copies that different gratings take.
The photovoltaic principals of the concrete Wavelength calibration scheme of the optical fiber grating temperature fire alarm system of this gas characteristic spectral absorption box and temperature control grating associating as shown in Figure 2, it is by wideband light source 1, adjustable F-P wave filter 2, fiber coupler I 3-1, fiber coupler II 4-1, fiber coupler III 3-2 fiber coupler III3-2, fiber coupler IV4-2, sensor fibre grating array 5, gas absorption box 6, form with reference to grating group 7, temperature control module 8, photodetector I 9-1, photodetector II 9-2, photodetector III9-3; Wideband light source 1 links to each other with adjustable F-P wave filter 2, signal processor dsp system 10 produces the scanning voltage signal and drives for adjustable F-P wave filter 2 provides electric signal, adjustable F-P wave filter 2 outputs meet fiber coupler I 3-1 port a, fiber coupler I3-1 port b output meets fiber coupler II 4-1 port b, and another road port c output meets fiber coupler III 3-2 port a; Fiber coupler II 4-1 port a output connects sensor fibre grating array 5, and sensor fibre grating array 5 reflected light arrive photodetector III 9-3 behind fiber coupler II 4-1 port c; Fiber coupler II 3-2 port b output connects gas absorption box 6, and 6 outputs of gas absorption box meet photodetector II 9-2; Fiber coupler II3-2 port c output meets fiber coupler IV4-2 port b, fiber coupler IV4-2 port a is connected to the reference grating group 7 of temperature control module 8, meets photodetector I 9-1 with reference to the 7 catoptrical outputs of grating group through fiber coupler IV4-2 port c; Photodetector I 9-1, photodetector II 9-2, photodetector III9-3 three outputs connect signal processor dsp system 10; Adjustable F-P wave filter 2 is connected with the signal processor dsp system.
Wherein:
Four of fiber coupler fiber coupler I 3-1, fiber coupler II 4-1, fiber coupler III 3-2, fiber coupler IV4-2; Gating is sold product with the city;
Sensor fibre grating array 5 and be city's pin product with reference to grating group 7; Reference light is deleted group 7 and is put into the constant temperature box, and it stablizes constant by temperature control module 8 controls;
Three of photodetector detector I 9-1, detector II 9-2, detector III9-3;
The signal processor dsp system is a high performance float-point DSP process chip.
The light that wideband light source 1 sends through adjustable F-P wave filter 2 go out to penetrate narrow band light and by fiber coupler I3-1 after be divided into two-way, the one tunnel is added to sensing grating array 5 through fiber coupler II 4-1; Another road has two-way output again behind fiber coupler II 3-2, one output connects gas absorption box 6, directly be added to detector II 9-2 after the light signal transmission, another exports the reference grating group 7 that temperature control module 8 is arranged in succession through fiber coupler IV4-2 fiber coupler II 3-2, and reflected signal is passed to detector I 9-1 through fiber coupler IV4-2; Sensor fibre grating array 5 is added to detector III9-3 after fiber coupler III4-1 reflection; The output signal of detector I 9-1, detector II 9-2, detector III 9-3 is handled by signal processor dsp system 10; Scanning voltage signal generator in the adjustable F-P wave filter 2 produces the voltage scanning signal and drives adjustable F-P wave filter 2 and realize length scannings, and synchronous signal processor dsp system 10 is connected realization scanning voltage signals collecting with scanning voltage signal generator in the adjustable F-P wave filter 2.
When carrying out real-time Wavelength calibration, produce the scanning voltage signal by signal processor dsp system 10, and acquisition and recording scanning voltage signal, the length scanning of realization F-P wave filter 2.Whenever collect one and absorb the peak shape voltage signal, just seek its corresponding peak position, obtain the scanning voltage value of F-P wave filter 2 this moment according to this peak position, wavelength-voltage data of noting all absorption peaks thus is right, afterwards with these data to simulating the variation funtcional relationship between wavelength-voltage.This funtcional relationship is exactly to be used for the foundation and the standard of demodulation FBG grating wavelength, native system each voltage scanning cycle in the grating wavelength demodulation is all carried out the Wavelength calibration process, be that system carries out real-time Wavelength calibration, and the centre wavelength scope of temperature control grating should preferably evenly distribute outside gas characteristic absorbing wavelength section.
In above-mentioned photovoltaic principals figure, wideband light source 1, adjustable F-P wave filter 2, fiber coupler I3-1, fiber coupler II 3-2, fiber coupler III4-1, fiber coupler IV4-2, sensor fibre grating array 5, gas absorption box 6, be light path part with reference to grating group 7, photodetector I 9-1, photodetector II 9-2, photodetector III9-3 and signal processor dsp system 10 are circuit part.
Wherein:
The detailed formation of light path part as shown in Figure 2;
Photo-detector circuit part as shown in Figure 3, it mainly is made up of first order operational amplifier U1, two-level operating amplifier U2, low pass integrated filter U3, photodiode OE1; The 4th pin of the 5th pin of U1, the 8th pin of U2, U3 meets power supply 5VCC respectively, and capacitor C 3, capacitor C 4, capacitor C 6, capacitor C 7, capacitor C 8, capacitor C 9 be a termination power 5VCC respectively, other end ground connection GND; The 1st, the 3 pin ground connection of photodiode OE1, the 2nd pin connects the 4th pin of U1; The 3rd pin of U1 is connected respectively to an end of capacitor C 2 and resistance R 2, and the other end of capacitor C 2, resistance R 2 all is connected to ground GND; One end of capacitor C 1 and resistance R 1 is connected respectively to the 1st pin of U1, and the other end is connected respectively to the 4th pin of U1; One end of resistance R 3 is connected to the 1st pin of U1, and the other end is connected to the 3rd pin of U2; One end of capacitor C 5, resistance R 4, resistance R 5 is connected to the 2nd pin of U2 simultaneously, and the other end of resistance R 4 is connected to ground GND, and the other end of capacitor C 5 and resistance R 5 connects the 1st pin of U2 and an end of resistance R 8 respectively, and the other end of resistance R 8 connects the 2nd pin of U3; Resistance R 6 is connected respectively to the 5th pin of U2 and the 5th pin of U3; Resistance R 7 is connected respectively to the 4th pin and the 7th pin of U3, an end ground connection GND of capacitor C 10, capacitor C 11, capacitor C 12, and the other end of capacitor C 10 is connected to the 1st, 6 pin of U3, and capacitor C 11, capacitor C 12 are connected respectively to the 8th pin of U3;
Signal processor dsp system electricity principle as shown in Figure 4, as the magnetic bead FER1 one termination 1.3V power supply that filtering is used, the other end is received the power supply input pin W9 of U1B; The supply pin AVDD of decoupling capacitance C22, capacitor C 23, capacitor C 24 1 termination U1B, other end ground connection GND; The E2 pin SPORT1_FS of U1B links the convst pin of ADC analog to digital converter, as the trigger pip that starts conversion; The A8 of U1B, B8, three pins of A7 respectively are SPORT1_DA, SPORT1_CLK, SPORT1_FS, receive serial data output, serial clock, the serial port synchronization frame of ADC respectively; Reading data after A by serial port realizes the demodulation of wavelength shift and the wavelength shift amount is converted to temperature variation; The I2C interface of U1B has two pin A10, B11, is respectively TWI_SCL, TWI_SDA, and the output triangular wave drives modulation F-P wave filter; U1B provides two UART serial ports, with external device communication.
Temperature sensing principle of the present utility model is as follows:
The utility model mainly is a kind of optical fiber grating temperature fire alarm system of large range high precision of real-time correction.It utilizes fiber grating in extraneous temperature variation, the characteristic that its catoptrical centre wavelength changes thereupon, the environment temperature of monitoring around the fiber grating, too high or heat up and can send alarm when too fast when temperature, and the affirmation warning position, thereby reach fire-proof and explosion-proof purpose.
It mainly adopts Fiber Bragg Grating (FBG) as temperature sensor, monitors each specified point temperature in real time.The FBG grating is a kind of novel optical passive component, and it is by upwards setting up periodic index distribution and change or controlling light in this regional dissemination and mode at fiber axis.Its temperature sensing principle is: the broadband light incident optical, to produce Mode Coupling, when satisfying bragg condition, grating will play the effect of a catoptron, arrowband light wave of reflected back (remaining light wave is gone out from the other end transmission of grating), the centre wavelength of this arrowband light wave are grating cloth loudspeaker lattice wavelength X
B, that is: λ
B=2n
EffΛ.Do the time spent when grating is subjected to ambient temperature, Λ and neff are affected by the external environment and change Δ Λ and Δ n
Eff, the reflection wavelength that causes meeting the Bragg condition is subjected to displacement Δ λ
B, mathematical model is: Δ λ
B=2n
EffΛ+2n
EffΔ Λ can obtain centre wavelength thus:
In the formula, last is that thermo-optic effect makes the result that the fibre core effective refractive index changes with temperature, back one then be since thermal expansion to make that pitch changes caused.According to the demonstration of lot of documents as can be known, two kinds of caused variation items of effect all are the linear function of temperature, explanation thus, the center wavelength shift of Fiber Bragg Grating FBG and the variation of its environment temperature are linear, and promptly wavelength/temperature variation relation is about 10pm/ ℃; But if when the Bragg grating is used for low temperature and high temp sensitive, centre wavelength and temperature variation no longer are once linear relationships, and the quafric curve that more approaches to rise concerns λ
B=aT
2+ bT+c.
More than be the mechanism of FBG grating temperature sensing, the utility model is according to this mechanism, and the reflection wave centre wavelength that satisfies the Bragg condition by detection is subjected to displacement Δ λ
BCome the temperature signal of detection effect on grating.
Optic fiber grating wavelength demodulation principle of the present utility model is as follows:
According to the sensing principle of above-mentioned FBG, native system need carry out demodulation at the real-time wavelength of FBG, and existing demodulation method is a lot, as adjustable F-P filter method, passive demodulation method, coupling raster method, non-equilibrium M-Z interferometric method and tunable narrowband optical source method etc.Native system has adopted a kind of tunable narrowband optical source method based on the F-P wave filter in order to obtain high-precision demodulating data.
Guaranteeing on certain measurement range, the basis than high s/n ratio and precision, with wideband light source and tunable F-P Design of Filter a kind of tunable narrowband optical source, promptly allow the tunable F-P wave filter of broadband light incident, the F-P wave filter is under the driving of sawtooth wave or sinusoidal wave scanning voltage, the narrow band light of the different centre wavelengths that outgoing is continuous, the centre wavelength of narrow band light is corresponding with scanning voltage.If with sawtooch sweep voltage scanning F-P wave filter, the centre wavelength of tunable optic filter transmitted light has the better linearity relation with corresponding scanning voltage.
Utilization is based on the tunable optical source scanning sensing grating that the F-P wave filter constitutes, and the theory structure that carries out the grating wavelength demodulation as shown in Figure 1.
The narrow band light of the outgoing of adjustable F-P wave filter scanning sensing FBG array, when the Bragg reflection kernel wavelength of narrow band light centre wavelength and FBG was identical, the light signal of photo-detector detection was the strongest, the voltage maximum of opto-electronic conversion, otherwise detectable signal very a little less than.Signal voltage that opto-electronic conversion obtains is through after amplification, filtering and the shaping, again by data acquisition and signal Processing, just can demodulate the wavelength of each grating according to the corresponding relation of the scanning voltage of F-P wave filter and its transmitted light centre wavelength.
Setting up demodulating system requires to meet the following conditions: (1) is adjustable, and F-P wave filter emergent light can scan each grating in the system successively; (2) the Bragg centre wavelength of each grating is different in the system, for effective wavelength coding, requires FBG1 under the equivalent environment to the Bragg centre wavelength of FBGn increasing or decreasing successively; When (3) requiring grating to be subjected to the outer signals modulation down wave length shift to take place, the centre wavelength non-overlapping copies of optical grating reflection that is to say that each grating will take the band of one section special use, the band non-overlapping copies that different gratings take.
Because the spectrum width of light source (SLED) is generally 40nm-50nm, the spectrum width of sensing Bragg grating is generally 0.07-0.6nm, when detecting outer signals, Bragg grating centre wavelength range of drift is slightly different with temperature-measuring range, 1-2nm generally will drift about, so not overlapped for the catoptrical spectrum peak that makes different FBG, can only connect 30 with interior FBG sensor in the passage, the concrete number of the sensing grating that connects decides according to the object of being monitored.
The utility model is mainly used in the temperature monitoring and the fire alarm in all kinds of places, as oil depot, ammunition depot and tunnel etc.
Optical fiber grating temperature fire alarm system of the present utility model has following characteristics:
1, the utility model adopts the technology that gas absorption box and constant temperature master grating are demarcated wavelength jointly, and effective demodulation of the accurate wavelength of system is interval big, can 1525-1565nm on a large scale within accurate demodulation wavelength; The simultaneity factor extended capability is strong, can insert a hundreds of sensing grating as system detector; Make optical fiber grating temperature fire alarm system point type sensing effect originally further trend towards linear sensor;
2, the utility model adopts optical fiber Bragg raster as heat detector, because the Bragg grating is good than other sensor temperature-sensitive characteristic, so the measuring accuracy height of system, stable performance;
3, system architecture is simple, is convenient to expansion, installs simple and easy.
Description of drawings
Fig. 1 gaseous spectrum absorption cell and temperature control grating associating optic fiber grating wavelength demodulation temperature-measurement principle synoptic diagram
The theory diagram of Fig. 2 gaseous spectrum absorption cell and temperature control grating associating optical fiber grating temperature fire alarm system
Fig. 3 gaseous spectrum absorption cell and temperature control grating associating optical fiber grating temperature fire alarm system photo-detector circuit figure
Fig. 4 signal processor dsp system electrical schematic diagram
1-wideband light source 2-F-P wave filter wherein
3-1-fiber coupler I 3-2-fiber coupler II
4-1-fiber coupler III 4-2-fiber coupler IV
5-sensor fibre grating array 6-gas absorption box
7-is with reference to grating group 8-temperature control module
9-1-photodetector I 9-2-photodetector II
9-3-photodetector III 10-signal processor dsp system
Embodiment
The utility model is described in further detail below in conjunction with drawings and Examples, but should not limit protection domain of the present utility model with this.
This example is a kind of large range high precision optical fiber grating temperature fire alarm system of real-time correction, its photovoltaic principals as shown in Figure 2, mainly by light source 1, F-P wave filter 2,1 * 2 fiber coupler I 3-1 and fiber coupler II 3-2,2 * 1 fiber coupler III4-1 and fiber coupler IV4-2, sensor fibre grating array 5, gas absorption box 6, constitute with reference to grating group 7, temperature control module 8, photodetector I 9-1, photodetector II 9-2, photodetector III9-3 and signal processor dsp system 10.
The output terminal of wideband light source 1 meets the port a of 1 * 2 fiber coupler I 3-1 through F-P wave filter 2, the port b of 1 * 2 fiber coupler I 3-1 meets the port b of 2 * 1 fiber coupler III4-1, the port a of 2 * 1 fiber coupler III4-1 connects sensing grating array 5, the port c of 2 * 1 fiber coupler III4-1 directly connects photodetector III9-3, connects signal processor dsp system 10 then; Simultaneously, the port c of 1 * 2 fiber coupler I3-1 meets the port a of 1 * 2 fiber coupler II 3-2, and the port b of 1 * 2 fiber coupler II 3-2 connects gas absorption box 6, meets photodetector II 9-2 then, through sending into signal processor dsp system 10 after the conversion; The port c of 1 * 2 fiber coupler II 3-2 connects 2 * 1 fiber coupler IV4-2 port b, 2 * 1 fiber coupler IV4-2 port a series connection finally connects signal processor dsp system 10 through photodetector I 9-1 with reference to grating group 7,2 * 1 fiber coupler IV4-2 port c; Signal processor dsp system 10 sends the scanning voltage signal and passes to F-P wave filter 2 and finish length scanning.
Wherein: light source 1 is amplified spontaneous emission ASE wideband light source, and its main part is gain media Er-doped fiber and high performance pump laser; The output light-wave section is 1525-1565nm, single-mode tail fiber output, and direct drive, output power are 23dBm;
The F-P wave filter 2 that adopts the merchant to sell is formed tunable narrowband optical source with ASE wideband light source 1, the output narrowband optical signal;
The splitting ratio of fiber coupler I 3-1, fiber coupler II 3-2, fiber coupler III4-1 and fiber coupler IV4-2 is 1: 1;
The C-band acetylene gas absorption cell that gas absorption box 6 adopts the merchant to sell;
Sensor fibre grating array 5 and be MOI-os4310 with reference to grating group 7;
Photodetector I 9-1, detector II 9-2, detector III9-3 adopt the InGaAs-PIN detector;
The high performance float-point DSP process chip that signal processor dsp system 10 selects for use the merchant to sell, the photoelectric conversion signal of acquisition scans voltage signal, sensing grating reflection, process constant temperature are with reference to the photoelectric conversion signal of grating group and the photoelectric conversion signal of process gas absorption box 6 respectively, and sampling rate is 50kHz.
Photo-detector circuit part as shown in Figure 3, it mainly is made up of first order operational amplifier U1, two-level operating amplifier U2, low pass integrated filter U3, photodiode OE1.The 4th pin of the 5th pin of U1, the 8th pin of U2, U3 meets power supply 5VCC respectively, and capacitor C 3, capacitor C 4, capacitor C 6, capacitor C 7, capacitor C 8, capacitor C 9 be a termination power 5VCC respectively, other end ground connection GND.The 1st, the 3 pin ground connection of photodiode OE1, the 2nd pin connects the 4th pin of U1.The 3rd pin of U1 is connected respectively to an end of capacitor C 2 and resistance R 2, and the other end of capacitor C 2, resistance R 2 all is connected to ground GND.One end of capacitor C 1 and resistance R 1 is connected respectively to the 1st pin of U1, and the other end is connected respectively to the 4th pin of U1.One end of resistance R 3 is connected to the 1st pin of U1, and the other end is connected to the 3rd pin of U2.One end of capacitor C 5, resistance R 4, resistance R 5 is connected to the 2nd pin of U2 simultaneously, and the other end of resistance R 4 is connected to ground GND, and the other end of capacitor C 5 and resistance R 5 connects the 1st pin of U2 and an end of resistance R 8 respectively, and the other end of resistance R 8 connects the 2nd pin of U3.Resistance R 6 is connected respectively to the 5th pin of U2 and the 5th pin of U3.Resistance R 7 is connected respectively to the 4th pin and the 7th pin of U3, an end ground connection GND of capacitor C 10, capacitor C 11, capacitor C 12, and the other end of capacitor C 10 is connected to the 1st, 6 pin of U3, and capacitor C 11, capacitor C 12 are connected respectively to the 8th pin of U3.
Wherein:
Operational amplifier U1 selects OPA1;
Two-level operating amplifier U2 selects OPA2;
Low pass integrated filter U3 selects LP1;
Photodiode OE1 selects pfotoelctric;
Resistance R 120M Ω;
Resistance R 220M Ω;
Resistance R 31.5K Ω;
Resistance R 42K Ω;
Resistance R 510K Ω;
Resistance R 61K Ω;
Resistance R 71K Ω;
Resistance R 81K Ω;
Capacitor C 15Pf;
Capacitor C 25Pf;
Capacitor C 30.1 μ f;
Capacitor C 410 μ f;
Capacitor C 510Pf;
Capacitor C 60.1 μ f;
Capacitor C 710 μ f;
Capacitor C 810 μ f;
Capacitor C 90.1 μ f;
Capacitor C 100.1 μ f;
Capacitor C 11100Pf;
Capacitor C 12100Pf;
Signal processor dsp system electricity principle as shown in Figure 4, as the magnetic bead FER1 one termination 1.3V power supply that filtering is used, the other end is received the power supply input pin W9 of U1B.The supply pin AVDD of decoupling capacitance C22, capacitor C 23, capacitor C 24 1 termination U1, other end ground connection GND.The E2 pin SPORT1_FS of U1B links the convst pin of ADC analog to digital converter, as the trigger pip that starts conversion.The A8 of U1B, B8, three pins of A7 respectively are SPORT1_DA, SPORT1_CLK, SPORT1_FS, receive serial data output, serial clock, the serial port synchronization frame of ADC respectively.Reading data after A by serial port realizes the demodulation of wavelength shift and the wavelength shift amount is converted to temperature variation.The I2C interface of U1B has two pin A10, B11, is respectively TWI_SCL, TWI_SDA, and the output triangular wave drives modulation F-P wave filter.U1B provides two UART serial ports, with external device communication.
Wherein:
U1B selects ADSP-21369;
Magnetic bead FER1 selects HH-1H3216-500;
Capacitor C 221000Pf;
Capacitor C 230.01 μ f;
Capacitor C 240.1 μ f.
This example makes some type sensing effect originally further trend towards linear sensor through site test; The measuring accuracy height, stable performance; System architecture is simple, is convenient to expansion, installs simple and easy.
Claims (8)
1. all kinds of places are implemented wavelength and are proofreaied and correct the gaseous spectrum absorption cell of large range high precision temperature monitoring and fire alarm in real time and unite the optical fiber grating temperature fire alarm system with the temperature control grating, it is characterized in that it is by wideband light source, adjustable F-P wave filter, sensing grating, fiber coupler, gas absorption box, form with reference to grating, photodetector and signal processor dsp system; Wideband light source links to each other with the adjustable F-P wave filter that is connected with the scanning voltage signal, after adjustable F-P wave filter output connects fiber coupler, one the tunnel connects sensing grating, the sensing grating reflected light connects photodetector behind fiber coupler, one the tunnel connects the gas absorption box behind another fiber coupler of another Lu Zaijing, and the output of gas absorption box connects photodetector, also have one the tunnel to connect with reference to grating, connect photodetector with reference to the grating reflected light behind another fiber coupler, photodetector output connects the signal processor dsp system;
The light that wideband light source sends goes out to penetrate narrow band light and is added to sensing grating by fiber coupler through adjustable F-P wave filter, and the sensing grating reflected light is transferred to photodetector through fiber coupler; The narrow band light of adjustable F-P wave filter outgoing simultaneously also is transferred to photodetector through the gas absorption box with reference to the light of optical grating reflection; After being converted to electric signal by photodetector, last entering signal processor dsp system is finished Wavelength demodulation and is scaled temperature variation, realizes temperature survey.
2. gaseous spectrum absorption cell according to claim 1 and temperature control grating associating fiber grating fire alarm system is characterized in that described temperature control grating centre wavelength is all or part of outside gas characteristic absorption spectrum frequency range.
3. gaseous spectrum absorption cell according to claim 1 and temperature control grating associating fiber grating fire alarm system, the Bragg centre wavelength that it is characterized in that each sensing grating in the system is different, and sensing grating FBG1 is to the Bragg centre wavelength of FBGn increasing or decreasing successively under the equivalent environment.
4. gaseous spectrum absorption cell according to claim 1 and temperature control grating associating fiber grating fire alarm system, it is characterized in that connecing in the passage 30 with interior sensing grating FBG, each sensor grating takies the band of one section special use, the band non-overlapping copies that different sensing gratings take.
5. gaseous spectrum absorption cell according to claim 1 and temperature control grating associating fiber grating fire alarm system, it is characterized in that the photovoltaic principals figure of described system is: it is by wideband light source (1), adjustable F-P wave filter (2), scanning voltage signal generator (3), fiber coupler I (3-1), fiber coupler II (4-1), fiber coupler III (3-2) fiber coupler III (3-2), fiber coupler IV (4-2), sensor fibre grating array (5), gas absorption box (6), with reference to grating group (7), temperature control module (8), detector I (9-1), detector II (9-2), detector III (9-3) forms; Wideband light source (1) links to each other with adjustable F-P wave filter (2), it is that adjustable F-P wave filter (2) provides electric signal to drive that signal Processing dsp system (10) produces the scanning voltage signal, adjustable F-P wave filter (2) output connects fiber coupler I (3-1) port (a), fiber coupler I (3-1) port (b) output connects fiber coupler II (4-1) port (b), and another road port (c) output connects fiber coupler III (3-2) port (a); Fiber coupler II (4-1) port (a) output connects sensor fibre grating array (5), and sensor fibre grating array (5) reflected light arrives detector III (9-3) behind fiber coupler II (4-1) port (c); Fiber coupler II (3-2) port (b) output connects gas absorption box (6), and gas absorption box (6) output meets detector II (9-2); Fiber coupler II (3-2) port (c) output connects fiber coupler IV (4-2) port (b), fiber coupler IV (4-2) port (a) is connected to the reference grating group (7) of temperature control module (8), meets detector I (9-1) with reference to the catoptrical output of grating group (7) through fiber coupler IV (4-2) port (c); Detector I (9-1), detector II (9-2), detector III (9-3) three outputs connect signal processor dsp system (10); Adjustable F-P wave filter (2) is connected with signal processor dsp system (10);
The light that wideband light source (1) sends through adjustable F-P wave filter (2) go out to penetrate narrow band light and by fiber coupler I (3-1) after be divided into two-way, the one tunnel is added to sensing grating array (5) through fiber coupler II (4-1); Another road has two-way output again behind fiber coupler II (3-2), one output connects gas absorption box (6), directly be added to detector II (9-2) after the light signal transmission, another exports the master grating group (7) that temperature control module (8) is arranged in succession through fiber coupler IV (4-2) fiber coupler II (3-2), and reflected signal is passed to detector I (9-1) through fiber coupler IV (4-2); Sensor fibre grating array (5) is added to detector III (9-3) after fiber coupler III (4-1) reflection; The output signal of detector I (9-1), detector II (9-2), detector III (9-3) is handled by signal processor (10); Scanning voltage signal generator generation voltage scanning signal in the adjustable F-P wave filter (2) drives adjustable F-P wave filter (2) and carries out length scanning, and the scanning voltage signal generator in synchronous signal processor (10) and the adjustable F-P wave filter (2) carries out the scanning voltage signals collecting.
6. gaseous spectrum absorption cell according to claim 5 and temperature control grating associating fiber grating fire alarm system is characterized in that described photo-detector circuit mainly is made up of first order operational amplifier U1, two-level operating amplifier U2, low pass integrated filter U3, photodiode OE1; The 4th pin of the 5th pin of U1, the 8th pin of U2, U3 meets power supply 5VCC respectively, and capacitor C 3, capacitor C 4, capacitor C 6, capacitor C 7, capacitor C 8, capacitor C 9 be a termination power 5VCC respectively, other end ground connection GND; The 1st, the 3 pin ground connection of photodiode OE1, the 2nd pin connects the 4th pin of U1; The 3rd pin of U1 is connected respectively to an end of capacitor C 2 and resistance R 2, and the other end of capacitor C 2, resistance R 2 all is connected to ground GND; One end of capacitor C 1 and resistance R 1 is connected respectively to the 1st pin of U1, and the other end is connected respectively to the 4th pin of U1; One end of resistance R 3 is connected to the 1st pin of U1, and the other end is connected to the 3rd pin of U2; One end of capacitor C 5, resistance R 4, resistance R 5 is connected to the 2nd pin of U2 simultaneously, and the other end of resistance R 4 is connected to ground GND, and the other end of capacitor C 5 and resistance R 5 connects the 1st pin of U2 and an end of resistance R 8 respectively, and the other end of resistance R 8 connects the 2nd pin of U3; Resistance R 6 is connected respectively to the 5th pin of U2 and the 5th pin of U3; Resistance R 7 is connected respectively to the 4th pin and the 7th pin of U3, an end ground connection GND of capacitor C 10, capacitor C 11, capacitor C 12, and the other end of capacitor C 10 is connected to the 1st, 6 pin of U3, and capacitor C 11, capacitor C 12 are connected respectively to the 8th pin of U3.
7. gaseous spectrum absorption cell according to claim 5 and temperature control grating associating fiber grating fire alarm system, it is characterized in that signal Processing dsp system electricity principle is: as the magnetic bead FER1 one termination 1.3V power supply that filtering is used, the other end is received the power supply input pin W9 of U1B; The supply pin AVDD of decoupling capacitance C22, capacitor C 23, capacitor C 24 1 termination U1B, other end ground connection GND; The E2 pin SPORT1_FS of U1B links the convst pin of ADC analog to digital converter, as the trigger pip that starts conversion; The A8 of U1B, B8, three pins of A7 respectively are SPORT1_DA, SPORT1_CLK, SPORT1_FS, receive serial data output, serial clock, the serial port synchronization frame of ADC respectively; The I2C interface of U1B has two pin A10, B11, is respectively TWI_SCL, TWI_SDA, and the output triangular wave drives modulation F-P wave filter (2); U1B provides two UART serial ports with external device communication.
8. gaseous spectrum absorption cell according to claim 5 and temperature control grating associating fiber grating fire alarm system is characterized in that reference light deletes group (7) and put into the constant temperature box, controls it by temperature control module (8) and stablizes constant.
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| CN102288560A (en) * | 2011-07-01 | 2011-12-21 | 刘星 | Fiber-Bragg-grating-based combustion speed rate detector for combustible solid |
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