CN214749749U - Non-dispersive infrared gas analysis circuit based on embedded system - Google Patents
Non-dispersive infrared gas analysis circuit based on embedded system Download PDFInfo
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Abstract
The utility model relates to an infrared gas analysis circuit of non-dispersion based on embedded system, including surveying subassembly, signal processing circuit, main control circuit, light source frequency modulation circuit, light source, environmental monitoring circuit, man-machine interaction circuit and power supply circuit, survey subassembly and signal processing circuit electricity and be connected, signal processing circuit and environmental monitoring circuit are connected with main control circuit electricity respectively, and main control circuit is connected with light source frequency modulation circuit electricity, and man-machine interaction circuit is connected with main control circuit electricity, and light source frequency modulation circuit's output is connected with the light source electricity. The utility model discloses well main control circuit combines the environmental information of environmental monitoring subassembly monitoring to compensate the processing and show to concentration value, the adjustable light source frequency of man-machine interaction circuit to adjust the infrared light intensity after by the partial absorption, thereby obtain gas concentration analysis result, with being suitable for different types of gas analysis, easy operation, the testing result is accurate, convenient development work, the save time cost.
Description
Technical Field
The utility model relates to a gas concentration analysis technical field especially relates to an infrared gas analysis circuit of non-dispersion based on embedded system.
Background
The principle applied to measuring gas concentration using a non-dispersive infrared gas analyzer is beer's law, whose formula is as follows:
I＝I0*e-KCL
wherein, each letter means as follows: i is the intensity of infrared light absorbed by the gas to be measured in the sample gas, I0The intensity of infrared light not absorbed by the reference gas; k is the absorption coefficient of the gas to be detected in the sample gas to infrared light, C is the concentration of the gas to be detected in the sample gas, and L is the length of the gas chamber.
For a non-dispersive infrared gas analysis device, the gas to be measured in the measured sample gas is determined, namely the infrared absorption coefficient k of the gas to be measured to the radiation wave band is certain, and the length L of the gas chamber is certain. From beer's law it can be seen that: by measuring the intensity I of infrared light not absorbed by the gas to be measured0The concentration C of the gas to be treated can be determined by the intensity I of the absorbed infrared light.
The existing non-dispersive infrared gas analyzer cannot be used as matched development equipment for gas analysis, and cannot be used universally and aim at specific infrared light, so that the infrared light absorption coefficient is also isolated, the gas analyzer cannot be used for analyzing gas concentrations with different absorption degrees, cannot adapt to different types and different types of gas analysis, and brings difficulty and time cost for development work.
Disclosure of Invention
The utility model aims to solve the technical problem that to the not enough of above-mentioned prior art, provide a based on embedded system non-dispersion infrared gas analysis circuit.
The utility model provides an above-mentioned technical problem's technical scheme as follows: a non-dispersive infrared gas analysis circuit based on an embedded system comprises a detection component, a signal processing circuit, a main control circuit, a light source frequency modulation circuit, a light source, an environment monitoring circuit, a man-machine interaction circuit and a power circuit, the output end of the detection component is electrically connected with the input end of the signal processing circuit, the output end of the signal processing circuit and the output end of the environment monitoring circuit are respectively and electrically connected with the signal input end of the main control circuit, the signal output end of the main control circuit is electrically connected with the input end of the light source frequency modulation circuit, the human-computer interaction circuit is electrically connected with the main control circuit, the output end of the light source frequency modulation circuit is electrically connected with the light source, and the power supply circuit is respectively and electrically connected with the signal processing circuit, the main control circuit, the light source frequency modulation circuit, the light source, the man-machine interaction circuit and the environment monitoring circuit.
The utility model has the advantages that: the utility model discloses a based on embedded system non-dispersion infrared gas analysis circuit, through the infrared light intensity information of surveying after being absorbed by the target gas part of detection subassembly to process the concentration value of back by main control circuit calculation target gas through signal processing circuit, main control circuit combines the environmental information of environmental monitoring subassembly monitoring right the concentration value is compensated and is handled and show, and simultaneously, the light source frequency can be adjusted to the human-computer interaction circuit, with the infrared light intensity of regulation after being absorbed by the part, thereby obtain gas concentration analysis result, can be suitable for different types of gas analysis, easy operation, the testing result is accurate, has greatly made things convenient for development work, has practiced thrift the time cost.
On the basis of the technical scheme, the utility model discloses can also do as follows the improvement:
further: the detection assembly comprises an air chamber and a detector, wherein an optical channel is arranged between two ends of the air chamber in a penetrating mode, the detector and the light source are arranged at two ends of the air chamber in a sealing mode respectively, and the emergent optical fibers of the light source irradiate to a receiving area of the detector through the optical channel.
The beneficial effects of the further scheme are as follows: the detector and the light source are respectively arranged at two ends of the air chamber in a sealing manner, so that part of infrared light energy emitted by the light source can be absorbed to be incident to a receiving area for detection so as to be received by the detector, and the intensity information of part of absorbed infrared light can be accurately detected, so that the concentration of the target group gas can be accurately calculated in the subsequent process.
Further: the signal processing circuit comprises a front-end signal conditioning circuit and a rear-end signal conditioning circuit, the front-end signal conditioning circuit comprises a front-end measuring signal conditioning circuit and a front-end reference signal conditioning circuit, and the rear-end signal conditioning circuit comprises a rear-end measuring signal conditioning circuit and a rear-end reference signal conditioning circuit;
the measuring signal output end of the detector is electrically connected with the input end of the front-end measuring signal conditioning circuit, the output end of the front-end measuring signal conditioning circuit is electrically connected with the input end of the rear-end measuring signal conditioning circuit, and the output end of the rear-end measuring signal conditioning circuit is electrically connected with the measuring signal input end of the main control circuit;
the reference signal output end of the detector is electrically connected with the input end of the front-end reference signal conditioning circuit, the output end of the front-end reference signal conditioning circuit is electrically connected with the input end of the rear-end reference signal conditioning circuit, and the output end of the rear-end reference signal conditioning circuit is electrically connected with the reference signal input end of the main control circuit.
The beneficial effects of the further scheme are as follows: can amplify the sinusoidal signal in measuring signal and the conditioned signal respectively through front end measuring signal conditioning circuit and front end reference signal conditioning circuit, and do not fall direct current signal wherein and amplify to restrain the signal and look for that high frequency noise, improve the function of SNR, make the signal possess stronger interference killing feature when carrying out remote transmission, give rear end signal conditioning circuit with effectual output signal and handle, rear end signal conditioning circuit carries out high frequency filtering and further enlarged function to the signal, overturns sinusoidal signal simultaneously, is about to sinusoidal negative semi-axis upset, makes negative voltage signal become the positive voltage signal, satisfies signal processing circuit's sampling condition.
Further: the front-end measurement signal conditioning circuit comprises an operational amplifier U17, a resistor R709, a resistor R710, a capacitor C64, a resistor R711 and a capacitor C68, wherein the non-inverting input end of the operational amplifier U17 is electrically connected with the detection signal output end of the detector, the non-inverting input end of the operational amplifier U17 is grounded through the resistor R709, the resistor R710 and the capacitor C64 are sequentially connected in series between the inverting input end of the operational amplifier U17 and the ground, the resistor R711 and the capacitor C68 are connected in parallel between the inverting input end and the output end of the operational amplifier U17, and the output end of the operational amplifier U17 is electrically connected with the input end of the rear-end measurement signal conditioning circuit;
the front-end reference signal conditioning circuit comprises an operational amplifier U19, a resistor R713, a capacitor C70, a resistor R714, a resistor R713 and a capacitor C71, wherein a non-inverting input end of the operational amplifier U19 is electrically connected with a reference signal output end of the detector, a non-inverting input end of the operational amplifier U19 is grounded through the resistor R713, the resistor R714 and the capacitor C70 are sequentially connected between an inverting input end of the operational amplifier U19 and the ground in series, the resistor R715 and the capacitor C71 are connected between an inverting input end and an output end of the operational amplifier U19 in parallel, and an output end of the operational amplifier U19 is electrically connected with an input end of the rear-end reference signal conditioning circuit.
The beneficial effects of the further scheme are as follows: the operational amplifier U17 and the operational amplifier U19 form a signal processing circuit with two channels, a negative feedback network is formed by the capacitor C64, the resistor R60, the resistor R61 and the capacitor C68 together, amplification of a measurement signal is achieved, meanwhile, the capacitor C61 is connected with the capacitor C68 in parallel to inhibit amplification of a high-frequency signal, the capacitor C64 is connected with the resistor R60 in series to inhibit amplification of a direct-current component in an original signal, and therefore the amplified signal is only a useful alternating-current signal output by the sensor.
Further: the rear-end measurement signal conditioning circuit comprises a variable resistor R69, a resistor R71, a capacitor C72, a resistor R66, an operational amplifier U20A, a resistor R73, a capacitor C74, a resistor R67, an operational amplifier U21C, a capacitor C73, a Schottky diode D10, a resistor R68, a resistor R70, an operational amplifier U21 70 and a resistor R70, wherein the output end of the front-end measurement signal conditioning circuit is electrically connected with the non-inverting input end of the operational amplifier U20 70 through the capacitor C70, the non-inverting input end of the operational amplifier U20 70 is grounded through the resistor R70, the resistor R70 and the variable resistor R70 are sequentially connected in series between the inverting input end of the operational amplifier U20 70 and the ground, the resistor R70 and the capacitor C70 are connected in parallel between the inverting input end and the output end of the operational amplifier U20 70, the output end of the operational amplifier U20 70 is electrically connected with the non-inverting input end of the operational amplifier U70 through the resistor R70, the capacitor C73 is electrically connected between the inverting input end and the output end of the operational amplifier U21C, the inverting input end and the output end of the operational amplifier U21C are respectively and correspondingly electrically connected with the pin No. 1 and the pin No. 3 of the schottky diode D10, the pin No. 2 of the schottky diode D10 is grounded through the resistor R68, the pin No. 2 of the schottky diode D10 is electrically connected with the non-inverting input end of the operational amplifier U21D, the inverting input end of the operational amplifier U21D is electrically connected with the non-inverting input end of the operational amplifier U21C through the resistor R70, the resistor R72 is electrically connected between the inverting input end and the output end of the operational amplifier U21D, and the output end of the operational amplifier U21D is electrically connected with the measurement signal input end of the main control circuit;
the back-end reference signal conditioning circuit comprises a capacitor C75, a resistor R74, a variable resistor R77, a resistor R79, an operational amplifier U20B, a resistor R81, a capacitor C77, a resistor R75, an operational amplifier U21B, a capacitor C76, a Schottky diode D11, a resistor R76, a resistor R78, an operational amplifier U22 78 and a resistor R78, wherein the output end of the front-end reference signal conditioning circuit is electrically connected with the non-inverting input end of the operational amplifier U20 78 through the capacitor C78, the non-inverting input end of the operational amplifier U20 78 is grounded through the resistor R78, the resistor R78 and the variable resistor R78 are electrically connected between the inverting input end of the operational amplifier U20 78 and the ground in sequence, the resistor R78 and the capacitor C78 are connected between the inverting input end and the output end of the operational amplifier U20 78 in parallel, the output end of the operational amplifier U20 78 is electrically connected with the non-inverting input end of the operational amplifier U78 through the resistor R78, the capacitor C76 is electrically connected between the inverting input end and the output end of the operational amplifier U21B, the inverting input end and the output end of the operational amplifier U21B are respectively and correspondingly electrically connected with the pin 1 and the pin 3 of the schottky diode D11, the pin 2 of the schottky diode D11 is grounded through the resistor R76, the pin 2 of the schottky diode D11 is electrically connected with the non-inverting input end of the operational amplifier U22C, the inverting input end of the operational amplifier U22C is electrically connected with the non-inverting input end of the operational amplifier U21B through the resistor R78, the resistor R80 is electrically connected between the inverting input end and the output end of the operational amplifier U22C, and the output end of the operational amplifier U22C is electrically connected with the reference signal input end of the main control circuit.
The beneficial effects of the further scheme are as follows: the capacitor C72, the resistor R66 and the operational amplifier U20A jointly form an active high-pass filter, signals with the frequency lower than the signal cut-off frequency are restrained and cannot be transmitted to a next-stage circuit, therefore, direct current signals and low-frequency noise signals are filtered, the resistor R69, the resistor R71, the resistor R73 and the capacitor C74 jointly form a negative feedback circuit, the signals are amplified in the same direction, the R60 is an adjustable resistor, the amplification factor can be adjusted, finally output signals are kept to the same level, and convenience is brought to back-end processing.
Further: the light source frequency modulation circuit comprises a boosting chip U2, an inductor L1, a resistor R2, a resistor R3, a capacitor C2, a capacitor C5, a capacitor C6, a resistor R1 and a MOS tube Q1, wherein a power supply input end of the boosting chip U2 is electrically connected with a +5V output end of a power supply circuit, a power supply input end of the boosting chip U2 is grounded through the capacitor C6, two inductor connecting ends of the boosting chip U2 are respectively electrically connected with two ends of the inductor L1, a ground end of the boosting chip U2 is grounded, an output end of the boosting chip U2 is electrically connected with the power supply input end of the light source, an output end of the boosting chip U2 is grounded through the capacitor C2, the resistor R2 is electrically connected between the output end and a feedback input end of the boosting chip U2, a feedback input end of the boosting chip U2 is grounded through the resistor R3, an enabling end of the boosting chip U2 is grounded through the capacitor C5, the grid electrode of the MOS tube Q1 is electrically connected with the signal output end of the main control circuit, the source electrode of the MOS tube Q1 is grounded, and the drain electrode of the MOS tube Q1 is electrically connected with the control signal input end of the light source.
The beneficial effects of the further scheme are as follows: the boost chip U2 provides a stable and reliable power supply for the light source, the MOS tube Q1 and the resistor R1 form a switching circuit, and the switching frequency of the MOS tube Q1 is controlled by the PWM wave output by the main control circuit, so that the frequency of the light source is controlled.
Further: the environment monitoring circuit comprises an air pressure monitoring circuit and a temperature monitoring circuit, and the output ends of the air pressure monitoring circuit and the temperature monitoring circuit are respectively electrically connected with the environment signal input end of the main control circuit.
The beneficial effects of the further scheme are as follows: the atmospheric pressure monitoring circuit and the temperature monitoring circuit can respectively monitor atmospheric pressure information and temperature information in the environment, and the measured gas concentration value is corrected by utilizing the environmental data, so that higher-precision concentration measurement data is obtained, and the use requirements under different scenes are met.
Further: the man-machine interaction circuit comprises a key and a display screen, and the key and the display screen are respectively electrically connected with the interaction port of the main control circuit.
The beneficial effects of the further scheme are as follows: a light source frequency setting command can be input through the key, so that the main control circuit can generate a driving signal according to the light source frequency setting command so as to drive the light source to adjust the frequency, the intensity of the partially absorbed infrared light is adjusted, and the concentration of different kinds of gas is measured.
Further: the non-dispersive infrared gas analysis circuit based on the embedded system further comprises a communication circuit, the main control circuit is electrically connected with the communication circuit, and the communication circuit is electrically connected with an external receiving terminal.
The beneficial effects of the further scheme are as follows: the communication circuit can be directly in communication connection with an external receiving terminal, so that data interaction between the communication circuit and the receiving terminal is conveniently realized, and test data are sent to the receiving terminal so as to carry out data analysis and processing in the next step.
Drawings
Fig. 1 is a schematic structural diagram of a non-dispersive infrared gas analysis circuit based on an embedded system according to an embodiment of the present invention;
fig. 2 is a schematic circuit diagram of a front-end signal conditioning circuit according to an embodiment of the present invention;
fig. 3 is a schematic circuit diagram of a back-end signal conditioning circuit according to an embodiment of the present invention;
fig. 4 is a schematic circuit diagram of a light source frequency modulation circuit according to an embodiment of the present invention.
Detailed Description
The principles and features of the present invention are described below in conjunction with the following drawings, the examples given are only intended to illustrate the present invention and are not intended to limit the scope of the present invention.
As shown in figure 1, the non-dispersive infrared gas analysis circuit based on the embedded system comprises a detection assembly, a signal processing circuit, a main control circuit, a light source frequency modulation circuit, a light source, an environment monitoring circuit, a man-machine interaction circuit and a power supply circuit, wherein the output end of the detection assembly is electrically connected with the input end of the signal processing circuit, the output end of the signal processing circuit is electrically connected with the output end of the environment monitoring circuit and the signal input end of the main control circuit respectively, the signal output end of the main control circuit is electrically connected with the input end of the light source frequency modulation circuit, the man-machine interaction circuit is electrically connected with the main control circuit, the output end of the light source frequency modulation circuit is electrically connected with the light source, and the power supply circuit is respectively connected with the signal processing circuit, the main control circuit, the light source frequency modulation circuit, The light source, the man-machine interaction circuit and the environment monitoring circuit are electrically connected.
The utility model discloses a based on embedded system non-dispersion infrared gas analysis circuit, through the infrared light intensity information of surveying after being absorbed by the target gas part of detection subassembly to process the concentration value of back by main control circuit calculation target gas through signal processing circuit, main control circuit combines the environmental information of environmental monitoring subassembly monitoring right the concentration value is compensated and is handled and show, and simultaneously, the light source frequency can be adjusted to the human-computer interaction circuit, with the infrared light intensity of regulation after being absorbed by the part, thereby obtain gas concentration analysis result, can be suitable for different types of gas analysis, easy operation, the testing result is accurate, has greatly made things convenient for development work, has practiced thrift the time cost.
The embodiment of the utility model provides an in, main control unit is according to the calculation process who calculates the concentration value of target gas through the infrared light intensity information after signal processing circuit handles: the instrument respectively penetrates two infrared beams through a non-light-absorbing reference gas chamber and a light-absorbing sample gas chamber, so that the intensity I of the beams reaching the terminal of the reference gas chamber0Intensity of infrared beam greater than terminal of sample gas chamber, using I0With I's proportional relation, according to beer law, can solve the gaseous concentration C that awaits measuring in the sample gas, because this process is prior art, the utility model discloses well no longer detailed description to this is not the utility model discloses the protection content that requires.
The utility model discloses a in one or more embodiments, survey the subassembly and include to link up between both ends and be provided with the air chamber and the detector of light channel, detector and light source are sealed the setting respectively and are in the both ends of air chamber, just the optic fibre of light source outgoing shines via the light channel incides to the receiving area of detector. The detector and the light source are respectively arranged at two ends of the air chamber in a sealing manner, so that part of infrared light energy emitted by the light source can be absorbed to be incident to a receiving area for detection so as to be received by the detector, and the intensity information of part of absorbed infrared light can be accurately detected, so that the concentration of the target group gas can be accurately calculated in the subsequent process.
In order to conveniently find the optimal length of the air chamber, in practice, the air chambers with different lengths can be replaced according to needs, so that the test environment can be changed in a short time to obtain different test data, and the analysis of the measured data result is facilitated.
The utility model discloses a in one or more embodiments, signal processing circuit includes front end signal conditioning circuit and back end signal conditioning circuit, front end signal conditioning circuit includes front end measurement signal conditioning circuit and front end reference signal conditioning circuit, back end signal conditioning circuit includes back end measurement signal conditioning circuit and back end reference signal conditioning circuit.
The measuring signal output end of the detector is electrically connected with the input end of the front-end measuring signal conditioning circuit, the output end of the front-end measuring signal conditioning circuit is electrically connected with the input end of the rear-end measuring signal conditioning circuit, and the output end of the rear-end measuring signal conditioning circuit is electrically connected with the measuring signal input end of the main control circuit;
the reference signal output end of the detector is electrically connected with the input end of the front-end reference signal conditioning circuit, the output end of the front-end reference signal conditioning circuit is electrically connected with the input end of the rear-end reference signal conditioning circuit, and the output end of the rear-end reference signal conditioning circuit is electrically connected with the reference signal input end of the main control circuit.
Can amplify the sinusoidal signal in measuring signal and the conditioned signal respectively through front end measuring signal conditioning circuit and front end reference signal conditioning circuit, and do not fall direct current signal wherein and amplify to restrain the signal and look for that high frequency noise, improve the function of SNR, make the signal possess stronger interference killing feature when carrying out remote transmission, give rear end signal conditioning circuit with effectual output signal and handle, rear end signal conditioning circuit carries out high frequency filtering and further enlarged function to the signal, overturns sinusoidal signal simultaneously, is about to sinusoidal negative semi-axis upset, makes negative voltage signal become the positive voltage signal, satisfies signal processing circuit's sampling condition.
When the detector works, an output original signal is an alternating current sinusoidal signal, the signal frequency is the light source frequency, the amplitude of the sinusoidal signal at the moment is extremely small and is about 2-3mV, and the signal at the moment is superposed with a direct current voltage signal of about 500-600mV, so that a signal processing circuit is arranged at the front end (close to the detector), the circuit amplifies small signals without amplifying the direct current signal, suppresses high-frequency noise in the signals, improves the signal-to-noise ratio function, enables the signals to have stronger anti-interference capability during long-distance transmission, and transmits effective output signals to the rear end for processing.
In one or more embodiments of the present invention, as shown in fig. 2, the front-end measurement signal conditioning circuit includes an operational amplifier U17, a resistor R709, a resistor R710, a capacitor C64, a resistor R711, and a capacitor C68, the non-inverting input terminal of the operational amplifier U17 is electrically connected to the detection signal output terminal of the detector, the non-inverting input terminal of the operational amplifier U17 is grounded through the resistor R709, the resistor R710 and the capacitor C64 are sequentially connected in series between the inverting input terminal of the operational amplifier U17 and the ground, the resistor R711 and the capacitor C68 are connected in parallel between the inverting input terminal and the output terminal of the operational amplifier U17, and the output terminal of the operational amplifier U17 is electrically connected to the input terminal of the rear-end measurement signal conditioning circuit.
The operational amplifier U17 and the operational amplifier U19 form a signal processing circuit with two channels, a negative feedback network is formed by the capacitor C64, the resistor R60, the resistor R61 and the capacitor C68 together, amplification of a measurement signal is achieved, the amplification factor F is 1+ (R61/R60), meanwhile, the capacitor C61 and the capacitor C68 are connected in parallel, amplification of a high-frequency signal is restrained, the capacitor C64 and the resistor R60 are connected in series, amplification of a direct-current component in an original signal is restrained, and therefore the amplified signal is only a useful alternating-current signal output by a sensor.
The front-end reference signal conditioning circuit comprises an operational amplifier U19, a resistor R713, a capacitor C70, a resistor R714, a resistor R713 and a capacitor C71, wherein a non-inverting input end of the operational amplifier U19 is electrically connected with a reference signal output end of the detector, a non-inverting input end of the operational amplifier U19 is grounded through the resistor R713, the resistor R714 and the capacitor C70 are sequentially connected between an inverting input end of the operational amplifier U19 and the ground in series, the resistor R715 and the capacitor C71 are connected between an inverting input end and an output end of the operational amplifier U19 in parallel, and an output end of the operational amplifier U19 is electrically connected with an input end of the rear-end reference signal conditioning circuit. The working principle of the front-end measurement signal conditioning circuit is the same as that of the front-end measurement signal conditioning circuit, and the details are not repeated here.
In one or more embodiments of the present invention, as shown in fig. 3, the back-end measurement signal conditioning circuit includes a variable resistor R69, a resistor R71, a capacitor C72, a resistor R66, an operational amplifier U20A, a resistor R73, a capacitor C74, a resistor R67, an operational amplifier U21C, a capacitor C73, a schottky diode D10, a resistor R68, a resistor R70, an operational amplifier U21D, and a resistor R72, an output terminal of the front-end measurement signal conditioning circuit is electrically connected to a non-inverting input terminal of the operational amplifier U20A through the capacitor C72, a non-inverting input terminal of the operational amplifier U20A is grounded through the resistor R66, the resistor R66 and the variable resistor R66 are sequentially connected between an inverting input terminal of the operational amplifier U20 66 and the ground, the resistor R66 and the variable resistor R66 are connected in parallel between the inverting input terminal of the operational amplifier U20 66, the output terminal of the operational amplifier U20 is connected in series through the resistor R66, the output terminal of the operational amplifier U20A is electrically connected to the non-inverting input terminal of the operational amplifier U21C, the capacitor C73 is electrically connected between the inverting input end and the output end of the operational amplifier U21C, the inverting input end and the output end of the operational amplifier U21C are respectively and electrically connected with the pin No. 1 and the pin No. 3 of the Schottky diode D10, pin 2 of the Schottky diode D10 is grounded through the resistor R68, pin 2 of the Schottky diode D10 is electrically connected with the non-inverting input terminal of the operational amplifier U21D, the inverting input terminal of the operational amplifier U21D is electrically connected to the non-inverting input terminal of the operational amplifier U21C through the resistor R70, the resistor R72 is electrically connected between the inverting input end and the output end of the operational amplifier U21D, the output end of the operational amplifier U21D is electrically connected with the measurement signal input end of the main control circuit.
The capacitor C72, the resistor R66 and the operational amplifier U20A jointly form an active high-pass filter, signals with frequencies lower than the cut-off frequency of the signals are suppressed and cannot be transmitted to a next-stage circuit, therefore, filtering of direct-current signals and low-frequency noise signals is achieved, the resistor R69, the resistor R71, the resistor R73 and the capacitor C74 jointly form a negative feedback circuit, the signals are amplified in the same direction, the amplification factor F is 1+ (R73/(R69+ R71)), the R60 is an adjustable resistor, the amplification factor can be adjusted, the finally output signals are kept at the same level, and convenience is provided for back-end processing. The U21C, C73, D10, R68, R70, R70 and U21D jointly form a signal turnover circuit, when the signal is a positive half-cycle signal, the operational amplifier U21C has output, and finally the positive half-cycle signal is output through the U21D; when the signal is negative half cycle, the pin 8 output of the operational amplifier U21C is 0, the schottky diode D10 is turned off, and the negative half cycle signal enters the inverting input terminal of the operational amplifier U21D through R70, and finally the pin 14 output signal of the operational amplifier U21D is inverted, inverting the negative half cycle signal to the positive half cycle signal.
In one or more embodiments of the present invention, the back-end reference signal conditioning circuit includes a capacitor C75, a resistor R74, a variable resistor R77, a resistor R79, an operational amplifier U20B, a resistor R81, a capacitor C77, a resistor R75, an operational amplifier U21B, a capacitor C76, a schottky diode D11, a resistor R76, a resistor R78, an operational amplifier U22C, and a resistor R80, an output terminal of the front-end reference signal conditioning circuit is electrically connected to a non-inverting input terminal of the operational amplifier U20B through the capacitor C75, a non-inverting input terminal of the operational amplifier U20B is grounded through the resistor R74, the resistor R74 and the variable resistor R74 are electrically connected between an inverting input terminal of the operational amplifier U20 74 and the ground in sequence, the resistor R74 and the capacitor C74 are connected in parallel between the inverting input terminal of the operational amplifier U20 74, the output terminal of the operational amplifier U20B is electrically connected to the non-inverting input terminal of the operational amplifier U21B, the capacitor C76 is electrically connected between the inverting input end and the output end of the operational amplifier U21B, the inverting input end and the output end of the operational amplifier U21B are respectively and electrically connected with the pin No. 1 and the pin No. 3 of the Schottky diode D11, pin 2 of the Schottky diode D11 is grounded through the resistor R76, pin 2 of the Schottky diode D11 is electrically connected with the non-inverting input terminal of the operational amplifier U22C, the inverting input terminal of the operational amplifier U22C is electrically connected to the non-inverting input terminal of the operational amplifier U21B through the resistor R78, the resistor R80 is electrically connected between the inverting input end and the output end of the operational amplifier U22C, the output end of the operational amplifier U22C is electrically connected with the reference signal input end of the main control circuit.
In one or more embodiments of the present invention, as shown in fig. 4, the light source frequency modulation circuit includes a boost chip U2, an inductor L1, a resistor R2, a resistor R3, a capacitor C2, a capacitor C5, a capacitor C6, a resistor R1, and a MOS transistor Q1, a power input terminal of the boost chip U2 is electrically connected to a +5V output terminal of the power circuit, a power input terminal of the boost chip U2 is grounded via the capacitor C6, two inductor connecting terminals of the boost chip U2 are electrically connected to two ends of the inductor L1, a ground terminal of the boost chip U2 is grounded, an output terminal of the boost chip U2 is electrically connected to a power input terminal of the light source, an output terminal of the boost chip U2 is grounded via the capacitor C2, a resistor R2 is electrically connected between an output terminal and a feedback input terminal of the boost chip U2, a feedback input terminal of the boost chip 2 is grounded via the resistor R3, the enable end of the boosting chip U2 is grounded through the capacitor C5, the grid electrode of the MOS tube Q1 is electrically connected with the signal output end of the main control circuit, the source electrode of the MOS tube Q1 is grounded, and the drain electrode of the MOS tube Q1 is electrically connected with the control signal input end of the light source.
The boost chip U2 provides a stable and reliable power supply for the light source, the MOS tube Q1 and the resistor R1 form a switching circuit, and the switching frequency of the MOS tube Q1 is controlled by the PWM wave output by the main control circuit, so that the frequency of the light source is controlled.
The utility model discloses an in one or more embodiments, the environmental monitoring circuit includes atmospheric pressure monitoring circuit and temperature monitoring circuit, atmospheric pressure monitoring circuit and temperature monitoring circuit's output respectively with main control circuit's environmental signal input end electricity is connected. The atmospheric pressure monitoring circuit and the temperature monitoring circuit can respectively monitor atmospheric pressure information and temperature information in the environment, and the measured gas concentration value is corrected by utilizing the environmental data, so that higher-precision concentration measurement data is obtained, and the use requirements under different scenes are met. The embodiment of the utility model provides an in, atmospheric pressure monitoring circuit adopts the model to realize the barometry for BMP 280's high accuracy digital baroceptor, and this sensor uses the IIC agreement to carry out data communication with the outside, and it is fast to possess transmission speed, characteristics such as data stability. The temperature monitoring circuit can be an existing temperature sensor, and details are not repeated here.
The utility model discloses an in one or more embodiments, man-machine interaction circuit includes button and display screen, button and display screen respectively with main control circuit's mutual port electricity is connected. A light source frequency setting command can be input through the key, so that the main control circuit can generate a driving signal according to the light source frequency setting command so as to drive the light source to adjust the frequency, the intensity of the partially absorbed infrared light is adjusted, and the concentration of different kinds of gas is measured. The developer can directly display the observation data through the screen and modify the data by using the keys, thereby saving the operation of modifying in the program and downloading to the development board again, greatly saving the development cost and prolonging the service life of the singlechip.
The utility model discloses an in one or more embodiments, based on non-dispersion infrared gas analysis circuit of embedded system still include communication circuit, main control circuit with the communication circuit electricity is connected, communication circuit is connected with outside receiving terminal electricity. The communication circuit can be directly in communication connection with an external receiving terminal, so that data interaction between the communication circuit and the receiving terminal is conveniently realized, and test data are sent to the receiving terminal so as to carry out data analysis and processing in the next step. The utility model discloses in, communication circuit adopts RS232 serial communication module, but direct computer is connected and is realized the communication.
The utility model discloses an infrared gas analysis circuit based on embedded system non-dispersion provides a reliable and stable platform for gas analysis experiment test, the utility model discloses have air chamber length adjustable, the detector kind is convenient to be changed to and the light source model is convenient to be changed, only need simple step alright realize above-mentioned operation, thereby significantly reduced because need change the hardware in research and development test process, and consume a large amount of time and material resources, can change the debugging to the multiple hardware equipment that development personnel can think in the short time, and then shortened the research and development cycle. The utility model discloses still provide reliable and stable signal processing circuit, handle sensor output signal, possess high SNR, remain useful signal's output in the at utmost, realize high accuracy gas concentration measurement function.
The utility model discloses a based on embedded system non-dispersion infrared gas analysis circuit has carried on barometry circuit and temperature measurement circuit simultaneously, measures the atmospheric pressure and the temperature of current environment, utilizes these environmental data to revise by the gaseous concentration measurement value of being surveyed to obtain the concentration measurement data of higher accuracy. In addition, a communication circuit and a man-machine interaction circuit are also arranged, so that data can be uploaded to an upper computer or displayed directly by using a screen in the development process.
The above description is only for the preferred embodiment of the present invention, and is not intended to limit the present invention, and any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention should be included within the protection scope of the present invention.
Claims (9)
1. The utility model provides a based on embedded system non-dispersion infrared gas analysis circuit which characterized in that: including detecting subassembly, signal processing circuit, main control circuit, light source frequency modulation circuit, light source, environment monitoring circuit, man-machine interaction circuit and power supply circuit, the output of detecting the subassembly with signal processing circuit's input electricity is connected, signal processing circuit's output with environment monitoring circuit's output respectively with main control circuit's signal input part electricity is connected, main control circuit's signal output part with light source frequency modulation circuit's input electricity is connected, man-machine interaction circuit with main control circuit electricity is connected, light source frequency modulation circuit's output with the light source electricity is connected, power supply circuit respectively with signal processing circuit, main control circuit, light source frequency modulation circuit, light source, man-machine interaction circuit and environment monitoring circuit electricity are connected.
2. The embedded system non-dispersive infrared-based gas analysis circuit according to claim 1, wherein: the detection assembly comprises an air chamber and a detector, wherein an optical channel is arranged between two ends of the air chamber in a penetrating mode, the detector and the light source are arranged at two ends of the air chamber in a sealing mode respectively, and the emergent optical fibers of the light source irradiate to a receiving area of the detector through the optical channel.
3. The embedded system non-dispersive infrared-based gas analysis circuit according to claim 2, wherein: the signal processing circuit comprises a front-end signal conditioning circuit and a rear-end signal conditioning circuit, the front-end signal conditioning circuit comprises a front-end measuring signal conditioning circuit and a front-end reference signal conditioning circuit, and the rear-end signal conditioning circuit comprises a rear-end measuring signal conditioning circuit and a rear-end reference signal conditioning circuit;
the measuring signal output end of the detector is electrically connected with the input end of the front-end measuring signal conditioning circuit, the output end of the front-end measuring signal conditioning circuit is electrically connected with the input end of the rear-end measuring signal conditioning circuit, and the output end of the rear-end measuring signal conditioning circuit is electrically connected with the measuring signal input end of the main control circuit;
the reference signal output end of the detector is electrically connected with the input end of the front-end reference signal conditioning circuit, the output end of the front-end reference signal conditioning circuit is electrically connected with the input end of the rear-end reference signal conditioning circuit, and the output end of the rear-end reference signal conditioning circuit is electrically connected with the reference signal input end of the main control circuit.
4. The embedded system non-dispersive infrared gas analysis circuit according to claim 3, wherein: the front-end measurement signal conditioning circuit comprises an operational amplifier U17, a resistor R709, a resistor R710, a capacitor C64, a resistor R711 and a capacitor C68, wherein the non-inverting input end of the operational amplifier U17 is electrically connected with the detection signal output end of the detector, the non-inverting input end of the operational amplifier U17 is grounded through the resistor R709, the resistor R710 and the capacitor C64 are sequentially connected in series between the inverting input end of the operational amplifier U17 and the ground, the resistor R711 and the capacitor C68 are connected in parallel between the inverting input end and the output end of the operational amplifier U17, and the output end of the operational amplifier U17 is electrically connected with the input end of the rear-end measurement signal conditioning circuit;
the front-end reference signal conditioning circuit comprises an operational amplifier U19, a resistor R713, a capacitor C70, a resistor R714, a resistor R713 and a capacitor C71, wherein a non-inverting input end of the operational amplifier U19 is electrically connected with a reference signal output end of the detector, a non-inverting input end of the operational amplifier U19 is grounded through the resistor R713, the resistor R714 and the capacitor C70 are sequentially connected between an inverting input end of the operational amplifier U19 and the ground in series, the resistor R715 and the capacitor C71 are connected between an inverting input end and an output end of the operational amplifier U19 in parallel, and an output end of the operational amplifier U19 is electrically connected with an input end of the rear-end reference signal conditioning circuit.
5. The embedded system non-dispersive infrared gas analysis circuit according to claim 3, wherein: the rear-end measurement signal conditioning circuit comprises a variable resistor R69, a resistor R71, a capacitor C72, a resistor R66, an operational amplifier U20A, a resistor R73, a capacitor C74, a resistor R67, an operational amplifier U21C, a capacitor C73, a Schottky diode D10, a resistor R68, a resistor R70, an operational amplifier U21 70 and a resistor R70, wherein the output end of the front-end measurement signal conditioning circuit is electrically connected with the non-inverting input end of the operational amplifier U20 70 through the capacitor C70, the non-inverting input end of the operational amplifier U20 70 is grounded through the resistor R70, the resistor R70 and the variable resistor R70 are sequentially connected in series between the inverting input end of the operational amplifier U20 70 and the ground, the resistor R70 and the capacitor C70 are connected in parallel between the inverting input end and the output end of the operational amplifier U20 70, the output end of the operational amplifier U20 70 is electrically connected with the non-inverting input end of the operational amplifier U70 through the resistor R70, the capacitor C73 is electrically connected between the inverting input end and the output end of the operational amplifier U21C, the inverting input end and the output end of the operational amplifier U21C are respectively and correspondingly electrically connected with the pin No. 1 and the pin No. 3 of the schottky diode D10, the pin No. 2 of the schottky diode D10 is grounded through the resistor R68, the pin No. 2 of the schottky diode D10 is electrically connected with the non-inverting input end of the operational amplifier U21D, the inverting input end of the operational amplifier U21D is electrically connected with the non-inverting input end of the operational amplifier U21C through the resistor R70, the resistor R72 is electrically connected between the inverting input end and the output end of the operational amplifier U21D, and the output end of the operational amplifier U21D is electrically connected with the measurement signal input end of the main control circuit;
the back-end reference signal conditioning circuit comprises a capacitor C75, a resistor R74, a variable resistor R77, a resistor R79, an operational amplifier U20B, a resistor R81, a capacitor C77, a resistor R75, an operational amplifier U21B, a capacitor C76, a Schottky diode D11, a resistor R76, a resistor R78, an operational amplifier U22 78 and a resistor R78, wherein the output end of the front-end reference signal conditioning circuit is electrically connected with the non-inverting input end of the operational amplifier U20 78 through the capacitor C78, the non-inverting input end of the operational amplifier U20 78 is grounded through the resistor R78, the resistor R78 and the variable resistor R78 are electrically connected between the inverting input end of the operational amplifier U20 78 and the ground in sequence, the resistor R78 and the capacitor C78 are connected between the inverting input end and the output end of the operational amplifier U20 78 in parallel, the output end of the operational amplifier U20 78 is electrically connected with the non-inverting input end of the operational amplifier U78 through the resistor R78, the capacitor C76 is electrically connected between the inverting input end and the output end of the operational amplifier U21B, the inverting input end and the output end of the operational amplifier U21B are respectively and correspondingly electrically connected with the pin 1 and the pin 3 of the schottky diode D11, the pin 2 of the schottky diode D11 is grounded through the resistor R76, the pin 2 of the schottky diode D11 is electrically connected with the non-inverting input end of the operational amplifier U22C, the inverting input end of the operational amplifier U22C is electrically connected with the non-inverting input end of the operational amplifier U21B through the resistor R78, the resistor R80 is electrically connected between the inverting input end and the output end of the operational amplifier U22C, and the output end of the operational amplifier U22C is electrically connected with the reference signal input end of the main control circuit.
6. The embedded system non-dispersive infrared-based gas analysis circuit according to claim 1, wherein: the light source frequency modulation circuit comprises a boosting chip U2, an inductor L1, a resistor R2, a resistor R3, a capacitor C2, a capacitor C5, a capacitor C6, a resistor R1 and a MOS tube Q1, wherein a power supply input end of the boosting chip U2 is electrically connected with a +5V output end of a power supply circuit, a power supply input end of the boosting chip U2 is grounded through the capacitor C6, two inductor connecting ends of the boosting chip U2 are respectively electrically connected with two ends of the inductor L1, a ground end of the boosting chip U2 is grounded, an output end of the boosting chip U2 is electrically connected with the power supply input end of the light source, an output end of the boosting chip U2 is grounded through the capacitor C2, the resistor R2 is electrically connected between the output end and a feedback input end of the boosting chip U2, a feedback input end of the boosting chip U2 is grounded through the resistor R3, an enabling end of the boosting chip U2 is grounded through the capacitor C5, the grid electrode of the MOS tube Q1 is electrically connected with the signal output end of the main control circuit, the source electrode of the MOS tube Q1 is grounded, and the drain electrode of the MOS tube Q1 is electrically connected with the control signal input end of the light source.
7. The embedded system non-dispersive infrared-based gas analysis circuit according to claim 1, wherein: the environment monitoring circuit comprises an air pressure monitoring circuit and a temperature monitoring circuit, and the output ends of the air pressure monitoring circuit and the temperature monitoring circuit are respectively electrically connected with the environment signal input end of the main control circuit.
8. The embedded system non-dispersive infrared gas analysis circuit according to any of the claims 1 to 7, wherein: the man-machine interaction circuit comprises a key and a display screen, and the key and the display screen are respectively electrically connected with the interaction port of the main control circuit.
9. The embedded system non-dispersive infrared gas analysis circuit according to any of the claims 1 to 7, wherein: the intelligent terminal also comprises a communication circuit, wherein the main control circuit is electrically connected with the communication circuit, and the communication circuit is electrically connected with an external receiving terminal.
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN113237843A (en) * | 2021-01-19 | 2021-08-10 | 北立传感器技术（武汉）有限公司 | Non-dispersive infrared gas analysis circuit and analysis method based on embedded system |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN113237843A (en) * | 2021-01-19 | 2021-08-10 | 北立传感器技术（武汉）有限公司 | Non-dispersive infrared gas analysis circuit and analysis method based on embedded system |
| CN113237843B (en) * | 2021-01-19 | 2024-02-23 | 北立传感器技术（武汉）有限公司 | Non-dispersive infrared gas analysis circuit and analysis method based on embedded system |
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