CN206292203U - A kind of air NO based on electrochemical sensor2Detection system - Google Patents

Abstract

The utility model discloses a kind of air NO based on electrochemical sensor₂Detection system, belongs to atmosphere environment supervision field, and system includes sensor assembly, data acquisition and procession module, man-machine interaction visualization model；The sensor assembly includes NO₂Four electrode electrochemical sensors, Temperature Humidity Sensor；The data acquisition and procession module includes noiselike signal modulate circuit, DSP main control units；The man-machine interaction visualization model includes LabVIEW2015 platforms, sound and light alarm module, and the utility model compares tradition NO₂Detecting system is more succinct, small-sized, portable, is capable of achieving to ppb magnitudes low concentration of NO in air₂High-acruracy survey, when can precisely deduct low concentration electrochemical sensor null offset and ambient temperature and humidity change to NO₂The interference of testing result, improves the confidence level of testing result, and detection system stability is high, sensitivity is high, the linearity is high, human-computer interaction interface is excellent, possesses broad prospect of application.

Description

A kind of air NO based on electrochemical sensor2Detection system

Technical field

The utility model belongs to atmosphere environment supervision field, and in particular to a kind of air NO based on electrochemical sensor₂ Detection system.

Background technology

Recently as expanding economy, waste gas discharge gradually increases in production and living, wherein NO₂It is a kind of important air Trace gas, essentially from combustion of fossil fuel, automotive emission etc., it participates in the generation of photochemical catalysis ozone, can lead Photochemical fog is caused even to form acid rain, serious harm atmospheric environment and human health with the increase of ozone.Therefore the task of top priority It is to carry out to air NO₂The accurate monitoring of concentration and timely early warning.

Traditional NO₂Detecting instrument is mostly based on Spectrum Absorption Principle, and complex structure, disturbing factor are more, operation is required sternly It is lattice, bulky, it is impossible to meet it is succinct, accurate, portable the need for, therefore be to adapt to Atmospheric Trace NO₂Detecting devices it is small-sized Change, portability, devising can detect ppb magnitudes (10 based on electrochemical sensor^-9)NO₂Detection system.

Utility model content

The utility model purpose is can to realize being measured in ppb while succinct, small-sized detection system, portable demand is met Level is to trace NO in air₂The high-acruracy survey of concentration.

In order to achieve the above object, the technical scheme that the utility model is used for：

A kind of air NO based on electrochemical sensor₂Detection system, it is characterised in that：The system includes sensor die Block, data acquisition and procession module, man-machine interaction visualization model；The sensor assembly includes NO₂Four electrode electro Chemicals are passed Sensor, Temperature Humidity Sensor, 2 sensor signal outputs to data acquisition and procession module；The data acquisition and procession mould Block includes noiselike signal modulate circuit, DSP main control units, noiselike signal modulate circuit and NO₂Four electrode electro Chemicals are sensed Device is connected, and DSP main control units are connected with noiselike signal modulate circuit, Temperature Humidity Sensor respectively；The man-machine interaction is visual Changing module includes LabVIEW2015 platforms, sound and light alarm module, and LabVIEW2015 platforms are by RS485 serial ports and DSP master controls Unit is connected, and sound and light alarm module is connected with LabVIEW2015 platforms.

A kind of air NO based on electrochemical sensor according to claim 1₂Detection system, it is characterised in that： The sensor assembly uses the NO of Alphasense companies of Britain₂The electrode electrochemical sensors of-B43F four, comprising work electricity Pole, to electrode, reference electrode and auxiliary electrode totally four electrodes, the NO in air₂Diffuse into sensor internal and in work There is reduction reaction, working electrode output and NO in electrode₂The nA magnitude current signals that concentration is directly proportional, auxiliary electrode and work electricity There is identical nA magnitudes zero current pole, but auxiliary electrode does not reach NO₂Extracurrent will not be produced, institute is for compensation work Electrode zero current, is used to complete current loop to electrode, and reference electrode is used to ensure working electrode, auxiliary electrode constant potential； It is 16, the DHT22 digital hygro sensors of monobus communication mode that Temperature Humidity Sensor uses resolution ratio, is used to obtain ring Border temperature information and humidity information.

A kind of air NO based on electrochemical sensor according to claim 1₂Detection system, it is characterised in that： While noiselike signal modulate circuit ensures electrochemical sensor normal work in the data acquisition and procession module, to electricity The current signal of chemical sensor output carries out electric current-voltage conversion, plus and blowup and filtering；DSP main control units use TI 32 floating type TMS320F28335 of company are main control chip, and noiselike signal is adjusted using the chip internal ADC of 12 The two-way output of reason circuit carries out A/D conversions and obtains mV magnitudes working electrode and auxiliary electrode magnitude of voltage respectively, and according to auxiliary electricity Pole tension value and Temperature Humidity Sensor output signal are compensated by amendment to working electrode voltage value.

A kind of air NO based on electrochemical sensor according to claim 1₂Detection system, it is characterised in that： The man-machine interaction visualization model is based on LabVIEW2015 platforms come to NO₂Concentration shows that it passes through RS485 serial ports in real time Communicated with DSP main control units, the working electrode voltage data inversion after the compensation that LabVIEW2015 platforms are received to serial ports is obtained The ppb magnitudes NO in air₂Concentration value, recycles platform interior numerical value display control to show that control is real in main interface with waveform When display density value and depict NO₂Concentration real-time change curve, while contrasted with warning concentration value, more than then startup acousto-optic report It is alert.

Compared with prior art, the beneficial effects of the utility model are embodied in：

The utility model uses four electrode electrochemical sensors, and it increased compared to common three-electrode electrochemical sensor One auxiliary electrode is used to compensate zero current, because zero current can have a strong impact on measurement when detecting that gas concentration is very low Value, sensor internal working electrode is identical with auxiliary electrode local environment situation, due to the zero of the generation of temperature variation for working electrode Point drift is equal to the null offset that auxiliary electrode is produced, and unique difference is that working electrode reacts output and gas with object gas The electric current that concentration is directly proportional, and auxiliary electrode does not reach gas so signal is constant.Even if so zero point is with respect to school during detection Drift is generated on time, current null offset i.e. auxiliary electrode signal need to be only subtracted from working electrode signal just can obtain compensation Effective current signal after null offset, then the noiselike signal modulate circuit of matching design is converted into voltage signal, in system The influence that sensor zero point random drift just can be completely deducted during with measurement is demarcated, this zero compensation is big for high precision test The NO of ppb magnitudes in gas₂It is necessary；Using 32 floating type 28335DSP as main control chip, instruction cycle weakness reason speed Degree is fast, and complete A/D conversions based on 12 ADC resources of chip internal, it is to avoid the noise jamming of external change-over circuit, once turns Changing only needs 80ns；Changed come real-time display density as host computer using LabVIEW2015 platforms, the platform is provided easily schemes Shape programmed environment, can realize data acquisition, analysis, display and storage, and man-machine interaction is excellent, for the result of detection system Displaying has very big advantage, and the utility model compares tradition NO₂Detecting system is more succinct, small-sized, portable, can realize Ppb magnitudes are to NO in air₂The high resolution measurement of concentration.

Brief description of the drawings

Fig. 1 is the general frame of the present utility model；

Fig. 2 is noiselike signal modulate circuit figure of the present utility model.

Specific embodiment

The utility model is described in detail below in conjunction with the accompanying drawings：

As shown in figure 1, a kind of air NO based on electrochemical sensor₂Detection system, including sensor assembly, data are adopted Collection and processing module, man-machine interaction visualization model, wherein sensor assembly are connected with data acquisition and procession module, and data are adopted Collection is connected with processing module with man-machine interaction visualization model；The sensor assembly is using Alphasense companies of Britain NO₂The electrode electrochemical sensor of-B43F models four, comprising working electrode, to electrode, reference electrode and auxiliary electrode totally four electricity Pole, the NO in air₂Diffuse into sensor internal and reduction reaction, working electrode output and NO occur in working electrode₂Concentration The nA magnitude current signals being directly proportional, auxiliary electrode has identical nA magnitudes zero current with working electrode, but auxiliary electrode is contacted Less than NO₂Extracurrent will not be produced, institute is used to complete current loop for compensation working electrode zero current to electrode, Reference electrode is used to ensure working electrode, auxiliary electrode constant potential；Temperature Humidity Sensor uses resolution ratio to lead to for 16, monobus The DHT22 digital hygro sensors of letter mode, are used to obtain ambient temperature information and humidity information；The data acquisition and place While noiselike signal modulate circuit ensures electrochemical sensor normal work in reason module, to electrochemical sensor output Current signal carries out electric current-voltage conversion, plus and blowup and filtering；DSP main control units use 32 floating types of TI companies TMS320F28335 is main control chip, and noiselike signal modulate circuit two-way is exported using the chip internal ADC of 12 A/D conversions are carried out respectively obtains mV magnitudes working electrode and auxiliary electrode magnitude of voltage, and according to auxiliary electrode magnitude of voltage and warm and humid Degree sensor output signal is compensated by amendment to working electrode voltage value；The man-machine interaction visualization model is based on LabVIEW2015 platforms come to NO₂Concentration shows that it is communicated by RS485 serial ports with DSP main control units in real time, Working electrode voltage data inversion after the compensation that LabVIEW2015 platforms are received to serial ports obtains ppb magnitudes NO in air₂ Concentration value, recycles platform interior numerical value display control and waveform display control real-time display density value and to describe in main interface Go out NO₂Concentration real-time change curve, at the same with warning concentration value contrast, more than then starting sound and light alarm.

As shown in Fig. 2 on the one hand noiselike signal modulate circuit ensures electrochemical sensor normal work, on the one hand to work Make electrode carries out electric current-voltage conversion, plus and blowup and filtering respectively with auxiliary electrode output current；U1 represents electrochemistry Sensor, it is control circuit to be connected circuit with reference electrode to electrode, and wherein operational amplifier U2A possesses ultralow using single channel The AD8551 of noise zero shift, single supply 5V power such as U2B in figure, and working electrode is just the same with auxiliary electrode institute connection circuit, Per 2 operational amplifiers totally 4 are all placed all the way, U3A, U3B, U3C, U3D are on figure, therefore possess ultralow using four-way The LT6012 of noise and long-time stability, single supply 5V power such as U3E in figure, the number designation in circuit around operational amplifier Represent device pin；By working electrode all the way as a example by, previous operational amplifier rise across resistance amplification, convert the current into electricity Pressure, latter is played differential amplification, suppression circuit itself null offset and constant gain, while after output voltage is adjusted to Within the permission input voltage range of continuous DSP main control unit ADCs, this circuit final output two-way mV magnitude analog voltages.

Claims (4)

1. a kind of air NO based on electrochemical sensor₂Detection system, it is characterised in that：The system include sensor assembly, Data acquisition and procession module, man-machine interaction visualization model；The sensor assembly includes NO₂Four electrode electro Chemicals are sensed Device, Temperature Humidity Sensor, 2 sensor signal outputs to data acquisition and procession module；The data acquisition and procession module Including noiselike signal modulate circuit, DSP main control units, noiselike signal modulate circuit and NO₂Four electrode electrochemical sensors Connection, DSP main control units are connected with noiselike signal modulate circuit, Temperature Humidity Sensor respectively；The man-machine interaction visualization Module includes LabVIEW2015 platforms, sound and light alarm module, and LabVIEW2015 platforms are by RS485 serial ports and DSP master control lists Unit's connection, sound and light alarm module is connected with LabVIEW2015 platforms.

2. a kind of air NO based on electrochemical sensor according to claim 1₂Detection system, it is characterised in that：It is described Sensor assembly uses the NO of Alphasense companies of Britain₂The electrode electrochemical sensor of-B43F models four, comprising work electricity Pole, to electrode, reference electrode and auxiliary electrode totally four electrodes, the NO in air₂Diffuse into sensor internal and in work There is reduction reaction, working electrode output and NO in electrode₂The nA magnitude current signals that concentration is directly proportional, auxiliary electrode and work electricity There is identical nA magnitudes zero current pole, but auxiliary electrode does not reach NO₂Extracurrent will not be produced, institute is for compensation work Electrode zero current, is used to complete current loop to electrode, and reference electrode is used to ensure working electrode, auxiliary electrode constant potential； It is 16, the DHT22 digital hygro sensors of monobus communication mode that Temperature Humidity Sensor uses resolution ratio, is used to obtain ring Border temperature information and humidity information.

3. a kind of air NO based on electrochemical sensor according to claim 1₂Detection system, it is characterised in that：It is described While noiselike signal modulate circuit ensures electrochemical sensor normal work in data acquisition and procession module, to electrochemistry The current signal of sensor output carries out electric current-voltage conversion, plus and blowup and filtering；DSP main control units use TI companies 32 floating type TMS320F28335 are main control chip, and electricity is nursed one's health to noiselike signal using the chip internal ADC of 12 Road two-way output carries out the working electrode and auxiliary electrode magnitude of voltage that A/D conversions obtain mV magnitudes respectively, and according to auxiliary electrode Magnitude of voltage and Temperature Humidity Sensor output signal are compensated by amendment to working electrode voltage value.

4. a kind of air NO based on electrochemical sensor according to claim 1₂Detection system, it is characterised in that：It is described Man-machine interaction visualization model is based on LabVIEW2015 platforms come to NO₂Concentration shows that it passes through RS485 serial ports and DSP in real time Main control unit is communicated, and the working electrode voltage data inversion after the compensation that LabVIEW2015 platforms are received to serial ports is obtained greatly Ppb magnitudes NO in gas₂Concentration value, recycles platform interior numerical value display control to show in real time in main interface with waveform display control Show concentration value and depict NO₂Concentration real-time change curve, at the same with warning concentration value contrast, more than then starting sound and light alarm.