CN205484165U - Can carry out natural gas concentration detection appearance of monitoring to measuring result validity - Google Patents

Abstract

The utility model discloses a can carry out natural gas concentration detection appearance of monitoring to measuring result validity, including singlechip, humiture measured module and natural gas concentration detection sensor, is natural gas concentration detection sensor MQ 4 gas sensor, humiture measured module mainly comprise the SHT2X chip, natural gas concentration detection sensor 's analog signal output end with analog -to -digital conversion module's analog signal input is connected, the serial data end SDA of SHT2X chip is connected with the input -output ports of singlechip through first resistance R1, and the serial clock end SCL of SHT2X chip is connected with the input -output ports of singlechip through second resistance R2. The utility model has the advantages of temperature and humidity to the measuring ring border is monitored to accurate judgement measuring result validity.

Description

A kind of concentration of natural gas detector measurement result effectiveness being monitored

Technical field

This utility model relates to a kind of concentration of natural gas detector, a kind of can be to detection environment Humiture is monitored thus the effectiveness of concentration of natural gas measurement result realizes the detector judged, belongs to In Test and control field.

Background technology

Natural gas has been used widely as a kind of clean energy resource, but natural gas is in use There is also blast that some potential safety hazards, particularly natural gas leaking cause with fire in various security incidents In seem especially prominent.Therefore the detection of concentration of natural gas has demand widely at domestic and industrial circle.

The most widely used detection of natural gas sensor has a lot, and wherein MQ-4 gas sensor is normal The one seen, MQ-4 gas sensor have natural gas is had preferable sensitivity, functional reliability high, Service life length, response recover the feature such as quickly.But the measurement effectiveness of MQ-4 gas sensor with The temperature and humidity measuring environment is relevant, and the temperature and humidity of measurement environment exceedes certain limit and then measures knot Fruit is null result.But using MQ-4 gas sensor in prior art is that detection sensor realizes Concentration of natural gas measuring instrument can only rely on user subjectivity to judge roughly in use, and temperature and humidity is The no SC service ceiling exceeding sensor, therefore exists and can not be monitored the temperature and humidity measuring environment, Thus accurately judge the defect of measurement result effectiveness.

Additionally, MQ-4 gas sensor also has two-way detectable concentration signal output characteristic (analog output Export with Transistor-Transistor Logic level), wherein the detection sensitivity of Transistor-Transistor Logic level outfan can pass through a manual tune Whole potentiometer is adjusted: regulation sensitivity is increased clockwise, regulates sensitivity decrease counterclockwise.Cause Using MQ-4 gas sensor in this prior art is the concentration of natural gas measuring instrument that detection sensor realizes There is also following defect: manually adjust potentiometer realize sensitivity adjustment cause sensitivity adjustment randomness big, Accuracy is poor, it is impossible to realizes digitized and adjusts.

Utility model content

For deficiencies of the prior art, the purpose of this utility model is how to provide a kind of energy right The temperature and humidity measuring environment is monitored, thus accurately judges that the natural gas of measurement result effectiveness is dense Degree detector.

To achieve these goals, this utility model have employed following technical scheme.

A kind of concentration of natural gas detector measurement result effectiveness being monitored, it is characterised in that: Sensor is detected including single-chip microcomputer, temperature and humidity measurement module and concentration of natural gas；

Described concentration of natural gas detection sensor is MQ-4 gas sensor, and described concentration of natural gas detects Sensor has analog signal output；

Described temperature and humidity measurement module is mainly made up of SHT2X chip；

Described single-chip microcomputer is internally provided with analog-to-digital conversion module；

The analog signal output of described concentration of natural gas detection sensor and the mould of described analog-to-digital conversion module Intend signal input part to be connected；

The serial data end SDA of described SHT2X chip is defeated with the input of single-chip microcomputer by the first resistance R1 Outlet is connected, and the serial clock terminal SCL of described SHT2X chip passes through the second resistance R2 and single-chip microcomputer Input/output port be connected, the power end VCC of described SHT2X chip pass through the 3rd resistance R3 and list The input/output port of sheet machine is connected.

Further, a kind of concentration of natural gas detector being monitored measurement result effectiveness also wraps Including operational amplifier and electronic potentiometer, the negative input end of described operational amplifier detects with concentration of natural gas The analog signal output of sensor is connected；

The hot end of described electronic potentiometer is connected with power vd D, the cold end of electronic potentiometer Ground connection, the sliding end of electronic potentiometer is connected with the positive input terminal of described operational amplifier, electronic potential The controlled end of device is connected with the delivery outlet of single-chip microcomputer, the positive input terminal of described operational amplifier also with single-chip microcomputer Input port be connected；

The outfan of described operational amplifier is connected with the input port of single-chip microcomputer.

Further, described single-chip microcomputer uses MSP430G2553 chip, and described electronic potentiometer uses X9313 chip.

Compared to existing technology, this utility model has the advantage that

(1) using SHT2X chip in this utility model is that acp chip is simultaneously achieved temperature and humidity (SHT2X chip is a new generation of Sensirion company high-accuracy temperature-humidity sensing in the measurement of two kinds of ambient parameters Device, have that precision is high, low in energy consumption, degree of stability is good, the feature of the little and digital output of volume), the most natural Gas concentration measuring apparatus can be accurately on by measuring the concentration of natural gas measurement result that ambient temperature and humidity is affected Effectiveness is monitored, thus avoids the measurement error that user subjective judgment ambient temperature and humidity is brought With mistake.Additionally, this utility model be only additionally arranged a piece of chip i.e. achieve the detection of humiture parameter with The most independent temperature sensor module that would generally use in prior art and moisture sensor module phase Ratio, this utility model has that circuit structure is simple, with low cost, debug easy advantage.

(2) this utility model is additionally arranged sensitivity adjustment function, and electronic potentiometer is arranged to " pressure regulator ", Measuring sensitivity and can realize regulation by electronic potentiometer, the sliding end current potential of electronic potentiometer is low then Measure highly sensitive, that is to say that less concentration of natural gas detection sensor analog signals output end signal is (right Should relatively low concentration of natural gas) also result in operational amplifier output low level, on the contrary the slip of potentiometer It is low that terminal potential height then measures sensitivity, and because the sliding end current potential of electronic potentiometer is by controlling it Controlled end signal realizes what digitized adjusted, so sensitivity adjustment of the present utility model the most just can realize Digitized, accuracy is strong, reliability is high in adjustment.In addition the positive input terminal of operational amplifier also with single-chip microcomputer Input port be connected, therefore single-chip microcomputer can by internal analog-to-digital conversion module by operational amplifier just Input terminal voltage is converted to digital quantity, thus calculates magnitude of voltage, and this magnitude of voltage can be in LCDs Upper display, this makes sensitivity adjustment be achieved visualization and further precision.

Accompanying drawing explanation

Fig. 1 is circuit structure diagram of the present utility model；

Fig. 2 is the concentration of natural gas measuring instrument circuit structure diagram set up and measure sensitivity adjustment function；

Detailed description of the invention

With detailed description of the invention, this utility model is described in further detail below in conjunction with the accompanying drawings.

One, circuit structure

As it is shown in figure 1, a kind of concentration of natural gas detector measurement result effectiveness being monitored, Sensor is detected including single-chip microcomputer, temperature and humidity measurement module and concentration of natural gas.

Concentration of natural gas detection sensor uses MQ-4 gas sensor.It is right that MQ-4 gas sensor has Natural gas has preferable sensitivity and functional reliability height, length in service life, response recovery quickly. MQ-4 gas sensor is by 5V DC-voltage supply, and it has an analog signal output, this simulation Signal output part output 0-5V voltage, the highest then this signal voltage of sensor local environment concentration of natural gas is more High.This outer sensor also has Transistor-Transistor Logic level outfan, and the detection sensitivity of this outfan can be by one The potentiometer only manually adjusted is adjusted: regulation sensitivity is increased clockwise, regulates sensitivity counterclockwise Reducing, do not use this Transistor-Transistor Logic level outfan in this utility model, here is omitted.

Single-chip microcomputer uses common single-chip microcomputer to get final product (such as MSP430G2553 chip).

Temperature and humidity measurement module uses SHT2X chip, and it has subminiature volume, is particularly suitable for mobile Measurement equipment.The output of SHT2X chip, through the digital signal demarcated, is the I2C bus format of standard, Its incorporated amplifier, A/D converter, internal storage location and digital processing element, can detect simultaneously temperature and Humidity.Additionally, the resolution of SHT2X chip can be changed by input order, SHT2X chip Battery low-electricity quantity state can be detected, have the energy saver mode of extremely low power dissipation that there is the steady in a long-term of excellence Property.

Physical circuit annexation is: in order to realize concentration of natural gas detection sensor output signal collection, The analog signal output of concentration of natural gas detection sensor and the analog digital conversion mould being arranged within single-chip microcomputer The input end of analog signal of block is connected.

In order to realize the temperature and humidity measurement following circuit connecting relation of employing: the serial data end of SHT2X chip SDA is connected with the IO of single-chip microcomputer by the first resistance R1, the serial clock terminal SCL of SHT2X chip Being connected with the IO of single-chip microcomputer by the second resistance R2, the power end VCC of SHT2X chip is by the Three resistance R3 are connected with the IO of single-chip microcomputer.The power end VCC and earth terminal GND of SHT2X chip Between be provided with the first electric capacity C1.SHT2X uses the I2C bus protocol of standard to communicate, wherein, First resistance R1 and the second resistance R2 is the pull-up resistor of serial data line and serial time clock line.SHT2X Single-chip microcomputer IO, by the IO of the 3rd resistance R3 with single-chip microcomputer, is set to by force by the power end VCC of chip Recommending, single-chip microcomputer output electric current is up to 20mA, and the maximum operating currenbt of SHT2X is 330uA, IO High level voltage is about 3V, and this is the recommended work voltage of SHT2X, therefore from supply voltage and power supply electricity Flow two aspect analyses, be provided that the controllable electric power powered for SHT2X, and energy with single-chip microcomputer pin The quiescent current of SHT2X is reduced to 0.Additionally, SHT2X is a kind of mixed-signal IC, need low Noise is powered, and by the pin powered of single-chip microcomputer, is easily affected by the digital noise of microcontroller power supply, because of This, will add a RC wave filter in the energization pins of single-chip microcomputer, as it is shown in figure 1, the 3rd resistance R3 and First electric capacity C1 constitutes a RC wave filter.

This utility model is also additionally arranged measurement sensitive digitalization and adjusts function, and interlock circuit structure is as follows: As in figure 2 it is shown, circuit sets up electronic potentiometer and operational amplifier two chip block.Wherein electronic potentiometer is adopted Using X9313 chip, this electronic potentiometer has following pin: " increase input pin", " lifting input Pin", " hot end VH ", " cold end VL ", " hold VSS ", " sliding end VW " and " chip select input end", wherein " increase input pin", " lifting input pin" and " sheet Select input" it is the controlled end of electronic potentiometer.The negative input end of operational amplifier and concentration of natural gas The analog signal output of detection sensor is connected；The hot end of electronic potentiometer and power supply VCC phase Connecting, the cold end ground connection of electronic potentiometer, the sliding end of electronic potentiometer is with operational amplifier just Input is connected, and the controlled end of electronic potentiometer is connected with the delivery outlet of single-chip microcomputer, and operational amplifier is just Input is also connected with the input port of single-chip microcomputer；The outfan of operational amplifier and the input port of single-chip microcomputer It is connected.

Two, circuit operation principle

(1) what measurement result effectiveness was monitored realizes principle

In this utility model, SHT2X chip uses the I2C bus protocol of standard to communicate, SHT2X The temperature and humidity data that chip measurement obtains are entered by the incoming single-chip microcomputer of I2C bus the most in digital form Row processes the temperature and humidity data obtaining reality, on usual SDA data wire latter two (usually the 43 and 44 are used for transmitting relevant status information, and the 43rd represents the type measured, and " 0 " represents survey Amount temperature, " 1 " represents measurement humidity).

Finally, SHT2X chip serial data end SDA output data can obtain after set formula is changed Actual temperature and humidity data are the most permissible for example with formula T=-46.85+175.72 × (ST/216) Directly calculating the temperature of reality, wherein ST is that SHT2X chip is exported by serial data end SDA Relative temperature data.

Single-chip microcomputer measures the humiture data of environment by continual collection, and by itself and MQ-4 gas The use temperature of body sensor and use humidity bound numerical value compare can be accurately to by measurement ring The concentration of natural gas measurement result effectiveness that environmental temperature and humidity is affected is monitored.(MQ-4 gas sensor Use temperature range be :-10 DEG C～50 DEG C；RH range is: less than 95%Rh, above ginseng Number is the nominal parameters of these gas sensor sensor operation instructions).

The digitized of this external pelivimetry sensitivity adjusts and is achieved in that connecting and composing of electronic potentiometer One regulating circuit, the outfan of regulating circuit is the sliding end VW of electronic potentiometer, due to electronics electricity The hot end of position device is connected with power supply VCC, the cold end ground connection of electronic potentiometer, therefore electronics The sliding end VW voltage of potentiometer can change between supply voltage (5V) and ground voltage (0V), adjusts Joint precision is determined by the tap number of selected electronic potentiometer, and this utility model detailed description of the invention is illustrated X9313 chip degree of regulation is that 0.6V (can also select the electronic potential that other degree of regulation voltages are less Device chip, electronic potentiometer model is a lot, and differ a citing here).

During specific works, increase input pinTriggered by trailing edge, the trailing edge that this pin occurs The direction that sliding end VW is increased or decreased towards internal counter is moved, lifts input pinOn Logic level control the direction that electronic potentiometer sliding end VW moves；Increase input pinWith Lifting input pinSignal provided by single-chip microcomputer, thus realize the sliding end VW of electronic potentiometer Voltage continuously adjusts between 5V and 0V.

Operation principle based on above electronic potentiometer, concentration of natural gas detection sensor output signal (my god So gas concentration is the highest, and this signal voltage is the biggest) being able to can the voltage (electronics of digitized change with one The sliding end VW voltage of potentiometer) compare, when the output signal of natural gas concentration detection sensor When voltage is less than the sliding end voltage of electronic potentiometer, operational amplifier output terminal output high level, otherwise Output low level, and single-chip microcomputer can be sentenced by the low and high level of detection calculations amplifier out signal Whether disconnected concentration of natural gas exceeds standard (detecting that output low level then exceeds standard), measurement the most of the present utility model Sensitivity can realize regulation by electronic potentiometer, and the sliding end current potential of electronic potentiometer is low, measures Highly sensitive, that is to say that less concentration of natural gas detection sensor analog signals output end signal is (corresponding Relatively low concentration of natural gas) also result in operational amplifier output low level, on the contrary the sliding end of potentiometer It is low that current potential height then measures sensitivity, and because the sliding end current potential of electronic potentiometer is to be subject to by controlling it Control end signal realizes what digitized adjusted, so sensitivity adjustment of the present utility model the most just can realize number Word, accuracy is strong, reliability is high in adjustment.It should be noted that computing is put during above-mentioned adjustment Big device constitutes a voltage comparison module, the ginseng that sliding end voltage is voltage comparison module of electronic potentiometer Examine current potential.

In addition the positive input terminal of operational amplifier is also connected with the input port of single-chip microcomputer, and therefore single-chip microcomputer can The positive input terminal voltage of operational amplifier is converted to digital quantity by internal analog-to-digital conversion module, thus Calculating magnitude of voltage, this magnitude of voltage can be in liquid crystal display screen display, and this makes sensitivity adjustment be able to Realize visualization and further precision.Single-chip microcomputer can also be sent by the host computer being attached thereto Control parameter and realize the adjustment of regulating circuit output voltage, or defeated with single-chip microcomputer by two as shown in Figure 2 The button that entrance is connected carrys out the adjustment of real regulating circuit output voltage, and (single-chip microcomputer receives the electricity that button produces By sending the sliding end VW of control signal control electronic potentiometer to the controlled end of electronic potentiometer after Ping Voltage, exists between number of times and the sliding end controlled value of VW voltage of potentiometer that certain button is pressed One corresponding relation).

Finally illustrate, above example only in order to the technical solution of the utility model to be described and unrestricted, Although this utility model being described in detail with reference to preferred embodiment, those of ordinary skill in the art Should be appreciated that and the technical solution of the utility model can be modified or equivalent, without deviating from The objective of technical solutions of the utility model and scope, it all should be contained at claim model of the present utility model In the middle of enclosing.

Claims (3)

1. concentration of natural gas detector measurement result effectiveness being monitored, it is characterised in that: Sensor is detected including single-chip microcomputer, temperature and humidity measurement module and concentration of natural gas；

Described concentration of natural gas detection sensor is MQ-4 gas sensor, and described concentration of natural gas detects Sensor has analog signal output；

Described temperature and humidity measurement module is mainly made up of SHT2X chip；

Described single-chip microcomputer is internally provided with analog-to-digital conversion module；

The analog signal output of described concentration of natural gas detection sensor and the mould of described analog-to-digital conversion module Intend signal input part to be connected；

The serial data end SDA of described SHT2X chip is defeated with the input of single-chip microcomputer by the first resistance R1 Outlet is connected, and the serial clock terminal SCL of described SHT2X chip passes through the second resistance R2 and single-chip microcomputer Input/output port be connected, the power end VCC of described SHT2X chip pass through the 3rd resistance R3 and list The input/output port of sheet machine is connected.

A kind of natural gas being monitored measurement result effectiveness the most according to claim 1 is dense Degree detector, it is characterised in that also include operational amplifier and electronic potentiometer, described operational amplifier The analog signal output of negative input end and concentration of natural gas detection sensor be connected；

The hot end of described electronic potentiometer is connected with power vd D, the cold end of electronic potentiometer Ground connection, the sliding end of electronic potentiometer is connected with the positive input terminal of described operational amplifier, electronic potential The controlled end of device is connected with the delivery outlet of single-chip microcomputer, the positive input terminal of described operational amplifier also with single-chip microcomputer Input port be connected；

The outfan of described operational amplifier is connected with the input port of single-chip microcomputer.

A kind of natural gas being monitored measurement result effectiveness the most according to claim 2 is dense Degree detector, it is characterised in that described single-chip microcomputer uses MSP430G2553 chip, described electronic potential Device uses X9313 chip.