CN206114027U - Wide range gas flow measuring circuit of low -power consumption self -diagnosis - Google Patents

Abstract

The utility model discloses a wide range gas flow measuring circuit of low -power consumption self -diagnosis. The utility model discloses a rotation that large -traffic adoption wei root sensor detected the waist wheel produces the pulse and calculates accumulation flow. Four platinum resistors's bridge circuit is adopted in the measurement of low discharge, through the change of the calculating the bridge medium voltage gaseous flow that converts. The temperature and the pressure that obtain the pipeline through temperature, pressure sensor compensate measured data, reach mark condition flow. Body group part influence of being bullied during owing to the gaseous low discharge of adoption platinum resistance measurement is great, can revise on line platinum resistance flow measurement's result at the overlapping measuring range of two kinds of measuring circuits according to the measuring result of wei root sensor, improves gaseous little flow measurement's precision to the flow measurement range of circuit has been enlarged. Through element for low power consumption design measuring circuit to control the power supply of different modules, selectively open the power with closing module, reduced the consumption of whole circuit.

Description

A kind of wide range gas flow measurement circuit of low-power consumption self diagnosis

Technical field

This utility model belongs to detection of gas flow rate technical field, is related to a kind of wide range gas stream of low-power consumption self diagnosis Measurement circuit.

Background technology

Current industrial application, the effusion meter of wide range mainly has thermal flowmeter, and it mainly inserts two in pipeline Individual probe a, temperature for being used for measuring gas, the speed for being used for measuring gas flows through speed probe by measuring gas There is heat exchange in Shi Yuqi, the heat that speed probe the loses principle equal with the electrical power that circuit is provided can calculate outlet Body flow.Although thermal flowmeter has wider measurement range, thermal flow rate sensor is easily by gas composition medium Affect, change greatly, cause certainty of measurement to reduce, have some limitations.Roots type flowmeter is also called rotz flowmeter, category In volumetric flowmeter, critical role is seized of in gas flow measurement, measuring principle mainly connects fluid by measuring room Continuous to be divided into single known volume size, repeatedly cummulative metering fluid inside carries out flow measurement.With other types of flow Meter compares, reproducible although Roots type flowmeter measuring accuracy is high, and measurement range is little, and power consumption is big, is particularly susceptible to miscellaneous The impact of matter, causes certainty of measurement to reduce or even can not work.

The content of the invention

This utility model is directed to the deficiencies in the prior art, there is provided a kind of wide range gas flow of low-power consumption self diagnosis is surveyed Amount circuit.

This utility model solves the technical scheme taken of technical problem：

This utility model when big flow is measured, using Wiegand sensor；In Small flowrate measurement, using platinum resistance electricity Bridge；Wiegand sensor and platinum resistance electric bridge are transmitted to single-chip microcomputer Jing after respective signal processing circuit；Wherein Wiegand sensor is put The outer wall in pipeline is put, for detecting the rotation of two waist wheels, platinum resistance electric bridge is arranged on the geometric center of pipeline, for measuring The flow of small-flow gas, in gas flow direction, platinum resistance electric bridge is arranged on the segment distance before Wiegand sensor；The survey Amount circuit also includes temperature measuring circuit module and pressure measurement circuitry module, and the temperature wherein in temperature measuring circuit module is passed Sensor is arranged on the pipeline of the latter segment distance of Wiegand sensor；Pressure transducer in pressure measurement circuitry module is arranged on In the middle of platinum resistance electric bridge and Wiegand sensor on the pipeline of a segment distance.

Furtherly, magnet steel is installed, the rotation of waist wheel drives the rotation of magnet steel on one of waist wheel；As magnet steel Jing When crossing the tube wall equipped with Wiegand sensor, Wiegand sensor detection magnet steel rotates and exports pulse, is calculated by umber of pulse and is accumulated Flow.

Furtherly, the signal processing circuit of Wiegand sensor includes amplifying circuit and shaping circuit.

Furtherly, the signal processing circuit of platinum resistance electric bridge includes amplifying circuit, filter circuit and A/D convertor circuit.

Furtherly, temperature sensor adopts platinum resistance PT1000.

Furtherly, pressure transducer adopts piezoresistive silicon sensor.

Furtherly, the LCD display module being connected with single-chip microcomputer is also included.

The beneficial effects of the utility model are：The gas flow measurement circuit of this utility model design, is passed using Wiegand Sensor measures two waist wheels and rotates the measurement for realizing gas big flow, and the certainty of measurement of the method is affected little by gas composition. Due to being affected larger by gas composition when measuring gas low discharge using platinum resistance, can be according to the measurement result pair of Wiegand sensor The result of platinum resistance flow measurement carries out on-line amending, improves the precision of gas Small flowrate measurement, and expands whole circuit Measurement range.Meanwhile, can judge whether waist wheel rotates according to the measurement result of platinum resistance, realize the self diagnosis work(of measuring instrumentss Energy.The power supply of disparate modules circuit is controlled by circuit, the power supply of power supply is reduced, the purpose of power consumption is reduced.

Description of the drawings

Fig. 1 is the sensor scheme of installation of flow measurement circuit；

Fig. 2 is systematic survey schematic block circuit diagram；

Fig. 3 is the signal processing circuit figure of Wiegand sensor；

Fig. 4 is platinum resistance bridge circuit and amplification circuit diagram；

Fig. 5 is the two stage filter circuit diagram of platinum resistance measurement signal；

Fig. 6 is temperature, pressure detection circuit connection diagram；

Fig. 7 is A/D module circuit connection diagram；

Fig. 8 is low-power scm minimum system and each module connection circuit diagram.

Specific embodiment

This utility model is further illustrated below in conjunction with accompanying drawing.

With reference to the sensor scheme of installation of the flow measurement circuit of Fig. 1, Wiegand sensor is placed on the outer wall of pipeline, uses In the rotation for detecting two waist wheels, magnet steel is installed on one of waist wheel, platinum resistance electric bridge is arranged on the several of measurement pipeline What center, for measuring the flow of small-flow gas.In gas flow direction, platinum resistance electric bridge is arranged on before Wiegand sensor A segment distance, pressure transducer is arranged on the segment pipe in the middle of platinum resistance and Wiegand sensor, temperature sensor installation On the pipeline of the latter segment distance of Wiegand sensor.

Under normal operation, when big flow is measured, gas impact waist wheel is rotated, and the rotation of waist wheel drives turning for magnet steel It is dynamic.When magnet steel is through the tube wall equipped with Wiegand sensor, Wiegand sensor detection magnet steel rotates and exports pulse, by pulse Number calculates integrated flux.During low discharge, the power of test of waist wheel declines, and by platinum resistance electric bridge rill can be timely calculated The gas volume of amount, expands the measurement range of whole circuit.Meanwhile, pressure, the temperature sensor information of pipeline are gathered, work Gas flow volume under condition is converted into the volumetric flow of gas under mark condition.Gas is received when measuring gas low discharge due to platinum resistance Component affects larger, can be electric to platinum resistance in the overlap measurement range of two kinds of measuring circuits according to the measurement result of Wiegand sensor The flow results of bridge measurement carry out on-line amending, and correcting data can pass through the instantaneous delivery ratio calculation that two kinds of measuring circuits are obtained Obtain.

With reference to Fig. 2, measuring circuit system principle diagram of the present utility model is as shown in Figure 2.Whole control system is mainly wrapped Include one-chip computer module, platinum resistance electric bridge, Wiegand sensor, amplifying circuit, shaping circuit, filter circuit, A/D module, temperature sensing Device, pressure transducer, LCD display module.The pulse signal of Wiegand sensor output is through amplifying, shaping circuit, directly conveys To single-chip microcomputer.The voltage signal of platinum resistance electric bridge output is through amplifying, filter circuit, is then converted into numeral by A/D module Amount, is input to single-chip microcomputer.Temperature sensor adopts platinum resistance PT1000, and by circuit the voltage at PT1000 two ends is gathered, adopting The voltage signal of collection is converted into digital quantity and is input on single-chip microcomputer by A/D module；Pressure transducer is sensed using silicon piezoresistance type Device, by the pressure signal of collection one-chip computer module is directly defeated by；Single-chip microcomputer passes through the signal for collecting and processes, by LCD liquid Brilliant displays temperature, pressure and correlative flow information.

Fig. 3 is the signal processing circuit module 1 of Wiegand sensor.Wiegand sensor adopts WG102, chip U10 to select 74LVC2G17, audion selects 9013.The interface 1 of Wiegand sensor and one end of resistance R10, one end of electric capacity C10 connects； The interface 2 of Wiegand sensor and the other end of resistance R10, one end of resistance R11, the emitter stage of audion T10, electric capacity C11's One end connects, and is connected with digitally DGND；The other end of electric capacity C10 and the other end of resistance R11, the base stage of audion T10 Connection；The colelctor electrode of audion T10 and one end of resistance R12, the other end of electric capacity C11, the A1 ends connection of chip U10；Resistance The other end of R12 is connected with power supply 3V ends；The input A2 of the deferent segment Y1 and chip U10 of chip U10 is connected, chip U10's Deferent segment Y2 is connected with the pulse signal detection Pluse ends of single-chip microcomputer, and the GND ends of chip U10 are connected with digitally DGND.

Fig. 4 is platinum resistance bridge-type electricity circuit module 2 and amplification circuit module 3, and platinum resistance electric bridge adopts the platinum of four PT100 Resistance, accesses Huygens's bridge circuit, and operation amplifier chip selects AD8651.Wherein one end of platinum resistance PT1 and platinum resistance PT2 One end, the 3V ends connection of power supply, the other end of platinum resistance PT1 is connected with one end of one end of platinum resistance PT3, resistance R24；Platinum The other end of resistance PT2 is connected with one end of one end of platinum resistance PT4, resistance R25；The other end and platinum resistance of platinum resistance PT3 One end connection of PT4, the digitally connection of DGND ends；The other end of resistance R24 and the "-" end of amplifier chip, one end of resistance R26 Connection；The other end of resistance R25 and the "+" end of amplifier chip, one end of resistance R27 connects；The other end of resistance R27 and numeral Ground DGND connections；The outfan of amplifier chip U20 is connected with the other end of R26, and the voltage of output accesses the two stage filter electricity of Fig. 5 Road 4.

Fig. 5 is the two stage filter circuit diagram of platinum resistance measurement signal, and amplifier U30, U31 adopts single precision arithmetic amplifier LM741.Collected after voltage signal U by Fig. 4, using Butterworth LPF and LM741 operation amplifier circuits, obtained To stable voltage signal.Butterworth filter can be such that the curve of the frequency response in the range of the logical flat rubber belting of its correspondence forces as far as possible It is near flat, and curve there is no fluctuating, once in suppressed frequency band, it is zero that curve can be gradually reduced.Amplifying circuit is adopted With active load, designing the amplifying circuit of two-stage can reach higher voltage gain and wider common mode and difference-mode input electricity Pressure scope.And the circuit can also filter the noise signal outside frequency range.Specific circuit connection is as follows：

One end of resistance R30 is connected with the outfan of amplifier U20 of Fig. 4；The other end of resistance R30 and the one of resistance R31 End, one end connection of electric capacity C31；The other end of resistance R31 and one end of electric capacity C30, the "+" end of amplifier U30 connects；Electric capacity The other end of C30 is connected with digitally DGND；The "-" end of amplifier U30 is connected with one end of one end of resistance R32, resistance R33； The other end of resistance R32 is connected with digitally DGND；The outfan of amplifier U30 and the other end of electric capacity C31, resistance R33 it is another One end, one end connection of resistance R34.

The other end of resistance R34 is connected with one end of resistance R35, one end of electric capacity C33；The other end of resistance R35 and electricity Hold one end, the "+" end connection of amplifier U31 of C32；The other end of electric capacity C32 is connected with digitally DGND；The "-" end of amplifier U31 It is connected with one end of resistance R36, is connected with one end of resistance R37；The other end of resistance R36 is connected with digitally DGND；Amplifier The outfan of U31 is connected with the other end of electric capacity C33, the other end of resistance R37, and the voltage signal Vin for exporting and Fig. 6 The AIN1 ends connection of AD conversion chip.

Fig. 6 is the connection figure of AD system modules circuit 5.A/D chip U41 adopts the AD7714 chips of high accuracy 24, with reference to electricity The reference voltage of the high accuracy that pressure is provided using voltage chips AD780, it is 1MHz that A/D chip drives crystal oscillator X40.AD7714's Peripheral circuit is as follows:

The UDDA ends of U41 and the 3V ends of power supply, one end of electric capacity C42, one end of electric capacity C43, the UDD ends of U41, electric capacity One end connection of C44；The UDD ends of U41 and the 3V ends of power supply, one end of electric capacity C42, one end of electric capacity C43, the UDDA ends of U41, One end connection of electric capacity C44；The other end of electric capacity C42 is connected with simulation ground AGND；The other end of electric capacity C43 and simulation ground AGND Connection；The other end of electric capacity C44 is connected with digitally DGND.

The AIN1 ends of U41 are connected with the output voltage terminal of the U31 of Fig. 5；The AIN2 ends of U41 are connected with simulation ground AGND；U41 AGND ends with simulation ground AGND be connected；The DGND ends of U41 are connected with digitally DGND.

The UREFIN+ ends of U41 are connected with one end of the Uout ends of chip AD780, one end of electric capacity C40, electric capacity C41；U41 UREFIN- ends with simulation ground AGND be connected.U40 is AD780 chips, and the Uin ends of U40 are connected with power supply 3V；The GND ends of U40 It is connected with simulation ground AGND.The other end of electric capacity C40 is connected with simulation ground AGND；The other end of electric capacity C41 and simulation ground AGND Connection.

The BUF ends of U41 are connected with digitally DGND；The MCLKOUT ends of U41 are connected with one end of crystal oscillator X40；U41's MCLKIN ends are connected with the other end of crystal oscillator X40；The POL ends of U41 are connected with digitally DGND ends；

The STANDBY ends of U41 are connected with the RESET ends of the SYNC ends of U41, U41, and are connected with power supply 3V ends；U41's SYNC ends are connected with the STANDBY ends of U41, the RESET ends of U41, and are connected with power supply 3V ends；The RESET ends of U41 are with U41's SYNC ends, the STANDBY ends connection of U41, and be connected with power supply 3V ends；

The SCLK ends of U41 are connected with the MCLK ends of single-chip microcomputer；The DIN ends of U41 are connected with the P1.2 ends of single-chip microcomputer；U41's DOUT ends are connected with the P1.3 ends of single-chip microcomputer；The CS ends of U41 are connected with the P1.4 ends of single-chip microcomputer；The DRDY ends of U41 and single-chip microcomputer P1.5 ends connection.

Fig. 7 is that temperature, pressure detects circuit connection diagram.PT1000 is selected in temperature sensor in thermal module 6, accesses favour more This electric bridge, and current source supply is provided.One end of PT1000 is connected with one end of resistance R50, one end of current source；PT1000's The other end is connected with one end of resistance R51, the AIN4 ends of AD7714；The other end of resistance R51 and one end, the electric current of resistance R52 The other end connection in source；The other end of resistance R50 is connected with the other end of resistance R52, the AIN3 ends of AD7714.

Pressure transducer adopts the anode of the sensor of silicon piezoresistance type, pressure transducer to access power supply 3V in modular pressure 7 End, the negative terminal of pressure transducer accesses digitally DGND, and SDA ends and the SCL ends of pressure transducer directly connect with single-chip processor i/o mouth Connect.

Fig. 8 is low-power scm minimum system and each module connection circuit diagram.Low-power scm is selected MSP430F449 chips, power supply control chip selects TPS76930.The AVcc ends of single-chip microcomputer and DVcc ends, the one of tantalum electric capacity CD80 End, one end of electric capacity C81, one end connection of resistance R80, and be connected with power supply 3V.The other end of resistance R80 is with electric capacity C80's One end, the RST ends connection of single-chip microcomputer；The other end of electric capacity C80 is connected with digitally DGND.The XIN ends of single-chip microcomputer and crystal oscillator X80 One end, electric capacity C82 one end connection；The XOUT ends of single-chip microcomputer are connected with one end of the other end of crystal oscillator X80, electric capacity C83；Electricity The other end for holding C82 is connected with digitally DGND；The other end of electric capacity C83 is connected with digitally DGND.

Pressure transducer selects MS5637-30, and the signal of its SDA ends output is connected with the P2.2 of single-chip microcomputer, pressure sensing The signal of the SCL ends output of device is connected with the P2.3 of single-chip microcomputer；The leads ends corresponding with single-chip microcomputer liquid crystal of LCD display module 9 connect Connect；The pulse signal Pluse of Wiegand sensor output is connected to the P2.1 ends of single-chip microcomputer；Power supply control chip TPS76930's makes Energy end EN is connected with the P2.0 pins of single-chip microcomputer, and the power input IN and power supply 3V end of power supply control chip 8 is connected, chip The output end vo ut of TPS76930 and 3V ends, the 3V ends of amplification circuit module 3, the two stage filter of platinum resistance bridge circuit module 2 The 3V ends of circuit module 4, the 3V ends of thermal module 6, the 3V ends of A/D module 5, the 3V ends connection of modular pressure 7.

Circuit controls the Enable Pin of power supply control chip TPS76930, the different circuit modules of control by single-chip microcomputer P2.0 ends 3V on and off switch, reduce the power supply of power supply, reduce the purpose of power consumption.

To sum up, this practicality is newly converted into the flow of gas by the change of voltage in calculating bridge.By temperature, pressure Sensor obtains the temperature and pressure of pipeline and measurement data is compensated, and obtains bid condition flow.Due to being measured using platinum resistance Affected larger by gas composition during gas low discharge, can according to the measurement result of Wiegand sensor two kinds of measuring circuits overlap Measurement range carries out on-line amending to the result of platinum resistance flow measurement, the precision of gas Small flowrate measurement is improved, so as to expand The flow measurement range of circuit.By low-power consumption element designing measuring circuit, and the power supply of disparate modules is controlled, selected Property opening and closedown module power supply, reduce the power consumption of integrated circuit.

Claims (7)

1. the wide range gas flow measurement circuit of a kind of low-power consumption self diagnosis, it is characterised in that：The measuring circuit is in big flow During measurement, using Wiegand sensor；In Small flowrate measurement, using platinum resistance electric bridge；Wiegand sensor and platinum resistance electric bridge Jing Transmit to single-chip microcomputer after respective signal processing circuit；Wherein Wiegand sensor is placed on the outer wall of pipeline, for detecting two The rotation of waist wheel, platinum resistance electric bridge is arranged on the geometric center of pipeline, for measuring the flow of small-flow gas, in gas flowing On direction, platinum resistance electric bridge is arranged on the segment distance before Wiegand sensor；The measuring circuit also includes temperature measuring circuit mould Temperature sensor in block and pressure measurement circuitry module, wherein temperature measuring circuit module is arranged on the latter of Wiegand sensor On the pipeline of segment distance；Pressure transducer in pressure measurement circuitry module is arranged in the middle of platinum resistance electric bridge and Wiegand sensor On the pipeline of one segment distance.

2. the wide range gas flow measurement circuit of low-power consumption self diagnosis according to claim 1, it is characterised in that：Wherein A waist wheel on magnet steel is installed, the rotation of waist wheel drives the rotation of magnet steel；When magnet steel is through the pipe equipped with Wiegand sensor During wall, Wiegand sensor detection magnet steel rotates and exports pulse, and by umber of pulse integrated flux is calculated.

3. the wide range gas flow measurement circuit of low-power consumption self diagnosis according to claim 1, it is characterised in that：Wiegand The signal processing circuit of sensor includes amplifying circuit and shaping circuit.

4. the wide range gas flow measurement circuit of low-power consumption self diagnosis according to claim 1, it is characterised in that：Platinum electricity The signal processing circuit of conducting bridge includes amplifying circuit, filter circuit and A/D convertor circuit.

5. the wide range gas flow measurement circuit of low-power consumption self diagnosis according to claim 1, it is characterised in that：Temperature Sensor adopts platinum resistance PT1000.

6. the wide range gas flow measurement circuit of low-power consumption self diagnosis according to claim 1, it is characterised in that：Pressure Sensor adopts piezoresistive silicon sensor.

7. the wide range gas flow measurement circuit of low-power consumption self diagnosis according to any one of claim 1 to 6, it is special Levy and be：Also include the LCD display module being connected with single-chip microcomputer.