CN205843871U - Teletransmission digital pressure measurement apparatus - Google Patents
Teletransmission digital pressure measurement apparatus Download PDFInfo
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- CN205843871U CN205843871U CN201620181863.8U CN201620181863U CN205843871U CN 205843871 U CN205843871 U CN 205843871U CN 201620181863 U CN201620181863 U CN 201620181863U CN 205843871 U CN205843871 U CN 205843871U
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Abstract
A kind of teletransmission digital pressure measurement apparatus, the measurement pressure bowden pipe end being connected with tested pressure source is installed and measures an electrode plate in pressure capacitance device, constitute, with another block circuit board being fixed on measurement apparatus support, the measurement pressure capacitance device Cx associated by measuring pressure with outside, Cx determine that the agitator of frequency of oscillation will be converted to digitized frequency variation signal by the change of measuring pressure.Device of the present utility model passes through digital demodulation, it is thus achieved that the tested force value of digitized of pinpoint accuracy.This utility model simple in construction, low cost, in high precision, highly reliable, coordinate nonpolarity two-wire system two-way communication power supply integration Interface design, can be widely applied to pressure measxurement and need the occasion of distant place digital management.
Description
Technical field
A kind of teletransmission digital pressure measurement apparatus.
Background technology
Pressure measxurement is physical quantity very conventional in automation equipment, extensively should in particular with hydraulic test
With, pressure measxurement is increasingly extensive.Having pointer pressure known to pressure gauge, its precision is low, fragile, it is impossible to a distant place
Copy reading.There is special pressure transmitter can realize digitized to read, but cost is high, install complexity.
CN87207181U discloses one " capacitive distance-reading manometer " utility model, and ZL93225621.X provides one
Plant " distance-transmission pressure gauge ".These two kinds of utility models, outside original mechanical pressure gauge part, separately add one and are made up of moving plate, stator
The moving plate of capacitor, as electric pressure signal transducer, is arranged on Pressure gauge sector gear by air capacitor, and by stator
It is arranged on Pressure gauge clamping plate one air capacitor of formation, capacitance variations is transformed to current signal output.One of them is real
With the novel circuit diagram provided by utility model, voltage amplitude value V is definite value with frequency of oscillation by adjustment, it is intended to
Realize flowing through the electric current measuring pressure capacitance device Cx to be directly proportional to measuring pressure capacitance device Cx capacitance, and measure pressure capacitance device
Cx capacitance is directly proportional to by measuring pressure.This technical scheme at least has the disadvantage that
First, sectional wheel is installed air capacitor repacking task greatly, inconvenience is installed；
Second, one of them provides the utility model of current converter circuit to use an audion to carry out the line of secondary meter
Propertyization processes, and linearisation weak effect, certainty of measurement are low, poor stability；
3rd, measurement by capacitance, when not taking shielding measure, is easily affected by outside sensing, the precision of measurement, stably
Property can be impacted；
4th, in the way of electric current, export precision and the reliability affecting telemeasurement.
Utility model content
Problem to be solved in the utility model:
The purpose of this utility model be utility model a kind of be easily installed, digitized, can arrange in the distance and copy reading
, in high precision, the pressure gauge of high stability.
This utility model is achieved in that
(1) it is the elastic sensing element Bourdon tube (Bourdon tubes) measuring pressure, also known as bourdon tube (expansion tube)；
(2) be in Bourdon tube termination in fixation measuring pressure capacitance device the fixture of electrode plate A；(3) it is to measure pressure electricity
Container one electrode plate A；(4) it is to measure another electrode plate B in pressure capacitance device；Battery lead plate A (3) and battery lead plate B (4) has one
Fixed area, less parallel is placed, is not connected, constitute a capacity plate antenna；(5) it is main control circuit of the present utility model
Plate.Master control circuit board (5) is fixed on the support of teletransmission digital pressure measurement apparatus, and measures in pressure capacitance device another
One electrode plate B (4) is then fixed together with (5).When in Bourdon tube, measured pressure increases, Bourdon tube stretches laterally,
Measure electrode plate A (3) in pressure capacitance device and followed by Bourdon tube termination away from measuring another block in pressure capacitance device
The direction of battery lead plate B (4) is moved, and the condenser capacity being made up of battery lead plate A (3) and battery lead plate B (4) reduces.In Bourdon tube
When measured pressure reduces, Bourdon tube shrinks to inner side, measures electrode plate A (3) in pressure capacitance device and followed by Bourdon tube
Termination is moved, by battery lead plate A (3) and battery lead plate B towards the direction of another electrode plate B (4) in measurement pressure capacitance device
(4) condenser capacity constituted strengthens；(6) it is the support of pressure gauge；(7) it is the shell of pressure gauge.
Measuring pressure capacitance device Cx is the institute with measured pressure correlation being made up of battery lead plate A (3) and battery lead plate B (4)
State measurement pressure capacitance device；(8) it is RCx RC oscillator or LCx LC oscillator, wherein resistance R and inductance L
Value is fixing, and the capacitance measuring pressure capacitance device Cx determines frequency of oscillation；(9) it is oscillating circuit (8) outputting oscillation signal
Cycle or the measuring unit of frequency, wherein comprise measurement initial data cumulative mean process software, with eliminate measure during
Data jump, it is achieved the smooth output of raw measurement data；(10) it is measurement data linearisation demodulated methed processing unit.?
In the case of a lot, measure the measuring unit (9) of oscillator signal period, measurement data linearisation demodulated methed processing unit (10),
Storage and processing unit (11) are completed by same microprocessor (single-chip microcomputer).During measuring, the change of measured pressure is led
Causing Bourdon tube change in displacement, be made up of the electric capacitance change measuring pressure capacitance device Cx change in displacement, electric capacitance change causes shakes
Swing the frequency change of device, the frequency changed or Periodic measurements calculate and demodulate the digitized that can directly read by measuring pressure
Value.Changed the Bourdon tube change in displacement caused among these by measuring pressure, finally demodulate readable high-precision numerical pressure
Measured value needs to make linearisation demodulation process；(11) it is storage and processing unit；(12) it is communication interface and power supply offer circuit
Unit；(13) it is distant place management station, user carries out distant place management.
Storage and processing unit (11) at least to complete following task:
A, by tested for described digitized force value enter refresh storage, standby；
B, there is the teletransmission digital pressure measurement apparatus of locally displayed function will give this by the tested force value of described digitized
Ground display shows；
C, receive from the instruction of communication interface (12), and perform instruction；
D, arrange when needing, address information that energy storage is addressed by distant place management station.
Communication interface and power supply provide the main task of circuit unit (12) at least:
A, reception from the instruction of distant place management station (13) and are sent to storage and processing unit (11) by foreign channels；
B, storage and the information that sends of processing unit (11) are sent to distant place management station (13) by foreign channels；
C, obtain the working power required for described teletransmission digital pressure measurement apparatus by foreign channels.
The Bourdon tube (1) being connected with tested pressure source, when being increased by measuring pressure, the termination of Bourdon tube (1) is to overhanging
Exhibition, drives electrode plate A (3) in the measurement pressure capacitance device being fixed on termination another away from measuring in pressure capacitance device
The direction of one electrode plate B (4) is moved, the measurement pressure capacitance device Cx capacity being made up of battery lead plate A (3) and battery lead plate B (4)
Reduce.When in Bourdon tube, measured pressure reduces, Bourdon tube shrinks to inner side, measures electrode plate A in pressure capacitance device
(3) followed by Bourdon tube termination to move, by electrode towards the direction of another electrode plate B (4) in measurement pressure capacitance device
The measurement pressure capacitance device Cx capacity that plate A (3) and battery lead plate B (4) is constituted strengthens.Described measurement pressure capacitance device Cx capacity is with quilt
Pressure measurement dynamics and associate change, cause by measure pressure capacitance device Cx determine frequency of oscillation oscillating circuit (8) output signal
The association change in frequency or cycle.Tested pressure change amount causes the knots modification of Bourdon tube termination displacement, identical by pressure measurement
Under power knots modification, the sensitivity of the biggest measurement of knots modification of Bourdon tube termination displacement is the highest.Under normal circumstances, model is normally being measured
By the design length of Bourdon tube, wall thickness, elasticity in enclosing, it is ensured that Bourdon tube termination there are about 1.8mm left and right displacement amount.Capacity plate antenna
The capacitance of device is proportional to polar plate area, the distance being inversely proportional between pole plate.Constitute the battery lead plate A of described measurement pressure capacitance device Cx
(3) and battery lead plate B (4) constitute capacitor part area the biggest, change identical between its battery lead plate A (3) and battery lead plate B (4)
Distance, cause measure pressure capacitance device Cx capacity knots modification the biggest, its certainty of measurement just can be made the highest.(9)
It is frequency or the measuring unit in cycle of oscillating circuit (8) outputting oscillation signal, can complete the most smart now with a lot of technology
The true cycle (frequency, reciprocal each other with the cycle) measures.One embodiment, the output of oscillating circuit (8) is directly connected to measure
The measuring unit (9) of oscillator signal period, measurement data linearisation demodulated methed processing unit (10), storage and processing unit
(11) on the external interrupt input pin of microprocessor (single-chip microcomputer), with the edge triggered interruption of input signal, then with micro-
Processor (single-chip microcomputer) timer internal and computing unit calculate time between interruptions that is the periodic quantity of input signal.When micro-
When processor (single-chip microcomputer) internal oscillator source uses tens megahertzs, the signal period value of measurement can be accurate to ns level.In order to anti-
The measured value caused due to mechanical vibration during only measuring is beated, can be by the N number of cycle much larger than the mechanical vibration cycle
Original measurement value adds up and is averaged, calculates oscillator signal period meansigma methods, it is possible to obtains overcoming and periodically shakes
The data jump that dynamic change causes, it is thus achieved that stable measurement data.An embodiment of the present utility model, by accumulation period number,
The data item such as the parameter of calculating meansigma methods are as the parameter that can arrange, by locally located mouth or the distant place management station of (11)
(13) it is configured by the communication protocol of agreement.By measuring the measuring unit (9) of oscillator signal period, measurement data Linearization solution
The vibration that commissioning amount processing unit (10), storage and processing unit (11) directly obtain by measuring (8) oscillator signal period is believed
Number period average to make linearization process by (11) and demodulation process just can be converted into the pressure data of tested pressure source.
Linearization process and an embodiment of demodulation process: the first step, first make described oscillator signal period meansigma methods
Data prediction, wherein first deducts regeneration measurement data to be converted by the basic data beyond measurement scope；Second step passes through
A conversion data list set up by experiment software, by the measured data values described to be converted in the range of each measurement corresponding
The individual pressure measuring value determined；3rd step, when described linearization process and demodulation processing device program process to described in wait to turn
After changing measured data values, by measurement data to be converted as the coordinate in conversion data list, then from this coordinate, obtain correspondence
Pressure measuring value.Owing to described conversion data list is that the measured pressure value of all acquisitions has with linearizing through experiment
High certainty of measurement, can generally achieve the certainty of measurement of more than 0.5 grade.
Linearization process and an embodiment of demodulation process: the first step, put down described oscillator signal period by experiment
A mathematical model and mathematical formulae is set up between average and the actual pressure output value measured；Second step, in the range of measuring
Measured data values described to be converted as the parameter of mathematical formulae, by being calculated by the pressure measuring value of the determination of correspondence.
This method depends on the concordance of mathematical formulae and experimental data.
Linearization process and an embodiment of demodulation process: the first step, put down described oscillator signal period by experiment
A mathematical model and mathematical formulae is set up between average and the actual pressure output value measured；Second step, in the range of measuring
Measured data values described to be converted as the parameter of mathematical formulae, by being calculated by " the pressure to be used of the determination of correspondence
Measured value "；3rd step, sets up one by experiment software and arranges with " pressure measuring value to be used " conversion data as source data
Table, carries out secondary list and tables look-up output actual pressure measurements, or finds deviation value in lists and carry out calculating reality again
Pressure measuring value.
When former approach to obtain relatively high measurement accuracy, conversion data list must be sufficiently large, takies program space ratio
Relatively big, but modern MCU system road often can provide enough spaces, it may also be necessary to outside growth data list.Latter
Method needs accurate founding mathematical models and computing formula.Later approach takes into account the first two kind method again, first calculates, reduces
The quantity tabled look-up, then by acquisition high precision measuring data of tabling look-up.
Measure in pressure capacitance device electrode plate A (3) and measure another electrode plate B (4) composition in pressure capacitance device
The area of plate condenser part is the biggest, and the sensitivity of measuring pad spacing is the highest, and certainty of measurement is the highest.In prior art
Under the conditions of, as long as capacitor plate area is more than 180 square millimeters, polar plate spacing from by 0.2mm be changed to 2.2mm can with obtain
The pressure measurement accuracy of more than 0.5%.
A kind of teletransmission digital pressure measurement apparatus, has the Bourdon tube measuring pressure, has by battery lead plate A (3) and battery lead plate B
(4) the measurement pressure capacitance device Cx constituted, has by the oscillating circuit (8) measuring pressure capacitance device Cx capacity decision frequency of oscillation,
There are the measuring unit (9) measuring oscillator signal period, measurement data linearisation demodulated methed processing unit (10), store and process
Unit (11), communication interface and power supply provide circuit unit (12), it is characterized in that:
In a, measurement pressure capacitance device Cx, battery lead plate A (3) is fixed on the device moved together with Bourdon tube termination, surveys
In piezometric power capacitor Cx, another battery lead plate B (4) is fixed on the main circuit board being fixed together with support；
B, it is designed with and is changed the measurement pressure capacitance device Cx of capacity by Bourdon tube change in displacement, and by measuring pressure capacitance
Device Cx determines the oscillating circuit (8) of frequency of oscillation height；
C, by measure the measuring unit (9) of oscillator signal period, measurement data linearisation demodulated methed processing unit
(10), measurement and the measurement data Linearization solution in oscillating circuit (8) output signal cycle are mediated by storage and processing unit (11)
Reason obtains the numerical pressure value of measured pressure；
D and (13) two-way communication of distant place management station and the interface powered by distant place management station (13) be non-polar, two
Line, power supply and communicating integral.
Accompanying drawing explanation
Fig. 1 is the schematic diagram of teletransmission digital pressure measurement apparatus of the present utility model.(1) be measure pressure elasticity quick
Sensing unit Bourdon tube (Bourdon tubes), also known as bourdon tube (expansion tube)；(2) it is for fixation measuring in Bourdon tube termination
The fixture of electrode plate A in pressure capacitance device；(3) it is to measure electrode plate A in pressure capacitance device；(4) it is to measure pressure
Another electrode plate B in power capacitor；Battery lead plate A (3) and battery lead plate B (4) has certain area, and less parallel is placed, the most not
Connection, constitutes a capacity plate antenna；(5) it is master control circuit board of the present utility model.Master control circuit board (5) is fixed on far
Pass on the support of digital pressure measurement apparatus, measure another electrode plate B (4) in pressure capacitance device and be then fixed on (5)
Together.When in Bourdon tube, measured pressure increases, Bourdon tube stretches laterally, measures electrode plate A in pressure capacitance device
(3) followed by Bourdon tube termination and move, by electrode away from measuring the direction of another electrode plate B (4) in pressure capacitance device
The condenser capacity that plate A (3) and battery lead plate B (4) is constituted reduces.When in Bourdon tube, measured pressure reduces, Bourdon tube is inside
Side is shunk, and measures electrode plate A (3) in pressure capacitance device and followed by Bourdon tube termination towards near measuring in pressure capacitance device
The direction of another electrode plate B (4) is moved, and the condenser capacity being made up of battery lead plate (3) and (4) strengthens；(6) it is pressure measxurement
The support of device；(7) it is the shell of pressure gauge.
Fig. 2 is the theory diagram of this utility model governor circuit.Measuring pressure capacitance device Cx is by battery lead plate A (3) and electricity
The described measurement pressure capacitance device with measured pressure correlation that pole plate B (4) is constituted；(8) be RCx RC oscillator or
LCx LC oscillator, wherein the value of resistance R and inductance L is fixing, and the capacitance measuring pressure capacitance device Cx determines to shake
Swing frequency；(9) it is frequency or the measuring unit in cycle of oscillating circuit (8) outputting oscillation signal, wherein comprises measurement original number
Software is processed, to eliminate the data jump during measuring, it is achieved the smooth output of raw measurement data according to cumulative mean；(10)
It it is measurement data linearisation demodulated methed processing unit.During measuring, the change of measured pressure causes Bourdon tube displacement to become
Changing, be made up of the electric capacitance change measuring pressure capacitance device Cx change in displacement, electric capacitance change causes the frequency of agitator to become
Change, the frequency changed or Periodic measurements calculate and demodulate the tested force value of the digitized that can directly read；(11) it is storage
Deposit and processing unit；(12) it is communication interface and power supply offer circuit unit；(13) it is distant place management station, is responsible for this practicality
Novel teletransmission digital pressure measurement apparatus, wherein including but not limited to copy reading pressure data etc..
Fig. 3 is to measure pressure capacitance device one electrode plate A (3) and measure the one of another electrode plate B of pressure capacitance device (4)
Individual embodiment schematic diagram.It is made up of two sided pcb, and wherein (33) are the insulated substrates of two sided pcb；(34)
It is the conductive plate of one side, welds together with fixed support, the support wherein welded together with battery lead plate A (3), fixing
At the fixture (2) of electrode plate A in fixation measuring pressure capacitance device, with propping up that battery lead plate B (4) welds together
Frame is fixed in master control circuit board (5)；(32) it is the another side battery lead plate of printed circuit board, is to constitute to measure pressure capacitance device
The pole plate of Cx, this face of two pieces of pole plates of capacitor is placed face-to-face, so that capacitor distance is minimum；(31) it is that printed circuit is led
The insulating coating on electric layer surface, it is ensured that even if two pieces of pole plates are encountered the most also does not results in short circuit.
Fig. 4 is an embodiment of RCx resistance capacitance oscillating circuit (8).U1 and U2 is two equivalences in integrated circuit
Not gate；Cx and C1, C2 can equivalence regard measurement capacitor Cx ', R2 and a Cx as ' determine the frequency of this RC oscillator
Rate；R1 it is not necessary to, have R1 can improve stability and the safety of this agitator, when being not added with R1, at this, have one
The input of not gate U1 it is added in far above the oscillator signal of supply voltage；X1 end and X2 end can become the output of agitator
End.
In Fig. 4, C1 and C2 is to ensure that the embodiment of the safe and reliable work of agitator.C1 and Cx is connected in parallel, and C2 and
Cx is connected in series.The capacitance of C2 is designed as being far longer than the maximum capacitance of Cx, and when Cx is normal, C2 has little influence on
Measure, but when two pieces of pole plates of Cx are because of failed shorted, C2 just becomes the electric capacity of agitator, it is ensured that agitator continues vibration.C1's
Function is then the another kind of fault solving Cx: the capacitance of C1 is designed as the minimum capacity much smaller than Cx, when Cx is because of fault electricity
When capacity is close to zero, C1 can maintain agitator to vibrate.
Fig. 5 is the embodiment improving teletransmission digital pressure measurement apparatus reliability.(14) it is that this utility model is remote
Pass the digital pressure measurement apparatus theory diagram containing oscillating circuit (8)；(15) it is the common signal in oscillating circuit (8) circuit
Ground, Co is with being connected across common signal decoupling capacitor between (15) and shell (7).In the present embodiment, shell is metal
Making, label above is also metal.Decoupling capacitor Co capacitance is sufficiently large, is equivalent to be placed in oscillating circuit electric field screen
Cover internal.Decoupling capacitor Co should meet, when design, the needs that insulation is pressure.
Fig. 6 is an embodiment of communication interface circuit in this utility model teletransmission digital pressure measurement apparatus.D1 is
Protection element, absorbs moment overvoltage energy；Diode D2, diode D3, diode D4, diode D5 constitute rectifier bridge, make
Two wires input circuit is nonpolarity；D6 is commutation diode, resistance R5, electric capacity C3, electric capacity C4, and three-terminal voltage-stabilizing power supply U3 is constituted together
Working power circuit；Resistance R11, resistance R12, resistance R13, resistance R14 and comparator U4 constitute the input electrical signal of interface
Demodulator circuit, the signal of communication demodulated directly transports to (11)；Resistance R9, resistance R10, resistance R6, resistance R7, resistance R8 and three
Pole pipe Q1, audion Q2 constitute interface output communication current signal circuit；Co is with being connected across circuit signal and between shell 7
Decoupling Equivalent electric capacity, for improving pressure and reducing volume, can be in series by multiple chip capacitors.Storage and processing unit
(11) local pressure measuring value display circuit can also be comprised in, directly display the pressure measuring value of reality, and display power supply is equal
The working power circuit being made up of described communication interface circuit provides.
Detailed description of the invention
Implementation content cited by detailed description of the invention is part implementation content of the present utility model, and this utility model includes
Utility model content cited in detailed description of the invention and utility model feature, but it is not limited to these contents and technical characteristic.
In teletransmission digital pressure measurement apparatus of the present utility model, Bourdon tube (1) passes through pressure piping with outside by pressure measurement
Power source is connected.The change of external pressure source pressure can cause stretching, extension and the contraction of Bourdon tube.The stretching, extension of Bourdon tube and contraction
Cause in the measurement pressure capacitance device being fixedly mounted on Bourdon tube termination (2) electrode plate A (3) relative to battery lead plate B (4)
Distance change.Battery lead plate A (3) and battery lead plate B (4) constitutes this utility model middle plateform and measures two pieces of pole plates of capacitor.Quilt
The battery lead plate A (3) that measurement pressure change the causes distance change relative to battery lead plate B (4) defines measurement pressure capacitance device Cx
Electric capacitance change, cause resistance R and inductance L to be the RC oscillator of fixed value or inductance capacitance oscillating circuit (8) produce
Raw with by the frequency of measuring pressure positive association or mechanical periodicity.This frequency or mechanical periodicity are by measurement data linearisation demodulated methed
The demodulation of processing unit (10), calculates and demodulates the tested force value of the digitized that can directly read.Become by measuring pressure among these
Changing the Bourdon tube change in displacement caused, finally demodulating readable high-precision numerical pressure measured value needs to make Linearization solution
Mediate reason.Such as when being 1MPa by measuring pressure, (9) frequency measured is 3.256873MHz, and when by measuring pressure being
During 10MPa, (9) frequency measured is 5.754238MHz, by linearization process and the demodulation of (10), exports respectively
The tested pressure measuring value of readable digitized of 1.000MPa and 10.000MPa.
One embodiment, storage and processing unit (11), measurement data linearisation demodulated methed processing unit (10) and week
The measuring unit (9) of phase or frequency is to add external circuit with same microprocessor (single-chip microcomputer) to constitute.With tested pressure source
The Bourdon tube (1) being connected, when being increased by measuring pressure, the termination of Bourdon tube (1) flexes outward, and drives and is fixed on termination
In measurement pressure capacitance device, electrode plate A (3) is away from measuring the direction of another electrode plate B (4) in pressure capacitance device
Mobile, the measurement pressure capacitance device Cx capacity being made up of battery lead plate A (3) and battery lead plate B (4) reduces.In Bourdon tube measured
When pressure reduces, Bourdon tube shrinks to inner side, measure electrode plate A (3) in pressure capacitance device followed by Bourdon tube termination to
The direction of another electrode plate B (4) in measurement pressure capacitance device to move, be made up of battery lead plate A (3) and battery lead plate B (4)
Measurement pressure capacitance device Cx capacity strengthen.Described measurement pressure capacitance device Cx capacity associates change with being changed by measuring pressure,
Cause by oscillating circuit (8) output signal frequency or the association in the cycle change measuring pressure capacitance device Cx decision frequency of oscillation.
Tested pressure change amount causes the knots modification of Bourdon tube termination displacement, under identical tested pressure change amount, and Bourdon tube termination
The sensitivity of the biggest measurement of knots modification of displacement is the highest.Under normal circumstances, by design Bourdon tube in the range of normal measurement
Length, wall thickness, elasticity, it is ensured that Bourdon tube termination there are about 1.8mm left and right displacement amount.The capacitance of plate condenser is proportional to pole plate
Area, the distance being inversely proportional between pole plate.The battery lead plate A (3) and battery lead plate B (4) that constitute described measurement pressure capacitance device Cx are constituted
The area of capacitor part is the biggest, changes identical distance between its battery lead plate A (3) and battery lead plate B (4), the measurement pressure caused
The knots modification of power capacitor Cx capacity is the biggest, and its certainty of measurement just can be made the highest.Under prior art conditions, capacitance pole
As long as plate area is more than 180 square millimeters, polar plate spacing from by 0.2mm be changed to 2.2mm can with obtain more than 0.5% point
Distinguish precision.It is linear that the output of oscillating circuit (8) is directly connected to measure the measuring unit (9) of oscillator signal period, measurement data
Change the external interrupt input pin of microprocessor (single-chip microcomputer) in demodulated methed processing unit (10), storage and processing unit (11)
On, with the edge triggered interruption of input signal, then calculate input signal with microprocessor (single-chip microcomputer) timer internal
Time between interruptions that is the periodic quantity of input signal.When microprocessor (single-chip microcomputer) internal oscillator source uses tens megahertzs
Time, the signal period value of measurement can be accurate to ns level.In order to prevent the measured value caused due to mechanical vibration during measuring from jumping
Dynamic, the original measurement value in the N number of cycle much larger than the mechanical vibration cycle can be added up and be averaged again, calculate vibration
The meansigma methods of signal period measured value.Due to the measurement data that this meansigma methods has smoothed out mechanical vibration, instantaneous interference is constituted
Fluctuation, actual can obtain sufficiently stable measurement data.The periodicity of cumulative mean selects should be by actual application environment and should
Determine with needs: when use environment is mobile environment, and such as development machine, frequency of vibration is the lowest, it may be necessary in the several seconds
Data accumulation is averaging again, development machine is rocked the pressure change caused and smooths out；And some applied environment is more stable, need again
Want the transient change of observed pressure, then may only need the periodicity of ms level to add up and be averaging.An embodiment of the present utility model,
Using data item such as accumulation period number, the parameters calculating meansigma methods as the parameter that can arrange, user lead to according to actual needs
Cross locally located mouth to arrange, or arranged by distant place management station, meet reality application needs with optimal parameter.By (11)
Locally located mouth or distant place management station are configured by the communication protocol of agreement.By (11) directly by measuring (8) oscillator signal
The oscillator signal period meansigma methods that cycle obtains to make linearization process by (11) and demodulation process just can be converted into by pressure measurement
The pressure data in power source.
One embodiment of teletransmission digital pressure measurement apparatus, is characterized in that: can be by the locally located mouth of (11)
Or distant place management station carries out accumulation period number by the communication protocol of agreement, the parameter of calculating meansigma methods is configured, then in demodulation
Time the accumulation period number that arranges original measurement value added up be averaged again, calculate oscillator signal period meansigma methods.
Linearization process and an embodiment of demodulation process: the first step, go out elder generation by described oscillator signal period meansigma methods
Make data prediction, wherein the basic data beyond measurement scope is first deducted generation measurement data to be converted；Second step passes through
A conversion data list set up by experiment software, by the measured data values described to be converted in the range of each measurement corresponding
The individual pressure measuring value determined；3rd step, when described linearization process and demodulation processing device program process to described in wait to turn
After changing measured data values, by measurement data to be converted as the coordinate in conversion data list, then from this coordinate, obtain correspondence
Pressure measuring value.Owing to described conversion data list is that the measured pressure value of all acquisitions has with linearizing through experiment
High certainty of measurement, can generally achieve the certainty of measurement of more than 0.5 grade.
Linearization process and an embodiment of demodulation process: the first step, put down described oscillator signal period by experiment
A mathematical model and mathematical formulae is set up between average and the actual pressure output value measured；Second step, in the range of measuring
Measured data values described to be converted as the parameter of mathematical formulae, by being calculated by the pressure measuring value of the determination of correspondence.
This method depends on the concordance of mathematical formulae and experimental data.
Linearization process and an embodiment of demodulation process: the first step, put down described oscillator signal period by experiment
A mathematical model and mathematical formulae is set up between average and the actual pressure output value measured；Second step, in the range of measuring
Measured data values described to be converted as the parameter of mathematical formulae, by being calculated by " the pressure to be used of the determination of correspondence
Measured value ".3rd step, sets up one by experiment software and arranges with " pressure measuring value to be used " conversion data as source data
Table, carries out secondary list and tables look-up output actual pressure measurements, or finds deviation value in lists and carry out calculating reality again
Pressure measuring value.
When former approach to obtain relatively high measurement accuracy, conversion data list must be sufficiently large, takies program space ratio
Relatively big, but modern MCU system road often can provide enough spaces, it may also be necessary to outside growth data list.Latter
Method needs accurate founding mathematical models and computing formula.Later approach takes into account the first two kind method again, first calculates, reduces
The quantity tabled look-up, then by acquisition high precision measuring data of tabling look-up.
Communication interface and power supply provide circuit unit (12) to provide (11) and distant place management station (13) to carry out telecommunication
Interface.
Fig. 3 is to measure pressure capacitance device one electrode plate A (3) and measure the one of another electrode plate B of pressure capacitance device (4)
Individual embodiment schematic diagram.Battery lead plate A and battery lead plate B is constituted by two sided pcb, and wherein (33) are souble sided printed circuits
The insulated substrate of plate；(34) it is the conductive plate of one side, welds together with fixed support, wherein weld with battery lead plate A (3)
Support together is fixed on the fixture (2) of Bourdon tube termination electrode plate A in fixation measuring pressure capacitance device,
The support welded together with battery lead plate B (4) is fixed in master control circuit board (5)；(32) it is the another side of printed circuit board
Battery lead plate, is the pole plate constituting and measuring pressure capacitance device Cx, and this face of two pieces of pole plates of capacitor is placed face-to-face, so that electric capacity
Device distance is minimum；(31) it is the insulating coating of printed circuit conductive layer surface, it is ensured that even if two pieces of pole plates are encountered also do not result in
Short circuit.Using double-sided PCB manufacture to measure the very convenient batch production of capacitor plate and processing, concordance is good, and size is easily controlled
System.It is not only installed, line convenient, moreover it is possible to ensure the insulation between pole plate and fixture.
The embodiment measuring pressure capacitance device in teletransmission digital pressure measurement apparatus, is characterized in that:
A, measurement pressure capacitance device one electrode plate A (3) and measurement another electrode plate B of pressure capacitance device (4) are all to use
Two sided pcb manufactures, and constitutes the installation of measurement pressure capacitance device pole plate conductor planes opposite；
B, two sided pcb are not that the conductor layer measuring pressure capacitance device pole plate is for being welded and fixed support；
C, the one side being used as to measure capacitor conductor applied over have insulation material layer.
Fig. 4 is an embodiment of RCx resistance capacitance oscillating circuit (8).U1 and U2 is two equivalences in integrated circuit
Not gate；Cx and C1 is connected in parallel, Cx and C2 is connected in series, and C1, C2 and Cx equivalence can regard a measurement capacitor Cx ', R2 as
With Cx ' determines the frequency of this RC oscillator；R1 it is not necessary to, have R1 can improve this agitator stability and
Safety, when being not added with R1, has an input being added in not gate U1 far above the oscillator signal of supply voltage at this；X1 end and
X2 end can become the outfan of agitator.C1 and C2 is to ensure that the safe and reliable work of agitator.The capacitance design of C2
For being far longer than the maximum capacitance of Cx, when Cx is normal (capacitance is about a few pF to tens pF), C2 has little influence on measurement,
But when two pieces of pole plates of Cx are because of failed shorted, C2 just becomes the electric capacity of agitator, it is ensured that agitator continues vibration.The function of C1 is then
It is the another kind of fault solving Cx: the capacitance of C1 is designed as the minimum capacity much smaller than Cx, connects because of fault capacitance as Cx
When being bordering on zero, C1 can maintain agitator to vibrate.One embodiment C1 is 1pF, and C2 is 10nF.One embodiment, Cx first and
After C2 first connects, then it is connected in parallel with C1.
One embodiment of teletransmission digital pressure measurement apparatus, is characterized in that: oscillating circuit (8) is by the output of not gate U1
Hold the input with not gate U2 to connect to be connected with resistance-capacitance oscillator resistance R2 one end again, the output of U2 and equivalent measurement capacitor
Cx ' one end connects, and the other end of R2 is then connected with the Cx ' other end, also input through resistance R1 with U1.
One embodiment of teletransmission digital pressure measurement apparatus, is characterized in that: measure pressure capacitance in oscillating circuit (8)
Device Cx is parallel with a capacity less than the capacitor C1 measuring pressure capacitance device Cx, is in series with a capacitance much larger than measuring
The capacitor C2 of pressure capacitance device Cx.
Fig. 5 is the embodiment improving teletransmission digital pressure measurement apparatus reliability.(14) it is that this utility model is remote
Pass the digital pressure measurement apparatus theory diagram containing oscillating circuit (8)；(15) it is the common signal in oscillating circuit (8) circuit
Ground, Co is with being connected across common signal decoupling capacitor between (15) and shell (7).In the present embodiment, shell is metal
Making, label above is also metal.Decoupling capacitor Co capacitance is sufficiently large, is equivalent to oscillating circuit is placed in electricity
In field shield.Co should meet, when design, the needs that insulation is pressure.One embodiment, Co is by the paster of three 10nF/100V
Capacitances in series is constituted.
Teletransmission digital pressure measurement apparatus improves an embodiment of stability, it is characterized in that: oscillating circuit (8) circuit
In common signal ground and shell (7) between be connected to decoupling capacitor Co.
An embodiment of the present utility model, communication interface and power supply provide circuit unit to use two wires, communication power supply
Meter-BUS (the writing a Chinese character in simplified form M BUS) interface of unification.Described communication interface, when communication, is received by (13) descending transmission (12)
Time, for the signal of communication of supply voltage making alive form；By (12) when (13) upload transmission, transmission information is current signal.
Fig. 6 is the embodiment that this utility model teletransmission digital pressure measurement apparatus is bright.D1 is protection element, absorbs moment overvoltage
Energy；Diode D2, diode D3, diode D4, diode D5 constitute rectifier bridge, make two wires input circuit nonpolarity,
Without the concern for the polarity of communication line during actual application.When no matter interface of the present utility model has signal and no signal, all can
Ensureing there is a minimum voltage (such as 5V to 9V), D6 is commutation diode, resistance R5, electric capacity C3, electric capacity C4, three-terminal voltage-stabilizing electricity
Source U3 constitutes working power circuit by interface together, and wherein R5 ensures that it does not affect signal of communication demodulation；Resistance R11, resistance
R12, resistance R13, resistance R14 and comparator U4 constitute the input voltage signal demodulator circuit of interface, the downlink communication demodulated
Information is directly transported to (11), wherein resistance R13 it is not necessary to, the intrinsic standoff ratio of resistance R11 and resistance R12 ensures input signal
Voltage can reliably demodulate the communication information at comparator U4 in the case of worst；One embodiment, at R11 resistance
Zener diode by a resistive element and an Opposite direction connection is in series, stabilivolt the voltage stabilizing value produced, and strengthens defeated
Enter signal voltage change and be delivered to resistance R11, the change in voltage of resistance R12 dividing point；Resistance R9, resistance R10, resistance R6, electricity
Resistance R7, resistance R8 and audion Q1, audion Q2 constitute interface and upload output information current signal generating circuit, up output electricity
The current value of stream signal is selected by the size of resistance R7, general optional 10mA 20mA；Co be with being connected across circuit signal and
Decoupling Equivalent electric capacity between shell (7), for improving pressure and reducing volume, can be in series by multiple chip capacitors.
Storage and processing unit (11) can also comprise teletransmission digital pressure measurement apparatus upward pressure measured value display device, directly
The pressure measuring value that display is actual.The working power circuit that display power supply is made up of described communication interface provides.Display circuit
One embodiment is made up of LCD liquid crystal display, drive circuit and backlight luminescence element, and display is periodically at pressure
Reading pressure measuring value in measured value storage unit send display circuit to show.Another embodiment of display circuit is by LED number
Code display has directly been driven through current-limiting resistance by the single-chip processor i/o pin in (11).
One embodiment of described teletransmission digital pressure measurement apparatus, has diode D2, diode D3, diode
D4, diode D5 constitute rectifier bridge, have commutation diode D6, resistance R5, electric capacity C3, electric capacity C4, three-terminal voltage-stabilizing power supply U3 structure
The working power circuit become, has resistance R11, resistance R12 and comparator U4 to constitute input voltage information demodulator circuit, has resistance
R9, resistance R10, resistance R6, resistance R7, resistance R8 and audion Q1, audion Q2 constitute output current signal circuit, its feature
It is:
A, in working power circuit, it is serially connected with resistance R5；
B, the signal comparing pin of comparator U4 take from the output pin of three-terminal voltage-stabilizing power supply U3, and compare pin
Signal is taken from the dividing point of resistance R11 and resistance R12, and a pin of resistance R11 is connected on interface input power.
One embodiment of described teletransmission digital pressure measurement apparatus, is characterized in that: teletransmission digital pressure is measured
Fixture the most distally transmits pressure measuring value, is also designed with by LCD liquid crystal in teletransmission digital pressure measurement apparatus
Show device or LED charactron device, show the force value of measured pressure.
The effect of utility model
A kind of teletransmission digital pressure measurement apparatus, pacifies on the measurement pressure bowden pipe end being connected with tested pressure source
An electrode plate in pressure capacitance device measured by dress, and another block circuit board being fixed on measurement apparatus support is constituted and outside quilt
By measuring pressure capacitance device Cx, the measurement pressure capacitance device Cx of measuring pressure association, determines that the agitator of frequency of oscillation will be by measuring pressure
Change be converted to easily to measure, easy linearization process, easy digitized frequency variation signal.Device of the present utility model
Pass through digital demodulation, it is thus achieved that the tested force value of digitized of pinpoint accuracy.Pressure measurement data is by of the present utility model
Digitized conversion designs, it is possible to achieve on the premise of noncontact pointer-free pressure measxurement, pressure measurement accuracy is brought up to
More than 0.5%, conveniently realize distant place bi-directional digital communication transmission；The digitized of this utility model numerical pressure measured value
Filter, the de-stabilising effect that mechanical vibration etc. cause to pressure measxurement can be filtered out easily.This utility model structure
Simply, low cost, in high precision, highly reliable, coordinate nonpolarity two-wire system two-way communication power supply integration Interface design, do not only reach
The purpose of this utility model, and can be widely applied to pressure measxurement and need the occasion of distant place digital management.
Claims (6)
1. a teletransmission digital pressure measurement apparatus, has the Bourdon tube measuring pressure, has by battery lead plate A (3) and battery lead plate B
(4) the measurement pressure capacitance device Cx constituted, has by the oscillating circuit (8) measuring pressure capacitance device Cx capacity decision frequency of oscillation,
There are the measuring unit (9) measuring oscillator signal period, measurement data linearisation demodulated methed processing unit (10), store and process
Unit (11), communication interface and power supply provide circuit unit (12), it is characterized in that:
In a, measurement pressure capacitance device Cx, battery lead plate A (3) is fixed on the device moved together with Bourdon tube termination, measures pressure
In power capacitor Cx, another battery lead plate B (4) is fixed on the main circuit board being fixed together with support；
B, it is designed with and is changed the measurement pressure capacitance device Cx of capacity by Bourdon tube change in displacement, and by measuring pressure capacitance device Cx
Determine the oscillating circuit (8) of frequency of oscillation height；
C, by measure the measuring unit (9) of oscillator signal period, measurement data linearisation demodulated methed processing unit (10), storage
Deposit with processing unit (11) measurement in oscillating circuit (8) output signal cycle and measurement data linearisation demodulation process obtained by
Measure the numerical pressure value of pressure；
D and (13) two-way communication of distant place management station and the interface powered by distant place management station (13) are non-polar, two-wire systems
, power supply and communicating integral.
Teletransmission digital pressure measurement apparatus the most according to claim 1, is characterized in that:
A, measurement pressure capacitance device one electrode plate A (3) and measurement another electrode plate B of pressure capacitance device (4) are all with two-sided
Printed circuit board manufactures, and constitutes the installation of measurement pressure capacitance device pole plate conductor planes opposite；
B, two sided pcb are not that the conductor layer measuring pressure capacitance device pole plate is for being welded and fixed support；
C, be used as measure capacitor conductor one side on be coated with insulation material layer.
Teletransmission digital pressure measurement apparatus the most according to claim 1, is characterized in that: oscillating circuit (8) is by not gate
The input of the outfan of U1 and not gate U2 connects and is connected with resistance-capacitance oscillator resistance R2 one end, the output of not gate U2 and etc.
Effect measure capacitor Cx ' one end connect, the other end of resistance-capacitance oscillator resistance R2 then with the equivalent measurement capacitor Cx ' other end,
Also the input through resistance R1 with not gate U1 is connected.
Teletransmission digital pressure measurement apparatus the most according to claim 1, is characterized in that: in oscillating circuit (8) circuit
It is connected to decoupling capacitor Co between common signal ground and shell (7).
Teletransmission digital pressure measurement apparatus the most according to claim 1, have diode D2, diode D3, diode D4,
Diode D5 constitutes rectifier bridge, has commutation diode D6, resistance R5, electric capacity C3, electric capacity C4, and three-terminal voltage-stabilizing power supply U3 is constituted
Working power circuit, has resistance R11, resistance R12 and comparator U4 to constitute input voltage information demodulator circuit, has resistance R9, electricity
Resistance R10, resistance R6, resistance R7, resistance R8 and audion Q1, audion Q2 constitute output current signal circuit, it is characterized in that:
A, in working power circuit, it is serially connected with resistance R5；
B, the signal comparing pin of comparator U4 take from the output pin of three-terminal voltage-stabilizing power supply U3, and compare leg signal
Taking from the dividing point of resistance R11 and resistance R12, a pin of resistance R11 is connected on interface input power.
Teletransmission digital pressure measurement apparatus the most according to claim 1, is characterized in that: measure pressure in oscillating circuit (8)
Power capacitor Cx is parallel with a capacity less than the capacitor C1 measuring pressure capacitance device Cx, is in series with a capacitance and is much larger than
Measure the capacitor C2 of pressure capacitance device Cx.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201620181863.8U CN205843871U (en) | 2016-03-10 | 2016-03-10 | Teletransmission digital pressure measurement apparatus |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201620181863.8U CN205843871U (en) | 2016-03-10 | 2016-03-10 | Teletransmission digital pressure measurement apparatus |
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| CN205843871U true CN205843871U (en) | 2016-12-28 |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105571764A (en) * | 2016-03-10 | 2016-05-11 | 北京纳衡仪器仪表有限公司 | Remote-transmission digital pressure measuring device |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105571764A (en) * | 2016-03-10 | 2016-05-11 | 北京纳衡仪器仪表有限公司 | Remote-transmission digital pressure measuring device |
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| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| CF01 | Termination of patent right due to non-payment of annual fee | ||
| CF01 | Termination of patent right due to non-payment of annual fee |
Granted publication date: 20161228 Termination date: 20190310 |