A kind of pressure detection system and its calibration method with automatic calibration functionTechnical field
The present invention relates to pressure detection techniques, and in particular to a kind of pressure detection system with automatic calibration function and itsCalibration method.
Background technique
The automation field (such as air pressure therapeutic equipment) for accurately detecting atmospheric pressure is needed to need to carry out pressure detection,Pressure detection at present mainly carries out pressure detection using following two:
One is by pressure transducer circuit plus the method for potentiometer calibrates pressure transducer, but this pressureThe method precision detected by force is poor, and calibration process is excessively complicated, and the time is longer, and human cost is excessively high, in the application error compared withGreatly；
Another kind is to use directly to complete pressure detection using high-precision pressure transducer, although this method precisionHeight, but cost is obviously obvious excessively high.
Summary of the invention
In view of this, the present invention provides a kind of pressure detection system and its calibration method with automatic calibration function, purportUnder the premise of guaranteeing detection accuracy, the cost of detection pressure is farthest reduced.
The technical solution adopted by the present invention specifically:
A kind of pressure detection system with automatic calibration function, including error writing module, error memory module and mistakeDifference reads module, and the error information that error writing module obtains periodically is stored to error memory module, and error reads moduleError information is transferred, the pressure values of actual measurement add the error information, as exact pressure value.
In the above-mentioned pressure detection system with automatic calibration function, the error writing module specifically:
Single-chip microcontroller control standard gas source pressurizes simultaneously to pressure transducer and normal pressure sensor, and the normal pressure passesPressure measurement is transmitted to single-chip microcontroller by sensor, and the pressure transducer, will by interface circuit through signal amplifying and conditioning circuitPressure measurement is transmitted to single-chip microcontroller, and the single-chip microcontroller is sensed according to the pressure transducer received and the normal pressureThe pressure measurement of device calculates error between the two.
In the above-mentioned pressure detection system with automatic calibration function, the error memory module specifically:
The single-chip microcontroller from which further follows that error information according to error between the two, described in the single-chip microcontroller will obtainError is continuously written into storage unit by interface circuit, and with the variation of standard gas source output pressure, the storage unit is depositedAll error informations between the pressure transducer and the normal pressure sensor are stored up.
In the above-mentioned pressure detection system with automatic calibration function, the error reads module specifically:
The error information stored in the pressure measurement reference memory unit of the pressure transducer, can be obtained the pressureThe exact pressure value that strong sensor should be measured.
In the above-mentioned pressure detection system with automatic calibration function, the single-chip microcontroller passes through control gas source control circuitChange the output pressure of the standard gas source periodically in the measurement range of the pressure transducer.
A kind of automatic calibrating method of pressure detection system, including error write step, error storing step and error are readStep out, the error information that error write step obtains periodically are stored to error storing step, and error reading step is transferredThe pressure values of error information, actual measurement add the error information, as exact pressure value.
In the automatic calibrating method of above-mentioned pressure detection system, the error write step specifically:
Single-chip microcontroller control standard gas source pressurizes simultaneously to pressure transducer and normal pressure sensor, and the normal pressure passesPressure measurement is transmitted to single-chip microcontroller by sensor, and the pressure transducer, will by interface circuit through signal amplifying and conditioning circuitPressure measurement is transmitted to single-chip microcontroller, and the single-chip microcontroller is sensed according to the pressure transducer received and the normal pressureThe pressure measurement of device calculates error between the two.
In the automatic calibrating method of above-mentioned pressure detection system, the error storing step specifically:
The single-chip microcontroller from which further follows that error information according to error between the two, described in the single-chip microcontroller will obtainError is continuously written into storage unit by interface circuit, and with the variation of standard gas source output pressure, the storage unit is depositedAll error informations between the pressure transducer and the normal pressure sensor are stored up.
In the automatic calibrating method of above-mentioned pressure detection system, the error reading step specifically:
The error information stored in the pressure measurement reference memory unit of the pressure transducer, can be obtained the pressureThe exact pressure value that strong sensor should be measured.
In the automatic calibrating method of above-mentioned pressure detection system, the single-chip microcontroller makes institute by controlling gas source control circuitThe output pressure for stating standard gas source periodically changes in the measurement range of the pressure transducer.
The beneficial effect comprise that:
Pressure detection system of the invention is mainly used for needing accurately detecting the automatic control occasion of atmospheric pressure, such as airPressure therapy instrument and the detection of the pressure of similar field, compared with prior art, have easy to operate, automatic calibration accuracy high andFeature at low cost；Specifically:
Compared with the first scheme in background technique, the prior art using the common pressure transducer in market, with amplificationWhen device carries out signal condition, in the high-end of measured value, low side or entirety, there are 5~20% mistakes for semiconductor transducer outputDifference, and also not identical with the error of batch products, the linearity, adjust it is time-consuming and laborious, each sensor averagely need 5min withOn adjustment time, and the present invention realize its calibrate automatically function when, regulating time is minimum can be reduced to less than 1min,And the operation adjusted can carry out in batches；
Compared with the first scheme in background technique, the prior art uses commercially available high-precision sensor, and each is soldNearly hundred yuan of valence and the supply of material it is highly unstable, and the present invention realize its calibrate automatically function when, realizing with high-precision passUnder the premise of sensor same calibration precision, the cost of each pressure module reduces by 70% or more, and cost is substantially reduced.
Detailed description of the invention
When considered in conjunction with the accompanying drawings, the present invention can be more completely and better understood.Attached drawing described herein is used to provideA further understanding of the present invention, examples and descriptions thereof are used to explain the present invention, does not constitute improper limitations of the present invention.
Fig. 1 is a kind of structural schematic diagram of the pressure detection system with automatic calibration function of the present invention；
Fig. 2 is the calibration flow diagram of pressure detection system of the invention.
Specific embodiment
The technical scheme of the present invention will be explained in further detail with reference to the accompanying drawings and embodiments.
A kind of pressure detection system with automatic calibration function as shown in Figure 1, was manufactured in sensor moduleCheng Zhong is calibrated in the following ways:
Pressure transducer and normal pressure sensor are connected into standard gas source simultaneously, single-chip microcontroller (MCU) controls standard gas sourceIt pressurizes simultaneously to pressure transducer and normal pressure sensor, MCU obtains pressure transducer and normal pressure sensor to standardSimultaneously error between the two is calculated in the measurement result of air pressure pressure, in which: normal pressure sensor is by as calibration functionPressure transducer and signal amplifying and conditioning circuit the integration composition of energy, therefore undesired signal amplifies；But pressure transducer is examinedThe signal measured then need signal amplifying and conditioning circuit to amplify after through interface circuit (connecting line either winding displacement and socket contact pinCombination) it is sent to MCU, in fact, obtained error amount is often multiple groups numerical value since sample magnitude is too many and initial value is indefinitePerhaps multiple groups numerical value or difference are obtained one group of slope as error information by difference after MCU is calculated, it may be assumed that MCU is sampled simultaneouslyAfter sampling, normal pressure sensor and pressure transducer is calculated in the value of normal pressure sensor and pressure transducerError, and convert error to the data being made of zero point value and multiple groups linearity slope, be saved in and deposited by interface circuitIn reservoir, after the output pressure of standard gas source changes a cycle in the measurement range of pressure module, depositing in pressure moduleReservoir is all error informations stored in the period between pressure transducer and normal pressure sensor.
Standard gas source therein is by the solenoid valve block of a pressure pump, pressure vessel and an output pressure at passing throughBy the way of electronic signal control (i.e. gas source control circuit in Fig. 2), the pressure values of output are gently adjusted.
As a kind of preferred embodiment, the pressure applied to the standard gas source in pressure detection system of the invention adjusts modelIt encloses for 0~100KPa, adjusting step-length is 1KPa, and a cycle of standard gas source refers to that output pressure is gradually increased to maximum by 0The process of value, maximum value therein are the arbitrary values being set according to actual conditions as less than 100KPa, such as: according to the speed of 1KPa/sSpend the process that the pressure of pressure transducer and standard brick pressure transducer is incremented to 40KPa by 0.
Calibration circuit mainly includes by MCU, high-precision normal pressure sensor and gas source control circuit and is gasThe accessory power supply (alternating current of 12V DC or 220V, determined by gas source) etc. of source control circuit power supply, working principle is specificIt is as shown in Figure 2:
MCU control gas source control circuit makes standard gas source output pressure (stop or start by the key being set on MCUOutput, the pressure values of output are observed by display screen in real time), pressure transducer to be calibrated (after signal amplifies) and high-precisionNormal pressure sensor measure the pressure respectively and it be transmitted to MCU by interface circuit, MCU calculates pressure transducerPressure error between normal pressure sensor is written by interface circuit by the error information that pressure error obtains and is storedDevice.
So, in the application process of sensor module, user only needs to measure the output valve of pressure transducer, thenIn conjunction with the error information stored in memory, so that it may the pressure data after obtaining accurate calibration.
As can be seen that the link of manual adjustment amplifier circuit is omitted in calibration method of the invention, without being intendedIt is total to calculate to realize calibration, under the premise of greatly improving production efficiency, calibration error is reduced, so that the stabilization of systemProperty is improved.
In general, the precision of the normal pressure sensor of calibration module is higher than the pressure transducer of pressure module at leastAn order of magnitude；That is: according to the pressure transducer being calibrated can be with the pressure of precise measurement 1KPa, normal pressure passes at this timeSensor then should can be with the pressure of precise measurement 0.1KPa.
In practical projects, storage unit of the memory as error information can also be replaced using the MCU of low cost, directlyOutput digit signals are connect, so, user can further save the cost of A/D conversion when using sensor module, willThe error of A/D conversion reduces.
In conjunction with attached drawing, embodiments of the present invention are described in detail above, and attached drawing herein is for providing to thisInvention is further understood.Obviously, the foregoing is merely the preferable specific embodiment of the present invention, but protection scope of the present inventionBe not limited thereto, it is any be to one skilled in the art can readily occur in, essentially without be detached from it is of the inventionChange or replacement are also all included in the scope of protection of the present invention.