CN103697969A - Ultrasonic liquid level tracker system and method based on low-power-consumption single-chip microcomputer - Google Patents
Ultrasonic liquid level tracker system and method based on low-power-consumption single-chip microcomputer Download PDFInfo
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Abstract
The invention discloses an ultrasonic liquid level tracker system based on a low-power-consumption single-chip microcomputer. The ultrasonic liquid level tracker system comprises a low-power-consumption liquid level recording handheld PDA (Personal Digital Assistant), wherein the low-power-consumption liquid level recording handheld PDA can be used for acquiring the history liquid level data of a correspondingly matched low-power-consumption liquid level recorder, or a low-power-consumption liquid level recording handheld PDA corresponds to the history liquid level data of at least one correspondingly matched low-power-consumption liquid level recorder.
Description
Technical field
The present invention relates to a kind of supersonic liquid level and follow the tracks of, particularly a kind ofly can be used for the automobile mounted supersonic liquid level tracker system and method based on low-power scm.
Background technology
Along with developing rapidly of embedded microprocessor technology, oil mass level gauging instrument progressively develops to electromechanical integration from mechanical principle such as early stage employing ball floats.The technology trend of level gauging instrument development both at home and abroad mainly contains following three focuses:
1, intellectuality;
2, the liquid level gauge of non-contact measurement;
3, the small-scale liquid bit switch of new principle;
In the liquid level gauge of non-contact measurement, there are a lot of liquid level gauges based on different measuring principle: radar level gauge, laser liquid level gauge, gamma-rays tank gage, ultrasonic level gage etc.Wherein, ultrasonic level gage is the most a kind of technology of development at present, at aspects such as technology, cost, precision, installations, has comprehensive advantage.Ultrasonic measuring distance technology is the velocity of propagation in medium and run into the principle that test solution position surface produces reflection based on ultrasound wave, ultrasonic transducer transmitting ultrasonic pulse signal, to receiving the required time of echo, has just represented the distance between medium and ultrasonic transducer.
Level gauging instrument adopts mechanical principle in early days mostly both at home and abroad, along with developing rapidly of embedded microprocessor technology, level gauging instrument is from adopting the mechanical principle such as ball float progressively to electromechanical integration development, and the main development feature of present level gauging technology is:
1, adapt to international market needs, capture technical field commanding elevation;
2, production and market is closely connected;
3, height products quality consciousness, produces increasingly automated;
4, production-supply-marketing networking, comprehensive technical service;
Germany Endress+Hauser (grace Si Haosi, be called for short E+H company) be one of leader of automatic field in world wide, E+H corporate HQ is positioned at Switzerland, successively in world industry states such as Germany, Switzerland, France, the U.S., Japan, China, set up the production center in large scale, in the whole world, have and surpass 60,000 employees and study, develop, produce and sell and the work such as maintenance, have individual independently subsidiary company more than 70 and be distributed in the whole world, the qualitative control that E+H company is strict and complete quality assurance system all reach ISO9001 international standard.Its surface label weldering automatic production line of investing to build production is that the whole world is fastest, speed is other companies 3 times.
The DCS measuring system measuring accuracy of Holland Honeywell (Honeywell) company is high, stable, adaptive capacity to environment is strong, scalability good, agreement is flexible, is widely used in each tank field, the whole world.In the Intelligent radar liquid level gauge performance test of the said firm, on the measurement passage of 18 meters long, radar detection head and laser acquisition head automatically every one millimeter of positive and negative measurement once, have guaranteed the high precision of measuring.
China also has very large gap in level gauging technical field with comparing abroad.The prodution and development of domestic measuring instrument mainly adopts Importing Foreign Advanced Technology, imitated external advanced product, and the modes such as joint agency, lack the core technology that has completely autonomous property right.Domesticly at measuring instrument field ubiquity, that product performance index is low, Meter Reliability can be poor, enterprise's scientific research technical strength is weak, production equipment falls behind, think little of the problems such as after services of product.In recent years, due to the continuous effort of China in accurate measurement instrument field, occurred that some new and high technology liquid level gauge product meets or exceeds international most advanced level, but at traction, the aspects such as market share also far away cannot with abroad compare.
The BJLM-80 servo-type level meter technology of Beijing Jun Youxin industry Science and Technology Ltd. research and development is novel, multiple functional, can measure liquid level, different liquids interphase, single-point temperature, medial temperature, segmentation density, average density, segmentation pressure etc. simultaneously.This measuring precision is high, to the measuring accuracy of liquid level be ± 1mm, interfacial precision are ± 2mm, temperature accuracy ± 0.2 ℃, density accuracy ± 0.5kg/m3.These properties of product are reliable, easy to use, broken the monopolization of external product in this field, filled up domestic blank.
Optical research Suo Yu Wuhan University of the Chinese Academy of Sciences has all succeeded in developing the liquid level detection system based on optical fiber.The UBG light-guide electronic tank gage of Beijing Aeronautic Intelligent Control Engineering Co.'s development, can reach ± 2mm of its precision; MET-I type magnetic effect tank gage precision is 0.05%.The BL30 radar level gauge precision that nineteen ninety-five is released is ± [1+ outage * 3 ‰] [1].These products in succession research and develop the development that has successfully greatly promoted China's Technology of Level Detection, for catching up with and surpassing international advanced technology, made contribution.
The current situation of domestic and international ultrasonic measuring distance technology: ultrasonic ranging is to utilize ultrasonic reflections principle to detect the non-contact type article position measuring mode of normal pressure or the interior liquid level of low pressure vessel or solid material level, can be widely used in the various liquid or solid level gaugings of the industry such as chemical industry, electric power, metallurgy, light industry, water treatment or civilian department, and can measure the flow in open channel, weir body.Ultrasonic level gage is with fastest developing speed a kind of in non-contact liquid level meter, both at home and abroad to ultrasonic range finder research, mainly intelligent in wide range range finding, pinpoint accuracy range finding and range finding, several directions such as networking.Detecting ultrasonic wave-wave and echo that intelligentized ultrasonic level gage is launched it with a set of powerful software systems are conventionally analyzed.
What Australia HAWK company released makes ultrasonic measuring distance technology have great breakthrough based on HPAWK technology SULTAN series high energy sound wave noncontact level meter technology, these series of products have overcome the impact of generation decay in propagation process of sound wave, optimized the recognition technology to the various echo of complexity, greatly widened the application scenario of ultrasonic measuring distance technology, made ultrasonic ranging disturb the multiple severe working environment more, material is larger applicable to production tank, dust.HPAWK technology has outstanding Echo Processing technology, and 5 to 50KHZ superelevation is sent out ripple frequency makes its maximum range can reach 120 meters; Applicable media temperature is-20 ℃ to+175 ℃; The full-automatic regulation of intelligence is sent out ripple frequency, and temperature difference compensation function makes its more stable work reliable automatically.SULTAN series of products are used intelligent regulation technology, have improved reliability and the performance index of ultrasound wave product.These series of products are thrown opponent in the back far away on the ranging technology of 5KHz and 120 meters (can reach 195 meters under ecotopia).At present, SULTAN High Power Acoustic Wave position meter comes into operation on the nearly 800 cover run coal bins of national power plant, and ruuning situation is good.
Domestic ultrasonic range finder of the same type is owing to being difficult to break through the technical bottleneck of lower frequency (5kHz) and transmitting high-energy ripple, generally send out wave energy a little less than, generally be applied to measure the simple occasion of small distance, can not disturb greatly at dust the long-term good working order that keeps in the situation of work under bad environment.With regard to the angle of market, general enterprises can not adopt expensive most advanced and sophisticated stadimeter in a large number for the consideration of cost control aspect, and the prevailing or low price in market at home adopts the common stadimeter of high performance-price ratio of mature technology.Domestic range finding measuring instrument manufacturer need in the market expansion and skill upgrading slowly but surely progressively catch up with and surpass world's advanced technology, improves enterprise competitiveness.
Summary of the invention
Article of the present invention a kind of hardware invention and its method of work of the supersonic liquid level tracker system based on low-power scm, detailed invention and its performance index of supersonic liquid level tracker system that should be based on low-power scm are the content that the present invention mainly sets forth.
Level gauging is applied to widely all types of industries and measures and control in occasion.For example, in Oil & Gas Storage process, liquid level in Accurate Measurement storage tank is correctly to calculate oil reserve, determine stock, calculate throughput rate, guarantee safe important measures, if it is bad that oil tank level is measured control, the accident such as there will be oil spilling " roof fall " or find time, if oil-gas separator liquid level is higher or on the low side there will be " run oil ", " gas blowby " accident, have a strong impact on the safety of equipment and production.In production of hydrocarbons, particularly in oil-gas gathering and transportation storing and transporting system, oil, rock gas and association sewage will various production equipments and separated in canister, storage with process, the measurement of thing position with control guaranteeing that normal production and device security are vital, otherwise can produce great accident.
Develop rapidly along with new and high technologies such as the signal processing technologies such as computer technology, microelectric technique, sensor technology, digital signal processing (DSP), FPGA (Field Programmable Gate Array) controls (PLC), level gauging technology and level gauging instrument obtained significant progress, to adapt to more and more higher application requirements.It is an important milestone in level gauging technical development process that microprocessor is introduced to liquid level measuring system, and the application of microprocessor makes the precision of liquid level gauge reach unprecedented height.At present, the technology trend of level gauging instrument development both at home and abroad mainly contains following three features: 1, intellectuality; 2, the liquid level gauge of non-contact measurement; 3, the small-scale liquid bit switch of new principle.Particularly the level gauging technology based on new principle is swift and violent in development in recent years, in the level gauging technology of extensively using, and ball float method and obtained utilization the most widely in the ultrasonic Method for Measuring occurring thereafter.
With regard to measurement environment, liquid level measuring system is used in the very severe and complex environment of condition conventionally, the installation environment of liquid level gauge possesses an even multinomial condition in for example high temperature, high pressure, low temperature, low pressure, vacuum, high humility, deep-etching, high radiation, many dust conventionally, and this work accommodation ability to liquid level gauge has proposed strict requirement; With regard to mounting condition, complicated industrial environment has harsh restriction to the installation of liquid level gauge, how accurate complicated liquid level gauge is installed simply and easily also the invention of liquid level gauge has been proposed to requirement; From plant maintenance and device, change, longer non-maintaining time and how to change more easily device under high-risk condition, even shut down and change device, be a huge challenge.
Level gauging technology can be divided into contact measurement and non-cpntact measurement by way of contact classification, by metering system, can be divided into continuous coverage and one-point measurement, by measuring principle, can be divided into:
1, based on manual measurement method: glass tube method, glass plate method, double-colored water level method, hand gauging method;
2, based on hydraulic pressure: air blast, differential pressure method, HTG method;
3, based on law of buoyancy: float method, floating drum method, ball float method, servo method, heavy cylinder method;
4, based on liquid level sensor electrical quantity, change: capacitance method, electric-resistivity method, inductance method;
5, the time based on propagating by detection signal: magnetostriction method, supercritical ultrasonics technology, modulation type optical method, microwave method;
6, other: the polytypes such as magnetic turnover panel method, vibratory drilling method, nuclear radiation method, Fiber Optical Sensor Based.
The testing agency of the liquid-level tracking instrument that the present invention invents is installed in special vehicle fuel tank cap, adopts non-contact measurement, requires that oil mass testing agency measures accurately, volume is little, low in energy consumption, reliability is strong.Because testing agency works in automotive oil tank inside, need to bear the different rugged surroundings such as the interior high temperature of automotive oil tank, high pressure, low temperature, high humility, deep-etching, testing agency under extreme conditions also needs to keep good working order.By to following table 1 to the consulting of table 3, get rid of contact type measurement mode, the present invention determines to adopt ultrasound wave as level gauging mode.
Table 1 liquid level, interface level measurement instrument type selecting table
The common liquid level gauge Performance Ratio of table 2
The usable condition of table 3 liquid level gauge to different medium
Table look-up known, ultrasonic measurement mode precision is high, measures influenced littlely under corrosive medium and liquid gasification environment, is applicable to the measurement to liquid such as gasoline or diesel oil, but installs relatively complicatedly, and expense is relatively high.When for the monitoring of automobile oil mass for example, ultrasonic measurement task is in the present invention relatively simple, due to automobile starting, suddenly stop, during acceleration and deceleration operation, in fuel tank, liquid sloshing is violent, Gu mainly relies on software judgement to remove invalid value to the accurate measurement of Fuel Oil Remaining in fuel tank, not high to the accuracy requirement of measuring.The aerial velocity of propagation of ultrasound wave is approximately 334m/s (under normal temperature condition), velocity of propagation in same medium is relatively constant, compare with the speed (3 * 108m/s) of laser, it is much slow that hyperacoustic velocity of propagation is wanted, therefore by software to the transmitting of ultrasonic pulse signal and much easier with respect to metering systems such as laser to the post-processed of echo time of reception.
Compare with the level gauging mode of other kind, ultrasound wave location has following characteristics:
(1) non-contact measurement: it is inner that ultrasonic transducer can be arranged on special vehicle fuel tank cap, directly do not contact with fluid to be measured, makes to adopt more succinct liquid level gauge invention, facilitates daily servicing.
(2) the reliability high life is long: ultrasonic transducer does not have movable member, does not have the mechanical fault causing because of mechanical wear, thereby its reliability is higher than most liquid level gauges of contact-type metering system that adopt with serviceable life.
(3) suitable environment is wide: ultrasonic measurement mode can measure easily there is strong volatility, corrosivity, liquid that viscosity is larger or poisonous, avoid stained by fluid to be measured,
(4) relatively low cost: the present invention is less demanding to the measuring accuracy of ultrasonic transducer, to the analysis of measurement result, mainly rely on software to realize, therefore can adopt other low cost of entry level, high performance-price ratio ultrasonic transducer, in the situation that guaranteeing measuring accuracy, reduce Costco Wholesale.
The propagation of mechanical vibration in medium forms mechanical wave, and frequency is called ultrasound wave higher than the mechanical wave of 20kHz, and modern ultrasonic technology can obtain the ultrasound wave up to 109Hz frequency.Ultrasound wave has the special nature of a lot of practicalities, for example 1, good directionality; 2, vibration frequency is high; 3, concentration of energy; 4, portability power is large; 5, on two media interface, there is high-energy reflectance etc.Thus, can find out that ultrasound wave is particularly suitable for the measurement of distance.In addition produced in recent years hyperacoustic components and parts is greatly improved and improves in manufacturing process, make ultrasonic technology more and more be subject to the attention of each side, the device instrument that the ultrasound wave of take is principle has been widely used in industrial or agricultural, in war industry and daily life.
The physical influence generation frequency of utilization electricity and magnetic is the hyperacoustic important method of artificial generation higher than the high-frequency mechanical vibration of 20kHz.
(1) piezoelectric-type ultrasonic generator: the crystal-cut such as quartz, barium titanate are become after suitable shape, its surface is added to an alternating voltage, along with the no continuous variation of plane of crystal positive and negative charge, wafer can be done mechanical-stretching motion rapidly along with the variation of electric charge.Because alternating voltage can reach very high frequency, voltage acts on the propagation in medium of high-frequency mechanical vibration that wafer produces and produces ultrasound wave thus.
(2) magnetostrictive ultrasound generator: some metal material that nickel, alfer etc. has magnetostrictive effect can produce mechanical-stretching distortion under the effect of alternating magnetic field, the material that this class is had to a magnetostrictive effect is made plug shape and is positioned over the high-frequency mechanical vibration that can cause material in the coil that is connected with high-frequency alternating electric current, thereby produces ultrasound wave.
Hyperacoustic fundamental property:
(1) good directionality: ultrasound wave wavelength is very short, so the impact that diffraction effect produces the direction of propagating is little, makes ultrasonic energy can concentrate bunchy, hyperacoustic this characteristic makes ultrasound wave be widely used at aspects such as range findings.
(2) can there is the sound intensity of large intensity: because hyperacoustic frequency can reach very high (modern ultrasonic technology can obtain the ultrasound wave up to 109Hz frequency), therefore, the highest sound intensity obtaining up to 5000Wcm-2, this intensity is enough to smash metal, the object that adamas etc. are hard.
(3) additional sound pressure level is large: ultrasound wave can have the very large sound intensity, can cause larger sound pressure amplitudes.Hyperacoustic this characteristic can be so that the additional sound pressure level of medium increases and causes the tension and compression effect to medium in the short time, in liquid, produce " cavitation " or " cavitation phenomenon ", cause instantaneous formation minute bubbles in liquid, bubble under specific condition can cause resonance, thereby produces increasing temperature and pressure and electric discharge texts at liquid internal.
(4) penetration power is strong: decay when ultrasound wave is propagated in liquid, solid is very little, can easier penetrate the solid thickness of tens meters.
(5) significant reflecting effect: if having obvious reflection when ultrasound wave runs into the interphase of different medium in communication process.Numerous application such as the detection that this characteristic is submarine sonar, nondestructive examination, liquid level range finding, human lesion research provide scientific basis.
The relation of the velocity of sound and temperature and medium: hyperacoustic velocity of propagation is subject to temperature, the impact of the factors such as medium kind, following table 4 and table 5 are respectively relation table and the parameters,acoustic of sound wave in different medium of the velocity of sound and temperature.While adopting the interior liquid level of ultrasound examination fuel tank, because fuel tank environment of living in is changeable, thereby oily the temperature inside the box is subject to ectocine, changes and affect the velocity of sound, if can impact the degree of accuracy of measuring without suitable amendment scheme.
The gasoline of storing in fuel tank, diesel oil etc. are effumability liquid, if temperature is higher, fuel oil volatilization is serious, gas in fuel tank between liquid level and transducer non-air but the large many mixed gass of density ratio air, the medium that now can be equal to ultrasonic transmission changes, for guaranteeing measuring accuracy, the velocity of propagation of ultrasound wave in different medium need to be discussed.
The relation of table 4 velocity of sound and temperature
| Temperature (℃) | 14 | 16 | 20 | 23 | 26 |
| Speed (m/s) | 339.84 | 341.02 | 343.37 | 345.12 | 346.87 |
Parameters,acoustic in table 5 different medium
Computing formula used when real work of the present invention should, on theoretical calculation formula basis, obtain by continuous debugging and correction.A large amount of test datas by analysis, finally obtain oil mass computing formula for (take cuboid container as example):
Theoretical calculating: h1=t * ((331+T * 0.6)/2) (1-1)
Actual correction calculation: h=h1-h1/50-h1/15 (h1<60)
h=h1-h1／25-h1／15 (h1≥60) (1-2)
Liquid measure is calculated: V=(H-h) * L * W (1-3)
Wherein: h1: calculated value (mm);
T: time (s);
T: temperature (℃);
H: corrected value (mm);
L: liquid case length (mm);
W: liquid case width (mm);
V: liquid casing amasss (mm3)
Hardware invention:
A kind of supersonic liquid level tracker system based on low-power scm, it is comprised of two parts, comprise that the low power-consumption liquid level registering instrument and being installed in testee is for collecting the historical data of liquid level recorder instrument, and then can import the laggard line program statistical study of Computer Database, the low power-consumption liquid level of monitoring easily liquid level situation of change in visual mode records hand-held PDA.
Low power-consumption liquid level registering instrument, it has following functions module:
Minimum system:
Minimum system comprises power circuit, and low power-consumption liquid level registering instrument adopts three joint dry cell series-feds, and the input voltage of 4.5V is provided, and input voltage is to ultrasonic wave module, and the modules such as temperature compensation are directly powered.Single-chip microcomputer and LCD MODULE that registering instrument is detected are adopted to 3.3V power supply, adopt two joint dry cell series-feds; Crystal oscillating circuit, the basic clock module of single-chip microcomputer is mainly comprised of parts such as numerically-controlled oscillator DCO, low frequency crystal oscillator LFXT1, high frequency crystal oscillator LFXT2, in order to export the clock of 3 kinds of different frequencies: MCLK (main system clock), SMCLK (subsystem time), ACLK (auxiliary clock).Inventing a plurality of clock sources is in order to solve the contradictory relation between processing speed and low-power consumption, when different working modes, make system works can in the situation that meeting system needs, reduce system power dissipation under different clock sources, low-power scm of the present invention is controlled oscillator DCO at inner integrated digital, so need invention low frequency crystal oscillator and high frequency crystal oscillator two parts circuit in system invention.Low frequency crystal oscillator LFXT1 supports super low-power consumption, and it uses the crystal of a 32.768kHz under low frequency mode.This crystal can directly not be connected on XIN and XOUT pin by any electric capacity.Low frequency crystal oscillator LFXT1 is generally operational in the 32.768kHz low frequency mode of acquiescence, also can support high frequency mode and high speed crystal by additional electric capacity, we use low frequency mode in the present invention, and crystal oscillator is directly connected on single-chip microcomputer through XIN and XOUT.High frequency crystal oscillator LFXT2 is also referred to as the second oscillator XT2, and it provides clock signal XT2CLK while being operated in high frequency mode for single-chip microcomputer, and the frequency of the external high frequency oscillator of low-power scm is 450kHz to 8MHz.In native system, the second oscillator XT2 adopts the crystal of 8MHz, and the electric capacity of external 2 33pF of XT2 is connected to XT2IN and XT2OUT; Reset circuit generally all should have reset circuit corresponding thereto in comprising the Circuits System of controller, could after system powers on, reset well like this, makes system in stable running status.Simple reset circuit generally can be divided into RC and reset and chip reset, and chip reset mode has very high stability and reliability, and cheap more unstable but RC resets, reliability is not high, can not adopt in high speed and huge system.The present invention is comparatively simple, and RC resets and two kinds of modes of chip reset all can adopt, and for cost-saving, native system adopts RC reset mode.
Ultrasonic wave module:
Ultrasonic wave module is the core component of measurement function in the present invention, is generally divided into transmitter and receiver two parts.Of the present invention is DYP-ME007 ultrasonic distance measuring module, and its frequency of operation is 40Hz, BURN-THROUGH RANGE 3.5m, nearest detection range 3cm, absolute error ± 3mm.
T/R40-16 type ultrasonic sensor performance parameter is as shown in table 6:
Table 6T/R40-16 type ultrasonic sensor performance parameter table
Ultrasonic sensor has different acoustic pressure energy level and sensitivity under different frequency of operation, generally the working range of sensor is controlled to each performance index optimum condition.T/R40-16 ultrasonic sensor is when incoming frequency is 40kHz, and each characteristic is all in optimum Working, and therefore in order to obtain best result of use, must to make single-chip microcomputer output wave frequency be 40kHz.
Low-power scm is by the pulse of Trig port input 10ms, trigger ultrasonic wave module preliminary work, when receiving high level, catch register CCR0 and start timing, transmitter sends ultrasound wave to medium simultaneously, when receiving echoed signal, ECHO port becomes low level immediately, and register stops timing, so the time of high level is exactly the time of transmission.CJ_PW pin is the control pin of low-power scm to ultrasonic wave module switch.
Infrared module:
The liquid level data that low power-consumption liquid level registering instrument records is stored in the E2PROM storer carrying, when storage data are full or need derived data, the historical data that the infrared data communication function that user can carry by vehicle-mounted oil mass registering instrument and infrared copy meter PDA is collected each tested vehicle oil consumption registering instrument.
When carrying out data transmission, vehicle-mounted oil mass registering instrument transfers data to infrared emission head by transceiver, then by infrared emission head, data transmission is arrived to outside receiving equipment.In the present invention, we adopt the UART Universal Asynchronous Receiver Transmitter MAX3100CEE chip of MAXIM company and the serial infrared transceiver module TFDU4100 of U.S. Vishay (prestige generation) company.
MAX3100 UART Universal Asynchronous Receiver Transmitter:
The feature of MAX3100:
1, support high-speed communication, highest communication baud rate can reach 230kbps;
2, can work in the system of upper frequency;
3, support low-voltage, low-power consumption;
4, chip volume is little, can save and print version space;
5, support infrared communication;
MAX3100 chip has DIP, tri-kinds of packing forms of QSOP and TQFN-EP, and it is QSOP encapsulation that the present invention can adopt MAX3100CEE: TFDU4100 serial infrared transceiver module:
The TFDU4100 serial infrared transceiver module that infrared emission partly adopts U.S. Vishay (prestige generation) company to release.This module meets IrDA1.2 serial infrared transmission standard, and its highest Infrared Transmission speed can reach 115.2Kbit/s, the parts such as infrared emission, transmission, control IC that this Infrared Transmission inside modules is integrated.
The characteristic of TFDU4100 infrared transceiver module has:
1, meet IrDA1.2 serial infrared transmission standard;
2, operating voltage (2.7V-5.5V) in a big way;
3, by Vccl/SD port, can control module enter low-power consumption dormant state;
4, larger transmission range (can reach 3m when 115.2Kbit/s);
5, inner with over-pressure safety device, do not need annex;
Low-power scm is controlled MAX3100 chip by SHDN pin and whether is entered standby mode, IRQ pin is triggered and is interrupted by low level, the DIN of MAX3100 chip, DOUT, SLCK, tetra-pins of CS are responsible for communication and control, and its effect is respectively data input, data output, communication clock is controlled and the chip selection signal of MAX3100.
Temperature compensation module:
Temperature is mainly reflected in two aspects to the impact of vehicle-mounted oil mass registering instrument measuring accuracy.The one, the impact of temperature on ultrasonic propagation velocity; The 2nd, the impact of transmission medium on ultrasonic transmission speed.Gasoline, the fuel oils such as diesel oil are volatile liquid, and in the situation that temperature is higher, fuel oil volatilization is serious, and now the medium of ultrasonic transmission is the gas between liquid level and transducer non-air but the large many mixed gas of density ratio air in fuel tank.
Hyperacoustic velocity of propagation and temperature have close relationship, and the approximate formula of its conversion is formula (3-1):
C=Co+0.607×T (3-1)
Acoustic velocity 332m/s when Co is 0 ℃ in formula, T be actual temperature (℃).
If can obtain the temperature of current measurement environment, can to data result, revise by software, so we add temperature compensation module in vehicle-mounted oil mass registering instrument.
The LM35 temperature sensor that the National of being Semiconductor of the present invention (National Semiconductor) produces.The voltage linear that LM35 temperature sensor is exported corresponding with Celsius temperature, easy to use, superior more many than the linear temperature sensor of pressing absolute temperature scale (ATS) calibration.This transducer sensitivity is 10.0mV/ ℃, precision is 0.4 ℃ to 0.8 ℃ (in 55 ℃ to+150 ℃ temperature ranges), in static temperature, self-heating effect is 0.08 ℃, operating voltage is wider, can in 4 to 20V voltage range, normally work, reproducible, low output impedance, can single supply and positive-negative power work.In addition, LM35 quiescent current approximately 50 μ A at 25 ℃ when single supply pattern, very power saving, meets the invention requirement of low-power consumption of the present invention.
LM35 pin is described below:
1, Vout: digital signal input/output terminal;
2, GND: power supply ground;
3 ,+Vs: external power supply input end (ground connection when the parasite power mode of connection);
Temperature compensation module, wherein TEM_PW pin is the control pin of single-chip microcomputer to temperature compensation module switch, TEM pin meets the A/D pin P6.3/A3 of low-power scm.
Clock module:
PCF8563 of the present invention is a multifunction timepiece/calendar chip with extremely low power dissipation that PHILIPS (Philip) company releases.PCF8563 is a technical grade product, has the several functions such as warning, timer, clock output, is the high clock chip of a cost performance.This chip has been widely used in each production field at present.
PCF8563 has 16 eight bit registers, comprising: the I2C bus interface of address register, built-in 32.768kHz oscillator (with an inner integrated capacitance), frequency divider, programmable clock out, timer, alarm, detection of power loss device and 400kHz that can auto-increment.
The present invention selects this chip to be mainly because its extremely low power consumption and excellent performance performance.
Each pin function of PCF8563 clock chip is as follows:
Table 7PCF8563 clock chip pin function abridged table
| Symbol | Number of pins | Function |
| OSCI | 1 | Oscillator input |
| OSCO | 2 | Oscillator output |
| INT | 3 | Interrupt output (is opened leakage; Low level effective) |
| VSS | 4 | Power supply ground |
| SDA | 5 | Serial data I/O |
| SCL | 6 | Serial clock input |
| CLKOUT | 7 | Clock output (opening Lou) |
| VDD | 8 | Positive supply |
The characteristic of PCF8563 clock chip:
The characteristic abridged table of table 8PCF8563 clock chip
PCF8563 clock chip triggers INT pin opening timing by low level, with I2C bus P_SCLK, P_SDA transmission information.
E2PROM memory module:
Vehicle-mounted oil mass tracker can be stored in local E2PROM storer by oil tank liquid level information after regularly detecting the oil tank liquid level state of tested vehicle, for importing computer, carries out data analysis.The present invention adopts the AT24C04 chip of U.S. ATMEL (liking special Mel) company as storer.
AT24C04 is a kind of Serial E 2PROM storer of CMOS manufacturing process, has the storage space of 4K.In invention, can adopt the storer that the storage spaces such as AT24C16 are larger, to increase memory space, extending data derives the cycle, makes tracker performance better.In view of too small can not the satisfying the demand of storage space of AT24C04, FLASH storage space and the E2PROM memory module of on brassboard, taking low-power scm to carry 60K are used in conjunction with.As calculated, the storage space of 50K can meet trimestral storage needs.
Each pin function of AT24C04 is as shown in table 9 below:
Table 9AT24C04 pin function abridged table
| Pin title | Number of pins | Function |
| A0、A1、A2 | 1、2、3 | Address of devices is selected |
| SDA | 5 | Serial data input/output terminal |
| SCL | 6 | Serial clock input end |
| WP | 7 | Write-protect input end |
| Vcc | 8 | Power positive end (+1.8V to 6.0V operating voltage) |
| Vss | 4 | Power supply ground |
The hardware invention of E2PROM memory module, EEP_PW pin is the control pin of low-power scm to this module switch.EEP_SDA and EEP_SCL pin order sheet under-chassis P3.6 and P3.7 two pins.
Key-press module:
The number of keys that will use required for the present invention is less, adopts free-standing button invention, and a button occupies separately an I/O mouth.Button one end ground connection in circuit invention, the other end is connected with certain I/O mouth of single-chip microcomputer, after starting working, give I/O poll tax on children one high level, single-chip microcomputer constantly detects this I/O mouth and whether becomes low level, when button is closed, be equivalent to this I/O mouth and join by button and ground, become low level, once program detects I/O mouth, become low level, illustrate that button is pressed, then carry out corresponding instruction.Can directly connect the duty that a LED light emitting diode carry out display system at I/O mouth in invention circuit.
If increase other functions such as wireless module in the present invention, while needing more button operations, can adopt the invention of determinant (matrix form) keyboard.Matrix keyboard two ends are all connected with single-chip processor i/o mouth, during detection, first send a certain low level of classifying as, all the other several row are high level, then immediately Polling once each row whether have low level, if can confirm that the button being pressed is which row of which row just a certain behavior low level detected.This invention mode can greatly reduce I/O mouth use amount when number of keys is more.
Low power-consumption liquid level records hand-held PDA:
Low power-consumption liquid level records hand-held PDA and has following functions module: the minimum system different from above-mentioned minimum system structure according to actual conditions structure based on low-power scm, infrared communication module, key control module, local LCD MODULE, SD card interface module, RS232 communication module.Infrared communication module is responsible for communicating by letter with oil mass detector, receives the liquid level data of oil mass detector storage, can arrange the systematic parameter of oil mass detector simultaneously; Data processing memory module stores the infrared data that receive into local SD card; Computer can be configured infrared copy meter instrument by RS232 interface.The low-power scm that low power-consumption liquid level registering instrument and low power-consumption liquid level record in hand-held PDA can adopt MSP430 single-chip microcomputer.
A kind of noncontact box lid type vehicle fuel quantity tracker that the present invention can provide a kind of frame model based on above-mentioned " the supersonic liquid level tracker system based on low-power scm " to develop, for example:
A noncontact box lid type vehicle fuel quantity tracker, its invention structure and performance index are as follows:
The level gauging degree of depth can reach 1.3m, oil mass time data memory can reach 3 months, dormancy working current is less than 0.1mA, 3 joint 1.5V dry cells can reach 3 months service time, infrared communication speed can reach 115200bps, and infrared communication distance can reach 1.5m, and infrared copy meter instrument has the storage of 1G SD card, be connected and be configured with computer RS232 interface, host computer adopts MS SQL-Server database to carry out data storage.
Its main contents comprise following a few part:
(1) vehicle-mounted oil mass registering instrument
Vehicle-mounted oil mass registering instrument be take low-power scm as processing core, extends out ultrasonic measurement circuit, oil mass record storage E2PROM circuit, temperature survey compensating circuit, infrared communication module, real-time clock module, power management module.Temperature compensation module is used for measuring temperature value ultrasonic velocity is revised, and time when real-time clock module is used for record measurement liquid level, infrared communication module is for sending to infrared copy meter PDA by the oil mass data of measurement.
(2) infrared copy meter PDA
Infrared copy meter PDA, for gathering the historical oil mass data of a plurality of vehicle-mounted oil mass registering instruments, be take low-power scm equally as processing core, extends out infrared communication module, key control module, local LCD MODULE, SD card interface module, RS232 communication module.Infrared communication module is responsible for communicating by letter with oil mass detector, receives the liquid level data of oil mass detector storage, can arrange the systematic parameter of oil mass detector simultaneously; Data processing memory module stores the infrared data that receive into local SD card; Computer can be configured infrared copy meter instrument by RS232 interface.
A kind of technical scheme that can be used is as follows:
A low power-consumption liquid level registering instrument, is characterized in that, comprises as follows:
(1) be installed on the low power-consumption liquid level registering instrument of testee top;
(2) low power-consumption liquid level records hand-held PDA, low power-consumption liquid level record hand-held PDA (2) corresponding at least one can with the low power-consumption liquid level registering instrument (1) of its pairing, a low power-consumption liquid level records information and the storage that hand-held PDA (2) can record one or more low power-consumption liquid level registering instruments (1).
Above-mentioned low power-consumption liquid level registering instrument, is characterized in that: have
Minimum system, described minimum system at least comprises power circuit, crystal oscillating circuit, reset circuit, described minimum system is used for making low-power scm can at least be provided electric energy, vibration and reset signal;
Sound wave module, described sound wave module is divided into transmitter and receiver two parts, for transmitting and reception acoustic signals, for offering low-power scm;
Infrared module, records between hand-held PDA and carries out data transmission for low power-consumption liquid level registering instrument and low power-consumption liquid level, and meanwhile, infrared module also can adopt known any data transfer means, bluetooth for example, wireless network, cable network;
, due to temperature, there is indivisible being closely connected between sonic transmissions speed and transmission medium three in temperature compensation module, low power-consumption liquid level registering instrument comprises temperature compensation module, for range finding is proofreaied and correct;
Clock module, for providing clock signal;
Memory module, the data that monitor for storing low power-consumption liquid level registering instrument, and storage;
Key-press module, for power consumption liquid level recorder instrument is controlled, key-press module adopts the mode of scan control to carry out signal input:
The processing core of low power-consumption liquid level registering instrument also can arrange based on DSP.
Above-mentioned low power-consumption liquid level registering instrument, is characterized in that: the power electronic devices in the sound wave liquid level logging recorder system based on low power-consumption liquid level registering instrument is preferentially selected the device based on memristor, and wherein, memory module adopts the storer based on memristor.
Above-mentioned low power-consumption liquid level registering instrument, it is characterized in that: each low power-consumption liquid level registering instrument (1) records hand-held PDA (2) from each low power-consumption liquid level and all has different data encodings, when this coding is used for making low power-consumption liquid level registering instrument (1) and low power-consumption liquid level to record hand-held PDA (2) carrying out data transmission, low power-consumption liquid level records hand-held PDA (2) can judge which platform connected low power-consumption liquid level registering instrument (1) is, or why encode, so that each low power-consumption liquid level registering instrument (1) can be judged identification, be not confused.
Above-mentioned low power-consumption liquid level registering instrument, is characterized in that: low power-consumption liquid level registering instrument (1) or low power-consumption liquid level record the medium that can manually set sonic transmissions on hand-held PDA (2), and when manually arranging, medium is defaulted as oil gas mixture.
Above-mentioned low power-consumption liquid level registering instrument, it is characterized in that: low-power scm is controlled MAX3100 chip by SHDN pin and whether entered standby mode, IRQ pin is triggered and is interrupted by low level, the DIN of MAX3100 chip, DOUT, SLCK, tetra-pins of CS are responsible for communication and control, and its effect is respectively data input, data output, communication clock is controlled and the chip selection signal of MAX3100.
Above-mentioned low power-consumption liquid level registering instrument, it is characterized in that: memory module adopts the AT24C04 chip of U.S. ATMEL (liking special Mel) company as storer, AT24C04 is a kind of Serial E 2PROM storer of CMOS manufacturing process, the storage space that has 4K, when too small can not the satisfying the demand of storage space of AT24C04, on on printed circuit board (PCB), take FLASH storage space and E2PROM memory module that low-power scm carries to be used in conjunction with, make its storage space at least can meet trimestral storage needs.
Above-mentioned low power-consumption liquid level registering instrument, it is characterized in that: low-power scm is by the pulse of Trig port input 10ms, trigger ultrasonic wave module preliminary work, when receiving high level, catch register CCR0 and start timing, transmitter sends ultrasound wave to medium simultaneously, when receiving echoed signal, ECHO port becomes low level immediately, register stops timing, thus the time of high level be exactly transmission time, CJ_PW pin is the control pin of low-power scm to ultrasonic wave module switch.
A kind of computing method of the technical scheme that can be used are as follows:
A method for liquid-level tracking, is characterized in that, liquid-level tracking method comprises theoretical calculating and actual correction calculation two parts, wherein,
Theoretical calculation formula is:
h1=t×((331+T×0.6)／2) (1-1)
Actual correction calculation formula is:
h=h1-h1／50-h1／15 (h1<60)
h=h1-h1／25-h1／15 (h1≥60) (1-2)
Liquid measure is calculated:
V=(H-h)×L×W (1-3)
Wherein:
H1: calculated value (mm);
T: time (s);
T: temperature (℃);
H: corrected value (mm);
L: liquid case length (mm);
W: liquid case width (mm);
V: liquid casing amasss (mm3)
A kind of method for liquid-level tracking described above, is characterized in that, is calculating liquid level theoretical value, the actual corrected value of liquid level, liquid measure value, or any when relating to data and calculating, if there is data from overflow, crash to wait while causing the not normal situation of liquid-level tracking, end process, and autoboot carries out.
The present invention can be used for for example following occasion: the oil mass pick-up unit of vehicle is generally built in vehicle inner oil tube at present, by flowing through the oil mass testing agency of oil pipe, carries out real-time fuel consumption calculating, and then feedback measured value is to control desk.This oil mass pick-up unit has just been closed after vehicle stop starts, cannot realize oil mass service condition do not interrupt supervision.The present invention can be modified to a kind of engineering truck oil mass tracker that utilizes non-contact ultrasonic range finding, be placed in the case lid of fuel tank, with low-power consumption wake-up mode, regularly detect the fluid level condition of oil tank of vehicle, according to the tank model setting in advance, calculate fuel consumption and be stored in local storage.After operation a period of time, can collect by hand-held PDA the historical data of each vehicle oil consumption registering instrument, import the laggard line program statistical study of Computer Database, with the visual mode use fuel oil situation of monitor vehicle easily, control malice stolen event.Oil comsumption recorder can also configure wireless module, and oil consumption record can be real-time transmitted to vehicle-mounted GPRS service centre.
Noncontact box lid type vehicle fuel quantity tracker can be widely used in the fuel oil service condition supervision that vehicle transport team, steelworks fleet, engineering truck taxi company, building operation Dui Deng unit carry out engineering truck.Have a wide range of applications occasion, also there is certain economic benefit.
Accompanying drawing explanation
Fig. 1 is ultrasonic ranging principle schematic.
embodiment
A kind of supersonic liquid level tracker system based on low-power scm, it is comprised of two parts, comprise that the low power-consumption liquid level registering instrument and being installed in testee is for collecting the historical data of liquid level recorder instrument, and then can import the laggard line program statistical study of Computer Database, the low power-consumption liquid level of monitoring easily liquid level situation of change in visual mode records hand-held PDA.
Low power-consumption liquid level registering instrument, it has following functions module:
Minimum system:
Minimum system comprises power circuit, and low power-consumption liquid level registering instrument adopts three joint dry cell series-feds, and the input voltage of 4.5V is provided, and input voltage is to ultrasonic wave module, and the modules such as temperature compensation are directly powered.Single-chip microcomputer and LCD MODULE that registering instrument is detected are adopted to 3.3V power supply, adopt two joint dry cell series-feds; Crystal oscillating circuit, the basic clock module of single-chip microcomputer is mainly comprised of parts such as numerically-controlled oscillator DCO, low frequency crystal oscillator LFXT1, high frequency crystal oscillator LFXT2, in order to export the clock of 3 kinds of different frequencies: MCLK (main system clock), SMCLK (subsystem time), ACLK (auxiliary clock).Inventing a plurality of clock sources is in order to solve the contradictory relation between processing speed and low-power consumption, when different working modes, make system works can in the situation that meeting system needs, reduce system power dissipation under different clock sources, low-power scm of the present invention is controlled oscillator DCO at inner integrated digital, so need invention low frequency crystal oscillator and high frequency crystal oscillator two parts circuit in system invention.Low frequency crystal oscillator LFXT1 supports super low-power consumption, and it uses the crystal of a 32.768kHz under low frequency mode.This crystal can directly not be connected on XIN and XOUT pin by any electric capacity.Low frequency crystal oscillator LFXT1 is generally operational in the 32.768kHz low frequency mode of acquiescence, also can support high frequency mode and high speed crystal by additional electric capacity, we use low frequency mode in the present invention, and crystal oscillator is directly connected on single-chip microcomputer through XIN and XOUT.High frequency crystal oscillator LFXT2 is also referred to as the second oscillator XT2, and it provides clock signal XT2CLK while being operated in high frequency mode for single-chip microcomputer, and the frequency of the external high frequency oscillator of low-power scm is 450kHz to 8MHz.In native system, the second oscillator XT2 adopts the crystal of 8MHz, and the electric capacity of external 2 33pF of XT2 is connected to XT2IN and XT2OUT; Reset circuit generally all should have reset circuit corresponding thereto in comprising the Circuits System of controller, could after system powers on, reset well like this, makes system in stable running status.Simple reset circuit generally can be divided into RC and reset and chip reset, and chip reset mode has very high stability and reliability, and cheap more unstable but RC resets, reliability is not high, can not adopt in high speed and huge system.The present invention is comparatively simple, and RC resets and two kinds of modes of chip reset all can adopt, and for cost-saving, native system adopts RC reset mode.
Ultrasonic wave module:
Ultrasonic wave module is the core component of measurement function in the present invention, is generally divided into transmitter and receiver two parts.Of the present invention is DYP-ME007 ultrasonic distance measuring module, and its frequency of operation is 40Hz, BURN-THROUGH RANGE 3.5m, nearest detection range 3cm, absolute error ± 3mm.
Ultrasonic sensor has different acoustic pressure energy level and sensitivity under different frequency of operation, generally the working range of sensor is controlled to each performance index optimum condition.T/R40-16 ultrasonic sensor is when incoming frequency is 40kHz, and each characteristic is all in optimum Working, and therefore in order to obtain best result of use, must to make single-chip microcomputer output wave frequency be 40kHz.
Low-power scm is by the pulse of Trig port input 10ms, trigger ultrasonic wave module preliminary work, when receiving high level, catch register CCR0 and start timing, transmitter sends ultrasound wave to medium simultaneously, when receiving echoed signal, ECHO port becomes low level immediately, and register stops timing, so the time of high level is exactly the time of transmission.CJ_PW pin is the control pin of low-power scm to ultrasonic wave module switch.
Infrared module:
The liquid level data that low power-consumption liquid level registering instrument records is stored in the E2PROM storer carrying, when storage data are full or need derived data, the historical data that the infrared data communication function that user can carry by vehicle-mounted oil mass registering instrument and infrared copy meter PDA is collected each tested vehicle oil consumption registering instrument.
When carrying out data transmission, vehicle-mounted oil mass registering instrument transfers data to infrared emission head by transceiver, then by infrared emission head, data transmission is arrived to outside receiving equipment.In the present invention, we adopt the UART Universal Asynchronous Receiver Transmitter MAX3100CEE chip of MAXIM company and the serial infrared transceiver module TFDU4100 of U.S. Vishay (prestige generation) company.
MAX3100 UART Universal Asynchronous Receiver Transmitter:
The feature of MAX3100:
1, support high-speed communication, highest communication baud rate can reach 230kbps;
2, can work in the system of upper frequency;
3, support low-voltage, low-power consumption;
4, chip volume is little, can save and print version space;
5, support infrared communication;
MAX3100 chip has DIP, tri-kinds of packing forms of QSOP and TQFN-EP, and it is QSOP encapsulation that the present invention can adopt MAX3100CEE: TFDU4100 serial infrared transceiver module:
The TFDU4100 serial infrared transceiver module that infrared emission partly adopts U.S. Vishay (prestige generation) company to release.This module meets IrDAl.2 serial infrared transmission standard, and its highest Infrared Transmission speed can reach 115.2Kbit/s, the parts such as infrared emission, transmission, control IC that this Infrared Transmission inside modules is integrated.
The characteristic of TFDU4100 infrared transceiver module has:
1, meet IrDA1.2 serial infrared transmission standard;
2, operating voltage (2.7V-5.5V) in a big way;
3, by Vccl/SD port, can control module enter low-power consumption dormant state;
4, larger transmission range (can reach 3m when 115.2Kbit/s);
5, inner with over-pressure safety device, do not need annex;
Low-power scm is controlled MAX3100 chip by SHDN pin and whether is entered standby mode, IRQ pin is triggered and is interrupted by low level, the DIN of MAX3100 chip, DOUT, SLCK, tetra-pins of CS are responsible for communication and control, and its effect is respectively data input, data output, communication clock is controlled and the chip selection signal of MAX3100.
Temperature compensation module:
Temperature is mainly reflected in two aspects to the impact of vehicle-mounted oil mass registering instrument measuring accuracy.The one, the impact of temperature on ultrasonic propagation velocity; The 2nd, the impact of transmission medium on ultrasonic transmission speed.Gasoline, the fuel oils such as diesel oil are volatile liquid, and in the situation that temperature is higher, fuel oil volatilization is serious, and now the medium of ultrasonic transmission is the gas between liquid level and transducer non-air but the large many mixed gas of density ratio air in fuel tank.
Hyperacoustic velocity of propagation and temperature have close relationship, and the approximate formula of its conversion is formula (3-1):
C=Co+0.607×T (3-1)
Acoustic velocity 332m/s when Co is 0 ℃ in formula, T be actual temperature (℃).
If can obtain the temperature of current measurement environment, can to data result, revise by software, so we add temperature compensation module in vehicle-mounted oil mass registering instrument.
The LM35 temperature sensor that the National of being Semiconductor of the present invention (National Semiconductor) produces.The voltage linear that LM35 temperature sensor is exported corresponding with Celsius temperature, easy to use, superior more many than the linear temperature sensor of pressing absolute temperature scale (ATS) calibration.This transducer sensitivity is 10.0mV/ ℃, precision is 0.4 ℃ to 0.8 ℃ (in 55 ℃ to+150 ℃ temperature ranges), in static temperature, self-heating effect is 0.08 ℃, operating voltage is wider, can in 4 to 20V voltage range, normally work, reproducible, low output impedance, can single supply and positive-negative power work.In addition, LM35 quiescent current approximately 50 μ A at 25 ℃ when single supply pattern, very power saving, meets the invention requirement of low-power consumption of the present invention.
LM35 pin is described below:
1, Vout: digital signal input/output terminal;
2, GND: power supply ground;
3 ,+Vs: external power supply input end (ground connection when the parasite power mode of connection);
Temperature compensation module, wherein TEM_PW pin is the control pin of single-chip microcomputer to temperature compensation module switch, TEM pin meets the A/D pin P6.3/A3 of low-power scm.
Clock module:
PCF8563 of the present invention is a multifunction timepiece/calendar chip with extremely low power dissipation that PHILIPS (Philip) company releases.PCF8563 is a technical grade product, has the several functions such as warning, timer, clock output, is the high clock chip of a cost performance.This chip has been widely used in each production field at present.
PCF8563 has 16 eight bit registers, comprising: the I2C bus interface of address register, built-in 32.768kHz oscillator (with an inner integrated capacitance), frequency divider, programmable clock out, timer, alarm, detection of power loss device and 400kHz that can auto-increment.
The present invention selects this chip to be mainly because its extremely low power consumption and excellent performance performance.
PCF8563 clock chip triggers INT pin opening timing by low level, with I2C bus P_SCLK, P_SDA transmission information.
E2PROM memory module:
Vehicle-mounted oil mass tracker can be stored in local E2PROM storer by oil tank liquid level information after regularly detecting the oil tank liquid level state of tested vehicle, for importing computer, carries out data analysis.The present invention adopts the AT24C04 chip of U.S. ATMEL (liking special Mel) company as storer.
AT24C04 is a kind of Serial E 2PROM storer of CMOS manufacturing process, has the storage space of 4K.In invention, can adopt the storer that the storage spaces such as AT24C16 are larger, to increase memory space, extending data derives the cycle, makes tracker performance better.In view of too small can not the satisfying the demand of storage space of AT24C04, FLASH storage space and the E2PROM memory module of on brassboard, taking low-power scm to carry 60K are used in conjunction with.As calculated, the storage space of 50K can meet trimestral storage needs.
The hardware invention of E2PROM memory module, EEP_PW pin is the control pin of low-power scm to this module switch.EEP_SDA and EEP_SCL pin order sheet under-chassis P3.6 and P3.7 two pins.
Key-press module:
The number of keys that will use required for the present invention is less, adopts free-standing button invention, and a button occupies separately an I/O mouth.Button one end ground connection in circuit invention, the other end is connected with certain I/O mouth of single-chip microcomputer, after starting working, give I/O poll tax on children one high level, single-chip microcomputer constantly detects this I/O mouth and whether becomes low level, when button is closed, be equivalent to this I/O mouth and join by button and ground, become low level, once program detects I/O mouth, become low level, illustrate that button is pressed, then carry out corresponding instruction.Can directly connect the duty that a LED light emitting diode carry out display system at I/O mouth in invention circuit.
If increase other functions such as wireless module in the present invention, while needing more button operations, can adopt the invention of determinant (matrix form) keyboard.Matrix keyboard two ends are all connected with single-chip processor i/o mouth, during detection, first send a certain low level of classifying as, all the other several row are high level, then immediately Polling once each row whether have low level, if can confirm that the button being pressed is which row of which row just a certain behavior low level detected.This invention mode can greatly reduce I/O mouth use amount when number of keys is more.
Low power-consumption liquid level records hand-held PDA:
Low power-consumption liquid level records hand-held PDA and has following functions module: the minimum system different from above-mentioned minimum system structure according to actual conditions structure based on low-power scm, infrared communication module, key control module, local LCD MODULE, SD card interface module, RS232 communication module.Infrared communication module is responsible for communicating by letter with oil mass detector, receives the liquid level data of oil mass detector storage, can arrange the systematic parameter of oil mass detector simultaneously; Data processing memory module stores the infrared data that receive into local SD card; Computer can be configured infrared copy meter instrument by RS232 interface.
Computing formula used when real work of the present invention should, on theoretical calculation formula basis, obtain by continuous debugging and correction.A large amount of test datas by analysis, finally obtain oil mass computing formula for (take cuboid container as example):
Theoretical calculating: h1=t * (331+T * 0.6)/2 (1-1)
Actual correction calculation: h=h1-h1/50-h1/15 (h1<60)
h=h1-h1／25-h1／15 (h1>>60) (1-2)
Liquid measure is calculated: V=(H-h) * L * W (1-3)
Wherein: h1: calculated value (mm);
T: time (s);
T: temperature (℃);
H: corrected value (mm);
L: fuel tank length (mm);
W: fuel tank width (mm);
V: oil mass volume (mm3)
The present invention can provide a kind of noncontact box lid type vehicle fuel quantity tracker that a kind of frame model based on above-mentioned " the supersonic liquid level tracker system based on low-power scm " develops as embodiments of the invention:
A noncontact box lid type vehicle fuel quantity tracker, its invention structure and performance index are as follows:
The level gauging degree of depth can reach 1.3m, oil mass time data memory can reach 3 months, dormancy working current is less than 0.1mA, 3 joint 1.5V dry cells can reach 3 months service time, infrared communication speed can reach 115200bps, and infrared communication distance can reach 1.5m, and infrared copy meter instrument has the storage of 1G SD card, be connected and be configured with computer RS232 interface, host computer adopts MS SQL-Server database to carry out data storage.
Its main contents comprise following a few part:
(1) vehicle-mounted oil mass registering instrument
Vehicle-mounted oil mass registering instrument be take low-power scm as processing core, extends out ultrasonic measurement circuit, oil mass record storage E2PROM circuit, temperature survey compensating circuit, infrared communication module, real-time clock module, power management module.Temperature compensation module is used for measuring temperature value ultrasonic velocity is revised, and time when real-time clock module is used for record measurement liquid level, infrared communication module is for sending to infrared copy meter PDA by the oil mass data of measurement.
(2) infrared copy meter PDA
Infrared copy meter PDA, for gathering the historical oil mass data of a plurality of vehicle-mounted oil mass registering instruments, be take low-power scm equally as processing core, extends out infrared communication module, key control module, local LCD MODULE, SD card interface module, RS232 communication module.Infrared communication module is responsible for communicating by letter with oil mass detector, receives the liquid level data of oil mass detector storage, can arrange the systematic parameter of oil mass detector simultaneously; Data processing memory module stores the infrared data that receive into local SD card; Computer can be configured infrared copy meter instrument by RS232 interface.
The present invention is a kind of low power-consumption liquid level measuring system with bright market prospects, in its hardware system the type selecting of each chip and connected mode be all through research staff after design completes through repeatedly testing, Optimizing Reconstruction, mentality of designing of the present invention is also a kind of design that is more suitable for promoting the use drawing after seeking the opinion of a large amount of fields of measurement technician, the present invention has low-power consumption, long standby, cost is low, the advantages such as dependable performance, its hardware design and developing thought are original creation, the present invention has three property described in patent field, there is practicality, novelty is with creative, simultaneously, the present invention discloses main hardware circuit design and type selecting in detail, now entered the pre-production phase, in the urgent need to patent protection.
Those skilled in the art will be appreciated that; above embodiment is only for the present invention is described; and be not used as limitation of the invention; as long as within connotation scope of the present invention, within the appropriate change that above embodiment is done and variation all drop on the scope of protection of present invention.
Claims (10)
1. a low power-consumption liquid level registering instrument, is characterized in that, comprises as follows:
(1) be installed on the low power-consumption liquid level registering instrument of testee top;
(2) low power-consumption liquid level records hand-held PDA, low power-consumption liquid level record hand-held PDA (2) corresponding at least one can with the low power-consumption liquid level registering instrument (1) of its pairing, a low power-consumption liquid level records information and the storage that hand-held PDA (2) can record one or more low power-consumption liquid level registering instruments (1).
2. a kind of low power-consumption liquid level registering instrument according to claim 1, is characterized in that: have
Minimum system, described minimum system at least comprises power circuit, crystal oscillating circuit, reset circuit, described minimum system is used for making low-power scm can at least be provided electric energy, vibration and reset signal;
Sound wave module, described sound wave module is divided into transmitter and receiver two parts, for transmitting and reception acoustic signals, for offering low-power scm;
Infrared module, records between hand-held PDA and carries out data transmission for low power-consumption liquid level registering instrument and low power-consumption liquid level, and meanwhile, infrared module also can adopt known any data transfer means, bluetooth for example, wireless network, cable network;
, due to temperature, there is indivisible being closely connected between sonic transmissions speed and transmission medium three in temperature compensation module, low power-consumption liquid level registering instrument comprises temperature compensation module, for range finding is proofreaied and correct;
Clock module, for providing clock signal;
Memory module, the data that monitor for storing low power-consumption liquid level registering instrument, and storage;
Key-press module, for power consumption liquid level recorder instrument is controlled, key-press module adopts the mode of scan control to carry out signal input;
The processing core of low power-consumption liquid level registering instrument also can arrange based on DSP.
3. a kind of low power-consumption liquid level registering instrument according to claim 2, it is characterized in that: the power electronic devices in the sound wave liquid level logging recorder system based on low power-consumption liquid level registering instrument is preferentially selected the device based on memristor, wherein, memory module adopts the storer based on memristor.
4. a kind of low power-consumption liquid level registering instrument according to claim 2, it is characterized in that: each low power-consumption liquid level registering instrument (1) records hand-held PDA (2) from each low power-consumption liquid level and all has different data encodings, when this coding is used for making low power-consumption liquid level registering instrument (1) and low power-consumption liquid level to record hand-held PDA (2) carrying out data transmission, low power-consumption liquid level records hand-held PDA (2) can judge which platform connected low power-consumption liquid level registering instrument (1) is, or why encode, so that each low power-consumption liquid level registering instrument (1) can be judged identification, be not confused.
5. a kind of low power-consumption liquid level registering instrument according to claim 2, it is characterized in that: low power-consumption liquid level registering instrument (1) or low power-consumption liquid level record the medium that can manually set sonic transmissions on hand-held PDA (2), when manually arranging, medium is defaulted as oil gas mixture.
6. a kind of low power-consumption liquid level registering instrument according to claim 2, it is characterized in that: low-power scm is controlled MAX3100 chip by SHDN pin and whether entered standby mode, IRQ pin is triggered and is interrupted by low level, the DIN of MAX3100 chip, DOUT, SLCK, tetra-pins of CS are responsible for communication and control, and its effect is respectively data input, data output, communication clock is controlled and the chip selection signal of MAX3100.
7. a kind of low power-consumption liquid level registering instrument according to claim 2, it is characterized in that: memory module adopts the AT24C04 chip of U.S. ATMEL (liking special Mel) company as storer, AT24C04 is a kind of Serial E 2PROM storer of CMOS manufacturing process, the storage space that has 4K, when too small can not the satisfying the demand of storage space of AT24C04, on on printed circuit board (PCB), take FLASH storage space and E2PROM memory module that low-power scm carries to be used in conjunction with, make its storage space at least can meet trimestral storage needs.
8. a kind of low power-consumption liquid level registering instrument according to claim 2, it is characterized in that: low-power scm is by the pulse of Trig port input 10ms, trigger ultrasonic wave module preliminary work, when receiving high level, catch register CCR0 and start timing, transmitter sends ultrasound wave to medium simultaneously, when receiving echoed signal, ECHO port becomes low level immediately, register stops timing, therefore the time of high level is exactly the time of transmission, and CJ_PW pin is the control pin of low-power scm to ultrasonic wave module switch.
9. for a method for liquid-level tracking, it is characterized in that: liquid-level tracking method comprises theoretical calculating and actual correction calculation two parts, and theoretical calculation formula is:
h1=t×((331+T×0.6)／2) (1-1)
Actual correction calculation formula is:
h=h1-h1／50-h1／15 (h1<60)
h=h1-h1／25-h1／15 (h1≥60) (1-2)
Liquid measure is calculated:
V=(H-h)×L×W (1-3)
Wherein:
H1: calculated value (mm);
T: time (s);
T: temperature (℃);
H: corrected value (mm);
L: liquid case length (mm);
W: liquid case width (mm);
V: liquid casing amasss (mm3).
10. a kind of method for liquid-level tracking according to claim 9, it is characterized in that: calculating liquid level theoretical value, the actual corrected value of liquid level, liquid measure value, or any when relating to data and calculating, if there is data from overflow, crash and wait while causing the not normal situation of liquid-level tracking, end process, and autoboot process.
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