CN106989847B - Error correcting method in system of Pt-resistance - Google Patents
Error correcting method in system of Pt-resistance Download PDFInfo
- Publication number
- CN106989847B CN106989847B CN201710175753.XA CN201710175753A CN106989847B CN 106989847 B CN106989847 B CN 106989847B CN 201710175753 A CN201710175753 A CN 201710175753A CN 106989847 B CN106989847 B CN 106989847B
- Authority
- CN
- China
- Prior art keywords
- resistance
- error
- platinum
- measurement
- platinum resistance
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01K—MEASURING TEMPERATURE; MEASURING QUANTITY OF HEAT; THERMALLY-SENSITIVE ELEMENTS NOT OTHERWISE PROVIDED FOR
- G01K15/00—Testing or calibrating of thermometers
- G01K15/005—Calibration
Landscapes
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Measurement Of Resistance Or Impedance (AREA)
Abstract
The invention discloses a kind of error correcting method based in resistance ratios method system of Pt-resistance, the present invention uses excitation current source reverse flow technique, eliminates the influence of parasitic thermo-electromotive force and system drifting in the measurement such as platinum resistance connector, analog switch circuit；It analyzes by the measurement error that gain resistor mismatch and lead resistance introduce in amplifying circuit, proposes correction function form, demarcated by amplifying circuit common-mode rejection ratio and lead resistance real-time measurement determines correction function parameter.The present invention passes through the analysis to error each in circuit structure, it establishes functional relation and calculates each error coefficient, to be modified to the resistance value for measuring platinum resistance, the results showed that temp measuring system, after error correction, the accuracy of temperature measurement is significantly improved.
Description
Technical field
The present invention relates to field of temperature measurement, relate more specifically to a kind of based in resistance ratios method system of Pt-resistance
Error correcting method.
Background technique
Temperature is the important parameter in daily life and production activity, is related to national economy, scientific research and social construction
Etc. various aspects, accurately and efficiently obtain temperature information be of great significance.In geologic prospect, environment measuring, industry spot multiple spot
The fields such as data acquisition, do not require nothing more than realization high precision measuring temperature, also require instrument portable, can be steady for a long time in field or scene
Fixed work, and it is easy to operate, cost performance is high.With science and technology be constantly progressive, thermometry just towards high-precision, it is low at
Originally, small integrated development.Platinum resistance is most accurate and most stable of temperature sensor, due to having high-precision, preferably linear
The advantages that degree, splendid interchangeability and long-time stability, it is widely used in high-precision field of temperature measurement.
Currently, high-precision thermal resistance method measurement temperature uses the platinum resistance of four-wire system mainly to eliminate measurement caused by lead
Error.In precise temperature measurement system, resistance signal often passes through bridge circuit and is converted to voltage signal, then through enhanced processing and modulus
Converter conversion, is eventually sent to single-chip microcontroller and is handled.But due to circuit components performance, environment temperature, platinum resistance self-heating
The influence of effect, there are large errors when making system testing, and gain resistor mismatches on lead resistance and difference amplifier
It will influence the accuracy of thermometric.
Summary of the invention
For the not high problem of accuracy in the existing portable platinum resistance temperature measuring system mentioned in background technique, originally
Invention uses four-wire system platinum resistance temperature sensor, devises a kind of portable high-accuracy thermometric electricity based on resistance ratios method
Road, and propose a kind of method for correcting error.
The technical solution adopted by the present invention is that:
Contain multinomial error, the main common-mode error including on difference amplifier, lead error, parasitic thermoelectricity in temperature measurement circuit
Gesture error etc., wherein most importantly common-mode error, the shadow of its size difference degree between by gain resistor on difference amplifier
It rings.The modification method of the error are as follows: by the influence of each error term in analysis circuit, establish voltage ratio and platinum resistance, ginseng
The functional relation between resistance, lead resistance and analog switch conducting resistance is examined, which is connected into measuring resistance
Case adjusts resistance box to measure the measuring resistance of different resistance values, standard resistance box indicating value is substituted into above-mentioned function as true value and is closed
It is in formula, repeatedly measurement composition multi head linear equation group can solve to obtain each error term coefficient, finally obtain the amendment of platinum resistance
Formula, to correct the resistance value of platinum resistance.
The working principle of the temperature measurement circuit are as follows: four-wire system platinum resistance is made as temperature transducer, high stable metal foil resistance
For reference resistance, the two, which is connected, simultaneously to be driven by constant-current source, by analog switch switching channel, analog-digital converter convert platinum resistance and
Voltage on reference resistance is sent to single-chip microcontroller with the voltage after will converting, single-chip microcontroller data are handled after again by platinum
The temperature that resistance measures is sent to host computer and shows.
The beneficial effects of the present invention are: being effectively reduced using constant-current source unidirectional driving series connection platinum resistance and reference resistance
Error caused by parasitic electromotive force in lead resistance and circuit；Using high-resolution analog-digital converter and high stable metal foil electricity
Resistance improves the precision and stability of temp measuring system；By the analysis to error each in circuit structure, functional relation is established simultaneously
Each error coefficient is calculated, to be modified to the resistance value for measuring platinum resistance, the results showed that temp measuring system passes through error
After amendment, the accuracy of temperature measurement is significantly improved.
Detailed description of the invention
Fig. 1 is the structure chart of high precision measuring temperature system；
Fig. 2 is the schematic diagram of constant-current source driving and switching circuit；
Fig. 3 is the schematic diagram of Pt Resistance Temperature Measuring Circuit；
Fig. 4 is error analysis schematic diagram；
Specific embodiment
The present invention will be described in further detail with reference to the accompanying drawing.
As shown, Fig. 1 is the structure chart of high-precision platinum resistor temperature measuring system of the present invention, platinum resistance is as temperature sensing
Device, it is to be varied with temperature and changed and be in the characteristic of certain functional relation to carry out thermometric using resistance value, by measuring its electricity
Resistance value extrapolates testee temperature, and here it is the working principles of platinum resistance temperature sensor.High-precision platinum resistor temperature measuring system
It include: precision constant current source driving circuit, analog switch switching circuit, voltage follower, the differential amplification electricity of Voltage-current conversion
Road, high stable metal foil resistance and analog-digital converter and single-chip microcontroller are constituted.
The analog switch switching circuit is low on-resistance, low-power consumption, binary channels double-pole double throw cmos device, plays and cuts
Change the effect in constant-current source direction and selection amplification access；Voltage follower is ultra-low noise operational amplifier, defeated using amplifier
Enter the big characteristic of impedance, realizes impedance matching；Differential amplifier circuit be by low noise, low distortion, super low-power consumption differential amplification
Device and gain resistor composition, the precision resistance that gain resistor is 4 0.1%, realize differential gain configuration；High stable metal foil electricity
Resistance is the high-accuracy resistance of 100 Ω that precision is 0.01%, and temperature drift coefficient is 0.05ppm；Analog-digital converter is 32 moulds of sigma-delta type
Number converter realizes digital filtering using high frequency multiplication oversampling technique, reduces the requirement to sensor signal filtering, pass through
Oversampling technique is used in combination with noise shaping and digital filtering technique, is improved its effective resolution；Single-chip microcontroller is
STM32 series mini processor is the center to thermometric Row control and data processing.
Fig. 2 is the precision constant current source driving circuit of Voltage-current conversion, is put using the operation of ultra-low noise, low imbalance
Large chip ADA4528 stablizes the constant-current source of output to provide, and wherein R1=R2=100K, R3=R4=10K, are that precision is
0.1% resistance, R5=330 Ω, the constant-current source I=0.75mA of output.
Fig. 3 is Pt Resistance Temperature Measuring Circuit schematic diagram, and platinum resistance is connected with reference resistance, and both threads are logical in four-wire system platinum resistance
Constant-current source, in addition two are pressure-wire, and circuit amplification factor is denoted as G；When constant-current source flows to reference resistance from platinum resistance, amplification
The voltage of platinum resistance is denoted as Volt afterwards1, the voltage of reference resistance is denoted as Volt2；When constant-current source flows to platinum resistance from reference resistance
When, the voltage of platinum resistance is denoted as Volt after amplification3, the voltage of reference resistance is denoted as Volt4；It is parasitic on platinum resistance access in circuit
Electromotive force is denoted as EMF1, offset drift is denoted as OFFSET1, parasitic electromotive force is denoted as EMF on reference resistance access2, offset drift note
For OFFSET2:
Volt1=G (I × RPT+EMF1)+OFFSET1 (1)
Volt2=G (I × Rref+EMF2)+OFFSET2 (2)
Volt3=G (- I × RPT+EMF1)+OFFSET1 (3)
Volt4=G (- I × Rref+EMF2)+OFFSET2 (4)
It can be obtained according to above formula:Thus formula can be seen that assuming that electricity
Road amplification factor G it is constant and not by be measured influence when, can be eliminated in circuit by constant-current source commutation method parasitic on lead
The influence of electromotive force and offset drift to measurement platinum resistance resistance value, the resistance value of platinum resistance is only with the voltage ratio of measurement and with reference to electricity
It hinders related.
Fig. 4 is error analysis schematic diagram, and RF1=RF2=250 Ω, RG1=RG2=2K Ω are 0.1% precision electricity
Resistance forms simple external feedback network, realizes differential gain configuration；Since the resistance value of these feedback resistances not fully matches,
So that circuit amplification factor G is influenced by feedback resistance resistance value, ifIn conjunction with above-mentioned analysis
Formula (5) then can be obtained if voltage ratio is M in analysis of the step to circuit differential amplified voltage:
It can be seen that due on difference amplifier gain resistor mismatch that there are error coefficient β's to voltage ratio
It influences, if β is bigger, the deviation of platinum resistance resistance value is bigger, and accuracy is lower.
However, the error of temp measuring system is not only influenced by the difference degree between gain resistor, also by lead electricity
The influence of resistance and analog switch conducting resistance.In order to analyze the influence of each error, the function expression of platinum resistance is re-established.
As shown in figure 4, RPTAnd RrefRespectively represent the resistance value of platinum resistance and reference resistance, LPA、LPB、LPCAnd LPDIt is in platinum resistance respectively
Lead resistance, LRA、LRB、LRCAnd LRDIt is the lead resistance on reference resistance respectively.RonA、RonBIt is leading on analog switch
Be powered resistance (relay or CMOS multiplexer), OFFA、OFFB、OFFC、OFFDThe bias voltage of output amplifier, due to putting
The input impedance of big device is big, can ignore in the influence of sampling end wires and conducting resistance.
Similarly, the first step is to measure the voltage of platinum resistance when electric current flows on reference resistance from platinum resistance, inputs mould
The platinum resistance voltage of number converter is denoted as Vin1, expression formula is as follows:
Vin1=α { (I × RPT+OFFB-OFFA)+β[I(LPD+LRA+Rref+
LRD+RonB)+OFFB]}+OFFC-OFFD (6)
Second step is to measure the voltage of reference resistance when electric current flows on reference resistance from platinum resistance, and input modulus turns
The reference resistance voltage of parallel operation is denoted as Vin2, expression formula is as follows:
Vin2=α { (I × Rref+OFFB-OFFA)+β[I(LRD+RonA)+
OFFB]}+OFFC-OFFD (7)
Third step is to measure the voltage of platinum resistance when electric current flows in platinum resistance from reference resistance, inputs analog-to-digital conversion
The platinum resistance voltage of device is denoted as Vin3, expression formula is as follows:
Vin3=α { (- I × RPT+OFFB-OFFA)+β[I(RPT+LRA+
RonA)+OFFB]}+OFFC-OFFD (8)
4th step is to measure the voltage of reference resistance when electric current flows in platinum resistance from reference resistance, and input modulus turns
The reference resistance voltage of parallel operation is denoted as Vin4, expression formula is as follows:
Vin4=α { (- I × Rref+OFFB-OFFA)+β[I(Rref+LRA+
LPD+RPT+LPA+RonA)+OFFB]}+OFFC-OFFD(9)
If voltage ratioHad according to formula (6)~(9):
Wherein:
ΔL1=LPA-LPD-LRA-LRD
ΔL2=LPA+LPD+LRA-LRD
ΔRon=RonA-RonB
According to the physical length of lead in circuit, lead resistance can be measured directly, or by it with β and REF as not
Know error coefficient, equation is established in substitution formula (10) can also solve.According to formula (10), release voltage ratio and resistance and
Relational expression comprising error term is as follows:
By analysis it is found that resistance ratio and voltage ratio relational expression are more complicated due to every error in circuit, close
It is that error term coefficient present in formula is bigger, RPTDeviation it is then bigger, accuracy is lower, it is therefore desirable to correct error coefficient β,
The value of reference resistance and lead resistance.Modified method are as follows: platinum resistance is replaced with calibrated measuring resistance, the system half-mark
Quasi- resistance obtains voltage ratio M, using calibrated measuring resistance as platinum resistance true value RPT, Rref, lead resistance, β are unknown ginseng
Number measures the measuring resistance of multiple and different resistance values, substitutes into formula (10) composition multi head linear equation group and solves correlated error item
Coefficient, by error term coefficient substitute into formula (11), obtain the correction value of platinum resistance resistance value.
Experimental verification: circuit board measures the precision resistance of different resistance values, guarantees to soak precision resistance under same experimental conditions
Not in small-sized oil bath, and real-time temperature control is carried out to oil bath, by measuring for a long time, test result display is existing without obvious drift
As thermometric precision is better than 1.6mK；After error correcting method, the temperature measurement accuracy of temp measuring system is significantly increased,
In 0~500 Ω range, the measuring resistance resistance value that temp measuring system measures after amendment differs maximum with true value and only has 0.00295 Ω, temperature
Coefficient is floated in ± 15ppm hereinafter, with 0.00295 Ω of maximum absolute error calculating, corresponding ITS-90 standard phasing meter uses platinum resistance
At 0 DEG C 3850 × 10-6/ DEG C Calculation of Sensitivity, revised maximum temperature detection relative error is 0.007 DEG C.
In conjunction with the system of Pt-resistance based on resistance ratios method of the invention designed and the error correcting method of proposition, no
It only can be realized high precision measuring temperature, and low in energy consumption, exquisite portable, area is only 120mm × 77mm, has high-precision, does not know
The characteristics of spending small, inexpensive, small integrated meets and leads in geologic prospect, environment measuring, industry spot multi-point data acquisition etc.
The thermometric requirement in domain, can long-term stable work, and easy to operate, cost performance is high, be suitable for portable high-accuracy temperature measurer,
Digital temperature meter, the development of resistance temperature marking apparatus and intelligent high precision measuring temperature quasi-instrument.
Claims (2)
1. the error correcting method in system of Pt-resistance, the temp measuring system of this method includes based on Voltage-current conversion
Constant current source driving circuit, analog switch, voltage follower, difference amplifier, high stable state reference resistance, sigma-delta type analog-to-digital conversion
Device, microcontroller, which is characterized in that common-mode error, reference resistance, lead resistance and analog switch conducting resistance in analysis circuit
Influence to measurement establishes the functional relation between platinum resistance and every error, with the standard electric of calibrated different resistance values
Resistance substitution platinum resistance, the true value of platinum resistance is denoted as with the measuring resistance resistance value of calibration, true value is substituted into functional relation, repeatedly
Measurement forms polynary quadratic equation group and can solve to obtain each error term coefficient, and error coefficient is substituted into correction function in real time,
The amendment for realizing platinum resistance resistance value achievees the purpose that improve thermometric accuracy；
The platinum resistance RPTFunctional relation between every error is as follows:
Wherein,
ΔL1=LPA-LPD-LRA-LRD
ΔL2=LPA+LPD+LRA-LRD
ΔRon=RonA-RonB
LPAAnd LPDIt is the lead resistance in platinum resistance, LR respectivelyAAnd LRDIt is the lead resistance on reference resistance respectively；RonA、
RonBIt is the conducting resistance on analog switch, M is the ratio obtained by four voltage measurements, and β is to miss caused by common-mode error
Poor coefficient, RrefFor reference resistance resistance value.
2. error correcting method according to claim 1, which is characterized in that common-mode error, ginseng in analysis analysis circuit
When examining the influence of resistance, lead resistance and analog switch conducting resistance to measurement, platinum resistance excitation electricity is realized using analog switch
Stream commutation is completed under backward current excitation by carrying out the one-shot measurement of platinum resistance both end voltage in the case where forward current motivates
The measurement again of platinum resistance both end voltage measurement result will ask poor twice, eliminate parasitic thermo-electromotive force and system in measurement circuit
The influence of drift.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201710175753.XA CN106989847B (en) | 2017-03-22 | 2017-03-22 | Error correcting method in system of Pt-resistance |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201710175753.XA CN106989847B (en) | 2017-03-22 | 2017-03-22 | Error correcting method in system of Pt-resistance |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN106989847A CN106989847A (en) | 2017-07-28 |
| CN106989847B true CN106989847B (en) | 2019-09-06 |
Family
ID=59412892
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201710175753.XA Active CN106989847B (en) | 2017-03-22 | 2017-03-22 | Error correcting method in system of Pt-resistance |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN106989847B (en) |
Families Citing this family (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN107702822B (en) * | 2017-09-21 | 2019-05-10 | 中国计量大学 | A kind of multichannel quick high accuracy temp measuring system based on intersection polling mechanism |
| KR20190064893A (en) * | 2017-12-01 | 2019-06-11 | 에스케이하이닉스 주식회사 | Digital temperature sensing circuit |
| CN111380624B (en) * | 2018-12-27 | 2021-12-21 | 瑞昱半导体股份有限公司 | Temperature calculation parameter providing circuit, temperature calculation parameter providing method, and temperature monitoring method |
| CN109870487B (en) * | 2019-02-18 | 2021-06-22 | 中国石油天然气集团有限公司 | Method, device and system for compensating resistance of conductivity sensor verification lead |
| CN110488889A (en) * | 2019-07-11 | 2019-11-22 | 湖南明康中锦医疗科技发展有限公司 | A kind of Breathing Suppotion device temperature collection control method and system |
| CN114720009B (en) * | 2022-06-09 | 2022-09-16 | 中国船舶重工集团公司第七0七研究所 | Digital high-precision temperature measurement system and method for relative gravimeter |
Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102539925A (en) * | 2010-12-30 | 2012-07-04 | 北京中科微纳物联网技术股份有限公司 | High-accuracy dynamic testing method for sensor |
| CN102829888A (en) * | 2011-06-15 | 2012-12-19 | 上海电器科学研究院 | Method for eliminating three-wire heating resistor measurement errors |
| CN204085729U (en) * | 2014-09-26 | 2015-01-07 | 江南大学 | A kind of high-precision platinum resistance temperature measurement mechanism |
| CN105784176A (en) * | 2016-05-25 | 2016-07-20 | 北京先驱威锋技术开发公司 | Temperature measuring system and method based on platinum resistor |
| CN106404207A (en) * | 2016-11-08 | 2017-02-15 | 辽宁师范大学 | Platinum resistance-based wide-range high-precision temperature measuring instrument and measuring method thereof |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20100002747A1 (en) * | 2008-07-03 | 2010-01-07 | Bosch Enrique Company | System and method for n'th order digital piece-wise linear compensation of the variations with temperature of the non-linearities for high accuracy digital temperature sensors in an extended temperature range |
-
2017
- 2017-03-22 CN CN201710175753.XA patent/CN106989847B/en active Active
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102539925A (en) * | 2010-12-30 | 2012-07-04 | 北京中科微纳物联网技术股份有限公司 | High-accuracy dynamic testing method for sensor |
| CN102829888A (en) * | 2011-06-15 | 2012-12-19 | 上海电器科学研究院 | Method for eliminating three-wire heating resistor measurement errors |
| CN204085729U (en) * | 2014-09-26 | 2015-01-07 | 江南大学 | A kind of high-precision platinum resistance temperature measurement mechanism |
| CN105784176A (en) * | 2016-05-25 | 2016-07-20 | 北京先驱威锋技术开发公司 | Temperature measuring system and method based on platinum resistor |
| CN106404207A (en) * | 2016-11-08 | 2017-02-15 | 辽宁师范大学 | Platinum resistance-based wide-range high-precision temperature measuring instrument and measuring method thereof |
Non-Patent Citations (1)
| Title |
|---|
| 高精度铂电阻测温系统;胡鹏程等;《光学精密工程》;20140430;第22卷(第4期);第988页-995页 * |
Also Published As
| Publication number | Publication date |
|---|---|
| CN106989847A (en) | 2017-07-28 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN106989847B (en) | Error correcting method in system of Pt-resistance | |
| CN103837253B (en) | A kind of CMOS temperature transmitter | |
| CN207472443U (en) | Multichannel three-wire system resistance temperature measurement circuit | |
| CN109375291A (en) | A kind of temperature and air pressure suitable for sonde and humidity measuring instrument and method | |
| CN205102947U (en) | Three -way formula platinum resistance PT100 temperature detection circuit | |
| CN117516740A (en) | T-shaped thermocouple signal processing device and method | |
| CN107228886B (en) | The measuring device and method of the conductivity Resistivity testing of water | |
| CN110388993B (en) | Low-impedance temperature sensor and temperature measurement method thereof | |
| Fasoli et al. | A general circuit for resistive bridge sensors with bitstream output | |
| CN102594276B (en) | Gain calibration system for instrument amplifier and gain calibration method | |
| CN104483033A (en) | CMOS (complementary metal-oxide-semiconductor transistor) temperature sensor circuit with wide temperature range | |
| CN214041538U (en) | Current and voltage detection circuit based on single chip microcomputer | |
| CN106092361A (en) | A kind of temperature sampling circuit | |
| CN207515923U (en) | A kind of programmable high precision temperature compensation system | |
| CN111208346B (en) | Small signal voltage measuring device and method | |
| CN205748693U (en) | A kind of high accuracy number thermometer | |
| CN110440945B (en) | High-precision low-temperature drift discrete type double-matching constant current source temperature measuring circuit | |
| CN212364401U (en) | Resistance sensor measuring circuit for measuring weak signal | |
| CN212646965U (en) | Single-point calibration circuit structure realized by built-in resistance network of digital multimeter | |
| CN104168023A (en) | High-precision analog-to-digital converter | |
| CN211013290U (en) | High-precision low-temperature-drift discrete double-matching constant-current source temperature measurement circuit | |
| CN209821627U (en) | Multichannel strain signal synchronous acquisition system | |
| CN207570691U (en) | A kind of signal acquisition circuit of double temperature sensor | |
| CN113820029A (en) | PT100 temperature acquisition circuit for acquisition terminal | |
| CN215893819U (en) | Multi-channel temperature detection circuit and device |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |