CN206161180U - Wide -range high accuracy temperature measurement device based on platinum resistance - Google Patents
Wide -range high accuracy temperature measurement device based on platinum resistance Download PDFInfo
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Abstract
The utility model discloses a wide -range high accuracy temperature measurement device based on platinum resistance, is the temperature measurement width in 200 DEG C~800 DEG C, wide -range high accuracy temperature measurement device based on platinum resistance constitutes as follows: power supply circuit (1), constant current source circuit (2), temperature sensor (3), processing circuit (4), AD converting circuit (5), singlechip (6), display (7), accumulator (8), button module (9), reset circuit (10), crystal oscillator circuit (11), temperature correction module (12) and data signal processing module (13). The utility model discloses satisfy to measure the requirement, high accuracy temperature measurement device after the calibration is interval 0 DEG C~100 DEG C of temperature measurement, and temperature measurement reaches 5/1000ths. Temperature measurement is high, measuring range is wide, the price is low, has comparatively huge economic value and social value.
Description
Technical field
The utility model is related to the structure design and applied technical field of temperature measuring set, specifically provides a kind of based on platinum
The wide-range high-precision temperature measuring set of resistance.
Background technology
Temperature survey understands temperature, provides foundation using temperature for people, has extensive in actual production life
Using its range of application is from daily life to scientific research.High-resolution hydrocode technology is improved to ambient temperature
The key of control, this allows for high-resolution hydrocode technology becomes the factor that can not ignore in industrial development.Thus design
The wide High Precision Temperature Measuring Instruments of a kind of high precision, temperature-measuring range are very important, and this will greatly promote our societies
Development, the productive life for giving people brings great convenience.
People are highly desirable to obtain a kind of excellent High Precision Temperature Measuring Instruments of technique effect.
Utility model content
The purpose of this utility model is to provide a kind of wide-range high-precision temperature measuring set based on RTD.
The wide-range high-precision temperature measuring set based on RTD constitutes as follows：Power circuit 1, constant-current source drives electricity
Road 2, temperature sensor 3, signal processing circuit 4, A/D change-over circuits 5, single-chip microcomputer 6, display 7, holder 8, key-press module 9,
Reset circuit 10, crystal oscillating circuit 11, temperature correction module 12, data-signal processing module 13；Wherein, power circuit 1 and constant current
Source driving circuit 2, A/D change-over circuits 5 and single-chip microcomputer 6 constitute electrical connection, constant current source driving circuit 2 and the structure of signal processing circuit 4
Into electrical connection, the signal processing circuit 4 includes the equivalent resistance of four leads of connection temperature sensor 3, respectively first
Resistance, second resistance, 3rd resistor and the 4th resistance, wherein, first resistor, constant current source driving circuit 2, second resistance and temperature
Sensor 3 is followed in series to form loop by wire, and one end of 3rd resistor is connected to first resistor and temperature biography by wire
Between sensor 3, the A/D sampling compensating lines of the other end connection A/D change-over circuits 5 of 3rd resistor, one end of the 4th resistance passes through
Wire is connected between second resistance and temperature sensor 3, and the other end of the 4th resistance connects compensating line over the ground, signal transacting electricity
Road 4 is connected by A/D change-over circuits 5 with single-chip microcomputer 6, display 7, holder 8, key-press module 9, reset circuit 10 and crystal oscillator electricity
Road 11 is connected respectively with single-chip microcomputer 6, and key-press module 9 is connected by temperature correction module 12 with data-signal processing module 13,
Data-signal processing module 13 is connected with single-chip microcomputer 6.
The temperature sensor 3 adopts PT100 platinum sensors, the connection temperature stabilization of the constant current source driving circuit 2
The high high-accuracy resistance of coefficient, the temperature varying coefficient of this high-accuracy resistance is 1ppm, i.e. 1 DEG C of temperature change, its change in resistance
For 106Ω, the electric current of the output of the constant current source driving circuit 2 can not be more than 4mA.
The measuring method puts variation of ambient temperature with resistance be close to linear relation according to RTD, by thermometric
Scope is divided into some sections, and each of which section is linear, and each section of temperature is chosen two and clicked through by the resolution ratio of PT100 up to 1mK
Row correction, therefore theoretical calculation precision is up to 0.001 DEG C.
The A/D change-over circuits 5 adopt the LTC2492 analog-digital converters of 24, and its precision is up to VREF/224, VREFAbout etc.
In 1.1V, using formula Rt=R0(1+At+Bt2+C(t-100)t3) and formula Rt=(1+At+Bt2) adopt numerical approximation algorithm
Solve.
When the environment temperature that RTD is placed changes between -200 DEG C～800 DEG C, it puts variation of ambient temperature
With resistance be close to linear relation.National regulations PT RTDs at 0 DEG C, its resistance value R0=100 Ω, its characteristic curve
As shown in Figure 1.
RTD mainly has resistance and allows two kinds of errors.Wherein A allowable errors are equal to ± (0.15+0.002t), and B is allowed
Error is equal to ± (0.30+0.005t), and t represents temperature value in formula.
When -200 DEG C≤t≤0 DEG C, the resistance of RTD is with the function expression of temperature change：
Rt=R0(1+At+Bt2+C(t-100)t3) (1)
When 0 DEG C≤t≤850 DEG C, the resistance of RTD is with the function expression of temperature change：
Rt=(1+At+Bt2) (2)
In formula, RtThe resistance value of RTD, R when representing t DEG C0The resistance value of RTD, this paper design processes when representing 0 DEG C
The resistance of middle selection is Pt, the R of standard Pt0Equal to ohm.The value of A, B, C is respectively：A=3.9082 × 10-3, B=-
5.80195×10-7, C=-4.2735 × 10-12。
Numerical approximation algorithm is utilized according to above-mentioned principle, an array is taken and is had following data, array is set in program as T
(K) 24 data, are had in the array, data are as follows：
8388.608,4194.304,2097.152,1048.576,0524.288,0262.144,0131.072,
0065.536,0032.768,0016.384,0008.192,0004.096,0002.048,0001.024,0000.512,
0000.256,0000.128,0000.064,0000.032,0000.016,0000.008,0000.004,0000.002,
0000.001。
Program adopts cycle accumulor mode, as K=1,8388.608 is brought into formula (2), calculates resistance value, will
Value RTWith RTD resistance R of actual measurementPT100It is compared, if bigger than actual measurement resistance value, i.e. RT＞ RPT100,
Then, this data is not added up, if less than actual measurement resistance value, i.e. RT＜ RPT100, then, this data is added up.Once
Circulation 24 times, T (K) value that above-mentioned condition is most met at last is added, and obtains the calculated value of platinum resistance temperature.
The signal processing circuit 4 uses the four-wire system connection after improving, and is to ensure the precision of measurement and stablize
Degree.X in Fig. 51、X2、X3、X4It is respectively the equivalent resistance of four leads of platinum sensor.With R4The magnitude of voltage of resistance as
Reference voltage R in the design4Value is 510 Ω, and reference voltage, the design of constant-current source drastically influence the survey of circuit
Accuracy of measurement and stability.Reference voltage VREFWhether stable and Low Drift Temperature is to ensure that high precision measuring temperature instrument herein has height
The important prerequisite of precision.The mirror current source constituted with triode 8550 is reducing external interference, it is to avoid error.On this basis
Connect high-accuracy resistance R0, the temperature varying coefficient of this high-accuracy resistance is 1ppm, i.e. 1 DEG C of temperature change, and its change in resistance is
10-6Ω, R in the design0Value is Ω.Theoretical according to electronic circuit, the electric current I of RTD PT sensors is：
Reference voltage VREFFor：
VRef=I × R4 (4)
The voltage and precision resistance R of PT sensors0Voltage be respectively：
VPT100=I × RPT100 (5)
VR0=I × R0 (6)
Finally take the voltage and precision resistance R for obtaining PT sensors0Both voltage voltage ratio, i.e.,
So as to eliminate the curent change that constant-current source is affected due to factors such as temperature drifts so that output voltage ratio with
RTD is into good linear relationship.
The voltage signal for obtaining is sampled by 24 A/D converter LTC2492, then by signal to ATmega32
Single-chip microcomputer, single-chip microcomputer carries out data processing and preserves and display data.The stability of the design temperature measurement of the circuit can reach
To 1 ‰.
Core devices of the utility model using ATmega32 single-chip microcomputers as control circuit, have selected 24 LTC2492 to make
For A/D converter, temperature sensor has selected PT100, thermometric width at -200 DEG C～800 DEG C, because PT100 sensors are allowed
By the electric current for being not higher than 4mA, minimum placed-depth can not be less than 200mm, and its high precision reaches 1mK, using PT100 temperature with electricity
Resistance resistance change and linearly change, sample circuit employs improved four-wire system connection, at the same gather RTD voltage and
Reference voltage, and a stable, lasting electric current is provided for circuit with constant-current source, eliminate the error due to accessing lead resistance
And the temperature drift that RTD exciting current causes is on thermometric impact.Data processing is using Function Approximation Algorithm and temperature school
Normal operation method, so as to realize high-resolution hydrocode, theoretical calculation precision is up to 0.001 DEG C.
The utility model meets measurement request, and the High Precision Temperature Measuring Instruments after calibration are interval 0 DEG C～100 DEG C in thermometric,
Temperature measurement accuracy reaches 5/1000ths.Temperature measurement accuracy is high, temperature-measuring range is wide, price is low, with more huge economic worth and society
Can be worth.
Description of the drawings
Fig. 1 is the characteristic curve of RTD；
Fig. 2 is measurement temperature schematic diagram；
Fig. 3 is the schematic diagram based on the wide-range high-precision temperature measuring set of RTD；
Fig. 4 is RTD four-wire system wiring diagram；
Fig. 5 is constant current source driving circuit figure；
Fig. 6 is the schematic diagram of LTC2492；
The circuit diagram of Fig. 7 key-press modules；
Wide-range high-precision temperature measuring set workflow diagrams of the Fig. 8 based on RTD；
Specific embodiment
As shown in figure 3, the conversion of power circuit 1, constant current source driving circuit 2, temperature sensor 3, signal processing circuit 4, A/D
Circuit 5, single-chip microcomputer 6, display 7, holder 8, key-press module 9, reset circuit 10, crystal oscillating circuit 11, temperature correction module 12,
Data-signal processing module 13；Wherein, power circuit 1 is constituted with constant current source driving circuit 2, A/D change-over circuits 5 and single-chip microcomputer 6
Electrical connection, constant current source driving circuit 2 and signal processing circuit 4 constitute electrical connection, and the signal processing circuit 4 includes connection temperature
The equivalent resistance of four leads of sensor 3, respectively first resistor, second resistance, 3rd resistor and the 4th resistance, wherein,
First resistor, constant current source driving circuit 2, second resistance and temperature sensor 3 are followed in series to form loop by wire, and the 3rd is electric
One end of resistance is connected between first resistor and temperature sensor 3 by wire, the other end connection A/D conversion electricity of 3rd resistor
The A/D sampling compensating lines on road 5, one end of the 4th resistance is connected between second resistance and temperature sensor 3 by wire, and the 4th
The other end of resistance connects compensating line over the ground, and signal processing circuit 4 is connected by A/D change-over circuits 5 with single-chip microcomputer 6, display
7th, holder 8, key-press module 9, reset circuit 10 and crystal oscillating circuit 11 are connected respectively with single-chip microcomputer 6, and key-press module 9 is by temperature
Degree calibration module 12 is connected with data-signal processing module 13, and data-signal processing module 13 is connected with single-chip microcomputer 6.
The A/D change-over circuits 5 adopt the LTC2492 analog-digital converters of 24, and its precision is up to VREF/224, VREFAbout etc.
In 1.1V, using formula Rt=R0(1+At+Bt2+C(t-100)t3) and formula Rt=(1+At+Bt2) adopt numerical approximation algorithm
Solve.
The key-press module 9 include 4 operating keys, specially 1 esc key, 1 ↑ directionkeys and 1 ↓ directionkeys, 4
One end ground connection of operating key, another termination I/O mouths and pull-up resistor.
As shown in figure 1, when the environment temperature that RTD is placed changes between -200 DEG C～800 DEG C, it puts ring
Border temperature change is with resistance be close to linear relation.National regulations PT RTDs at 0 DEG C, its resistance value R0=100 Ω,
Its characteristic curve is as shown in Figure 1.
RTD mainly has resistance and allows two kinds of errors.Wherein A allowable errors are equal to ± (0.15+0.002t), and B is allowed
Error is equal to ± (0.30+0.005t), and t represents temperature value in formula.
When -200 DEG C≤t≤0 DEG C, the resistance of RTD is with the function expression of temperature change：
Rt=R0(1+At+Bt2+C(t-100)t3) (1)
When 0 DEG C≤t≤850 DEG C, the resistance of RTD is with the function expression of temperature change：
Rt=(1+At+Bt2) (2)
In formula, RtThe resistance value of RTD, R when representing t DEG C0The resistance value of RTD, this paper design processes when representing 0 DEG C
The resistance of middle selection is Pt, the R of standard Pt0Equal to ohm.The value of A, B, C is respectively：A=3.9082 × 10-3, B=-
5.80195×10-7, C=-4.2735 × 10-12。
Numerical approximation algorithm is utilized according to above-mentioned principle, an array is taken and is had following data, array is set in program as T
(K) 24 data, are had in the array, data are as follows：
8388.608,4194.304,2097.152,1048.576,0524.288,0262.144,0131.072,
0065.536,0032.768,0016.384,0008.192,0004.096,0002.048,0001.024,0000.512,
0000.256,0000.128,0000.064,0000.032,0000.016,0000.008,0000.004,0000.002,
0000.001。
Program adopts cycle accumulor mode, as K=1,8388.608 is brought into formula (2), calculates resistance value, will
Value RTWith RTD resistance R of actual measurementPT100It is compared, if bigger than actual measurement resistance value, i.e. RT＞ RPT100,
Then, this data is not added up, if less than actual measurement resistance value, i.e. RT＜ RPT100, then, this data is added up.Once
Circulation 24 times, T (K) value that above-mentioned condition is most met at last is added, and obtains the calculated value of platinum resistance temperature.
So simple linear relationship is not met in reality between platinum resistance temperature and resistance always, by other conditions
Affect, there is deviation.
High precision measuring temperature instrument selects RTD as temperature transducer, and RTD selects improved four-wire system wiring method, can
It is prevented effectively from the error that lead resistance is brought to temperature survey.By constant-current supply to RTD provide one it is stable, lasting
Electric current, is sent to A/D converter conversion after the change in resistance that RTD causes in temperature changing process is transformed into electric signal
Into data signal, then receive via single-chip microcomputer, analyze, process and result of calculation is corrected, if necessary single-chip microcomputer is extraneous
Key-press module can carry out initialization operation to system, finally by single-chip microcomputer process data by numeral method out.Its
Operation principle is as shown in Figure 2.
RTD PT100 temperature sensors are according to made by the characteristic that RTD is varied with temperature, when environment temperature to be measured
When degree changes, the resistance of RTD also changes therewith, so as to temperature signal is converted into resistance signal, then by detecting platinum
Resistance signal is converted into voltage signal by the magnitude of voltage of resistance.The LTC2492A/D converters of 24 are respectively to the electricity of RTD PT
The voltage of pressure and high-accuracy resistance is read out, and the voltage signal of reading is converted into data signal.Data signal is sent to
ATMEGA32 single-chip microcomputers, microprocessor meeting basis is carried out in advance with the program that Function Approximation Algorithm is write as core to data signal
Parsing computing, so as to obtain the measurement temperature of environment to be measured, finally by the temperature that numeral method is measured.
The signal processing circuit 4 adopts the four-wire system mode of connection, refers to the both sides difference of the i.e. RTD of temperature sensor 3
Connect and draw two wires, be a kind of high-precision temp measuring method.It distinguishes external A/D samplings on two-wire system mode of connection and mends
Repay line and A/D compensating line over the ground.Wherein, by the change transitions of RTD into electric signal, other two for the wire of RTD one end
Electric signal is sent to signal processor by bar wire.Such mode of connection completely cuts down the impact of lead resistance, can be used for
High precision, apart from remote place.Note the current control for exporting constant-current source within 4mA simultaneously, it is to avoid electric current is excessive to be caused
RTD is overheated and brings error to measurement.
Constant-current source resistance itself is infinitely great, with it is independent of temperature variations the characteristics of, so as to be widely used in circuit
Design among, its Main Function is to provide the not constant current that changes with load change for designed circuit.
Need accurately to measure the situation of change of RTD resistance in the design circuit of high precision measuring temperature instrument, so as to by change in resistance
It is transformed into electric signal, so as to be converted into data signal, so as to obtain the temperature of environment to be measured.Constant-current source is accurately to measure RTD
The precondition of resistance.
Reference voltage, the design of constant-current source drastically influence the certainty of measurement and stability of circuit.Reference electricity
Pressure VREFWhether stable and Low Drift Temperature is to ensure that high precision measuring temperature instrument herein has high-precision important prerequisite；Meanwhile, it is employing
The platinum resistance temperature sensor of the four-wire system mode of connection provides stable constant-current source and is also necessary, and platinum resistance temperature
Sensor by electric current definitely not above 4mA.
As shown in figure 4, the signal processing circuit 4 uses the four-wire system connection after improving, it is to ensure measurement
Precision and stability.X in Fig. 51、X2、X3、X4It is respectively the equivalent resistance of four leads of platinum sensor.With R4Resistance
Magnitude of voltage R in the design as reference voltage4Value is 510 Ω, and reference voltage, the design of constant-current source drastically influence
The certainty of measurement and stability of circuit.Reference voltage VREFWhether stable and Low Drift Temperature is to ensure high precision measuring temperature herein
Instrument has high-precision important prerequisite.The mirror current source constituted with triode 8550 is reducing external interference, it is to avoid error.
Connect high-accuracy resistance R on the basis of this0, the temperature varying coefficient of this high-accuracy resistance is 1ppm, i.e. 1 DEG C of temperature change, its resistance
Value changes are 10-6Ω, R in the design0Value is Ω.Theoretical according to electronic circuit, the electric current I of RTD PT sensors is：
Reference voltage VREFFor：
VRef=I × R4 (4)
The voltage and precision resistance R of PT sensors0Voltage be respectively：
VPT100=I × RPT100 (5)
VR0=I × R0 (6)
Finally take the voltage and precision resistance R for obtaining PT sensors0Both voltage voltage ratio, i.e.,
So as to eliminate the curent change that constant-current source is affected due to factors such as temperature drifts so that output voltage ratio with
RTD is into good linear relationship.
The voltage signal for obtaining is sampled by 24 A/D converter LTC2492, then by signal to ATmega32
Single-chip microcomputer, single-chip microcomputer carries out data processing and preserves and display data.The stability of the design temperature measurement of the circuit can reach
Arrive
1‰.The High Precision Temperature Measuring Instruments of table 1 emulate data
According to the design circuit and Fig. 3 system architecture FB(flow block)s of Fig. 5, the system circuit test is verified change current potential
The resistance of device measures potentiometer simulating platinum resistance temperature sensor test using the desk-top multimeter 8808A of fluke five and half
Resistance calibrated, take part measurement data as shown in table 1.According to the systematic survey sampled data of table 1, V100It is to represent accurate
Resistance R0Voltage, VPT100It is the voltage of platinum sensor, the resistance of platinum sensor can be calculated by formula (7), then leads to
Cross formula (1) and formula (2) solves measured temperature.Calculate through data, mean error 1.1 ‰, worst error 4 ‰.
To ensure the precision and stability of measurement, we devise one and do reference voltage with 510 Ohmic resistances, with three poles
The mirror current source that pipe 8550 is constituted is reducing external interference, it is to avoid error.On this basis one ohm of series connection is high-accuracy
Resistance, 1 DEG C of temperature change, the increased resistance value of this high-accuracy resistance is 106/ mono-.To ensure that the high accuracy for designing herein is surveyed
The temperature measurement accuracy and stability of amount instrument, we using the high-accuracy resistance of ohm and PT take respectively analog voltage do the method for ratio come
Obtain magnitude of voltage.Its circuit design is referring to Fig. 5.
The Main Function of A/D change-over circuits 5 is that analog signal is become data signal, the system independent design A/D
Converter.It is 0.5LSB, 1LSB=V that what ADC was selected is voltage resolutionREF/224, VREFSpan be 0.1～VCC,24
The LTC2492 of position, it complies fully with requirement of the system to precision, and the design of LTC2492 is as shown in Figure 6.
Parameter setting and the calibration of temperature for convenience of high precision measuring temperature instrument, ad hoc meter key-press module 9, key-press module 9 is wrapped
Containing 4 control buttons, their function is respectively ESC, ENTER, both direction key.To realize the control function of circuit, 4 controls
Button one end ground connection processed, another termination I/O mouths and pull-up resistor.Each button is equal to a mechanical switch on keyboard, when
When key is pressed, circuit is in connected state, and it is low level now to correspond to single-chip microcomputer mouth line；When button it is released, whole circuit
It is off, now mouth line corresponding with single-chip microcomputer is high level.The circuit of key-press module is as shown in Figure 7.
Key-press module 9 can be directly connected into single key circuit, each button list using free-standing button with I/O lines
Solely connect an I/O mouth line, in separate state, this key arrangement avoids producing impact to other I/O mouth lines.This electricity
Road figure is designed with Low level effective, and when button disconnects, pull-up resistor ensure that I/O mouth lines have high level.
Temperature correction module 12 is mainly used in the numerical value to measured temperature carries out linear gauging, the temperature value that system is surveyed
Error and solution temperature equation caused by the difference main by sensor of error, the difference of constant-current source, analog-digital converter is produced
Raw error etc. is constituted, it is comprehensive apparently these be linear, useable linear equation is being modified.Its update equation computing formula
For：Y=ax+b, needs first to determine two parameters of a and b in equation before calculating, by with two-point measurement value and normal temperature value
Method relatively can try to achieve two parameters of a and b, and x is substituted into formula：In y=ax+b, the y for solving is exactly revised result.
During determining two parameters of a and b, 0 DEG C and DEG C two points are preferably selected as two-point measurement value.
When -200 DEG C≤t≤0 DEG C, the resistance of RTD is with the function expression of temperature change：
Rt=R0(1+At+Bt2+C(t-100)t3) (1)
When 0 DEG C≤t≤850 DEG C, the resistance of RTD is with the function expression of temperature change：
Rt=(1+At+Bt2) (2)
By system compensation.Temperature measuring set test data such as table 2 and the institute of table 3.
Mixture of ice and water final test data after the calibration of table 2
Boiling water final test data after the calibration of table 3
According to the characteristic curve of RTD, its update equation computing formula is：Y=ax+b.By temperature correction parameter journey
The numerical value of ordered pair measured temperature carries out linear gauging, consider error caused by the difference of constant-current source, analog-digital converter with
And the error useable linear equation produced by solution temperature equation etc. is being modified.Need first to determine a and b in equation before calculating
Two parameters, we select 0 DEG C can to try to achieve two parameters of a and b by the method compared with normal temperature value with two-point measurement value
X is substituted into formula solving two parameters of a and b as two-point measurement value with DEG C of two points：In y=ax+b, the y for solving is exactly
Revised result.
The wide-range based on RTD can be seen that by the measurement data of temperature measuring set before and after comparison calibration high
Accurate temperature measuring instrument meets measurement request, and the High Precision Temperature Measuring Instruments after calibration are interval 0 DEG C～100 DEG C in thermometric, thermometric
Precision reaches 5/1000ths.Temperature measurement accuracy is high, temperature-measuring range is wide, price is low, with more huge economic worth and social value.
Claims (4)
1. a kind of wide-range high-precision temperature measuring set based on RTD, it is characterised in that：The width amount based on RTD
Journey High Precision Temperature Measuring Instruments constitute as follows：Power circuit（1）, constant current source driving circuit（2）, temperature sensor（3）, at signal
Reason circuit（4）, A/D change-over circuits（5）, single-chip microcomputer（6）, display（7）, holder（8）, key-press module（9）, reset circuit
（10）, crystal oscillating circuit（11）, temperature correction module（12）, data-signal processing module（13）；Wherein, power circuit（1）With perseverance
Stream source driving circuit（2）, A/D change-over circuits（5）And single-chip microcomputer（6）Constitute electrical connection, constant current source driving circuit（2）At signal
Reason circuit（4）Constitute electrical connection, the signal processing circuit（4）Including connection temperature sensor（3）Four leads it is equivalent
Resistance, respectively first resistor, second resistance, 3rd resistor and the 4th resistance, wherein, first resistor, constant current source driving circuit
（2）, second resistance and temperature sensor（3）Loop is followed in series to form by wire, one end of 3rd resistor is connected by wire
It is connected to first resistor and temperature sensor（3）Between, the other end connection A/D change-over circuits of 3rd resistor（5）A/D sampling mend
Line is repaid, one end of the 4th resistance is connected to second resistance and temperature sensor by wire（3）Between, the other end of the 4th resistance
Connect compensating line over the ground, signal processing circuit（4）By A/D change-over circuits（5）With single-chip microcomputer（6）It is connected, display（7）, storage
Storage（8）, key-press module（9）, reset circuit（10）And crystal oscillating circuit（11）Respectively with single-chip microcomputer（6）It is connected, key-press module
（9）By temperature correction module（12）With data-signal processing module（13）It is connected, data-signal processing module（13）With monolithic
Machine（6）It is connected.
2. according to the wide-range high-precision temperature measuring set described in claim 1 based on RTD, it is characterised in that：The temperature
Sensor（3）Using PT100 platinum sensors, the constant current source driving circuit（2）Connection temperature varying coefficient is 1ppm's
The high high-accuracy resistance of temperature stabilization coefficient, the constant current source driving circuit（2）The electric current of output can not be more than 4mA.
3. according to the wide-range high-precision temperature measuring set described in claim 1 based on RTD, it is characterised in that：The A/D
Change-over circuit（5）Using the LTC2492 analog-digital converters of 24.
4. according to the wide-range high-precision temperature measuring set described in claim 1 based on RTD, it is characterised in that：The button
Module（9）Including 4 operating keys, specially 1 esc key, 1 ↑ directionkeys and 1 ↓ directionkeys, a termination of 4 operating keys
Ground, another termination I/O mouths and pull-up resistor.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
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| CN201621201692.7U CN206161180U (en) | 2016-11-08 | 2016-11-08 | Wide -range high accuracy temperature measurement device based on platinum resistance |
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| CN201621201692.7U CN206161180U (en) | 2016-11-08 | 2016-11-08 | Wide -range high accuracy temperature measurement device based on platinum resistance |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| 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 |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| 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 |
| CN106404207B (en) * | 2016-11-08 | 2020-04-03 | 辽宁师范大学 | Wide-range high-precision temperature measuring instrument based on platinum resistor and measuring method thereof |
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