CN203054250U - Automatic meteorological station temperature calibration system - Google Patents
Automatic meteorological station temperature calibration system Download PDFInfo
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- CN203054250U CN203054250U CN 201220521928 CN201220521928U CN203054250U CN 203054250 U CN203054250 U CN 203054250U CN 201220521928 CN201220521928 CN 201220521928 CN 201220521928 U CN201220521928 U CN 201220521928U CN 203054250 U CN203054250 U CN 203054250U
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Abstract
In order to solve problems of temperature calibration in an automatic meteorological station, an automatic meteorological station temperature calibration system is designed according to relations between automatic meteorological station temperature measurement accuracy and a temperature measurement range. The system comprises a test current generation circuit, a potentiometer regulating circuit, a platinum resistor sensor, a signal conditioning circuit, an A/D converting circuit, an isolator circuit, a CPU processing circuit, a display, a reference power supply and a power supply module.
Description
Technical field
The utility model relates to a kind of automatic weather station temperature calibration system, belongs to the aeromerric moasurenont technical field.
Background technology
Hu Fan, Yang Hengxiang " discussion of temperature sensor at auto weather stations field calibration " is that the weather station temperature sensor is calibrated separately, need dismantle censorship to automatic weather station, detected also and will install, and increased the burden of calibration.
Pointed out the defective that automatic weather station dismounting calibration and manual calibration exist and worked out complete software system design in " the automatic weather station field calibration is compiled the card system " literary composition of Huang Ling, but do not have supporting hardware design, also need by existing calibration system during use.
Yi Xianjun etc. are temperature element with the platinum resistance in " a kind of high-precision temperature metering circuit design ", have at first solved high-acruracy survey to the problem that requires of some harshnesses of hardware circuit, but precision only reach ± 0.4 ℃; Fang Yixi etc. are temperature element with the platinum resistance in " based on the High Accuracy Temperature Measure System of PT1000 ", use three-wire system constant current source driving method and secondary voltage mensuration and greatly reduce temperature measurement error, the experiment measuring error is not more than 0.01 ℃ in measurement range, but owing to reasons such as device selections, temperature-measuring range is all narrow, can not be used for the calibration of automatic weather station temp measuring system.
Summary of the invention
In order to solve the temperature correction problem of automatic weather station, according to the relation between automatic weather station temperature measurement accuracy and the temperature-measuring range, the utility model has designed a kind of automatic weather station temperature calibration system.
The purpose of this utility model realizes by following measure:
The automatic weather station temperature calibration system comprises that measuring current produces circuit, potentiometer regulating circuit, platinum sensor, signal conditioning circuit, A/D change-over circuit, isolator circuit, CPU treatment circuit, display, reference power supply and power module.
The measuring current that measuring current produces the circuit generation produces voltage signal through signal conditioning circuit, again through A/D change-over circuit, isolator circuit, delivering to CPU handles, the result is shown by display, power module provides voltage source for each circuit, and wherein measuring current produces circuit and A/D change-over circuit common reference power supply.
Described platinum sensor adopts the PT1000 temperature sensor.
Described measuring current produces circuit and comprises: OPA277 amplifier U3, U7, resistance R 27, R28, R29, R36, R37, R40, potentiometer R31, R32 and capacitor C 39; Capacitor C 39 connects reference voltage source output, and reference voltage source output connects OPA277 amplifier U7 input end in the same way through resistance R 29, output terminal and the reverse input end of resistance R 29 and R27 series connection OPA277 amplifier U3; The reverse input end of OPA277 amplifier U7 connects the output terminal of OPA277 amplifier U7 through resistance R 37 ground connection through resistance R 40; The reference resistance that the input end in the same way of resistance U3 constitutes through the potentiometer regulating circuit connects the output terminal of OPA277 amplifier U7.
Described potentiometer regulating circuit: comprise resistance R 1, R3 and potentiometer R2, R4, after resistance R 1 and the potentiometer R2 series connection, be in series with resistance R 3 and potentiometer R4 parallel circuit again.
The A/D change-over circuit adopts 24 high-precision A 7799 A/D converters.
Described signal conditioning circuit comprises: OPA277 amplifier U4, U8, platinum resistance PT1000, resistance R 30, R39, R30, R41, R42, R25, R26, R34, R35, potentiometer R33, R38 and capacitor C 30, C31, C34, C35, C36; The zero degree reference resistance ground connection that measuring current input platinum resistance PT1000 constitutes through the potentiometer regulating circuit, the U4 reverse input end connects output terminal, import termination platinum resistance PT1000 current input terminal in the same way, OPA277 amplifier U8 imports termination platinum resistance PT1000 current output terminal in the same way, reverse input end is through R41 ground connection, connect output terminal through R42, OPA277 amplifier U4, U8 output termination filtering circuit is to connect capacitor C 30 back ground connection behind the OPA277 amplifier U4 output terminal connecting resistance R25, connect C31 ground connection again behind the resistance R 25 connecting resistance R26, connect capacitor C 35 ground connection again behind the OPA277 amplifier U8 output terminal connecting resistance R34, connect capacitor C 36 back ground connection behind the resistance R 34 connecting resistance R35, resistance R 26 and resistance R 35 indirect C34, OPA277 amplifier U4, U8 exports 5 pin and 6 pin that filtered voltage meets AD7799 respectively.
Described isolator circuit adopts the ADUM5401 isolating chip.
Described CPU processor adopting AT89S52 is the MCU microprocessor.
The utlity model has following advantage:
24 high-precision A 7799 that it is temperature sensor that the utility model adopts PT1000, have a good AFE (analog front end) for AD converter, be integrated with the isolating chip ADUM5401 position isolator of the isolated DC/DC converter of isoPower, design and satisfy the temp measuring system that sub-thing is seized temperature correction scope and precision.
Description of drawings
Fig. 1 is automatic weather station calibration temp measuring system.
Fig. 2 produces circuit for measuring current.
Fig. 3 is the potentiometer regulating circuit.
Fig. 4 is signal conditioning circuit.
Fig. 5 is A/D convertor circuit.
Fig. 6 is the isolator circuit.
Fig. 7 is power module.
Fig. 8 is digital circuit blocks.
Embodiment
PT1000 is that platinum resistance temperature sensor, ADR421 are that reference voltage source, OPA2277 are that amplifier, AD7799 are that A/D converter, ADUM5401 digital isolator, AT89S52 are the MCU microprocessor in the utility model, and the each several part hardware circuit is as follows:
1, measuring current produces circuit
The stability of measuring current directly determines precision and the stability of this total system, it produces circuit as shown in Figure 2, the constant measuring current that this circuit produces is by two additional wire of PT1000, convert temperature variant resistance signal to be convenient to measure voltage signal, by two p-wire measurement voltage signal in addition of PT1000.
2, potentiometer calibration adjustments circuit
Be illustrated in figure 3 as the potentiometer regulating circuit,
Series connection back with
Parallel circuit series connection constitute the potentiometer regulating circuit.
Be the fixed resistance less than required resistance value,
Be the adjustable potentiometer for coarse adjustment, and
With
The maximum value sum greater than required resistance value.
Be the fixed resistance of resistance 10 Ω and the adjustable potentiometer of 100 Ω
Connect, can realize the Precision trimming of 0～9 Ω.At first regulate
Make resistance near required resistance, regulate again
Make final resistance in error range near required resistance.
Because platinum resistance and temp measuring system circuit have influenced temperature measurement accuracy jointly when measuring, for reducing systematic error, improve system accuracy, the reference resistance that zero degree resistance and measuring current produce in the circuit in the hardware circuit replaces with the potentiometer regulating circuit respectively.
3, signal conditioning circuit
Signal conditioning circuit as shown in Figure 4, this circuit is connected PT1000 with the zero degree reference resistance, after amplifier adjusting filtering, the magnitude of voltage at two resistance two ends is sent into the differential input end of AD7799, variable quantity when directly measuring the relative zero degree of platinum resistance voltage, this method can reach high measuring accuracy.
Be combined as the potentiometer regulating circuit, regulate the zero degree reference resistance R value that produces PT1000.The voltage signal of U4 output inserts 5 pin of AD after filtering, the voltage signal of U8 output is got involved 6 pin of AD after filtering.
4, the selection of high-precision difference AD
As Fig. 5, the resolution of temp measuring system and precision depend on the A/D converting unit to a great extent, so selecting for use of AD is extremely important.Native system AD conversion chip is selected AD7799.AD7799 has following characteristics: low-power consumption; 0.0015% low nonlinearity degree; Conversion accuracy reaches 24 no error codes; The synchronous trap of 50Hz and 60Hz is eliminated power frequency supply and is disturbed; The low-noise programmable instrument amplifier of built-in one 128 gains; 3 difference input channels; Have the SPI data-interface, can be connected with MCU easily.Use the difference input of AD can effectively suppress neighbourhood noise and dc error, because noise can disturb and all there is the dc error source in two-way two paths of signals simultaneously, subtract each other operation after the difference and can effectively eliminate noise, thereby reduce error.And AD7799 has complete AFE (analog front end), can directly measure the faint simulating signal of platinum sensor output, can simplify circuit and make the measuring accuracy of native system reach requirement.
Because the design's temperature-measuring range is bigger, the temperature drift error that reference voltage produces is also bigger.Native system produces shared reference voltage source: the ADR421 of circuit with AD and measuring current.When temperature change, the drift simultaneously of the reference voltage of current source and AD, drift error can be cancelled out each other, thereby further reduces systematic error.1,2,15,16 pin of AD connect 13,14,11,12 pin of isolator ADUM5401 respectively.
5, isolator circuit
As Fig. 6, there is high frequency noise in single-chip microcomputer numeral output line, directly links to each other with AD and can introduce AD to noise, reduces the conversion accuracy of AD converter, so the design adopts digital isolator ADUM5401 to isolate.ADUM5401 has four DC-25Mbps signal channel isolations, makes to realize between AD7799 and the single-chip microcomputer that signal is isolated completely, avoids single-chip microcomputer that noise is introduced AD; ADUM5401 also is integrated with the isolated DC/DC converter of isoPower, for all artificial circuit parts provide the power supply of 5V power supply, thereby realizes the isolation fully of digital power and analog power.The peripheral circuit of ADUM5401 as shown in Figure 6.3,4,5,6 pin of ADUM5401 connect 21,22,23,24 pin of AT89S51 respectively.
6, power module:
As shown in Figure 7, the power supply input is by the power supply of LM7805 conversion generation+5V voltage as digital module, + 5V voltage is as the former limit power supply of ADUM5401 chip, output isolates+and 5V secondary power supply is as the positive supply of mimic channel, and+5V secondary power supply input ICL7662 generation-5V voltage is as the negative supply of mimic channel.
7, the digital circuit principle as shown in Figure 8.
Form as shown in Figure 1, principle of work of the present utility model is as follows:
Can need not give formula in conjunction with Fig. 1 explanation in detail again
Hardware components uses the four-wire system platinum sensor as temperature element for the influence of eliminating lead resistance, reference resistance (size equals the zero degree resistance of platinum resistance) connect with platinum resistance, with measuring current as driving, the direct measuring voltage of difference analogue input channel by signal conditioning circuit and A/D converter is with the variation of temperature amount, and the data after A/D converter is handled are used least square method data to be carried out sectional linear fitting through the digital circuit blocks microprocessor and handled the brilliant demonstration of real time temperature liquor charging that the back obtains.
After system finishes it has been carried out its precision of experimental verification and can measurement range satisfy alignment requirements.After the PT100 platinum resistance of the PT1000 platinum resistance of the utility model automatic weather station temperature calibration system and modular system all inserted calibration cell, at first the calibration cell temperature is transferred to 0 ℃ and 80 ℃ system is regulated calibration, the corresponding CODE sign indicating number in calibration back is respectively 8388620 and 16267930, every about 10 ℃ measuring system is once calibrated measurement then.The calibration cell temperature is transferred near the test point, after treating that the modular system temperature displayed is basicly stable, every 3min the mean value that same temperature spot carries out measuring and obtain respectively for 10 times automatic weather station intelligent temperature calibration system and modular system is done contrast, and do suitable correction in the bigger region point of error, repeatedly draw the final system measurement data after the experiment, as shown in table 1, the temperature measurement accuracy of native system can reach 0.06 ℃ as can be seen.Can be used for the calibration to present domestic most of automatic weather station.
During calibration, whether normally the temperature data contrast that the temperature data that native system is recorded and host computer and same time automatic weather station record is obtained relative error and is just known automatic weather station temperature measurement fraction fortune.
Table 1 systematic survey data
| Test point | Actual standard temperature-averaging value | System records the temperature-averaging value | Average error |
| -50 | -49.36475 | -49.3445 | 0.02025 |
| -40 | -40.43114 | -40.47429 | -0.04314 |
| -30 | -30.40638 | -30.4517 | -0.04532 |
| -20 | -20.38405 | -20.443177 | -0.059127 |
| -10 | -10.36725 | -10.34592 | 0.02133 |
| 0 | 0.80959 | 0.810 | 0.0041 |
| 10 | 10.15 | 10.206 | 0.056 |
| 20 | 20.18075 | 20.17398 | -0.0067 |
| 30 | 30.291 | 30.3249 | 0.0339 |
| 40 | 40.41175 | 40.47073 | 0.05855 |
| 50 | 50.39325 | 50.35393 | -0.03932 |
| 60 | 60.48375 | 60.4687 | -0.01505 |
| 70 | 70.543 | 70.4854 | -0.0576 |
| 80 | 79.53632 | 79.4755 | 0.005082 |
Claims (8)
1. the automatic weather station temperature calibration system is characterized in that: comprise that measuring current produces circuit, potentiometer regulating circuit, platinum sensor, signal conditioning circuit, A/D change-over circuit, isolator circuit, CPU treatment circuit, display, reference power supply and power module; The measuring current that described measuring current produces the circuit generation produces voltage signal through signal conditioning circuit, again through A/D change-over circuit, isolator circuit, delivering to CPU handles, the result is shown by display, power module provides voltage source for each circuit, and wherein measuring current produces circuit and A/D change-over circuit common reference power supply.
2. system according to claim 1 is characterized in that: described platinum sensor employing PT1000 temperature sensor.
3. system according to claim 1 is characterized in that: described measuring current produces circuit and comprises: OPA277 amplifier U3, U7, resistance R 27, R28, R29, R36, R37, R40, potentiometer R31, R32 and capacitor C 39; Capacitor C 39 connects reference voltage source output, and reference voltage source output connects OPA277 amplifier U7 input end in the same way through resistance R 29, output terminal and the reverse input end of resistance R 29 and R27 series connection OPA277 amplifier U3; The reverse input end of OPA277 amplifier U7 connects the output terminal of OPA277 amplifier U7 through resistance R 37 ground connection through resistance R 40; The reference resistance that the input end in the same way of resistance U3 constitutes through the potentiometer regulating circuit connects the output terminal of OPA277 amplifier U7.
4. system according to claim 1 is characterized in that: described potentiometer regulating circuit: comprise resistance R 1, R3 and potentiometer R2, R4, after resistance R 1 and the potentiometer R2 series connection, be in series with resistance R 3 and potentiometer R4 parallel circuit again.
5. system according to claim 1 is characterized in that: 24 high-precision A 7799 A/D converters of A/D change-over circuit employing.
6. system according to claim 5, it is characterized in that: described signal conditioning circuit comprises: OPA277 amplifier U4, U8, platinum resistance PT1000, resistance R 30, R39, R30, R41, R42, R25, R26, R34, R35, potentiometer R33, R38 and capacitor C 30, C31, C34, C35, C36; The zero degree reference resistance ground connection that measuring current input platinum resistance PT1000 constitutes through the potentiometer regulating circuit, the U4 reverse input end connects output terminal, import termination platinum resistance PT1000 current input terminal in the same way, OPA277 amplifier U8 imports termination platinum resistance PT1000 current output terminal in the same way, reverse input end is through R41 ground connection, connect output terminal through R42, OPA277 amplifier U4, U8 output termination filtering circuit is to connect capacitor C 30 back ground connection behind the OPA277 amplifier U4 output terminal connecting resistance R25, connect C31 ground connection again behind the resistance R 25 connecting resistance R26, connect capacitor C 35 ground connection again behind the OPA277 amplifier U8 output terminal connecting resistance R34, connect capacitor C 36 back ground connection behind the resistance R 34 connecting resistance R35, resistance R 26 and resistance R 35 indirect C34, OPA277 amplifier U4, U8 exports 5 pin and 6 pin that filtered voltage meets AD7799 respectively.
7. system according to claim 1 is characterized in that: described isolator circuit employing ADUM5401 isolating chip.
8. system according to claim 1, it is characterized in that: described CPU processor adopting AT89S52 is the MCU microprocessor.
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|---|---|---|---|
| CN 201220521928 CN203054250U (en) | 2012-10-12 | 2012-10-12 | Automatic meteorological station temperature calibration system |
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|---|---|---|---|
| CN 201220521928 CN203054250U (en) | 2012-10-12 | 2012-10-12 | Automatic meteorological station temperature calibration system |
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Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103940533A (en) * | 2014-02-14 | 2014-07-23 | 湖北汽车工业学院 | Measurement and control method for engine coolant temperature sensor, and measurement and control system thereof |
| CN104062025A (en) * | 2014-07-09 | 2014-09-24 | 成都千嘉科技有限公司 | Energy-saving automatic AD temperature collecting monitoring system |
| CN104316209A (en) * | 2014-11-18 | 2015-01-28 | 吉林大学 | Aircraft engine inlet temperature measuring device and measuring method thereof |
| CN104898737A (en) * | 2015-04-03 | 2015-09-09 | 上海申腾信息技术有限公司 | Temperature acquisition fault self-diagnosis system |
| CN107727061A (en) * | 2017-09-27 | 2018-02-23 | 武汉霸云创新科技有限公司 | A kind of electro-optical distance measurement system and method for autonomous atmospheric correction |
| CN109375291A (en) * | 2018-10-09 | 2019-02-22 | 成都信息工程大学 | A kind of temperature and air pressure suitable for sonde and humidity measuring instrument and method |
| CN112649106A (en) * | 2020-12-24 | 2021-04-13 | 西安翔腾微电子科技有限公司 | Novel single-chip platinum resistor signal conditioning circuit and conditioning method |
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2012
- 2012-10-12 CN CN 201220521928 patent/CN203054250U/en not_active Expired - Fee Related
Cited By (11)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103940533A (en) * | 2014-02-14 | 2014-07-23 | 湖北汽车工业学院 | Measurement and control method for engine coolant temperature sensor, and measurement and control system thereof |
| CN104062025A (en) * | 2014-07-09 | 2014-09-24 | 成都千嘉科技有限公司 | Energy-saving automatic AD temperature collecting monitoring system |
| CN104062025B (en) * | 2014-07-09 | 2016-10-26 | 成都千嘉科技有限公司 | A kind of energy-conservation automatic AD temperature acquisition monitoring system |
| CN104316209A (en) * | 2014-11-18 | 2015-01-28 | 吉林大学 | Aircraft engine inlet temperature measuring device and measuring method thereof |
| CN104898737A (en) * | 2015-04-03 | 2015-09-09 | 上海申腾信息技术有限公司 | Temperature acquisition fault self-diagnosis system |
| CN107727061A (en) * | 2017-09-27 | 2018-02-23 | 武汉霸云创新科技有限公司 | A kind of electro-optical distance measurement system and method for autonomous atmospheric correction |
| CN107727061B (en) * | 2017-09-27 | 2021-03-09 | 武汉霸云创新科技有限公司 | Photoelectric distance measurement system and method for autonomous weather correction |
| CN109375291A (en) * | 2018-10-09 | 2019-02-22 | 成都信息工程大学 | A kind of temperature and air pressure suitable for sonde and humidity measuring instrument and method |
| CN109375291B (en) * | 2018-10-09 | 2019-12-27 | 成都信息工程大学 | Temperature, air pressure and humidity measuring device and method suitable for sonde |
| CN112649106A (en) * | 2020-12-24 | 2021-04-13 | 西安翔腾微电子科技有限公司 | Novel single-chip platinum resistor signal conditioning circuit and conditioning method |
| CN112649106B (en) * | 2020-12-24 | 2023-08-04 | 西安翔腾微电子科技有限公司 | Single-chip platinum resistor signal conditioning circuit and conditioning method |
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