CN201497594U - High-precision platinum resistance temperature measuring device - Google Patents
High-precision platinum resistance temperature measuring device Download PDFInfo
- Publication number
- CN201497594U CN201497594U CN2009202304190U CN200920230419U CN201497594U CN 201497594 U CN201497594 U CN 201497594U CN 2009202304190 U CN2009202304190 U CN 2009202304190U CN 200920230419 U CN200920230419 U CN 200920230419U CN 201497594 U CN201497594 U CN 201497594U
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- capacitor
- resistance
- platinum resistance
- precision
- oscillator
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Abstract
The utility model discloses a high-precision platinum resistance temperature measuring device which comprises an RC oscillator (101), a frequency measuring chip (102), a reference clock circuit (103) and a singlechipe (104), wherein a platinum resistance sensor can form the RC oscillator (101) together with a fixed capacitor through the two-wire system connection. When temperature changes, resistance value of a platinum resistance also changes therewith, which leads to the changes of the oscillation frequency of the oscillator, therefore the changes of the platinum resistance are modulated into time change frequency signals, then a frequency measuring chip is used to measure the frequency change amount which is then input the singlechip, and the resolving from the frequency change to the temperature change can be finished in the singlechip through higher-order polynomial, thereby realizing the high-precision temperature measurement through utilizing the platinum resistance. The high-precision platinum resistance temperature measuring device has the characteristics of high temperature measurement precision, low cost and excellent stability.
Description
Technical field
The utility model relates to a kind of temperature measurement system, especially a kind of high-precision platinum resistor temperature measuring device.
Background technology
Temperature is one of 7 fundamental physical quantities in the International System of Units.Standard platinum resistance thermometer has characteristics such as high precision, high sensitivity and high stability, thereby is widely used in the temperature survey of intelligent instrumentation.Existing method is earlier resistance variations to be converted to voltage signal by resistance bridge mostly, pass through a series of filtering and processing and amplifying again after, send into A/D converter and finish temperature acquisition.These class methods need be resolved two problems: (1) because the influence that temperature is brought platinum resistance resistance and amplifier, system can produce certain systematic error when variation of ambient temperature.In pinpoint accuracy was measured, seeking the efficient temperature compensation method was one of difficult problem that need face.(2) along with the raising of measuring accuracy, the price of high resolution A/D converter heightens, and causing the surveying instrument cost too high is another problem that is faced.
The utility model content
The purpose of the utility model design is at the deficiencies in the prior art, and the platinum resistor temperature measuring device of a kind of low cost, high measurement accuracy is provided.
The technical scheme that the utility model adopted is:
High-precision platinum resistor temperature measuring device of the present utility model comprises RC oscillator, frequency measurement chip, reference clock circuit, single-chip microcomputer; The output terminal of RC oscillator is connected with the input end of frequency measurement chip, and the output terminal of reference clock circuit is connected with the clock end of frequency measurement chip, and the frequency measurement chip is connected by spi bus with single-chip microcomputer; Described RC oscillator comprises first capacitor C 1 and platinum sensor Rt, wherein the end of platinum sensor Rt is connected with the N pin of frequency measurement chip, the platinum sensor Rt other end links to each other the other end ground connection of first capacitor C 1 with the P pin of frequency measurement chip, an end of first capacitor C 1 respectively.
Reference clock circuit in the high-precision platinum resistor temperature measuring device of the present utility model comprises first resistance R 1, second resistance R 2, second capacitor C 2, the 3rd capacitor C 3, crystal oscillator X1 and inverter ic 1; Wherein an end of first resistance R 1 is connected with an end of second capacitor C 2, the other end of second capacitor C 2 is connected back ground connection with the end of crystal oscillator X1, the other end of crystal oscillator X1 is connected back ground connection with an end of the 3rd capacitor C 3, the other end of the 3rd capacitor C 3 is connected with an end of second resistance R 2, the input end of inverter ic 1 respectively, and the output terminal of inverter ic 1 is connected with the other end of first resistance R 1, the other end of second resistance R 2, the CLK pin of frequency measurement chip respectively.
The single-chip microcomputer that high-precision platinum resistor temperature measuring device of the present utility model adopts is the C8051F021 single-chip microcomputer.
Beneficial effect:
The beneficial effects of the utility model are:
(1), platinum resistance adopts the two-wire system connection, constitutes the RC oscillator with fixed capacity, and the platinum resistance variable quantity is converted to frequency signal, solved the nonlinear problem that the unbalanced resistance bridge is brought in the classic method;
(2), platinum resistance is operated in passive states, and entire circuit is made up of digit chip, removed the compensation problem that uncertain factors such as warm change cause from;
(3), by the survey frequency variable quantity, directly resolve the change in resistance of platinum resistance, thereby calculate the dut temperature value by higher order polynomial, save the A/D link, when high precision measuring temperature, significantly reduced equipment cost;
Description of drawings
Fig. 1 is a structural representation of the present utility model.
Embodiment
Below in conjunction with accompanying drawing enforcement of the present utility model is made and to be further specified.
As shown in Figure 1, high-precision platinum resistor temperature measuring device of the present utility model comprises RC oscillator 101, frequency measurement chip 102, reference clock circuit 103 and single-chip microcomputer 104; RC oscillator 101 comprises first capacitor C 1 and platinum sensor Rt, platinum resistance adopts the two-wire system connection, the one end links to each other with an end of first capacitor C 1, be connected to simultaneously the P pin of frequency measurement chip 102 again, an other end is connected to the N pin of frequency measurement chip 102, the other end ground connection of first capacitor C 1, frequency measurement chip 102 and single-chip microcomputer 104 are connected by spi bus, and reference clock circuit 103 is connected with the CLK pin of frequency measurement chip 102; Reference clock circuit 103 comprises first resistance R 1, second resistance R 2, second capacitor C 2, the 3rd capacitor C 3, crystal oscillator X1 and inverter ic 1; Wherein an end of first resistance R 1 is connected with an end of second resistance R 2, an end of second capacitor C 2 respectively, the other end of second capacitor C 2 is connected back ground connection with the end of crystal oscillator X1, the other end of crystal oscillator X1 is connected back ground connection with an end of the 3rd capacitor C 3, the other end of the 3rd capacitor C 3 is connected with the other end of second resistance R 2, the input end of inverter ic 1 respectively, and the output terminal of inverter ic 1 is connected with the other end of first resistance R 1, the CLK pin of frequency measurement chip 102 respectively.
High-precision platinum resistor temperature measuring device of the present utility model, when temperature changes, platinum sensor Rt changes with the temperature variation of measuring object and causes the oscillation frequency of RC oscillator 101 to change, thereby with platinum sensor Rt change modulates is the time varying frequency signal, measure this frequency variation by single-chip microcomputer 104 controlled frequency measured chip 102 again, measured value is sent into single-chip microcomputer 104, after in single-chip microcomputer 104, utilizing iir filter to carry out filtering, finish frequency change to the resolving of temperature variation with higher order polynomial again, calculate actual temperature value.
Platinum sensor Rt is put into the demarcation environment, in the measurement range of platinum sensor Rt, evenly change the calibration cell temperature, the temperature value that while recording frequency count value and standard thermodynamic scale obtain, with higher order polynomial two groups of data are returned then, obtain the mapping relations of count value and standard temperature value, thereby obtain one group of multinomial coefficient, the new count value that records later on can be calculated corresponding temperature with this group coefficient.The polynomial expression exponent number is high more in theory, and precision is high more, but resource consumption is also big more, and temperature measuring equipment of the present utility model adopts 11 rank polynomial expressions when thermometric resolves, and not only system calibrating, calibration process are simple, also is convenient to software automation and realizes.
Claims (3)
1. a high-precision platinum resistor temperature measuring device is characterized in that: comprise RC oscillator (101), frequency measurement chip (102), reference clock circuit (103), single-chip microcomputer (104); The output terminal of RC oscillator (101) is connected with the input end of frequency measurement chip (102), the output terminal of reference clock circuit (103) is connected with the clock end of frequency measurement chip (102), and frequency measurement chip (102) is connected by spi bus with single-chip microcomputer (104); Described RC oscillator (101) comprises first capacitor C 1 and platinum sensor Rt, wherein the end of platinum sensor Rt is connected with the N pin of frequency measurement chip (102), the platinum sensor Rt other end links to each other the other end ground connection of first capacitor C 1 with the P pin of frequency measurement chip (102), an end of first capacitor C 1 respectively.
2. high-precision platinum resistor temperature measuring device according to claim 1 is characterized in that: described reference clock circuit (103) comprises first resistance R 1, second resistance R 2, second capacitor C 2, the 3rd capacitor C 3, crystal oscillator X1 and inverter ic 1; Wherein an end of first resistance R 1 is connected with an end of second capacitor C 2, the other end of second capacitor C 2 is connected back ground connection with the end of crystal oscillator X1, the other end of crystal oscillator X1 is connected back ground connection with an end of the 3rd capacitor C 3, the other end of the 3rd capacitor C 3 is connected with an end of second resistance R 2, the input end of inverter ic 1 respectively, and the output terminal of inverter ic 1 is connected with the other end of first resistance R 1, the other end of second resistance R 2, the CLK pin of frequency measurement chip (102) respectively.
3. high-precision platinum resistor temperature measuring device according to claim 1 is characterized in that: described single-chip microcomputer (104) is the C8051F021 single-chip microcomputer.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2009202304190U CN201497594U (en) | 2009-08-20 | 2009-08-20 | High-precision platinum resistance temperature measuring device |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2009202304190U CN201497594U (en) | 2009-08-20 | 2009-08-20 | High-precision platinum resistance temperature measuring device |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN201497594U true CN201497594U (en) | 2010-06-02 |
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN2009202304190U Expired - Fee Related CN201497594U (en) | 2009-08-20 | 2009-08-20 | High-precision platinum resistance temperature measuring device |
Country Status (1)
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| CN (1) | CN201497594U (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104062026A (en) * | 2013-03-22 | 2014-09-24 | 上海丽恒光微电子科技有限公司 | Temperature sensor |
-
2009
- 2009-08-20 CN CN2009202304190U patent/CN201497594U/en not_active Expired - Fee Related
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104062026A (en) * | 2013-03-22 | 2014-09-24 | 上海丽恒光微电子科技有限公司 | Temperature sensor |
| CN104062026B (en) * | 2013-03-22 | 2017-04-26 | 上海丽恒光微电子科技有限公司 | Temperature sensor |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| C17 | Cessation of patent right | ||
| CF01 | Termination of patent right due to non-payment of annual fee |
Granted publication date: 20100602 Termination date: 20100820 |