CN204228286U - A kind of Moisture Meter temperature collection circuit - Google Patents
A kind of Moisture Meter temperature collection circuit Download PDFInfo
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- CN204228286U CN204228286U CN201420629104.4U CN201420629104U CN204228286U CN 204228286 U CN204228286 U CN 204228286U CN 201420629104 U CN201420629104 U CN 201420629104U CN 204228286 U CN204228286 U CN 204228286U
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Abstract
The utility model relates to a kind of temperature collection circuit, and particularly a kind of Moisture Meter temperature collection circuit, is characterized in that: comprise temperature sensor, precision resister voltage divider, difference instrument amplifier, voltage follower.Distinctive feature of the present utility model is: reasonably combined by conventional device, circuit self can reach ± 0.5 DEG C of sampling precision, and traditional adjustable potentiometer calibration method need not be re-used, not only greatly simplify debugging calibration operation, the stability of system also strengthens greatly, is very applicable to industrialized mass production.
Description
Technical field
The utility model relates to a kind of temperature collection circuit, particularly a kind of Moisture Meter temperature collection circuit.
Background technology
At present, grain sample pulverizes mainly through muller by online moisture detector, and then the resistance measured between muller or electric capacity, obtains grain moisture content after demarcation.Because the resistance of cereal or the temperature of capacitance and tested cereal have larger relevance, therefore current high-end online moisture detector both increases grain temperature measurement function, is used for revising Moisture Meter measurement result.
The temperature measurement schemes of current widespread use has: 1) thermistor method, and advantage is that circuit is simple, and shortcoming is thermistor is semiconductor devices, and poor anti jamming capability is fragile, is not suitable for industrial occasions application; 2) PT100 platinum resistance temperature probe, its advantage is that stability is high, and shortcoming is that direct impedance is little, wiring needs 3 line or 4 lines, and amplifier circuit is complicated, needs with calibration sample circuits such as potentiometers.
Utility model content
The purpose of this utility model is to overcome above-mentioned deficiency, there is provided a kind of Moisture Meter temperature collection circuit, the temperature of the tested grain sample of Measurement accuracy, not only greatly strengthen the stability of system, also greatly simplify debugging calibration operation, be particularly suitable for industrialized mass production.
For realizing above-mentioned technical purpose, the scheme that the utility model provides is: a kind of Moisture Meter temperature collection circuit, it is characterized in that: comprise PT1000 film platinum resistor temperature sensor, biasing resistor, precision resister voltage divider, difference instrument amplifier, voltage follower, reference power source and ADC, described PT1000 film platinum resistor temperature sensor and biased 10K resistant series, described precision resister voltage divider is 10K and 1.2K, 1/4W, 0.1% precision plug-in unit metalfilmresistor, described difference instrument amplifier is chip AD623ARZ, described voltage follower is chip AD8605ARTZ, described ADC is 12 ADC that STM32 ARM chip carries, described reference power source is the 3.3V that voltage stabilizing chip LM1117 voltage stabilizing obtains, PT1000 platinum resistance temperature sensor and biased 10K resistant series, be connected to difference instrument amplifier AD623ARZ(U1 again) positive input terminal, 10K and 1.2K resistant series forms the negative input end that voltage divider is connected to difference instrument amplifier U1, resistance R7 is connected to 1 of U1, 8 pin are to arrange gain amplifier, resistance R5, R6 voltage divider in series, be connected to voltage follower AD8605ARTZ(U2) positive input terminal, the output port of U2 is connected with self negative input end, form voltage follower, and be connected to 5 pin of difference instrument amplifier U1, 7 pin of difference instrument amplifier U1 are final output signal, be connected to the ADC input pin that STM32 ARM chip carries, the 3.3V that voltage stabilizing chip LM1117 voltage stabilizing obtains is used for as ADC, resitstance voltage divider is powered.
The utility model advantage is: reasonably combined by conventional device, circuit self can reach ± 0.5 DEG C of sampling precision, and need not re-use traditional adjustable potentiometer calibration, not only greatly simplify debugging calibration operation, the stability of system also strengthens greatly, is very applicable to industrialized mass production.
Accompanying drawing explanation
Fig. 1 is electrical block diagram of the present utility model.
Fig. 2 is that the utility model temperature exports with voltage and contrasts figure.
Embodiment
The utility model is described further below with reference to embodiment see Fig. 1 ~ 2.
A kind of temperature collection circuit, particularly a kind of Moisture Meter temperature collection circuit, it is characterized in that: comprise PT1000 film platinum resistor temperature sensor, biasing resistor, precision resister voltage divider, difference instrument amplifier, voltage follower, reference power source and ADC, described PT1000 film platinum resistor temperature sensor and biased 10K resistant series, described precision resister voltage divider is 10K and 1.2K, 1/4W, 0.1% precision plug-in unit metalfilmresistor, described difference instrument amplifier is chip AD623ARZ, described voltage follower is chip AD8605ARTZ, described ADC is 12 ADC that STM32 ARM chip carries, described reference power source is the 3.3V that voltage stabilizing chip LM1117 voltage stabilizing obtains, PT1000 platinum resistance temperature sensor and biased 10K resistant series, be connected to difference instrument amplifier AD623ARZ(U1 again) positive input terminal, 10K and 1.2K resistant series forms the negative input end that voltage divider is connected to difference instrument amplifier U1, resistance R7 is connected to 1 of U1, 8 pin are to arrange gain amplifier, resistance R5, R6 voltage divider in series, be connected to voltage follower AD8605ARTZ(U2) positive input terminal, the output port of U2 is connected with self negative input end, form voltage follower, and be connected to 5 pin of difference instrument amplifier U1, 7 pin of difference instrument amplifier U1 are final output signal, be connected to the ADC input pin that STM32 ARM chip carries, the 3.3V that voltage stabilizing chip LM1117 voltage stabilizing obtains is used for as ADC, resitstance voltage divider is powered.
The present embodiment provides a kind of Moisture Meter temperature collection circuit, and as shown in Figure 1, temperature sensor R1 adopts novel PT1000 film platinum resistor, and its impedance is comparatively large, and lead resistance can be ignored usually, and wiring can adopt 2 line systems, comparatively simply.Resistance R4 adopts 10K, 0.1%, 1/4W plug-in unit metalfilmresistor.Precision resister voltage divider R2, R3 adopt common 1/4W, 0.1% precision plug-in unit metalfilmresistor.Difference instrument amplifier U1 adopts the chip AD623ARZ of ADI company of the U.S., and this amplifier supports that single supply 5V powers, and input and output are rail-to-rail, and offset voltage is less than 200uV, and temperature drift is low, and gain is arranged by external resistance R7.Voltage follower U2 selects the chip AD8605ARTZ of ADI company, and offset voltage is less than 65uV, is used to provide the reference power supply of output.Resistance R5, R6 adopt 10K, 0.1%, 1/4W plug-in unit metalfilmresistor, are used for providing voltage reference to voltage follower U2.12 ADC that ADC sampling uses the STM32 ARM chip of ST company to carry, reference power source is the 3.3V that conventional voltage stabilizing chip LM1117 voltage stabilizing obtains.
As shown in Figure 1, the connected mode of this circuit is: temperature sensor R1 connects with biasing resistor R4, then is connected to the positive input terminal of difference instrument amplifier U1.Resistance R2, R3 voltage divider in series, is connected to the negative input end of difference instrument amplifier U1.Resistance R7 is connected to 1,8 pin of U1 to arrange gain amplifier.Resistance R5, R6 voltage divider in series, is connected to the positive input terminal of voltage follower U2.The output port of U2 is connected with self negative input end, forms voltage follower, and is connected to 5 pin of difference instrument amplifier U1.7 pin of difference instrument amplifier U1 are final output signal, are connected to the ADC input pin that STM32 ARM chip carries.The 3.3V that voltage stabilizing chip LM1117 voltage stabilizing obtains is used for as the power supply such as ADC, resitstance voltage divider.
As shown in Figure 2, be the corresponding relation of the present embodiment probe temperature and output voltage, ADC transformation result.Actual tests result shows, this circuit need not be calibrated, and can reach ± the measuring accuracy of 0.5 DEG C near reference point.
Claims (1)
1. a Moisture Meter temperature collection circuit, it is characterized in that: comprise PT1000 film platinum resistor temperature sensor, biasing resistor, precision resister voltage divider, difference instrument amplifier, voltage follower, reference power source and ADC, described PT1000 film platinum resistor temperature sensor and biased 10K resistant series, described precision resister voltage divider is 10K and 1.2K, 1/4W, 0.1% precision plug-in unit metalfilmresistor, described difference instrument amplifier is chip AD623ARZ, described voltage follower is chip AD8605ARTZ, described ADC is 12 ADC that STM32 ARM chip carries, described reference power source is the 3.3V that voltage stabilizing chip LM1117 voltage stabilizing obtains, PT1000 platinum resistance temperature sensor and biased 10K resistant series, be connected to difference instrument amplifier AD623ARZ(U1 again) positive input terminal, 10K and 1.2K resistant series forms the negative input end that voltage divider is connected to difference instrument amplifier U1, resistance R7 is connected to 1 of U1, 8 pin are to arrange gain amplifier, resistance R5, R6 voltage divider in series, be connected to voltage follower AD8605ARTZ(U2) positive input terminal, the output port of U2 is connected with self negative input end, form voltage follower, and be connected to 5 pin of difference instrument amplifier U1, 7 pin of difference instrument amplifier U1 are final output signal, be connected to the ADC input pin that STM32 ARM chip carries, the 3.3V that voltage stabilizing chip LM1117 voltage stabilizing obtains is used for as ADC, resitstance voltage divider is powered.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201420629104.4U CN204228286U (en) | 2014-10-28 | 2014-10-28 | A kind of Moisture Meter temperature collection circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201420629104.4U CN204228286U (en) | 2014-10-28 | 2014-10-28 | A kind of Moisture Meter temperature collection circuit |
Publications (1)
| Publication Number | Publication Date |
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| CN204228286U true CN204228286U (en) | 2015-03-25 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201420629104.4U Expired - Fee Related CN204228286U (en) | 2014-10-28 | 2014-10-28 | A kind of Moisture Meter temperature collection circuit |
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| CN (1) | CN204228286U (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106525267A (en) * | 2016-12-16 | 2017-03-22 | 山东金洲科瑞节能科技有限公司 | Bus type temperature measuring device |
| CN107468216A (en) * | 2017-09-26 | 2017-12-15 | 江苏精微特电子股份有限公司 | Moisture of skin measuring circuit and moisture of skin measuring instrument |
-
2014
- 2014-10-28 CN CN201420629104.4U patent/CN204228286U/en not_active Expired - Fee Related
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106525267A (en) * | 2016-12-16 | 2017-03-22 | 山东金洲科瑞节能科技有限公司 | Bus type temperature measuring device |
| CN107468216A (en) * | 2017-09-26 | 2017-12-15 | 江苏精微特电子股份有限公司 | Moisture of skin measuring circuit and moisture of skin measuring instrument |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| CF01 | Termination of patent right due to non-payment of annual fee | ||
| CF01 | Termination of patent right due to non-payment of annual fee |
Granted publication date: 20150325 Termination date: 20211028 |