CN203177993U - Temperature measuring circuit - Google Patents
Temperature measuring circuit Download PDFInfo
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- CN203177993U CN203177993U CN 201320131816 CN201320131816U CN203177993U CN 203177993 U CN203177993 U CN 203177993U CN 201320131816 CN201320131816 CN 201320131816 CN 201320131816 U CN201320131816 U CN 201320131816U CN 203177993 U CN203177993 U CN 203177993U
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- measuring circuit
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- 238000002955 isolation Methods 0.000 abstract description 11
- 238000006243 chemical reaction Methods 0.000 abstract description 3
- 230000003750 conditioning effect Effects 0.000 abstract 3
- 239000004020 conductor Substances 0.000 description 7
- 238000001914 filtration Methods 0.000 description 6
- BASFCYQUMIYNBI-UHFFFAOYSA-N platinum Chemical compound [Pt] BASFCYQUMIYNBI-UHFFFAOYSA-N 0.000 description 6
- 239000003990 capacitor Substances 0.000 description 5
- 230000003321 amplification Effects 0.000 description 3
- 238000010586 diagram Methods 0.000 description 3
- 238000003199 nucleic acid amplification method Methods 0.000 description 3
- 229910052697 platinum Inorganic materials 0.000 description 3
- 239000000654 additive Substances 0.000 description 2
- 230000000996 additive effect Effects 0.000 description 2
- 238000009529 body temperature measurement Methods 0.000 description 2
- 230000009977 dual effect Effects 0.000 description 2
- 238000005259 measurement Methods 0.000 description 2
- 230000001105 regulatory effect Effects 0.000 description 2
- 102000005591 NIMA-Interacting Peptidylprolyl Isomerase Human genes 0.000 description 1
- 108010059419 NIMA-Interacting Peptidylprolyl Isomerase Proteins 0.000 description 1
- 102000007315 Telomeric Repeat Binding Protein 1 Human genes 0.000 description 1
- 108010033711 Telomeric Repeat Binding Protein 1 Proteins 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000000034 method Methods 0.000 description 1
- 230000035945 sensitivity Effects 0.000 description 1
- 238000003466 welding Methods 0.000 description 1
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Abstract
The utility model relates to a temperature measuring circuit. The temperature measuring circuit comprises a three-wire system bridge type measuring circuit used for measuring temperature, a reference voltage generation circuit used for providing reference voltage for the three-wire system bridge type measuring circuit, an isolation circuit and a conditioning circuit, wherein the three-wire system bridge type measuring circuit is connected with an input end of the conditioning circuit, an output end of the conditioning circuit is connected with an input end of the isolation circuit, an output end of the isolation circuit is used for connecting with an A/D conversion module, the temperature measuring circuit is further provided with an isolation power source, the isolation power source respectively provides power for the three-wire system bridge type measuring circuit and the isolation circuit, and interference of an input signal can be filtered. The temperature measuring circuit solves problems of low measuring precision and power anti-interference capability existing in a temperature measuring circuit in the prior art and improves reliability and stability of a system.
Description
Technical field
The utility model relates to a kind of temperature measuring circuit.
Background technology
The temperature measurement circuit of using always generally uses thermistor to be the basis at present, utilizes its resistance value to become the characteristics of certain funtcional relationship with temperature, and the non electrical quantity variation of temperature is converted into the variation of impedance and measures.After being converted into electrical quantities, the analog quantity input processor that utilizes operational amplifier to handle, again by processor according to the impedance of thermistor and the funtcional relationship of voltage, calculate impedance, thus the indirect temperature that draws.
Application number is one piece of patent documentation " a kind of thermal resistance temperature surveying circuit " of 200610028999.6, as shown in Figure 1, comprise reference voltage source, three-wire system thermal resistance, lead-in wire voltage drop amplifier, fundamental operation amplifier, compensating resistance R4 and R7, thermal resistance driving voltage setting resistance R 5 and R6, and output sensitivity is set resistance R 3 and range is set resistance R 1 and R2.Resistance by choose reasonable compensating resistance R4 and R7, when stube cable resistance equates, this circuit output voltage Vt and Rt are by the funtcional relationship of determining, irrelevant with the conductor resistance of stube cable line, Vt is through the A/D conversion, calculate the resistance Rt of thermal resistance by software, calculate temperature value according to the relation of the known function between Rt and the temperature t again, be measurement result.
It is to be solved that this temperature measurement circuit has many problems to have when utilizing temperature sensor measurement: the additive error that conductor resistance brings is big, at the bottom of the measuring accuracy; Owing to there is not buffer circuit, analog quantity is disturbed and is difficult for removing poor anti jamming capability; Reference data power supply precision is not high, inadequately problem such as stable.
The utility model content
The purpose of this utility model provides a kind of temperature measuring circuit, and existing temperature measuring circuit measuring accuracy is low in order to solve, the problem of poor anti jamming capability.
For achieving the above object, scheme of the present utility model is: a kind of temperature measuring circuit, comprise a three-wire system bridge-type metering circuit that is used for thermometric, reference voltage generating circuit and a modulate circuit that is used to described three-wire system bridge-type metering circuit that reference voltage is provided, the input end of described three-wire system bridge-type metering circuit connects described reference voltage generating circuit, its output terminal connects the input end of described modulate circuit, this temperature measuring circuit also comprises a buffer circuit, the input end of described buffer circuit connects the output terminal of described modulate circuit, and the output of described buffer circuit is used for connecting the A/D modular converter.
Described buffer circuit is an operational amplifier, adopts AMC1200.
This temperature measuring circuit also comprises an insulating power supply circuit that is used to described modulate circuit and described buffer circuit that power supply is provided.
Described modulate circuit is an instrument amplifier of be used for to eliminate isolating the error that the operational amplifier impedance causes sampled value.
The beneficial effect that the utility model reaches: increased a buffer circuit in the temperature measuring circuit of the present utility model, in order to analog quantity is isolated, eliminate the interference of analog quantity, solved the problem of the difficult removal of analog quantity interference, poor anti jamming capability in the existing temperature measuring circuit;
Buffer circuit of the present utility model adopts the operational amplifier with isolation features, than general isolating device, as optocoupler, eliminate effective to the interference in the simulating signal, when can carry out the linear transfer amplification to the difference analogue amount of modulate circuit output it is isolated, improved measuring accuracy;
The insulating power supply circuit of the utility model setting simultaneously can be used for the undesired signal of filtering input signal, further improve the antijamming capability of temperature measuring circuit, has improved reliability and degree of stability;
The utility model uses three-wire system bridge-type metering circuit, adopt three divider resistances and temperature sensor PT100 to form the arm resistance of measuring bridge, temperature sensor PT100 adopts the three-wire system connection, by waiting long lead to insert brachium pontis, make conductor resistance be eliminated, reference voltage generating circuit provides the high-accuracy voltage source for electric bridge simultaneously, when bridge balance is broken, output millivolt step voltage has reduced measuring error, has improved measuring accuracy.
Description of drawings
Fig. 1 is existing temperature measuring circuit schematic diagram;
Fig. 2 is the utility model circuit structure block diagram;
Fig. 3 is the utility model circuit theory diagrams.
Embodiment
The utility model is described in more detail below in conjunction with accompanying drawing.
As shown in Figure 2, the utility model comprises reference voltage generating circuit, three-wire system bridge-type metering circuit, modulate circuit, isolation arithmetical unit amplifying circuit and insulating power supply circuit, and temperature-measuring range is-50 ℃-600 ℃.
Reference voltage generating circuit: this circuit front-end connect insulating power supply+15V, utilize two regulating resistors and three an ends parallel voltage-stabilizing diode able to programme, for reference voltage generating circuit carries out pressure regulation.When insulating power supply was switched on, reference voltage generating circuit can produce a reference voltage, and this voltage is as the positive supply of three-wire system bridge-type metering circuit electric bridge.
Three-wire system bridge-type metering circuit: based on platinum resistance temperature sensor PT100, PT100 is a kind of temperature element of widespread use, the mode of connection is divided into two-wire system and three-wire system dual mode, two-wire system sensor resistance changing value be connected the output valve that the conductor resistance value constitutes sensor jointly, because the additive error that conductor resistance brings makes actual measured value higher, be used for the less demanding occasion of measuring accuracy; The advantage of three-wire system connection is that the aequilateral conductor length with PT100 is added in respectively on the brachium pontis of both sides, makes conductor resistance be eliminated.The industrial three-wire system connection that generally all adopts.This circuit adopts three divider resistances and PT100 to constitute the arm resistance of measuring bridge, when electric bridge because PT100 temperature influence no longer during balance, pressure difference signal that will a millivolt level of output.
Modulate circuit: the purpose of this modulate circuit is isolated the error that the operational amplifier impedance causes sampled value for eliminating.After need being amplified through the modulate circuit that instrument amplifier constitutes by the pressure difference signal of the millivolt level of front end output, be divided to the input range (millivolt level) of isolating operational amplifier.Excessive in order to prevent input voltage, input end respectively adds a stabilivolt.
Isolating operation amplifier circuit: AMC1200 is a kind of operational amplifier with isolation, and it can amplify the difference analogue amount, simultaneously analog quantity is isolated, and eliminates the interference of following analog quantity.The simulating signal of instrument amplifier output is inserted isolated amplifier isolate and amplifies, thereby output signal arrives processor.
Insulating power supply circuit: for the undesired signal in the filtering input signal, the power supply of metering circuit should be isolated with digital circuit, every drive test temperature loops has independent DC-DC insulating power supply circuit, the insulating power supply circuit is that the 5V power supply is converted to ± 15V, and+3.3V power supply uses for modulate circuit, isolation operation amplifier circuit.
As shown in Figure 3, reference voltage generating circuit is by resistance R 1, R2, R3 and three ends parallel voltage-stabilizing diode able to programme T1 form, the termination power end V1+ of R1, another termination three ends parallel voltage-stabilizing diode able to programme T1(TL431) negative electrode, resistance R 2 is the regulating resistor of reference voltage generating circuit with R3, the anode of the termination T1 of R3, and the anode of T1 links to each other with GNDA, the negative electrode of the termination T1 of R2, the other end of R2 is connected with the other end of R3, the series connection point of R2 and R3 is connected the reference pin of T1, power end V1+ connect insulating power supply U3 1 pin (+15V), power end GNDA connects 6 pins of U3.When insulating power supply is switched on, just produced the reference voltage of a 4.098V between the negative electrode of T1 and the GNDA, this voltage is as the positive supply of electric bridge.
In the three-wire system bridge-type metering circuit, adopt R4, R5, R6 and PT100 platinum resistance R constitute the arm resistance of measuring bridge, R4=R5 wherein, R6 is 33 Ω precision resistances.PT100 has three leads, and wherein lead is received the power end GNDA of electric bridge, and other two meet PIN1 and PIN2 respectively.When PT100 platinum resistance R is not equal to R6, the electric bridge imbalance, pressure difference signal with a millivolt level of output, this voltage signal connects 2 pin and 3 pin of U1, through being amplified by instrument amplifier U1 computing, 6 pins of U1 are output as the voltage signal that obtains of expectation, through electric resistance partial pressure, insert the input end of U2.Excessive for preventing input voltage, before 2 pin of U1 and 3 pin, add 5V stabilivolt WY1 respectively, WY2.In this circuit, voltage amplification factor is 1+50k Ω/R7, rationally adjusts R4, and R5 can change the size of bridge output voltage, adjusts the enlargement factor that R7 can change circuit.
The instrument amplifier U1 that constitutes modulate circuit is dual power supply, its pin 7 connects respectively with pin 4+15V and-15V.Two pins of capacitor C 1 connect respectively+15V and GNDA, and two pins of capacitor C 2 connect respectively-15V and GNDA.
1 and pin two of insulating power supply U3 pin are distinguished the VCC(+5V of welding system power supply as input pin) and GND, output pin 5,6,7 respectively output-15V, GNDA ,+15V, be to reference voltage generating circuit, isolate the amplifier U1 of operation amplifier circuit, the U2 power supply.
Variation along with the impedance of PT100 temperature sensor, after the amplification of the output of electric bridge through the amplifying circuit linearity, voltage signal can not directly be delivered to processor and handle, in order to guarantee the anti-interference and reliability of system, to carry out the AD conversion just can deliver to processor after the voltage signal of U1 output must amplify through the U2 isolation.
1 pin of isolating operational amplifier U2 connect the 8 pin insulating power supplies of U3 (+5V), 4 pin meet GNDA, meet filter capacitor C6 between 1 pin and 4 pin, C6 plays the effect into the filtering of amplifier U2 power decoupling, 2 pin and 3 pin of isolating operational amplifier U2 are input pins, the RC filtering circuit that termination is made up of R8 and C5 before 2 pin, before 3 pin, connect the RC filtering circuit of being formed by R9 and C4, meet filter capacitor C3 between the pin 2 of U2 and the pin 3,5 pin of U2 and 8 pin provide output voltage for isolating operational amplifier, wherein 5 pin of U2 connect 2 pin of insulating power supply U3,8 pin of U2 connect 3 pin of insulating power supply U3, add decoupling filter capacitor C7 between 5 pin of U2 and 8 pin, and 6 pin of U2 and 7 pin are for isolating the output pin of operational amplifier, 6 pin of U2, the output signal process R10 of 7 pin, R11, the RC filtering circuit that C8 forms, final output signal AOUT1, AOUT1 are the aanalogvoltage differential signal that processor need be handled.
Claims (4)
1. temperature measuring circuit, comprise three-wire system bridge-type metering circuit, reference voltage generating circuit and a modulate circuit that is used to described three-wire system bridge-type metering circuit that reference voltage is provided that is used for thermometric, described three-wire system bridge-type metering circuit output terminal connects the input end of described modulate circuit, it is characterized in that, this temperature measuring circuit also comprises a buffer circuit, the input end of described buffer circuit connects the output terminal of described modulate circuit, and the output of described buffer circuit is used for connecting the A/D modular converter.
2. temperature measuring circuit according to claim 1 is characterized in that, described buffer circuit is an operational amplifier, adopts AMC1200.
3. temperature measuring circuit according to claim 1 is characterized in that, this temperature measuring circuit also comprises an insulating power supply circuit that is used to described modulate circuit and described buffer circuit that power supply is provided.
4. temperature measuring circuit according to claim 1 is characterized in that, described modulate circuit is an instrument amplifier of be used for to eliminate isolating the error that the operational amplifier impedance causes sampled value.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 201320131816 CN203177993U (en) | 2013-03-21 | 2013-03-21 | Temperature measuring circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 201320131816 CN203177993U (en) | 2013-03-21 | 2013-03-21 | Temperature measuring circuit |
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| Publication Number | Publication Date |
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| CN203177993U true CN203177993U (en) | 2013-09-04 |
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| Application Number | Title | Priority Date | Filing Date |
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| CN 201320131816 Expired - Fee Related CN203177993U (en) | 2013-03-21 | 2013-03-21 | Temperature measuring circuit |
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Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105571739A (en) * | 2016-01-28 | 2016-05-11 | 山东鲁能智能技术有限公司 | Detecting system and detecting method for charging gun head temperature of electric vehicle |
| CN106092362A (en) * | 2016-08-26 | 2016-11-09 | 江苏远望仪器有限公司 | Three-wire type platinum resistance thermometer sensor, PT100 system for detecting temperature |
| 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 |
| CN106768460A (en) * | 2016-12-02 | 2017-05-31 | 杭州创睿新能源科技有限公司 | A kind of charging pile pipette tips temperature collection circuit and method |
| CN109163819A (en) * | 2018-10-15 | 2019-01-08 | 西安爱生技术集团公司 | One kind having linear high-precision unmanned vehicle engine cylinder temperature thermometer |
| CN110806228A (en) * | 2019-04-24 | 2020-02-18 | 神盾股份有限公司 | Calibration circuit for sensor and related sensor |
| CN114485975A (en) * | 2021-12-27 | 2022-05-13 | 北京航天测控技术有限公司 | Three-wire system temperature measuring circuit for thermocouple rapid cold end compensation system |
-
2013
- 2013-03-21 CN CN 201320131816 patent/CN203177993U/en not_active Expired - Fee Related
Cited By (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105571739A (en) * | 2016-01-28 | 2016-05-11 | 山东鲁能智能技术有限公司 | Detecting system and detecting method for charging gun head temperature of electric vehicle |
| CN105571739B (en) * | 2016-01-28 | 2018-11-13 | 山东鲁能智能技术有限公司 | A kind of electric vehicle charging pipette tips system for detecting temperature and detection method |
| CN106092362A (en) * | 2016-08-26 | 2016-11-09 | 江苏远望仪器有限公司 | Three-wire type platinum resistance thermometer sensor, PT100 system for detecting temperature |
| CN106768460A (en) * | 2016-12-02 | 2017-05-31 | 杭州创睿新能源科技有限公司 | A kind of charging pile pipette tips temperature collection circuit and method |
| 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 |
| CN106525267B (en) * | 2016-12-16 | 2023-08-01 | 山东金洲科瑞节能科技有限公司 | Bus type temperature measuring device |
| CN109163819A (en) * | 2018-10-15 | 2019-01-08 | 西安爱生技术集团公司 | One kind having linear high-precision unmanned vehicle engine cylinder temperature thermometer |
| CN110806228A (en) * | 2019-04-24 | 2020-02-18 | 神盾股份有限公司 | Calibration circuit for sensor and related sensor |
| US11175179B2 (en) | 2019-04-24 | 2021-11-16 | Egis Technology Inc. | Calibration circuit for use in sensor and related sensor thereof |
| CN114485975A (en) * | 2021-12-27 | 2022-05-13 | 北京航天测控技术有限公司 | Three-wire system temperature measuring circuit for thermocouple rapid cold end compensation system |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| ASS | Succession or assignment of patent right |
Owner name: XUJI ELECTRIC CO., LTD. Free format text: FORMER OWNER: XUJI GROUP CO., LTD. Effective date: 20131205 |
|
| C41 | Transfer of patent application or patent right or utility model | ||
| TR01 | Transfer of patent right |
Effective date of registration: 20131205 Address after: No. 1298 Xuchang City, Henan province 461000 XJ Avenue Patentee after: Xuji Electric Co., Ltd. Patentee after: Xuchang Xuji Software Technology Co., Ltd. Address before: No. 1298 Xuchang City, Henan province 461000 XJ Avenue Patentee before: Xuji Group Co., Ltd. Patentee before: Xuji Electric Co., Ltd. Patentee before: Xuchang Xuji Software Technology Co., Ltd. |
|
| 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: 20130904 Termination date: 20190321 |