CN216770823U - High-precision temperature measuring device - Google Patents
High-precision temperature measuring device Download PDFInfo
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- CN216770823U CN216770823U CN202123405212.2U CN202123405212U CN216770823U CN 216770823 U CN216770823 U CN 216770823U CN 202123405212 U CN202123405212 U CN 202123405212U CN 216770823 U CN216770823 U CN 216770823U
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Abstract
The utility model relates to temperature detection, in particular to a high-precision temperature measuring device which comprises a controller, an unbalanced bridge and an ADC (analog to digital converter) module, wherein the unbalanced bridge converts a detected temperature signal into a voltage signal, and the ADC module converts the voltage signal output by the unbalanced bridge into a digital signal and transmits the digital signal to the controller for processing; the technical scheme provided by the utility model can effectively overcome the defects of lower detection precision and narrower measurement range in the prior art.
Description
Technical Field
The utility model relates to temperature detection, in particular to a high-precision temperature measuring device.
Background
In some special occasions, the temperature needs to be monitored in real time, and the requirement on detection precision is high. Currently, there are two general methods for detecting temperature with high precision, one is to use a mercury thermometer with high precision, and the other is to use a temperature sensor with high precision. However, the mercury thermometer cannot perform real-time monitoring, the high-precision temperature sensor is expensive, the measurement range of the temperature sensor cannot be adjusted, and the application occasions are few. A low-cost high-precision temperature measuring device is designed at present, and meanwhile, the wide temperature measuring range can be achieved.
SUMMERY OF THE UTILITY MODEL
Technical problem to be solved
Aiming at the defects in the prior art, the utility model provides a high-precision temperature measuring device which can effectively overcome the defects of low detection precision and narrow measuring range in the prior art.
(II) technical scheme
In order to achieve the purpose, the utility model is realized by the following technical scheme:
a high-precision temperature measuring device comprises a controller, an unbalanced bridge and an ADC module, wherein the unbalanced bridge converts a detected temperature signal into a voltage signal, and the ADC module converts the voltage signal output by the unbalanced bridge into a digital signal and transmits the digital signal to the controller for processing.
Preferably, the voltage signal output by the unbalanced bridge is amplified by the amplifying circuit and transmitted to the ADC module for processing, and the unbalanced bridge comprises a thermal resistor R1, a resistor R2, a resistor R3, and a resistor R4.
Preferably, the amplifying circuit comprises a high input impedance differential amplifying circuit for accurately measuring the output voltage difference of the unbalanced bridge and a voltage follower circuit for isolating the output voltage of the high input impedance differential amplifying circuit and the input of the ADC module.
Preferably, the high-input-impedance differential amplification circuit comprises operational amplifiers U6, U9 and U7, wherein a non-inverting input terminal of the operational amplifier U6 is connected to the output terminal OP1 of the unbalanced bridge, an inverting input terminal of the operational amplifier U6 is connected to the output terminal OP1+ of the unbalanced bridge through a resistor R12, an inverting input terminal of the operational amplifier U9 is connected to the output terminal OP1+ of the unbalanced bridge, an inverting input terminal of the operational amplifier U9 is connected to the output terminal of the operational amplifier U16 through a resistor R16, a resistor R14 is connected between the resistor R12 and the resistor R16, an output terminal of the operational amplifier U6 is connected to an inverting input terminal of the operational amplifier U7 through a resistor R9, an output terminal of the operational amplifier U9 is connected to the non-inverting input terminal of the operational amplifier U7 through a resistor R17, and an inverting input terminal of the operational amplifier U7 is connected to the output terminal thereof through a resistor R10;
the voltage follower circuit comprises an operational amplifier U8, wherein the non-inverting input end of the operational amplifier U8 is connected to the output end of the operational amplifier U7 through a resistor R15, the inverting input end of the operational amplifier U8 is connected to the output end of the operational amplifier U7 through a resistor R13, and the output end of the operational amplifier U8 is connected with an ADC module.
Preferably, the intelligent temperature control system further comprises a storage module, an alarm and a power supply, the controller stores detected temperature data into the storage module, the alarm is driven to alarm when the temperature reaches a threshold value, and the power supply supplies power to the controller, the unbalanced bridge and the amplifying circuit.
Preferably, the power source is selected from a dry cell battery or a polymer lithium battery.
(III) advantageous effects
Compared with the prior art, in the high-precision temperature measuring device, in the temperature detection process, the resistance value of the thermal resistor changes along with the temperature change, so that the output of the unbalanced bridge also changes along with the temperature change, the temperature change range adaptive to the resistance value change range can be measured, when the temperature continuously changes, the resistance value of the thermal resistor also continuously changes, the measurement voltage also continuously changes, the ADC module is used for quantizing the signal output by the unbalanced bridge, if the signal output by the unbalanced bridge cannot reach the acquisition precision of the ADC module, the amplifying circuit can be used for amplifying the signal, and the detection precision can be effectively improved; when the real-time measurement is carried out, power is supplied by a dry battery or a polymer lithium battery instead of a power grid, so that the noise caused by the power grid can be eliminated, and the reliability of the detection precision is ensured.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below. It is obvious that the drawings in the following description are only some embodiments of the utility model, and that for a person skilled in the art, other drawings can be derived from them without inventive effort.
FIG. 1 is a diagram of the hardware connections of the present invention;
FIG. 2 is a schematic circuit diagram of an unbalanced bridge of the present invention;
FIG. 3 is a circuit diagram of an amplifying circuit according to the present invention;
FIG. 4 is a schematic circuit diagram of a controller according to the present invention;
FIG. 5 is a schematic circuit diagram of a power supply of the present invention;
fig. 6 is a schematic diagram of the output voltage of the unbalanced bridge, thermal resistor R1, as a function of temperature.
Detailed Description
In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention. It is to be understood that the embodiments described are only a few embodiments of the present invention, and not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
A high-precision temperature measuring device is shown in fig. 1, 2 and 4 and comprises a controller, an unbalanced bridge and an ADC module, wherein the unbalanced bridge converts a detected temperature signal into a voltage signal, and the ADC module converts the voltage signal output by the unbalanced bridge into a digital signal and transmits the digital signal to the controller for processing.
In the technical scheme of the application, the unbalanced bridge comprises a thermal resistor R1, a resistor R2, a resistor R3 and a resistor R4. Four arms of the unbalanced bridge:
when R is1＝R2＝R3＝R4While, UOP1+＝UOP1－；
When R1 ≠ R2 ≠ R3 ═ R4, UOP1+≠UOP1－，ΔUo＝UOP1+－UOP1－。
Wherein the content of the first and second substances,
U1for supply voltage, U, whose power supply is an unbalanced bridgeoAnd R1Correlation of R1The resistor is a thermal resistor, and the resistance value of the resistor can change along with the temperature change. When the thermal resistance R1 changes, the output of the unbalanced bridge also changes, and R2, R3, and R4 are fixed-resistance resistors.
Let the thermal resistance R1 be at temperature t0The resistance value of (A) is R (t)0) When the temperature coefficient is α, the resistance at the temperature t is R (t)0)[1+αt]Then, then
With change in temperature, UoChange of (1), Δ UoShould be as shown in figure 6.
The temperature detection device comprises a controller, a storage module, an alarm and a power supply, wherein the controller stores detected temperature data into the storage module, the alarm is driven to alarm when the temperature reaches a threshold value, and the power supply supplies power to the controller, the unbalanced bridge and the amplifying circuit. The dry battery or the polymer lithium battery is selected as the power supply, so that power supply ripples influencing the detection precision can be eliminated.
Calculating the subdivision voltage d delta U according to the temperature precision dt of the required samplingo＝UoX dt/t, based on the required detection precision, using ADC module to output unbalanced bridgeThe temperature data detected by the controller are stored in the storage module, and the alarm is driven to give an alarm when the temperature reaches a threshold value.
If d.DELTA.UoIf the size is too small, the acquisition precision of the ADC module cannot be achieved, the amplifying circuit can be used for amplifying the signal output by the unbalanced bridge; if d.DELTA.UoThe acquisition precision of the ADC module can be achieved, and the data can be directly transmitted to the ADC module.
As shown in fig. 4 and 5, the PA12 is connected with an ALARM-driven ALARM; the PB0 is connected with the battery and can detect the electric quantity of the battery; the PA7 is an ADC module carried by the controller and capable of converting an analog voltage signal to a digital signal.
As shown in fig. 3, the apparatus further includes an amplifying circuit, where the amplifying circuit amplifies the voltage signal output by the unbalanced bridge and transmits the amplified voltage signal to the ADC module for processing. The amplifying circuit comprises a high-input-impedance differential amplifying circuit used for accurately measuring the output voltage difference of the unbalanced bridge and a voltage follower circuit used for isolating the output voltage of the high-input-impedance differential amplifying circuit and the input of the ADC module.
The high-input-impedance differential amplifying circuit comprises operational amplifiers U6, U9 and U7, wherein the non-inverting input end of the operational amplifier U6 is connected with the output end OP1 of the unbalanced bridge, the inverting input end of the operational amplifier U6 is connected with the output end of the unbalanced bridge through a resistor R12, the non-inverting input end of the operational amplifier U9 is connected with the output end OP1+ of the unbalanced bridge, the inverting input end of the operational amplifier U9 is connected with the output end of the operational amplifier U16 through a resistor R16, a resistor R14 is connected between the resistor R12 and the resistor R16, the output end of the operational amplifier U6 is connected with the inverting input end of the operational amplifier U7 through a resistor R9, the output end of the operational amplifier U9 is connected with the non-inverting input end of the operational amplifier U7 through a resistor R17, and the inverting input end of the operational amplifier U7 is connected with the output end of the operational amplifier U10.
The voltage follower circuit comprises an operational amplifier U8, the non-inverting input end of the operational amplifier U8 is connected to the output end of the operational amplifier U7 through a resistor R15, the inverting input end of the operational amplifier U8 is connected to the output end of the operational amplifier U7 through a resistor R13, and the output end of the operational amplifier U8 is connected with the ADC module.
For a single differential operational amplifier, the calculation formula of the voltage of the output end is Uo'＝Rf/R(Ui1-Ui2) Magnification factor beta ═ RfThe input resistance R is related to the input resistance R, and for the operational amplifiers U6 and U9, the input resistance R is R3 and R1. Wherein R isfFor feedback resistance, refer to resistor R10 for op amp U7; r is the input resistance, referred to as resistances R9, R17 for operational amplifier U7; u shapei1、Ui2Are input voltages and are referred to as U7P, U7N for operational amplifier U7.
When the thermal resistance R1 changes, the amplification factor changes, so that the accurate differential pressure delta U cannot be measuredo. Therefore, a high-input-impedance differential amplifier circuit is configured by connecting resistance elements using three operational amplifiers U6, U9, and U7, U being UOP1－Non-inverting input terminal U6N, U of operational amplifier U6OP1+The non-inverting input terminal U9N of the operational amplifier U9 is inputted to UOP1+、UOP1－Amplification is performed.
The output end of the operational amplifier U6 and the output end of the operational amplifier U9 are respectively connected to the inverting input end U7P and the non-inverting input end U7N of the operational amplifier U7, and the amplification factor of the high-input-impedance differential amplification circuit is:
a fixed amplification factor is obtained, and the output of the operational amplifier U7 is kept stable.
When the output of the operational amplifier U7 is connected to the ADC module, the impedance of the ADC module affects the load resistance Ri of the operational amplifier. Therefore, an operational amplifier U8 is connected with a resistance element to form a voltage follower circuit, and the characteristics of high input impedance and low output impedance are utilized to isolate the output voltage of the high input impedance differential amplification circuit and the input of the ADC module, so that the output signal of the amplification circuit is not influenced by the ADC module.
It should be noted that the technical solution of the present application is only for providing a hardware configuration different from the prior art, so that the skilled person can implement further development under such a hardware configuration, and the software program can be programmed by the programmer in the field at a later stage according to the actual effect requirement.
The above examples are only intended to illustrate the technical solution of the present invention, but not to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; such modifications or substitutions do not depart from the spirit and scope of the corresponding technical solutions of the embodiments of the present invention.
Claims (4)
1. A high accuracy temperature measurement device which characterized in that: the temperature detection device comprises a controller, an unbalanced bridge and an ADC (analog to digital converter) module, wherein the unbalanced bridge converts a detected temperature signal into a voltage signal, and the ADC module converts the voltage signal output by the unbalanced bridge into a digital signal and transmits the digital signal to the controller for processing;
the voltage signal output by the unbalanced bridge is amplified by the amplifying circuit and transmitted to the ADC module for processing, and the unbalanced bridge comprises a thermal resistor R1, a resistor R2, a resistor R3 and a resistor R4;
the amplifying circuit comprises a high-input-impedance differential amplifying circuit used for accurately measuring the output voltage difference of the unbalanced bridge and a voltage following circuit used for isolating the output voltage of the high-input-impedance differential amplifying circuit and the input of the ADC module.
2. The high accuracy temperature measuring apparatus according to claim 1, wherein: the high-input-impedance differential amplification circuit comprises operational amplifiers U6, U9 and U7, wherein the non-inverting input end of the operational amplifier U6 is connected with the output end OP 1-of the unbalanced bridge, the inverting input end of the operational amplifier U6 is connected with the output end of the unbalanced bridge through a resistor R12, the non-inverting input end of the operational amplifier U9 is connected with the output end OP1+ of the unbalanced bridge, the inverting input end of the operational amplifier U9 is connected with the output end of the operational amplifier U16 through a resistor R16, a resistor R14 is connected between the resistor R12 and the resistor R16, the output end of the operational amplifier U6 is connected with the inverting input end of the operational amplifier U7 through a resistor R9, the output end of the operational amplifier U9 is connected with the non-inverting input end of the operational amplifier U7 through a resistor R17, and the inverting input end of the operational amplifier U7 is connected with the output end of the operational amplifier U10;
the voltage follower circuit comprises an operational amplifier U8, wherein the non-inverting input end of the operational amplifier U8 is connected to the output end of the operational amplifier U7 through a resistor R15, the inverting input end of the operational amplifier U8 is connected to the output end of the operational amplifier U7 through a resistor R13, and the output end of the operational amplifier U8 is connected with an ADC module.
3. The high accuracy temperature measuring apparatus according to claim 1, wherein: the temperature detection device is characterized by further comprising a storage module, an alarm and a power supply, the controller stores detected temperature data into the storage module, the alarm is driven to alarm when the temperature reaches a threshold value, and the power supply supplies power to the controller, the unbalanced bridge and the amplifying circuit.
4. A high accuracy temperature measuring apparatus according to claim 3, wherein: the power supply is selected from a dry battery or a polymer lithium battery.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202123405212.2U CN216770823U (en) | 2021-12-30 | 2021-12-30 | High-precision temperature measuring device |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202123405212.2U CN216770823U (en) | 2021-12-30 | 2021-12-30 | High-precision temperature measuring device |
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| Publication Number | Publication Date |
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| CN216770823U true CN216770823U (en) | 2022-06-17 |
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| Application Number | Title | Priority Date | Filing Date |
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| CN202123405212.2U Active CN216770823U (en) | 2021-12-30 | 2021-12-30 | High-precision temperature measuring device |
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| CN (1) | CN216770823U (en) |
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2021
- 2021-12-30 CN CN202123405212.2U patent/CN216770823U/en active Active
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