CN217084002U - Temperature measurement circuit and temperature control system based on thermocouple - Google Patents
Temperature measurement circuit and temperature control system based on thermocouple Download PDFInfo
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- CN217084002U CN217084002U CN202221060926.6U CN202221060926U CN217084002U CN 217084002 U CN217084002 U CN 217084002U CN 202221060926 U CN202221060926 U CN 202221060926U CN 217084002 U CN217084002 U CN 217084002U
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Abstract
The application discloses temperature measurement circuit and temperature control system based on thermocouple, temperature measurement circuit include thermocouple probe, thermocouple interface circuit, biasing circuit, amplifier circuit, single chip microcomputer circuit, cold junction compensating circuit and communication interface circuit. The thermocouple interface circuit superposes a thermoelectric conversion electric signal output by the thermocouple probe and a bias voltage signal output by the bias circuit and then sends the superposed electric signal to the amplifying circuit, the amplifying circuit amplifies the superposed electric signal obtained by superposition and then obtains a hot-end electric signal, the cold-end compensating circuit is used for converting a reference temperature value into a cold-end electric signal, and the single-chip circuit obtains a monitoring temperature value according to the hot-end electric signal and the cold-end electric signal and outputs the monitoring temperature value through the communication interface circuit. Because the output voltage of the thermocouple probe is improved through the bias circuit, the common operational amplifier can replace an instrument amplifier to realize a temperature measuring circuit based on a thermocouple, and further the production cost of the thermocouple sensor is reduced.
Description
Technical Field
The application relates to the technical field of temperature sensors, in particular to a temperature measuring circuit and a temperature control system based on a thermocouple.
Background
In the prior art, because the output voltage signal amplitude of the thermocouple sensor is relatively small, in order to be better sampled by an analog-to-digital converter, an instrument amplifier is generally required to be added between the thermocouple and the analog-to-digital converter, but the instrument amplifier is relatively expensive, and the application range of the thermocouple sensor is further limited.
Disclosure of Invention
The technical problem that this application mainly solved is how to reduce the manufacturing cost of thermocouple sensor.
According to a first aspect, an embodiment provides a thermocouple-based temperature measurement circuit, which includes a thermocouple probe, a thermocouple interface circuit, a bias circuit, an amplification circuit, a single-chip microcomputer circuit, a cold junction compensation circuit, and a communication interface circuit;
the thermocouple probe is connected with the thermocouple interface circuit and used for converting a temperature value of a measuring end into a thermoelectric conversion electric signal and sending the thermoelectric conversion electric signal to the thermocouple interface circuit;
the bias circuit is connected with the thermocouple interface circuit and is used for outputting a bias voltage signal to the thermocouple interface circuit;
the thermocouple interface circuit is connected with the amplifying circuit and is used for superposing the bias voltage signal and the thermoelectric conversion electric signal to obtain a superposed electric signal and sending the superposed electric signal to the amplifying circuit;
the amplifying circuit is connected with the single chip microcomputer circuit and used for amplifying the superposed electric signals to obtain hot-end electric signals and sending the hot-end electric signals to the single chip microcomputer circuit;
the cold end compensation circuit is connected with the single chip microcomputer circuit and used for converting a reference temperature value into a cold end electric signal and sending the cold end electric signal to the single chip microcomputer circuit;
the single chip circuit is connected with the communication interface circuit; the single chip microcomputer circuit is used for converting the hot end electric signal and the cold end electric signal into digital signals and acquiring a monitoring temperature value of a measuring end according to the hot end electric signal and the cold end electric signal which are converted into the digital signals; the single chip microcomputer circuit is also used for outputting the monitoring temperature value through the communication interface circuit.
In one embodiment, the thermocouple interface circuit includes a thermocouple interface and a capacitance C1;
the thermocouple interface comprises a probe positive connecting end and a probe negative connecting end, and the probe positive connecting end and the probe negative connecting end are used for being connected with the thermocouple probe;
two ends of the capacitor C1 are respectively connected with the probe positive connecting end and the probe negative connecting end, and the capacitor C1 is used as a filter capacitor.
In one embodiment, the amplifying circuit comprises a resistor R1, a resistor R2 and an amplifier U1B;
one end of the resistor R1 is connected with the negative input end of the amplifier U1B, and the other end is grounded;
one end of the resistor R2 is connected with the negative output/input end of the amplifier U1B, and the other end of the resistor R2 is connected with the output end of the amplifier U1B;
the positive input end of the amplifier U1B is connected with the positive connecting end of the probe, and the output end of the amplifier U1B is connected with the single chip microcomputer circuit.
In one embodiment, the bias circuit includes a resistor R3, a resistor R4, and an amplifier U1A;
one end of the resistor R3 is used for connecting a preset voltage source VCC1, and the other end is connected with the positive input end of the amplifier U1A;
one end of the resistor R4 is connected with the positive input end of the amplifier U1A, and the other end is grounded;
the negative input of amplifier U1A is connected to the output of amplifier U1A, and the output of amplifier U1A is connected to the probe negative connection.
In one embodiment, the cold end compensation circuit comprises a cold end electrical signal output end, a resistor R6, a resistor R7 and a capacitor C5;
the cold end electric signal output end is connected with the single chip microcomputer circuit;
one end of the resistor R6 is connected with the cold end electric signal output end, and the other end of the resistor R6 is used for being connected with a preset voltage source VCC 3;
one end of the resistor R7 is connected with the cold end electric signal output end, and the other end is grounded;
and one end of the capacitor C5 is connected with the cold-end electric signal output end, and the other end of the capacitor C5 is grounded.
In one embodiment, the resistor R6 is an NTC resistor.
In one embodiment, the single chip microcomputer circuit comprises a single chip microcomputer U1, a capacitor C3, a capacitor C4 and a resistor R5;
the model of the single chip microcomputer U1 is STC15W401 AS;
one end of the capacitor C3 is connected with a preset voltage source VCC0, and the other end of the capacitor C3 is connected with a pin 5 of the singlechip U1;
one end of the resistor R5 is connected with the pin 5 of the singlechip U1, and the other end is grounded;
one end of the capacitor C4 is connected with a pin 6 of the singlechip U1, and the other end of the capacitor C4 is connected with a pin 8 of the singlechip U1;
and a pin 6 of the singlechip U1 is connected with the preset voltage source VCC 0.
In one embodiment, the communication interface circuit comprises a communication interface, a diode D1 and a resistor R8;
the communication interface comprises a first connecting end, a second connecting end, a third connecting end and a fourth connecting end; the first connecting end of the communication interface is connected with a pin 11 of the single chip microcomputer U1, the second connecting end of the communication interface is connected with a pin 10 of the single chip microcomputer U1, the third connecting end of the communication interface is connected with a pin 9 of the single chip microcomputer U1, and the third connecting end of the communication interface is grounded;
the positive connection end of the diode D1 is connected with the first connection end of the communication interface, and the negative connection end of the diode D1 is used for connecting the preset voltage source VCC 0;
one end of the resistor R8 is connected with the first connection end of the communication interface, and the other end is connected with the fourth connection end of the communication interface.
In one embodiment, the model of the single chip microcomputer U1 is STC15W401 AS.
According to a second aspect, an embodiment provides a temperature control system, which includes a communication module and the temperature measurement circuit of the first aspect, wherein the communication module is connected to the communication interface circuit and configured to output the monitored temperature value.
In one embodiment, the temperature control system further comprises a power supply module, wherein the power supply module comprises an external power supply circuit and an energy storage power supply circuit; the energy storage power supply circuit comprises an energy storage battery which is a lithium battery.
According to the temperature measuring circuit of the embodiment, the output voltage of the thermocouple probe is improved through the biasing circuit, so that the ordinary operational amplifier can replace an instrument amplifier to realize the temperature measuring circuit based on the thermocouple, namely, the ordinary operational amplifier with low cost is used for realizing the temperature measurement of the thermocouple, and further, the production cost of the thermocouple sensor is reduced.
Drawings
FIG. 1 is a schematic diagram illustrating a structural connection of a temperature measurement circuit according to an embodiment;
FIG. 2 is a schematic diagram of the circuit connections of the temperature measurement circuit in one embodiment;
FIG. 3 is a schematic circuit diagram of a circuit of a single chip in one embodiment;
fig. 4 is a schematic structural connection diagram of a temperature control system according to an embodiment.
Detailed Description
The present invention will be described in further detail with reference to the following detailed description and accompanying drawings. Wherein like elements in different embodiments are numbered with like associated elements. In the following description, numerous details are set forth in order to provide a better understanding of the present application. However, those skilled in the art will readily recognize that some of the features may be omitted or replaced with other elements, materials, methods in different instances. In some instances, certain operations related to the present application have not been shown or described in detail in order to avoid obscuring the core of the present application from excessive description, and it is not necessary for those skilled in the art to describe these operations in detail, so that they may be fully understood from the description in the specification and the general knowledge in the art.
Furthermore, the features, operations, or characteristics described in the specification may be combined in any suitable manner to form various embodiments. Also, the various steps or actions in the method descriptions may be transposed or transposed in order, as will be apparent to one of ordinary skill in the art. Thus, the various sequences in the specification and drawings are for the purpose of describing certain embodiments only and are not intended to imply a required sequence unless otherwise indicated where such sequence must be followed.
The numbering of the components as such, e.g., "first", "second", etc., is used herein only to distinguish the objects as described, and does not have any sequential or technical meaning. The term "connected" and "coupled" when used in this application, unless otherwise indicated, includes both direct and indirect connections (couplings).
The following description is made of terms related to the present application:
the thermocouple sensor is a temperature measuring sensor, converts temperature information into thermal potential for output, and can obtain temperature information according to the relationship between temperature and thermal potential. The working principle of the thermocouple is based on the thermoelectric effect. The conductor A and the conductor B of two different materials are connected in series to form a closed loop, when the temperatures of two nodes are different, thermoelectromotive force is generated in the loop to form current, and the phenomenon is called thermoelectric effect.
The law of the intermediate conductor, in which a conductor of a third material is connected to a thermocouple loop, does not affect the total thermal electromotive force of the thermocouple loop as long as the temperatures of both ends of the conductor (of the third material) are equal, according to which the third conductor can be replaced by a measuring instrument, and the thermal electromotive force can be measured as long as the temperatures of both nodes are kept the same.
The potential output of the thermocouple is actually reflected by the temperature difference between the hot end and the cold end, and the conversion table is calculated assuming that the cold end is 0 ℃. It is also necessary to know the cold end temperature in practical applications. The thermoelectric voltage output range of the thermocouple is relatively small, for example, when the temperature difference between the hot end and the cold end of the K-type thermocouple is 10 ℃, the thermoelectric voltage is only 0.397mV, and the direct output is not suitable for being directly sampled by an analog-to-digital conversion circuit, so that the thermoelectric voltage is generally amplified by an amplifier. Generally, an instrumentation amplifier is used for amplification, see patent document No. CN201520225452.X "a thermocouple temperature measuring circuit", which adopts a precision instrumentation amplifier with model number AD8496, and a thermocouple cold end compensator is provided, and belongs to a J-type thermocouple amplifier with a range of 25-100 degrees. Compared with an instrumentation amplifier, the lowest output voltage of a common operational amplifier is limited, for example, an integrated circuit with the model number LM358 can only output 100mV, which is not beneficial to small signal amplification. The voltage output by the thermocouple is in the mV level, so the electric signal of the thermocouple using the common operational amplifier needs to be specially processed.
The thermocouple-based temperature measuring circuit in the embodiment of the application respectively outputs a hot end electric signal and a cold end electric signal according to the temperatures of the hot end and the cold end, the temperature measuring circuit comprises a thermoelectric coupling interface circuit, a bias circuit, an amplifying circuit, a single chip microcomputer circuit and a cold end compensating circuit, a bias voltage signal output by the bias circuit is superposed with a thermoelectric conversion electric signal generated by a thermocouple probe, and the superposed electric signal obtained by superposition is sent to the amplifying circuit. The amplifying circuit transmits the hot-end electric signal obtained after the superposition electric signal is amplified to an ADC channel of the single chip microcomputer circuit. The cold junction electrical signal of cold junction compensating circuit output also sends single chip circuit, and single chip circuit obtains the monitoring temperature value according to cold junction voltage signal and hot junction electrical signal, sends through communication interface circuit at last.
Example one
Referring to fig. 1, a schematic diagram of a structural connection of a temperature measuring circuit in an embodiment is shown, where the temperature measuring circuit includes a thermocouple probe 1, a thermocouple interface circuit 2, a bias circuit 3, an amplifying circuit 4, a single chip circuit 5, a cold junction compensation circuit 6, and a communication interface circuit 7. The thermocouple probe 1 is connected with the thermocouple interface circuit 2, and the thermocouple probe 1 is used for converting the temperature value of the measuring end into a thermoelectric conversion electric signal and sending the thermoelectric conversion electric signal to the thermocouple interface circuit 2. The bias circuit 3 is connected to the thermocouple interface circuit 2, and the bias circuit 3 is configured to output a bias voltage signal to the thermocouple interface circuit 2. The thermocouple interface circuit 2 is connected with the amplifying circuit 4, and the thermocouple interface circuit 2 is used for superposing the bias voltage signal and the thermoelectric conversion electric signal to obtain a superposed electric signal and sending the superposed electric signal to the amplifying circuit 4. The amplifying circuit 4 is connected with the single chip microcomputer circuit 5, and the amplifying circuit 4 is used for amplifying the superposed electrical signals to obtain hot-end electrical signals and sending the hot-end electrical signals to the single chip microcomputer circuit 5. Cold junction compensating circuit 6 is connected with single chip microcomputer circuit 5, and cold junction compensating circuit 6 is used for changing reference temperature value into the cold junction signal of telecommunication to send the cold junction signal of telecommunication to single chip microcomputer circuit 5. The single chip microcomputer circuit 5 is connected with the communication interface circuit 7, and the single chip microcomputer circuit 5 is used for converting the hot end electric signal and the cold end electric signal into digital signals and acquiring the monitoring temperature value of the measuring end according to the hot end electric signal and the cold end electric signal which are converted into the digital signals. The single chip circuit 5 is also used for outputting the monitoring temperature value through the communication interface circuit 7.
Referring to fig. 2, which is a schematic diagram illustrating circuit connections of the temperature measuring circuit according to an embodiment, the thermocouple interface circuit 2 includes a thermocouple interface P1 and a capacitor C1. The thermocouple interface P1 includes a probe positive connection end VIN + and a probe negative connection end VIN-, the probe positive connection end VIN + and the probe negative connection end VIN-for connection with the thermocouple probe 1. Two ends of the capacitor C1 are respectively connected with the positive connecting end VIN + of the probe and the negative connecting end VIN-, and the capacitor C1 is used as a filter capacitor to eliminate noise interference. In one embodiment, the amplifying circuit 4 includes a resistor R1, a resistor R2, and an amplifier U1B. One end of the resistor R1 is connected with the negative input end of the amplifier U1B, and the other end is grounded; one end of the resistor R2 is connected with the negative output/input end of the amplifier U1B, and the other end of the resistor R2 is connected with the output end of the amplifier U1B; the positive input end of the amplifier U1B is connected with the positive probe connecting end VIN +, and the output end of the amplifier U1B is connected with the singlechip circuit 5. In one embodiment, the bias circuit 3 includes a resistor R3, a resistor R4, and an amplifier U1A. One end of the resistor R3 is used for connecting a preset voltage source VCC1, and the other end is connected to the positive input terminal of the amplifier U1A. One end of the resistor R4 is connected to the positive input of the amplifier U1A, and the other end is grounded. The negative input of amplifier U1A is connected to the output of amplifier U1A, and the output of amplifier U1A is connected to the probe negative connection VIN-. In one embodiment, the amplifier U1A and the amplifier U1B are integrated circuits. In one embodiment, the integrated circuit is of the type LM324, a power input terminal of the integrated circuit is connected to a predetermined voltage source VCC2, and a capacitor C2 for filtering is provided, one end of the capacitor C2 is connected to the power input terminal of the integrated circuit, and the other end is grounded. In one embodiment, cold side compensation circuit 6 includes a cold side electrical signal output terminal, a resistor R6, a resistor R7, and a capacitor C5. The cold junction electrical signal output end is connected with singlechip circuit 5, and resistance R6's one end is connected with cold junction electrical signal output end, and the other end is used for connecting one and presets voltage source VCC 3. One end of the resistor R7 is connected with the cold end electric signal output end, and the other end is grounded. One end of the capacitor C5 is connected with the cold-end electric signal output end, and the other end is grounded. In one embodiment, the resistor R6 is an NTC resistor.
Referring to fig. 3, which is a schematic circuit connection diagram of a single chip microcomputer circuit in an embodiment, the single chip microcomputer circuit 5 includes a single chip microcomputer U1, a capacitor C3, a capacitor C4, and a resistor R5. In one embodiment, the type of the single chip microcomputer U1 is STC15W401 AS. One end of the capacitor C3 is used for being connected with a preset voltage source VCC0, and the other end is connected with a pin 5 of the singlechip U1. One end of the resistor R5 is connected with the pin 5 of the singlechip U1, and the other end is grounded. One end of the capacitor C4 is connected with a pin 6 of the singlechip U1, and the other end is connected with a pin 8 of the singlechip U1 and is grounded. Pin 6 of the single chip microcomputer U1 is connected with a preset voltage source VCC 0. In one embodiment, the communication interface circuit 7 includes a communication interface P2, a diode D1, and a resistor R8. The communication interface P2 includes a first connection end, a second connection end, a third connection end and a fourth connection end. The first connecting end of the communication interface P2 is connected with a pin 11 of the singlechip U1, the second connecting end of the communication interface P2 is connected with a pin 10 of the singlechip U1, the third connecting end of the communication interface P2 is connected with a pin 9 of the singlechip U1, and the third connecting end of the communication interface P2 is grounded. The positive connection end of the diode D1 is connected to the first connection end of the communication interface P2, and the negative connection end of the diode D1 is used for connecting to the preset voltage source VCC 0. One end of the resistor R8 is connected to the first connection end of the communication interface P2, and the other end is connected to the fourth connection end of the communication interface P2.
A control processor, an analog switch circuit, an analog-to-digital conversion circuit, a communication interface and an EEPROM are integrated in a single chip microcomputer with the model of STC15W401 AS. The input ports of the analog switch circuit respectively correspond to the pin 15 (ADC 0), the pin 16 (ADC 1), the pin 1 (ADC 2), the pin 2 (ADC 3), the pin 3 (ADC 4) and the pin 4 (ADC 5) of the single chip microcomputer U1. The capacitor C3 and the resistor R5 are reset circuits of the singlechip U1 and are used for resetting the singlechip U1. The communication interface comprises a serial port, SPI or IIC and the like. The communication interface circuit shown in fig. 3 adopts serial communication. The EEPROM of the single chip microcomputer U1 functions as a nonvolatile memory. Communication interface circuit 7 plays the effect of presetting voltage source VCC0 input simultaneously, and when presetting voltage source VCC0 disconnection, resistance R8 plays the effect of discharging, and whether singlechip U1's pin 11 monitors at the moment and presets voltage source VCC0 disconnection simultaneously.
Referring to fig. 4, a schematic diagram of a structural connection of a temperature control system in an embodiment is shown, in an embodiment, the present application further discloses a temperature control system, where the temperature control system includes a communication module 20 and the temperature measurement circuit 10, and the communication module 20 is connected to the communication interface circuit 7 and is configured to output a monitored temperature value. In one embodiment, the temperature control system further includes a power supply module 30, and the power supply module 30 includes an external power circuit and an energy storage power circuit. The energy storage power supply circuit comprises an energy storage battery, and the energy storage battery is a lithium battery.
The following explains the acquisition principle of the monitored temperature value:
the bias voltage signal output by the bias circuit is:
V_OFFSET=R4/(R3+R4)*3.3V； （1）
where V _ OFFSET is a voltage value of the bias voltage signal.
VADC2=VIN+*(R2/R1+1)； （2）
VIN+=VPI+V_ OFFSET； （3）
Wherein VADC2 is the voltage value of the hot side electrical signal, VP1 is the voltage value of the thermoelectric conversion electrical signal, and VIN + is the voltage value of the positive connection terminal of the probe.
VADC1=R7/(R6+R7)*3.3V； （4）
Where VADC1 is the voltage value of the cold side electrical signal, and the resistance value of R6 changes with changes in the reference temperature.
The acquisition formula of the monitoring temperature value comprises the following steps:
T K =T△+T NTC ； （5）
wherein the measured temperature value of the thermocouple probe is T K Reference temperature value of cold end is T NTC The difference between the measured temperature and the reference temperature is T delta, T NTC The resistance value of the NTC resistor R6 can be converted, wherein the resistance value of R6 can be calculated according to the formula (4). T delta can be obtained by conversion from VP1, wherein VP1 can be calculated according to equations (2) and (3).
The embodiment of the application discloses a temperature measurement circuit based on a thermocouple, which comprises a thermocouple probe, a thermocouple interface circuit, a bias circuit, an amplifying circuit, a single chip microcomputer circuit, a cold end compensation circuit and a communication interface circuit. The thermocouple interface circuit superposes a thermoelectric conversion electric signal output by the thermocouple probe and a bias voltage signal output by the bias circuit and then sends the superposed electric signal to the amplifying circuit, the amplifying circuit amplifies the superposed electric signal obtained by superposition and then obtains a hot-end electric signal, the cold-end compensating circuit is used for converting a reference temperature value into a cold-end electric signal, and the single-chip circuit obtains a monitoring temperature value according to the hot-end electric signal and the cold-end electric signal and outputs the monitoring temperature value through the communication interface circuit. Because the output voltage of the thermocouple probe is improved through the bias circuit, the ordinary operational amplifier can replace an instrument amplifier to realize a thermocouple-based temperature measurement circuit, namely, the ordinary operational amplifier with low cost is used for realizing the temperature measurement of the thermocouple, and further, the production cost of the thermocouple sensor is reduced.
The present application has been described with reference to specific examples, which are provided only to aid understanding of the present application and are not intended to limit the present application. For a person skilled in the art to which the application pertains, several simple deductions, modifications or substitutions may be made according to the idea of the application.
Claims (10)
1. A temperature measuring circuit based on a thermocouple is characterized by comprising a thermocouple probe, a thermocouple interface circuit, a bias circuit, an amplifying circuit, a single chip microcomputer circuit, a cold end compensation circuit and a communication interface circuit;
the thermocouple probe is connected with the thermocouple interface circuit and used for converting a temperature value of a measuring end into a thermoelectric conversion electric signal and sending the thermoelectric conversion electric signal to the thermocouple interface circuit;
the bias circuit is connected with the thermocouple interface circuit and is used for outputting a bias voltage signal to the thermocouple interface circuit;
the thermocouple interface circuit is connected with the amplifying circuit and is used for superposing the bias voltage signal and the thermoelectric conversion electric signal to obtain a superposed electric signal and sending the superposed electric signal to the amplifying circuit;
the amplifying circuit is connected with the single chip microcomputer circuit and used for amplifying the superposed electric signals to obtain hot-end electric signals and sending the hot-end electric signals to the single chip microcomputer circuit;
the cold end compensation circuit is connected with the single chip microcomputer circuit and used for converting a reference temperature value into a cold end electric signal and sending the cold end electric signal to the single chip microcomputer circuit;
the single chip circuit is connected with the communication interface circuit; the single chip microcomputer circuit is used for converting the hot end electric signal and the cold end electric signal into digital signals and acquiring a monitoring temperature value of a measuring end according to the hot end electric signal and the cold end electric signal which are converted into the digital signals; the single chip microcomputer circuit is also used for outputting the monitoring temperature value through the communication interface circuit.
2. The thermometric circuit of claim 1, wherein said thermocouple interface circuit comprises a thermocouple interface and a capacitance C1;
the thermocouple interface comprises a probe positive connecting end and a probe negative connecting end, and the probe positive connecting end and the probe negative connecting end are used for being connected with the thermocouple probe;
two ends of the capacitor C1 are respectively connected with the probe positive connecting end and the probe negative connecting end, and the capacitor C1 is used as a filter capacitor.
3. The thermometric circuit of claim 2, wherein said amplification circuit comprises resistor R1, resistor R2, and amplifier U1B;
one end of the resistor R1 is connected with the negative input end of the amplifier U1B, and the other end is grounded;
one end of the resistor R2 is connected with the negative output/input end of the amplifier U1B, and the other end of the resistor R2 is connected with the output end of the amplifier U1B;
the positive input end of the amplifier U1B is connected with the positive connecting end of the probe, and the output end of the amplifier U1B is connected with the single chip microcomputer circuit.
4. The thermometric circuit of claim 2, wherein said bias circuit comprises resistor R3, resistor R4, and amplifier U1A;
one end of the resistor R3 is used for connecting a preset voltage source VCC1, and the other end is connected with the positive input end of the amplifier U1A;
one end of the resistor R4 is connected with the positive input end of the amplifier U1A, and the other end is grounded;
the negative input of amplifier U1A is connected to the output of amplifier U1A, and the output of amplifier U1A is connected to the probe negative connection.
5. The temperature sensing circuit of claim 1 wherein said cold side compensation circuit comprises a cold side electrical signal output, a resistor R6, a resistor R7, and a capacitor C5;
the cold end electric signal output end is connected with the single chip microcomputer circuit;
one end of the resistor R6 is connected with the cold end electric signal output end, and the other end of the resistor R6 is used for being connected with a preset voltage source VCC 3;
one end of the resistor R7 is connected with the cold end electric signal output end, and the other end is grounded;
and one end of the capacitor C5 is connected with the cold-end electric signal output end, and the other end of the capacitor C5 is grounded.
6. The thermometric circuit of claim 5, wherein the resistor R6 is an NTC resistor.
7. The temperature measuring circuit of claim 1, wherein the single chip microcomputer circuit comprises a single chip microcomputer U1, a capacitor C3, a capacitor C4 and a resistor R5;
the model of the single chip microcomputer U1 is STC15W401 AS;
one end of the capacitor C3 is connected with a preset voltage source VCC0, and the other end of the capacitor C3 is connected with a pin 5 of the singlechip U1;
one end of the resistor R5 is connected with the pin 5 of the singlechip U1, and the other end is grounded;
one end of the capacitor C4 is connected with a pin 6 of the singlechip U1, and the other end of the capacitor C4 is connected with a pin 8 of the singlechip U1;
and a pin 6 of the singlechip U1 is connected with the preset voltage source VCC 0.
8. The thermometric circuit of claim 7, wherein said communication interface circuit comprises a communication interface, a diode D1 and a resistor R8;
the communication interface comprises a first connecting end, a second connecting end, a third connecting end and a fourth connecting end; the first connecting end of the communication interface is connected with a pin 11 of the single chip microcomputer U1, the second connecting end of the communication interface is connected with a pin 10 of the single chip microcomputer U1, the third connecting end of the communication interface is connected with a pin 9 of the single chip microcomputer U1, and the third connecting end of the communication interface is grounded;
the positive connection end of the diode D1 is connected with the first connection end of the communication interface, and the negative connection end of the diode D1 is used for connecting the preset voltage source VCC 0;
one end of the resistor R8 is connected with the first connection end of the communication interface, and the other end is connected with the fourth connection end of the communication interface.
9. A temperature control system comprising a communication module and a temperature measurement circuit according to any one of claims 1 to 8, wherein the communication module is connected to the communication interface circuit for outputting the monitored temperature value.
10. The temperature control system of claim 9, further comprising a power supply module comprising an external power circuit and an energy storage power circuit; the energy storage power supply circuit comprises an energy storage battery, and the energy storage battery is a lithium battery.
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| Application Number | Priority Date | Filing Date | Title |
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| CN202221060926.6U CN217084002U (en) | 2022-05-05 | 2022-05-05 | Temperature measurement circuit and temperature control system based on thermocouple |
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| CN202221060926.6U CN217084002U (en) | 2022-05-05 | 2022-05-05 | Temperature measurement circuit and temperature control system based on thermocouple |
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