Thermistor temperature measuring system and method based on pulse excitation signal source

Abstract

The invention relates to the technical field of measurement and control, and discloses a thermistor temperature measurement system and method based on a pulse excitation signal source, the system comprises a thermistor, a switch, a signal conditioning module, an analog-to-digital conversion module and a signal processing module which are electrically connected in sequence, and the signal conditioning module comprises a signal amplification circuit. The pulse excitation signal source is electrically connected with the switch; wherein the pulse excitation signal source is used for generating a periodic square wave signal and controlling on or off of the switch through the square wave signal; the square wave signal is synchronized with an enable signal of the analog-to-digital conversion module; and the signal processing module is used for calculating the temperature of the thermistor according to the signal output by the analog-to-digital conversion module. According to the invention, the problem that high-precision temperature measurement is difficult to realize on the premise of not sacrificing the signal-to-noise ratio in the prior art is solved.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of measurement and control technology, in particular to a thermistor temperature measurement system and method based on a pulse excitation signal source. BACKGROUND

[0002] Thermistors are widely used in industrial control, scientific experiments, consumer electronics and other fields for temperature measurement due to their high sensitivity, low cost, fast response and other advantages. The basic principle is to measure the resistance value and convert it to temperature value according to the resistance-temperature characteristic curve. Usually, a constant excitation current or voltage is applied to the thermistor by the measurement circuit, and the resistance value is calculated by measuring the voltage drop across it.

[0003] However, the prior art has the following shortcomings: 1. Self-heating effect causes measurement error: When a constant current flows through the thermistor, the current will heat itself up, causing its temperature to be higher than the true temperature of the environment being measured. This "self-heating effect" changes the resistance of the thermistor, introducing significant measurement error. In applications requiring high accuracy temperature measurement, this error is unacceptable.

[0004] 2. Conflict between signal-to-noise ratio and temperature rise: To reduce self-heating, the traditional method is to reduce the excitation current. But this will reduce the signal-to-noise ratio, making the measurement signal weak and susceptible to environmental electromagnetic interference, also affecting the measurement accuracy. Therefore, there is a difficult trade-off between accuracy and signal-to-noise ratio.

[0005] 3. High system complexity: For some high-precision applications, complex hardware circuits or heat dissipation structures may be required to reduce self-heating, which increases the cost, complexity and volume of the system. SUMMARY

[0006] To overcome the shortcomings of the prior art, the present application provides a thermistor temperature measurement system and method based on a pulse excitation signal source, which solves the problem of high-precision temperature measurement without sacrificing signal-to-noise ratio in the prior art.

[0007] The technical solution of the present application to solve the above technical problems is as follows: A thermistor temperature measurement system based on a pulse excitation signal source, comprising a thermistor, a switch, a signal conditioning module, an analog-to-digital conversion module and a signal processing module connected in sequence, the signal conditioning module comprising a signal amplification circuit, and further comprising a pulse excitation signal source electrically connected to the switch; Wherein, the pulse excitation signal source is used to generate a periodic square wave signal and control the switch to turn on or off through the square wave signal; the square wave signal is synchronized with the enable signal of the analog-to-digital conversion module; The signal processing module is configured to calculate the temperature of the thermistor according to the signal output by the analog-digital conversion module.

[0008] The present application has the following advantages: The present application has the following advantages: The present application improves the measurement accuracy: the temperature rise error caused by the continuous self-heating effect is fundamentally eliminated through the pulse "measurement-halt" working mode, so that the measurement result is closer to the real temperature of the measured environment, and the present application is particularly suitable for high-precision temperature measurement; the present application considers both the signal-to-noise ratio and the low power consumption: a larger excitation current can be used to obtain a voltage signal or a current signal with a high signal-to-noise ratio during the short measurement period; the overall power consumption is close to zero during the long halt period, thereby perfectly solving the contradiction between "high accuracy" and "low self-heating" in the traditional method; the present application has a simple structure and low cost: no complex constant temperature, heat dissipation or compensation hardware is needed, and the core control logic can be realized through a simple circuit or software, which greatly reduces the complexity and manufacturing cost of the system; the present application has wide applicability: it is particularly suitable for static or slowly changing temperature field measurement (such as environmental monitoring, device state monitoring, temperature distribution measurement of large test benches, etc.) with low sampling rate requirements, and can achieve the best performance in these scenarios.

[0009] Based on the above technical solution, the present application can be further improved as follows.

[0010] As a preferred technical solution, the square wave signal is a voltage signal or a current signal.

[0011] The present application has the following advantages when the above preferred technical solution is adopted: The present application has the following advantages when the above preferred technical solution is adopted:

[0012] As a preferred technical solution, when the square wave signal is at a high level, the analog-digital conversion module samples and converts the signal output by the signal conditioning module.

[0013] The present application has the following advantages when the above preferred technical solution is adopted: The present application has the following advantages when the above preferred technical solution is adopted:

[0014] As a preferred technical solution, the signal conditioning module further comprises a filter circuit electrically connected to the signal amplification circuit.

[0015] The present application has the following advantages when the above preferred technical solution is adopted: The present application has the following advantages when the above preferred technical solution is adopted:

[0016] As a preferred technical solution, the frequency range of the square wave signal is 0.01Hz-1000Hz.

[0017] The beneficial effects of the preferred technical solution are as follows: Such a frequency range makes the application range of the present application more extensive, and facilitates the selection of the pulse excitation signal source.

[0018] As a preferred technical solution, the duty cycle range of the square wave signal is 2% to 50%.

[0019] The beneficial effects of the preferred technical solution are as follows: Such a duty cycle range makes the application range of the present application more extensive, and facilitates the selection of the pulse excitation signal source.

[0020] As a preferred technical solution, the amplitude range of the square wave signal is 10 mu A to 10 mA or 1 mV to 1 V.

[0021] The beneficial effects of the preferred technical solution are as follows: Such an amplitude range makes the application range of the present application more extensive, and facilitates the selection of the pulse excitation signal source.

[0022] As a preferred technical solution, the thermistor and the signal processing module are integrated into one module.

[0023] The beneficial effects of the preferred technical solution are as follows: Integration into one module facilitates further reduction of volume occupation and wiring.

[0024] As a preferred technical solution, the thermistor is a platinum resistance.

[0025] The beneficial effects of the preferred technical solution are as follows: The platinum resistance has the advantages of high measurement accuracy, wide working temperature range, and stable chemical properties as a thermistor.

[0026] On the basis of the above technical solution, the present application further provides a thermistor temperature measurement method based on a pulse excitation signal source.

[0027] A thermistor temperature measurement method based on a pulse excitation signal source, which uses the thermistor temperature measurement system based on a pulse excitation signal source to measure the temperature of the thermistor, and includes the following steps: Set the frequency and duty cycle of the pulse excitation signal source; The pulse excitation signal source outputs a pulse excitation signal; The pulse excitation signal controls the switch to be turned on, and the signal conditioning module amplifies the voltage signal or current signal of the thermistor; The analog-to-digital conversion module samples and performs analog-to-digital conversion on the amplified voltage signal or current signal of the thermistor output by the signal conditioning module; When the pulse excitation signal controls the switch to turn off, the thermistor is de-energized and allows for natural cooling. The signal processing module calculates the temperature of the thermistor based on the signal output from the analog-to-digital converter module.

[0028] Compared with the prior art, the present invention has the following advantages: (1) The present invention significantly improves the measurement accuracy: by using the pulsed "measure-stop" working mode, the temperature rise error caused by the continuous self-heating effect is fundamentally eliminated, making the measurement result closer to the real temperature of the measured environment, which is particularly suitable for high-precision temperature measurement occasions; (2) The present invention takes into account both signal-to-noise ratio and low power consumption: During the short measurement period, a large excitation current can be used to obtain a voltage or current signal with a high signal-to-noise ratio; During the long interval, the overall power consumption is close to zero, thus perfectly solving the contradiction between "high accuracy" and "low self-heating" in the traditional method. (3) The present invention has a simple structure and low cost: no complex temperature control, heat dissipation or compensation hardware is required, and the core control logic can be implemented by simple circuits or software, which greatly reduces the complexity of the system and manufacturing cost. (4) The present invention has wide applicability: it is especially suitable for static or slowly changing temperature field measurement where the sampling rate requirement is not high (such as environmental monitoring, equipment status monitoring, temperature distribution measurement of large test benches, etc.), and can play its greatest advantage in these scenarios. Attached Figure Description

[0029] Fig. 1 This is a schematic diagram of the structure of a thermistor temperature measurement system based on a pulse excitation signal source according to the present invention; Fig. 2 This is a hardware block diagram of Embodiment 3 of the present invention; Fig. 3 This is the wiring diagram of the NI PXIe-9226 temperature acquisition module in Embodiment 3 of the present invention. Detailed Implementation

[0030] The present invention will be further described in detail below with reference to the embodiments and accompanying drawings, but the embodiments of the present invention are not limited thereto.

[0031] The principles and features of the present invention are described below. The embodiments given are only for explaining the present invention and are not intended to limit the scope of the present invention.

[0032] Example 1 like Figs. 1 to 3 As shown, a thermistor temperature measurement system based on a pulse excitation signal source includes a thermistor, a switch, a signal conditioning module, an analog-to-digital conversion module, and a signal processing module connected in sequence. The signal conditioning module includes a signal amplification circuit and a pulse excitation signal source electrically connected to the switch. The pulse excitation signal source is configured to generate a periodic square wave signal and control the on or off of the switch through the square wave signal; and the square wave signal is synchronized with an enable signal of the analog-digital conversion module. The signal processing module is configured to calculate the temperature of the thermistor according to the signal output by the analog-digital conversion module.

[0033] The present application has the following advantages: The present application has the following advantages: The present application improves the measurement accuracy: through the pulse type "measurement-halt" working mode, the temperature rise error caused by the continuous self-heating effect is fundamentally eliminated, so that the measurement result is closer to the real temperature of the measured environment, and the present application is particularly suitable for high-precision temperature measurement; the present application considers the signal-to-noise ratio and low power consumption: during the short measurement period, a larger excitation current can be used to obtain a voltage signal or a current signal with high signal-to-noise ratio; during the long halt period, the overall power consumption is close to zero, thereby perfectly solving the contradiction between "high accuracy" and "low self-heating" in the traditional method; the present application has simple structure and low cost: without complex constant temperature, heat dissipation or compensation hardware, the core control logic can be realized through a simple circuit or software, which greatly reduces the complexity and manufacturing cost of the system; the present application has wide applicability: it is particularly suitable for static or slowly changing temperature field measurement (such as environmental monitoring, device state monitoring, temperature distribution measurement of large test benches, etc.) with low sampling rate requirements, and can bring the greatest advantage in these scenarios.

[0034] On the basis of the above technical solution, the present application can also be improved as follows.

[0035] As a preferred technical solution, the square wave signal is a voltage signal or a current signal.

[0036] The above preferred technical solution has the following advantages: The voltage signal and the current signal can be selected as the square wave signal, and the pulse excitation signal source has a wide selection range.

[0037] As a preferred technical solution, when the square wave signal is high, the analog-digital conversion module samples and converts the signal output by the signal conditioning module.

[0038] The above preferred technical solution has the following advantages: When the square wave signal is high, the pulse excitation signal source is set, and the sampling is more intuitive and controllable.

[0039] As a preferred technical solution, the signal conditioning module further comprises a filter circuit electrically connected to the signal amplification circuit.

[0040] The above preferred technical solution has the following advantages: Filtering helps to remove the noise of the signal, further improving the accuracy of the measurement.

[0041] As a preferred technical solution, the frequency range of the square wave signal is 0.01Hz-1000Hz.

[0042] The beneficial effects of the above preferred technical solution are: Such a frequency range makes the application range of the present application more extensive, and facilitates the selection of the pulse excitation signal source.

[0043] As a preferred technical solution, the duty cycle range of the square wave signal is 2%-50%.

[0044] The beneficial effects of the above preferred technical solution are: Such a duty cycle range makes the application range of the present application more extensive, and facilitates the selection of the pulse excitation signal source.

[0045] As a preferred technical solution, the amplitude range of the square wave signal is 10μA-10mA or 1mV-1V.

[0046] The beneficial effects of the above preferred technical solution are: Such an amplitude range makes the application range of the present application more extensive, and facilitates the selection of the pulse excitation signal source.

[0047] As a preferred technical solution, the thermistor and the signal processing module are integrated into one module.

[0048] The beneficial effects of the above preferred technical solution are: Integration into one module facilitates further reduction of volume occupation and wiring.

[0049] As a preferred technical solution, the thermistor is a platinum resistance.

[0050] The beneficial effects of the above preferred technical solution are: The platinum resistance as a thermistor has the advantages of high measurement accuracy, wide working temperature range, stable chemical properties, etc.

[0051] On the basis of the above technical solution, the present application further provides a thermistor temperature measurement method based on a pulse excitation signal source.

[0052] A thermistor temperature measurement method based on a pulse excitation signal source, using the thermistor temperature measurement system based on a pulse excitation signal source to measure the temperature of the thermistor, comprising the following steps: Set the frequency and duty cycle of the pulse excitation signal source; The pulse excitation signal source outputs a pulse excitation signal; The pulse excitation signal controls the switch to be turned on, and the signal conditioning module amplifies the voltage signal or the current signal of the thermistor; The analog-digital conversion module samples and performs analog-digital conversion on the amplified voltage signal or the current signal of the thermistor output by the signal conditioning module; The pulse excitation signal controls the switch to be turned off, and the thermistor is powered off to be naturally cooled; The signal processing module calculates the temperature of the thermistor according to the signal output by the analog-digital conversion module.

[0053] Embodiment 2 As Figs. 1 to 3 As shown in the embodiment 1, the embodiment provides more detailed implementation.

[0054] In view of the deficiencies of the prior art, the present application aims to provide a solution that can effectively eliminate or greatly weaken the self-heating effect of the thermistor, and realize high-precision temperature measurement without sacrificing the signal-to-noise ratio.

[0055] The present application provides an anti-self-heating pulse measurement method for thermistor temperature measurement. The method replaces the traditional direct current excitation with a pulse excitation method, which fundamentally avoids the continuous heating of the thermistor.

[0056] The core improvement point of the present application is: Pulse excitation signal source: A pulse excitation signal is used to control the power switch of the measurement circuit. The signal source generates a periodic square wave pulse, which only powers the thermistor measurement circuit during a very short high level period and performs data acquisition, and is completely powered off during the majority of the low level period.

[0057] Synchronous acquisition and control: The analog-digital conversion module and the pulse excitation signal source work synchronously. The analog-digital conversion module only samples and holds the voltage signal across the thermistor during the active period of the excitation pulse. The synchronization includes: the enable signal frequency of the analog-digital conversion module is consistent with the frequency of the pulse excitation signal source, and the duty cycle of the enable signal of the analog-digital conversion module is consistent with the duty cycle of the pulse excitation signal source.

[0058] "Measurement-halt" cycle: In this way, the working mode of the thermistor becomes a cycle of "measurement-power-off heat dissipation-measurement". During the intermittent period between two measurements, the thermistor stops self-heating due to power-off, and has sufficient time to dissipate the small amount of heat generated to the measured environment, so that its temperature returns to the real temperature of the environment, and thus an accurate resistance value is obtained at the next measurement.

[0059] The system mainly comprises: a thermistor, a pulse excitation signal source, an electronic switch, a signal conditioning module, an analog-to-digital conversion module (ADC) and a signal processing module.

[0060] Thermistor: Placed at the temperature point to be measured.

[0061] Pulse excitation signal source and electronic switch: The pulse signal source outputs a square wave with a specific frequency and duty cycle, and controls the turn-on and turn-off of the electronic switch, so as to convert the stable DC power supply into a pulse voltage or current and apply it to the thermistor.

[0062] The signal conditioning module comprises a filter circuit and a signal amplification circuit. Preferably, the following modes can be adopted: (1) receiving the signal transmitted from the electronic switch, and then transmitting the signal to the analog-to-digital conversion module in turn through the filter circuit and the signal amplification circuit; (2) receiving the signal transmitted from the electronic switch, and then transmitting the signal to the analog-to-digital conversion module in turn through the signal amplification circuit and the filter circuit; (3) receiving the signal transmitted from the electronic switch, and then transmitting the signal to the analog-to-digital conversion module in turn through the first filter circuit, the signal amplification circuit and the second filter circuit.

[0063] Analog-to-digital conversion module: The enable signal thereof is synchronized with the pulse excitation signal. When the excitation pulse is at a high level, the analog-to-digital conversion module samples and subsequently processes the conditioned thermistor voltage signal or current signal to realize analog-to-digital conversion. It should be noted that the working principle and process of the analog-to-digital conversion module are not described in further detail because it belongs to the prior art.

[0064] Signal processing module: Receiving the digital signal transmitted by the analog-to-digital conversion module, and calculating the temperature value of the thermistor according to the pre-stored resistance-temperature characteristic curve of the thermistor.

[0065] The working process can adopt the following modes: (1) System initialization, setting pulse frequency and duty cycle. The principle of setting the duty cycle is: under the premise of ensuring the stability of the sampling signal, the duty cycle is as small as possible to give the thermistor enough heat dissipation time. Preferably, the pulse frequency (equal to the temperature acquisition frequency) ranges from 0.01 Hz to 1000 Hz, the duty cycle ranges from 2% to 50%, and the amplitude ranges from 10 μA to 10 mA or 1 mV to 1 V.

[0066] (2) The pulse excitation signal source outputs a high level, and the electronic switch is turned on to supply power to the thermistor.

[0067] (3) The signal conditioning module amplifies the voltage signal or current signal of the thermistor; (4) The analog-digital conversion module immediately samples the voltage or current across the amplified thermistor outputted by the signal conditioning module.

[0068] The sampling more specifically is as follows: Trigger: at the moment when the pulse excitation signal becomes high, the analog-digital conversion module sends a synchronous acquisition enable instruction; Stabilization: after the enable signal is sent, the program waits for a very short preset time (for example, 10 milliseconds) to allow the excitation current applied to the thermistor or the voltage signal across the thermistor to reach stability; Reading: the analog-digital conversion module performs a high-precision instantaneous value sampling on the signal across the thermistor after signal conditioning; Conversion and retention: the analog-digital conversion module converts the sampled analog voltage signal or current signal into a digital quantity and latches the value into a data register.

[0069] (5) The pulse excitation signal source output becomes low, the electronic switch is turned off, and the thermistor is completely powered off to start natural cooling.

[0070] (6) The signal processing module calculates the resistance using the voltage value or current value obtained during sampling, and then looks up the temperature value.

[0071] (7) The system enters the next "measurement-rest" cycle.

[0072] The advantages of the present application are as follows: (1) The present application significantly improves the measurement accuracy: through the pulse "measurement-rest" working mode, the temperature rise error caused by the continuous self-heating effect is fundamentally eliminated, making the measurement result closer to the true temperature of the measured environment, and being particularly suitable for high-precision temperature measurement occasions; (2) The present application takes into account the signal-to-noise ratio and low power consumption: during the short measurement period, a larger excitation current can be used to obtain a high signal-to-noise ratio voltage signal or current signal; during the long rest period, the overall power consumption is close to zero, thereby perfectly solving the contradiction between "high accuracy" and "low self-heating" in traditional methods; (3) The present application has a simple structure and low cost: without complex constant temperature, heat dissipation or compensation hardware, the core control logic can be realized through a simple circuit or software, greatly reducing the complexity and manufacturing cost of the system; (4) The present application has wide applicability: it is particularly suitable for static or slowly varying temperature field measurement (such as environmental monitoring, device status monitoring, temperature distribution measurement of large test benches, etc.) where the sampling rate requirement is not high, and can achieve the best results in these scenarios.

[0073] Example 3 As Figs. 1 to 3As shown, the embodiment is based on the embodiments 1 and 2, and the embodiment provides more refined implementation manners.

[0074] For example, the temperature is measured at a sampling rate of 1 Hz: Hardware platform: Program-controlled acquisition device: NI PXIe-1095 chassis, PXIe-8862 controller and NI PXIe-9226 temperature acquisition module (with an enabled current excitation source, replacing the role of an electronic switch).

[0075] Thermistor: straight-in thermistor temperature sensor. The thermistor and the acquisition device are connected in four-wire mode.

[0076] Computer: a computer installed with Windows 10 and NI supporting environment.

[0077] Software implementation: 1. Create a loop program for sequential execution.

[0078] First step (excitation and sampling): using the NI-DAQmx function, first pass through a "write" function node to enable the constant current source of the PXIe-9226 corresponding channel. Then, call the "delay" function to wait for 20 milliseconds to stabilize the signal. Finally, call the "read" function to perform a high-precision sampling.

[0079] Second step (power off): immediately pass through the "write" function node again to disable the constant current source of the channel.

[0080] Third step (heat dissipation and waiting): call the "delay" function to wait for 980 milliseconds (totaling 20 milliseconds in the first step, constituting a total sampling period of 1 second).

[0081] 2. Loop the above three steps.

[0082] Convert the data obtained by the analog-to-digital conversion module in real time in the program to obtain the temperature by table lookup method and record it.

[0083] As described above, the application can be well implemented.

[0084] In the description of the application, unless otherwise explicitly specified and limited, the terms "mounting", "connection", "connection", "fixing" and the like should be understood in a broad sense, for example, it can be fixedly connected, or it can be detachably connected, or it can be integrated; it can be mechanically connected, or it can be electrically connected; it can be directly connected, or it can be indirectly connected through an intermediate medium; it can be the internal communication of two elements or the interaction relationship between two elements, unless otherwise explicitly limited. For those skilled in the art, the specific meaning of the above terms in the application can be understood according to the specific circumstances.

[0085] In the description of this invention, the terms "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0086] In the description of this invention, although embodiments of the invention have been shown and described herein, it is to be understood that the above embodiments are exemplary and should not be construed as limiting the invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of this invention.

[0087] In the description of this invention, all features disclosed in all embodiments of this specification, or steps in all methods or processes implied in the disclosure, may be combined and / or extended or replaced in any way, except for mutually exclusive features and / or steps.

[0088] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Based on the technical essence of the present invention, any simple modifications, equivalent substitutions, and improvements made to the above embodiments within the spirit and principles of the present invention shall still fall within the protection scope of the present invention.

Claims

1. A thermistor temperature measurement system based on a pulsed excitation signal source, characterized by, The temperature measurement system comprises a thermistor, a switch, a signal conditioning module, an analog-to-digital conversion module and a signal processing module which are electrically connected in sequence. The signal processing module is configured to calculate the temperature of the thermistor according to the signal output by the analog-to-digital conversion module. The square wave signal is a voltage signal or a current signal.

2. A thermistor temperature measurement system based on a pulsed excitation signal source according to claim 1, characterized in that, When the square wave signal is at a high level, the analog-to-digital conversion module samples and converts the signal output by the signal conditioning module.

3. A thermistor temperature measurement system based on a pulsed excitation signal source according to claim 1, characterized in that, The signal conditioning module further comprises a filter circuit electrically connected to the signal amplification circuit.

4. The thermistor temperature measurement system based on a pulsed excitation signal source according to claim 1, characterized in that, The frequency range of the square wave signal is 0.01 Hz to 1000 Hz.

5. A thermistor temperature measurement system based on a pulsed excitation signal source according to claim 1, characterized in that, The duty cycle range of the square wave signal is 2% to 50%.

6. A thermistor temperature measurement system based on a pulsed excitation signal source according to claim 1, characterized in that, The amplitude range of the square wave signal is 10 μA to 10 mA or 1 mV to 1 V.

7. A thermistor temperature measurement system based on a pulsed excitation signal source according to claim 1, characterized in that, The thermistor and the signal processing module are integrated into one module.

8. A thermistor temperature measurement system based on a pulsed excitation signal source according to claim 1, characterized in that, The thermistor is a platinum resistor.

9. A thermistor temperature measurement system based on a pulsed excitation signal source according to any one of claims 1 to 8, characterized in that, The temperature measurement system comprises the following steps:

10. A method of thermistor temperature measurement based on a pulsed excitation signal source, characterized by, Setting the frequency and duty cycle of the pulse excitation signal source; The pulse excitation signal source outputs a pulse excitation signal; The pulse excitation signal controls the switch to turn on, and the signal conditioning module amplifies the voltage signal or current signal of the thermistor; The analog-to-digital conversion module samples and converts the amplified voltage signal or current signal of the thermistor output by the signal conditioning module; The pulse excitation signal controls the switch to turn off, and the thermistor is powered off for natural cooling; The signal processing module calculates the temperature of the thermistor according to the signal output by the analog-to-digital conversion module. ​

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