High-precision temperature detection method and detection circuit

Abstract

The application relates to temperature detection, in particular to a high-precision temperature detection method and a detection circuit. Different states are outputted through the output state control ports connected to the zero point resistance, the full-scale resistance and the temperature sensor terminal, so that the temperature detection circuit is in the condition of the zero point resistance and the temperature sensor being in series connection and the full-scale resistance and the temperature sensor being in series connection, voltage signals in each condition are collected, the resistance value of the temperature sensor eliminating the power voltage reading error and the linear error in the range is calculated by using the voltage signals, and finally the temperature value corresponding to the resistance value of the temperature sensor is calculated. The technical scheme provided by the application can effectively overcome the defect of low temperature measurement precision in the prior art.

Description

Technical Field

[0001] This invention relates to temperature detection, and more specifically to a high-precision temperature detection method and detection circuit. Background Technology

[0002] A resistance thermometer is a temperature sensor made from a material whose resistance changes with temperature. It features high accuracy, low temperature drift, and a wide range of applications. Measuring temperature with a resistance thermometer essentially involves measuring the resistance of the thermometer. However, in practical applications, due to errors in power supply voltage readings and linearity errors within the measurement range, the accuracy of temperature measurement can be relatively low. Summary of the Invention

[0003] (a) Technical problems to be solved

[0004] In view of the above-mentioned shortcomings of the existing technology, the present invention provides a high-precision temperature detection method and detection circuit, which can effectively overcome the defect of low temperature measurement accuracy in the existing technology.

[0005] (II) Technical Solution

[0006] To achieve the above objectives, the present invention provides the following technical solution:

[0007] A high-precision temperature detection method is proposed. By outputting different states through the output state control ports connected to the zero-point resistor, full-scale resistor, and temperature sensor, the temperature detection circuit is positioned in the case of the zero-point resistor and temperature sensor being connected in series, and the full-scale resistor and temperature sensor being connected in series. The voltage signal under each condition is collected, and the resistance value of the temperature sensor is calculated to eliminate the power supply voltage reading error and the linearity error within the measurement range using the voltage signal. Finally, the temperature value corresponding to the resistance value of the temperature sensor is calculated.

[0008] Preferably, the output state control ports connected to the zero-point resistor, full-scale resistor, and temperature sensor output different states, so that the temperature detection circuit is in the case of the zero-point resistor and temperature sensor being connected in series, and the full-scale resistor and temperature sensor being connected in series, and the voltage signal under each case is collected, including:

[0009] The first output state control port outputs power, the third output state control port outputs ground, the second output state control port outputs an open circuit, and the first voltage signal is acquired from the sampling port. This first voltage signal is the voltage to ground after the temperature sensor divides the zero-point resistor.

[0010] The first output state control port outputs ground, the third output state control port outputs power, the second output state control port outputs an open circuit, and the second voltage signal is acquired from the sampling port. This second voltage signal is the voltage to ground after the zero-point resistor divides the temperature sensor voltage.

[0011] The second output state control port outputs power, the third output state control port outputs ground, the first output state control port outputs an open circuit, and the third voltage signal is acquired from the sampling port. This third voltage signal is the voltage to ground after the temperature sensor divides the voltage of the full-scale resistor.

[0012] The second output state control port outputs ground, the third output state control port outputs power, the first output state control port outputs an open circuit, and the fourth voltage signal is acquired from the sampling port. This fourth voltage signal is the voltage to ground after the full-scale resistor divides the temperature sensor voltage.

[0013] The first output state control port, the second output state control port, and the third output state control port are respectively connected to the ends of the zero-point resistor, the full-scale resistor, and the temperature sensor.

[0014] Preferably, the calculation of the resistance value of the temperature sensor using a voltage signal to eliminate power supply voltage reading errors and linearity errors within the measurement range includes:

[0015] The first voltage signal V1 is represented by the following formula:

[0016]

[0017] The second voltage signal V2 is represented by the following formula:

[0018]

[0019] The third voltage signal V3 is represented by the following formula:

[0020]

[0021] The fourth voltage signal V4 is represented by the following formula:

[0022]

[0023] Based on equations ① and ②, we obtain:

[0024]

[0025] Based on equations ③ and ④, we obtain:

[0026]

[0027] The resistance R of the temperature sensor after error elimination t Expressed as follows:

[0028]

[0029] Among them, R t0R represents the resistance of the temperature sensor measured when the zero-point resistor is connected in series with the temperature sensor. t1 This indicates the resistance value of the temperature sensor when the full-scale resistor is connected in series with the temperature sensor. R0 is the resistance value of the zero-point resistor, R1 is the resistance value of the full-scale resistor, and VCC is the power supply voltage.

[0030] Preferably, the temperature sensor is a PT1000 temperature sensor;

[0031] The zero-point resistor is a precision resistor used as the zero point of the temperature measurement range, corresponding to the resistance value of the PT1000 temperature sensor at zero point.

[0032] The full-scale resistor is a precision resistor used to measure the full scale of the temperature range, corresponding to the resistance value of the PT1000 temperature sensor at full scale.

[0033] A high-precision temperature detection circuit includes a zero-point resistor, a full-scale resistor, a temperature sensor, a sampling port, and an output status control unit connected to the ends of the zero-point resistor, the full-scale resistor, and the temperature sensor.

[0034] The output status control unit outputs different states, which makes the temperature detection circuit either in series with the zero-point resistor and the temperature sensor, or in series with the full-scale resistor and the temperature sensor.

[0035] The sampling port is used to acquire the voltage signals of the zero-point resistor, the full-scale resistor, and the temperature sensor to ground when the temperature detection circuit is in the condition that the zero-point resistor is connected in series with the temperature sensor and the full-scale resistor is connected in series with the temperature sensor.

[0036] Preferably, the output status control unit includes a first output status control port, a second output status control port, and a third output status control port;

[0037] One end of the zero-point resistor is connected to the first output state control port, and the other end of the zero-point resistor is connected to the sampling port;

[0038] One end of the full-scale resistor is connected to the second output state control port, and the other end of the full-scale resistor is connected to the sampling port;

[0039] One end of the temperature sensor is connected to the third output status control port, and the other end of the temperature sensor is connected to the sampling port.

[0040] Preferably, the temperature sensor is a PT1000 temperature sensor;

[0041] The zero-point resistor is a precision resistor used as the zero point of the temperature measurement range, corresponding to the resistance value of the PT1000 temperature sensor at zero point.

[0042] The full-scale resistor is a precision resistor used to measure the full scale of the temperature range, corresponding to the resistance value of the PT1000 temperature sensor at full scale.

[0043] (III) Beneficial Effects

[0044] Compared with existing technologies, the high-precision temperature detection method and detection circuit provided by this invention outputs different states through various output state control ports, so that the temperature detection circuit is in the case of zero-point resistance and temperature sensor in series, and full-scale resistance and temperature sensor in series. The voltage signal under each case is collected, and the resistance value of the temperature sensor is calculated to eliminate power supply voltage reading error and linearity error within the range using the voltage signal. Thus, it can effectively eliminate related errors with low cost and simple circuit, obtain accurate temperature sensor resistance value, and then calculate accurate temperature value based on temperature sensor resistance value, effectively improving temperature measurement accuracy. Attached Figure Description

[0045] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the accompanying drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are merely some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without any creative effort.

[0046] Figure 1 This is a circuit diagram of the temperature detection circuit in this invention. Detailed Implementation

[0047] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0048] A high-precision temperature detection method is proposed. By controlling the output state of the zero-point resistor 5, the full-scale resistor 6, and the temperature sensor 7, different states are output, so that the temperature detection circuit is in the case where the zero-point resistor 5 is connected in series with the temperature sensor 7 and the full-scale resistor 6 is connected in series with the temperature sensor 7. The voltage signal under each case is collected, and the resistance value of the temperature sensor 7 is calculated to eliminate the power supply voltage reading error and the linearity error within the range. Finally, the temperature value corresponding to the resistance value of the temperature sensor 7 is calculated.

[0049] 1) By controlling the output states of the zero-point resistor 5, the full-scale resistor 6, and the temperature sensor 7, different states are output, so that the temperature detection circuit is in the case where the zero-point resistor 5 is connected in series with the temperature sensor 7 and the full-scale resistor 6 is connected in series with the temperature sensor 7, and the voltage signals under each case are collected, including:

[0050] The first output state control port 2 outputs power, the third output state control port 4 outputs ground, the second output state control port 3 outputs an open circuit, and the first voltage signal is collected from the sampling port 1. This first voltage signal is the voltage to ground after the temperature sensor 7 divides the zero-point resistor 5.

[0051] The first output state control port 2 outputs to ground, the third output state control port 4 outputs to power, the second output state control port 3 outputs to open circuit, and the second voltage signal is collected from the sampling port 1. This second voltage signal is the voltage to ground after the zero-point resistor 5 divides the temperature sensor 7.

[0052] The second output state control port 3 outputs power, the third output state control port 4 outputs ground, the first output state control port 2 outputs an open circuit, and the third voltage signal is collected from the sampling port 1. This third voltage signal is the voltage to ground after the temperature sensor 7 divides the voltage with the full-scale resistor 6.

[0053] The second output state control port 3 outputs to ground, the third output state control port 4 outputs to power, the first output state control port 2 outputs to open circuit, and the fourth voltage signal is acquired from the sampling port 1. This fourth voltage signal is the voltage to ground after the full-scale resistor 6 divides the temperature sensor 7.

[0054] The first output state control port 2, the second output state control port 3, and the third output state control port 4 are respectively connected to the ends of the zero-point resistor 5, the full-scale resistor 6, and the temperature sensor 7.

[0055] 2) Calculate the resistance of temperature sensor 7 using the voltage signal to eliminate power supply voltage reading errors and linearity errors within the measurement range, including:

[0056] The first voltage signal V1 is represented by the following formula:

[0057]

[0058] The second voltage signal V2 is represented by the following formula:

[0059]

[0060] The third voltage signal V3 is represented by the following formula:

[0061]

[0062] The fourth voltage signal V4 is represented by the following formula:

[0063]

[0064] Based on equations ① and ②, we obtain:

[0065]

[0066] Based on equations ③ and ④, we obtain:

[0067]

[0068] The resistance R of temperature sensor 7 after error elimination t Expressed as follows:

[0069]

[0070] Among them, R t0 This represents the resistance value R of temperature sensor 7 when zero-point resistor 5 is connected in series with temperature sensor 7. t1 R0 represents the resistance value of the temperature sensor 7 when the full-scale resistor 6 is connected in series with the temperature sensor 7. R1 represents the resistance value of the zero-point resistor 5, and VCC represents the resistance value of the full-scale resistor 6.

[0071] In the technical solution of the high-precision temperature detection method in this application, the temperature sensor 7 adopts a PT1000 temperature sensor, whose resistance changes with temperature. The current temperature value can be obtained by measuring its resistance.

[0072] Zero-point resistor 5 is a precision resistor used as the zero point of the temperature measurement range, corresponding to the resistance value of the PT1000 temperature sensor at zero point.

[0073] The full-scale resistor 6 is a precision resistor used for measuring the full scale of the temperature range, corresponding to the resistance value of the PT1000 temperature sensor at full scale.

[0074] A high-precision temperature detection circuit, such as Figure 1 As shown, it includes a zero-point resistor 5, a full-scale resistor 6, a temperature sensor 7, a sampling port 1, and an output status control unit connected to the ends of the zero-point resistor 5, the full-scale resistor 6, and the temperature sensor 7.

[0075] The output status control unit outputs different states, which makes the temperature detection circuit be in the case of zero-point resistor 5 connected in series with temperature sensor 7 and full-scale resistor 6 connected in series with temperature sensor 7.

[0076] Sampling port 1 is used to acquire the voltage signals of zero-point resistor 5, full-scale resistor 6, and temperature sensor 7 to ground when the temperature detection circuit is in the condition that the zero-point resistor 5 is connected in series with the temperature sensor 7 and the full-scale resistor 6 is connected in series with the temperature sensor 7.

[0077] The output status control unit includes a first output status control port 2, a second output status control port 3, and a third output status control port 4;

[0078] One end of the zero-point resistor 5 is connected to the first output state control port 2, and the other end of the zero-point resistor 5 is connected to the sampling port 1;

[0079] One end of the full-scale resistor 6 is connected to the second output state control port 3, and the other end of the full-scale resistor 6 is connected to the sampling port 1;

[0080] One end of the temperature sensor 7 is connected to the third output status control port 4, and the other end of the temperature sensor 7 is connected to the sampling port 1.

[0081] In the technical solution of the high-precision temperature detection circuit in this application, the temperature sensor 7 adopts a PT1000 temperature sensor, whose resistance changes with temperature. The current temperature value can be obtained by measuring its resistance.

[0082] Zero-point resistor 5 is a precision resistor used as the zero point of the temperature measurement range, corresponding to the resistance value of the PT1000 temperature sensor at zero point.

[0083] The full-scale resistor 6 is a precision resistor used for measuring the full scale of the temperature range, corresponding to the resistance value of the PT1000 temperature sensor at full scale.

[0084] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions will not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A high-precision temperature detection method, characterized in that: The different states are outputted by connecting each output state control port to the end of the zero point resistance (5), full scale resistance (6) and temperature sensor (7), so that the temperature detection circuit is in series connection of the zero point resistance (5) and temperature sensor (7) and series connection of the full scale resistance (6) and temperature sensor (7), and the voltage signals in each case are collected, and the resistance value of the temperature sensor (7) is calculated by using the voltage signals to eliminate the power voltage reading error and the linear error in the range, and finally the temperature value corresponding to the resistance value of the temperature sensor (7) is calculated; The different states are outputted by connecting each output state control port to the end of the zero point resistance (5), full scale resistance (6) and temperature sensor (7), so that the temperature detection circuit is in series connection of the zero point resistance (5) and temperature sensor (7) and series connection of the full scale resistance (6) and temperature sensor (7), and the voltage signals in each case are collected, and the resistance value of the temperature sensor (7) is calculated by using the voltage signals to eliminate the power voltage reading error and the linear error in the range, and finally the temperature value corresponding to the resistance value of the temperature sensor (7) is calculated; The first output state control port (2) outputs as a power supply, the third output state control port (4) outputs as ground, and the second output state control port (3) outputs as open circuit, and the first voltage signal is collected from the sampling port (1), which is the voltage of the temperature sensor (7) to the zero point resistance (5) divided by ground; The first output state control port (2) outputs as a power supply, the third output state control port (4) outputs as ground, and the second output state control port (3) outputs as open circuit, and the first voltage signal is collected from the sampling port (1), which is the voltage of the temperature sensor (7) to the zero point resistance (5) divided by ground; The second output state control port (3) outputs as a power supply, the third output state control port (4) outputs as ground, and the first output state control port (2) outputs as open circuit, and the third voltage signal is collected from the sampling port (1), which is the voltage of the temperature sensor (7) to the full scale resistance (6) divided by ground; The second output state control port (3) outputs as a power supply, the third output state control port (4) outputs as ground, and the first output state control port (2) outputs as open circuit, and the fourth voltage signal is collected from the sampling port (1), which is the voltage of the full scale resistance (6) to the temperature sensor (7) divided by ground; The first output state control port (2), the second output state control port (3) and the third output state control port (4) are respectively connected to the end of the zero point resistance (5), the full scale resistance (6) and the temperature sensor (7).

2. The high-precision temperature detection method of claim 1, wherein: The resistance value of the temperature sensor (7) is calculated by using the voltage signals to eliminate the power voltage reading error and the linear error in the range, including: The first voltage signal V1 is represented by the following formula: The second voltage signal V2 is represented by the following equation: The third voltage signal V3 is represented by the following equation: The fourth voltage signal V4 is expressed by the following equation: According to , Equation: According to , formula: the resistance R of the temperature sensor (7) after the error is eliminated t is expressed by the following equation: wherein R t0 represents the resistance value of the temperature sensor (7) measured when the zero point resistor (5) is connected in series with the temperature sensor (7), R t1 represents the resistance value of the temperature sensor (7) measured when the full scale resistor (6) is connected in series with the temperature sensor (7), R0 is the resistance value of the zero point resistor (5), R1 is the resistance value of the full scale resistor (6), and VCC is the power supply voltage.

3. The high-precision temperature detection method according to claim 1 or 2, characterized in that: The temperature sensor (7) is a PT1000 temperature sensor; The zero point resistance (5) is a precision resistance, which is used as the zero point of the temperature measurement range and corresponds to the resistance value when the PT1000 temperature sensor is at zero point; The full scale resistance (6) is a precision resistance, which is used as the full scale of the temperature measurement range and corresponds to the resistance value when the PT1000 temperature sensor is at full scale.

4. A detection circuit based on the high-precision temperature detection method of claim 1, characterized in that: The temperature detection circuit comprises a zero-point resistor (5), a full-scale resistor (6), a temperature sensor (7), a sampling port (1), and an output state control unit connected to the ends of the zero-point resistor (5), the full-scale resistor (6), and the temperature sensor (7); The output state control unit is configured to output different states so that the temperature detection circuit is in a state of the zero-point resistor (5) and the temperature sensor (7) being connected in series or the full-scale resistor (6) and the temperature sensor (7) being connected in series; The sampling port (1) is configured to collect voltage signals of the zero-point resistor (5), the full-scale resistor (6), and the temperature sensor (7) to ground in the state of the zero-point resistor (5) and the temperature sensor (7) being connected in series or the full-scale resistor (6) and the temperature sensor (7) being connected in series; The output state control unit comprises a first output state control port (2), a second output state control port (3), and a third output state control port (4); One end of the zero-point resistor (5) is connected to the first output state control port (2), and the other end of the zero-point resistor (5) is connected to the sampling port (1); One end of the full-scale resistor (6) is connected to the second output state control port (3), and the other end of the full-scale resistor (6) is connected to the sampling port (1); One end of the temperature sensor (7) is connected to the third output state control port (4), and the other end of the temperature sensor (7) is connected to the sampling port (1).

5. The high-precision temperature detection circuit of claim 4, wherein: The temperature sensor (7) is a PT1000 temperature sensor; The zero-point resistor (5) is a precision resistor used as a zero point of a temperature measurement range and corresponding to a resistance value of the PT1000 temperature sensor at a zero point; The full-scale resistor (6) is a precision resistor used as a full scale of the temperature measurement range and corresponding to a resistance value of the PT1000 temperature sensor at a full scale.

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