A platinum resistance temperature measurement method and temperature measurement device

Abstract

The present invention discloses a platinum resistance temperature measurement method and a temperature measurement device, which belongs to the field of temperature measurement technology and solves the problem that the existing platinum resistance temperature measurement method has high hardware requirements and complex calculation process. The temperature measurement method includes: obtaining the resistance value R of the platinum resistance temperature sensor in the platinum resistance temperature measurement circuit; t According to the formula T0=(R t / R0‑1) / A, solve to get the resistance value R t Corresponding temperature approximation T0: Perform regression correction on the temperature approximation T0; the regression correction process includes: setting the initial value of i to 0, and according to the formula δ i =B|T i | 2 Get the quadratic term value δ during the i-th regression correction i According to the formula T i+1 =(R t / R0‑1+|δ i |) / A obtains the temperature value T obtained by the i+1th regression correction i+1 ; If |T i+1 ‑T i |≤T th If the regression correction process is completed, the resistance value of the platinum resistance temperature sensor R t The corresponding temperature measurement value is T i+1 Otherwise, i=i+1, and jump to the formula (2) to obtain the quadratic term value δ at the time of the i-th regression correction i steps.

Description

Technical Field

[0001] The present invention relates to the technical field of temperature measurement, and in particular to a platinum resistance temperature measurement method and a temperature measurement device. Background Art

[0002] Platinum resistance temperature measurement is a common temperature measurement method. Its working principle is that the resistance value of a platinum resistor changes with temperature and shows a certain functional relationship. By measuring its resistance value, the temperature of the object being measured can be inferred. As the temperature rises, the resistance value of the platinum resistance temperature sensor increases; as the temperature drops, the resistance value of the platinum resistance temperature sensor decreases. Common platinum resistance temperature sensors include PT1000 and PT100. Among them, PT1000 has higher measurement accuracy than PT100. Platinum resistance temperature measurement methods include the following two:

[0003] 1. Formula calculation method

[0004] The corresponding relationship between temperature and resistance of PT1000 and PT100 platinum resistance temperature sensors can be expressed as:

[0005] When the temperature range is -200℃ to 0℃, the following formula is used to calculate the resistance:

[0006] R t =R0[1+At+Bt 2 +C(t-100℃)t h ] (1)

[0007] When the temperature range is 0℃ to 850℃, the following formula is used to calculate the resistance:

[0008] R t =R0[1+At+Bt 2 ] (2)

[0009] Among them, R t is the resistance value at temperature t℃, R0 is the resistance value at temperature 0℃, t is the temperature variable in ℃;

[0010] The resistance value R0 of a PT1000 temperature sensor at 0°C is 1KΩ, and the resistance value R0 of a PT100 temperature sensor at 0°C is 100Ω. Taking the PT1000 temperature sensor as an example, IEC 60751 stipulates that A, B, and C are constants, and their values ​​are: A = 3.9083 × 10 -3 , B=-5.775×10 -7 , C = -4.183 × 10 -12 The schematic diagram of the relationship between temperature and resistance curve is as follows: Figure 1As shown in the formula, in the range of 0℃ to 850℃, the relationship between temperature and thermal resistance presents a quadratic curve characteristic. After measuring the resistance value, the corresponding temperature value can be calculated by solving the quadratic equation.

[0011] The disadvantages of this method are: the process of solving quadratic equations is relatively cumbersome and the amount of calculation is too large, the processing power of the microcontroller is limited, the calculation process is time-consuming and will generate high power consumption, and the program writing is also quite complicated.

[0012] 2. Lookup table method

[0013] The specific resistance value of the platinum resistance temperature sensor within the set temperature range is stored, and the temperature value is obtained by comparing and judging the table. Taking the PT1000 temperature sensor as an example, the PT1000 resistance temperature table (0-100℃) is as follows: Figure 2 shown.

[0014] The drawback of this method is that it requires the MCU's FLASH memory to store the resistance-temperature table. However, a calibration point must be taken every degree Celsius, which requires sufficient FLASH memory space and is relatively complex to calculate.

[0015] How to solve the defects of the above two platinum resistance temperature measurement methods is an urgent problem to be solved. Summary of the Invention

[0016] In view of the above analysis, the embodiments of the present invention aim to provide a platinum resistance temperature measurement method and a temperature measurement device to solve the problems of high hardware requirements and complex calculation process of the existing platinum resistance temperature measurement method.

[0017] In one aspect, a platinum resistance temperature measurement method is disclosed, comprising:

[0018] Get the resistance value R of the platinum resistance temperature sensor in the platinum resistance temperature measurement circuit t ;

[0019] According to formula (1), the resistance value R is obtained t The corresponding temperature approximation T0 is:

[0020] T0=(R t / R0-1) / A (1)

[0021] Perform regression correction on the temperature approximation T0; the regression correction process includes:

[0022] Set the initial value of i to 0,

[0023] According to formula (2), the quadratic term value δ of the i-th regression correction is obtained i :

[0024] δi =B|T i | 2 (2)

[0025] According to formula (3), the temperature value T obtained by the i+1th regression correction is obtained i+1 :

[0026] T i+1 =(R t / R0-1+|δ i |) / A (3)

[0027] If |T i+1 -T i |≤T th If the regression correction process is completed, the resistance value of the platinum resistance temperature sensor R t The corresponding temperature measurement value is T i+1 Otherwise, i=i+1, and jump to the formula (2) to obtain the quadratic term value δ at the time of the i-th regression correction i Steps;

[0028] Among them, R0 represents the resistance value of the platinum resistance temperature sensor when the temperature is 0℃, A and B represent the linear coefficient and quadratic coefficient respectively, T th Indicates the temperature deviation threshold.

[0029] On the basis of the above solution, the present invention also makes the following improvements:

[0030] Furthermore, the platinum resistance temperature sensor is PT1000 or PT100.

[0031] Furthermore, the maximum temperature measurement range of the temperature measurement method is 0°C to 850°C.

[0032] Furthermore, when the platinum resistance temperature sensor is PT1000, A=3.9083×10 -3 , B=-5.775×10 -7 .

[0033] In another aspect, the present invention discloses a platinum resistance temperature measuring device, comprising:

[0034] A platinum resistance temperature measurement circuit is used to output a voltage related to the temperature change of the platinum resistance temperature sensor;

[0035] a resistance value determination module, configured to obtain the resistance value of a platinum resistance temperature sensor in the platinum resistance temperature measurement circuit based on the voltage output by the platinum resistance temperature measurement circuit;

[0036] The platinum resistance temperature measurement module is used to solve the temperature approximate value corresponding to the resistance value, perform regression correction on the temperature approximate value, and use the temperature value after regression correction as the temperature measurement value corresponding to the resistance value.

[0037] Based on the above solution, the following improvements are made:

[0038] Furthermore, in the platinum resistance temperature measurement module, the following steps are performed:

[0039] According to formula (1), the resistance value R of the platinum resistance temperature sensor is obtained t The corresponding temperature approximation T0 is:

[0040] T0=(R t / R0-1) / A (1)

[0041] Perform regression correction on the temperature approximation T0; the regression correction process includes:

[0042] Set the initial value of i to 0,

[0043] According to formula (2), the quadratic term value δ of the i-th regression correction is obtained i :

[0044] δ i =B|T i | 2 (2)

[0045] According to formula (3), the temperature value T obtained by the i+1th regression correction is obtained i+1 :

[0046] T i+1 =(R t / R0-1+|δ i |) / A (3)

[0047] If |T i+1 -T i |≤T th If the regression correction process is completed, the resistance value of the platinum resistance temperature sensor R t The corresponding temperature measurement value is T i+1 Otherwise, i=i+1, and jump to the formula (2) to obtain the quadratic term value δ at the time of the i-th regression correction i Steps;

[0048] Among them, R0 represents the resistance value of the platinum resistance temperature sensor when the temperature is 0℃, A and B represent the linear coefficient and quadratic coefficient respectively, T th Indicates the temperature deviation threshold.

[0049] Furthermore, the platinum resistance temperature measurement circuit includes: resistor R15, resistor R16, resistor R17, resistor R18, resistor R20, resistor R21, capacitor C19, capacitor C20, capacitor C21 and differential amplifier U1; wherein, one end of the platinum resistance temperature sensor J5 is grounded and the other end is connected to one end of the resistor R16, and the other end of the resistor R16 is connected to the power supply VCC_2V5; one end of the resistor R17 is connected to VCC_2V5 and the other end is connected to one end of the resistor R18, and the other end of the resistor R18 is grounded;

[0050] One end of the resistor R16 is connected in series with a resistor R20 and then connected to the non-inverting input of the differential amplifier U1. The other end of the resistor R17 is connected in series with a resistor R15 and then connected to the inverting input of the differential amplifier U1. A capacitor C19 is also connected in parallel between the inverting input and the non-inverting input of the differential amplifier U1. The -Vs pin of the differential amplifier U1 is connected to the REF pin and grounded. The Vs pin of the differential amplifier U1 is connected to the power supply VCC_3V3. Capacitors C20 and C21 are connected in parallel between the power supply VCC_3V3 and ground. A resistor R21 is connected in series between the RG pin and the -RG pin of the differential amplifier U1.

[0051] A voltage related to the temperature change of the platinum resistance temperature sensor is outputted through the output terminal of the differential amplifier U1.

[0052] Furthermore, the resistance values ​​of resistors R16 and R17 are equal, the resistance value of resistor R18 is equal to R0, the resistance values ​​of resistors R15 and R20 are equal, and resistor R21 is an amplifier gain resistor;

[0053] The resistors R15 , R16 , R17 , R18 , R20 , R21 and the differential amplifier U1 are selected to match the temperature measurement range of the platinum resistance temperature sensor.

[0054] Furthermore, in the resistance value determination module, the resistance value of the platinum resistance temperature sensor in the platinum resistance temperature measurement circuit is calculated based on the voltage output by the platinum resistance temperature measurement circuit and the voltage division relationship of each resistor in the platinum resistance temperature measurement circuit.

[0055] Furthermore, the resistance value determination module and the platinum resistance temperature measurement module are arranged in a single chip microcomputer.

[0056] Compared with the prior art, the present invention can achieve at least one of the following beneficial effects:

[0057] The platinum resistance temperature measurement method and temperature measurement device provided by the present invention have the following effects:

[0058] It can achieve approximate calculations for platinum resistance temperature measurement while meeting accuracy requirements, effectively reducing storage space usage and shortening calculation time. It can effectively calculate the resistance value of platinum resistance, reducing the difficulty of calculation while ensuring high accuracy.

[0059] In the present invention, the above-mentioned technical solutions can be combined with each other to achieve more preferred combinations. Other features and advantages of the present invention will be described in the following description, and some advantages will become apparent from the description or be learned through practice of the present invention. The objectives and other advantages of the present invention can be realized and obtained through the contents particularly pointed out in the description and drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0060] The accompanying drawings are only for the purpose of illustrating particular embodiments and are not to be considered limiting of the present invention. Like reference symbols denote like parts throughout the drawings.

[0061] Figure 1 This is a diagram showing the relationship between the temperature and resistance curve of the PT100 temperature sensor;

[0062] Figure 2 It is a PT1000 resistance temperature meter (0-100℃).

[0063] Figure 3 Flowchart of the platinum resistance temperature measurement method provided by an embodiment of the present invention;

[0064] Figure 4 A schematic structural diagram of a platinum resistance temperature measuring device provided in an embodiment of the present invention;

[0065] Figure 5 This is a platinum resistance temperature measurement circuit diagram provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0066] The preferred embodiments of the present invention will be described in detail below in conjunction with the accompanying drawings, wherein the accompanying drawings constitute a part of this application and are used together with the embodiments of the present invention to illustrate the principles of the present invention, and are not used to limit the scope of the present invention.

[0067] Example 1

[0068] Specific embodiment 1 of the present invention discloses a platinum resistance temperature measurement method, the flow chart is as follows Figure 3 As shown, the temperature measurement method includes:

[0069] Step S1: Obtain the resistance value R of the platinum resistance temperature sensor in the platinum resistance temperature measurement circuit t ;

[0070] Step S2: According to formula (3), solve and obtain the resistance value R tThe corresponding temperature approximation T0 is:

[0071] T0=(R t / R0-1) / A (3)

[0072] Step S3: performing regression correction on the temperature approximation value T0; the regression correction process includes:

[0073] Step S31: Set the initial value of i to 0,

[0074] Step S32: Obtain the quadratic term value δ during the i-th regression correction according to formula (4) i :

[0075] δ i =B|T i | 2 (4)

[0076] Step S3: Obtain the temperature value T obtained by the i+1th regression correction according to formula (5) i+1 :

[0077] T i+1 =(R t / R0-1+|δ i |) / A (5)

[0078] Step S34: If |T i+1 -T i |≤T th If the regression correction process is completed, the resistance value of the platinum resistance temperature sensor R t The corresponding temperature measurement value is T i+1 Otherwise, i=i+1, and jump to obtain the quadratic term value δ when the i-th regression correction is obtained according to formula (3) i (i.e., jump to step S32);

[0079] Among them, R0 represents the resistance value of the platinum resistance temperature sensor when the temperature is 0℃, A and B represent the linear coefficient and quadratic coefficient respectively, T th Indicates the temperature deviation threshold.

[0080] Preferably, the platinum resistance temperature sensor is PT1000 or PT100.

[0081] The following describes the formation process of the above steps:

[0082] The common temperature range is 0°C to 100°C. In this case, formula (2) in the background technology needs to be used. To avoid directly solving the quadratic equation, this embodiment proposes the following ideas:

[0083] First, remove the quadratic term in formula (2) to reduce the quadratic equation to a linear equation, and solve the temperature T0 according to formula (3);

[0084] Obviously, there is a large error between the temperature T0 and the actual temperature value obtained by directly solving formula (2). The quadratic term omitted in formula (3) is taken as a constant term, that is, δ0 is calculated according to formula (4). The temperature is recalculated based on the calculated δ0. At this time, formula (3) becomes formula (5).

[0085] It can be seen from this that omitting the quadratic term will make the calculated T0 value smaller than the actual temperature value, and the larger the actual temperature value, the greater the error. In order to ensure that the temperature near 0℃ and 100℃ still has a high accuracy, the measured temperature accuracy can be improved through multiple regression corrections, which can meet the high precision requirements within the required temperature range.

[0086] Since the idea proposed in this embodiment is implemented based on formula (2) in the background technology, the temperature measurement range of the temperature measurement method satisfies the maximum temperature range applicable to formula (2), which is 0°C to 850°C. Accordingly, the parameters (R0, A and B) involved in formula (2) are also directly used in the temperature measurement formula in this embodiment.

[0087] It should be noted that the temperature deviation threshold T in this embodiment is th It depends on the accuracy requirements in different application scenarios. Accordingly, the number of corrections in different application scenarios may also be different. For example, when the temperature deviation threshold T th When 0.5℃ is taken, the temperature range accuracy is required to be ±0.5℃. According to actual tests, 3-5 corrections can meet the requirements. When the temperature deviation threshold T th When taking 0.2℃, the temperature range accuracy is required to be ±0.2℃, and more than 10 corrections are required to meet the accuracy requirements.

[0088] Compared with existing technologies, the platinum resistance temperature measurement method provided in this embodiment can achieve approximate calculations of platinum resistance temperature measurements while meeting accuracy requirements, effectively reducing storage space usage and computation time. This method can effectively calculate the resistance value of a platinum resistance, reducing computational complexity while ensuring high accuracy.

[0089] Example 2

[0090] Example 2 of the present invention discloses a platinum resistance temperature measuring device, the structural diagram of which is shown in FIG. Figure 4 As shown, the device includes:

[0091] A platinum resistance temperature measurement circuit is used to output a voltage related to the temperature change of the platinum resistance temperature sensor;

[0092] a resistance value determination module, configured to obtain the resistance value of a platinum resistance temperature sensor in the platinum resistance temperature measurement circuit based on the voltage output by the platinum resistance temperature measurement circuit;

[0093] The platinum resistance temperature measurement module is used to solve the temperature approximate value corresponding to the resistance value, perform regression correction on the temperature approximate value, and use the temperature value after regression correction as the temperature measurement value corresponding to the resistance value.

[0094] Specifically, in the platinum resistance temperature measuring device provided in this embodiment, the platinum resistance temperature measuring circuit is as follows: Figure 5 As shown, it includes: resistor R15, resistor R16, resistor R17, resistor R18, resistor R20, resistor R21, capacitor C19, capacitor C20, capacitor C21 and differential amplifier U1; wherein, one end of the platinum resistance temperature sensor J5 is grounded and the other end is connected to one end of the resistor R16, and the other end of the resistor R16 is connected to the power supply VCC_2V5; one end of the resistor R17 is connected to VCC_2V5 and the other end is connected to one end of the resistor R18, and the other end of the resistor R18 is grounded; one end of the resistor R16 is connected in series with the resistor R20 and then connected to the non-inverting input end of the differential amplifier U1, The other end of resistor R17 is connected in series with resistor R15 and then to the inverting input of differential amplifier U1. A capacitor C19 is also connected in parallel between the inverting and non-inverting inputs of differential amplifier U1. The -Vs pin of differential amplifier U1 is connected to the REF pin and ground, and the Vs pin of differential amplifier U1 is connected to power supply VCC_3V3. Capacitors C20 and C21 are connected in parallel between power supply VCC_3V3 and ground. A resistor R21 is connected in series between the RG and -RG pins of differential amplifier U1. A voltage related to the temperature change of the platinum resistance temperature sensor is output through the output of differential amplifier U1. Resistors R16 and R17 have equal resistance values. Resistors R18 have a resistance value equal to R0. Resistors R15 and R20 have equal resistance values. In this circuit, J5 represents a two-wire platinum resistance temperature sensor. Resistors R16, R17, and R18, along with J5, form a Wheatstone bridge. Since resistors R16, R17, and R18 are fixed resistors, typically using 1 / 1000 precision and low temperature drift, the resistance of J5's platinum resistance temperature sensor also changes with temperature. When the resistance of J5's platinum resistance temperature sensor changes, a potential difference is generated at the test terminals, which is used to calculate the temperature. Resistors R15 and R20 are balancing resistors. U1 is an AD623 differential amplifier. Capacitors C19, C20, and C21 are filter capacitors. Resistor R21 is the amplifier gain resistor. Adjusting the value of resistor R21 changes the amplifier's gain. Connect U1's 6-pin ADC_PT pin to the microcontroller's ADC pin.

[0095] The selection of resistors R15, R16, R17, R18, R20, R21, and the differential amplifier U1 matches the temperature measurement range of the platinum resistance temperature sensor. For example, platinum resistance sensors are commonly used for supply and return water temperature measurement. The supply water temperature of the secondary network is generally designed to be 60-75°C, and the return water temperature is generally designed to be 35-50°C. In thermal secondary pipe network applications, high-precision measurement can be guaranteed within the range of 0-100°C. Therefore, by configuring the resistance values ​​of resistors R16, R17, R18, and R21, the change of platinum resistance with temperature in each temperature range can be measured. For example, according to the AD623 differential amplifier chip manual, the gain resistor R21 of the differential amplifier is 4.7K, that is, the differential amplifier amplification factor is G = (1 + 100 / 4.7) ≈ 22.3.

[0096] When the resistance of the J5 platinum resistance temperature sensor is 1KΩ, the Wheatstone bridge composed of resistors R16, R17, R18 and J5 is balanced, and the differential voltage entering the differential amplifier is 0. Figure 2 From the table, we can see that when the resistance value of J5 platinum resistance temperature sensor is 1KΩ, the corresponding temperature is 0℃.

[0097] The differential amplifier is powered by 3.3V and can output a maximum voltage of 3.3V. Since the amplification factor G of the differential amplifier is calculated to be 22.3 times, the maximum differential input voltage of the differential amplifier is 300 / 22.3≈148.0mV. The voltage divided by resistors R17 and R18 enters the "-" pin of the differential amplifier, and the voltage is 2500*(1000 / 1365)≈1831.5mV. In order to achieve the effect of the differential amplifier outputting 3.3V, it is necessary to ensure that the voltage entering the "+" pin of the differential amplifier is 1831.5+148.0=1979.5mV. That is, the voltage divided by resistors R16 and J5 is 1979.5mV, 2500*[R t / (R t +365)]=1979.5, calculate R t ≈1388.1Ω. Figure 2 From the table, we can see that the temperature of PT1000 platinum resistor is 1385Ω at 100℃.

[0098] From the above calculation, we can know that the circuit can measure the resistance of PT1000 platinum resistance sensor from 1000Ω to 1388.1Ω. Figure 2 The converted corresponding temperature is 0~100℃.

[0099] In the resistance determination module, the resistance value of the platinum resistance temperature sensor in the platinum resistance temperature measurement circuit is calculated based on the voltage output by the platinum resistance temperature measurement circuit and the voltage division relationship between the resistors in the platinum resistance temperature measurement circuit.

[0100] J5 platinum resistance value R t satisfy:

[0101] VCC_2V5*1000*[R t / (R t +R16)-R17 / (R17+R18)]*(1+100 / R21)=V_ADC

[0102] In this embodiment, VCC_2V5 is 2.5V; V_ADC is the voltage output by the platinum resistance temperature measurement circuit, in mV, with a value range of 0-3300mV. When the voltage output by V_ADC is 0mV, the R t is the minimum value of the platinum resistor; when the voltage output by V_ADC is 3300mV, the R t is the maximum value of the platinum resistance.

[0103] The platinum resistance temperature measurement module includes:

[0104] According to formula (6), the resistance value R of the platinum resistance temperature sensor is obtained t The corresponding temperature approximation T0 is:

[0105] T0=(R t / R0-1) / A (6)

[0106] Perform regression correction on the temperature approximation T0; the regression correction process includes:

[0107] Set the initial value of i to 0,

[0108] According to formula (7), the quadratic term value δ of the i-th regression correction is obtained i :

[0109] δ i =B|T i | 2 (7)

[0110] According to formula (8), the temperature value T obtained by the i+1th regression correction is obtained i+1 :

[0111] T i+1 =(R t / R0-1+|δ i |) / A (8)

[0112] If |Ti+1 -T i |≤T th If the regression correction process is completed, the resistance value of the platinum resistance temperature sensor R t The corresponding temperature measurement value is T i+1 Otherwise, i=i+1, and jump to the formula (7) to obtain the quadratic term value δ at the time of the i-th regression correction i Steps;

[0113] Among them, R0 represents the resistance value of the platinum resistance temperature sensor when the temperature is 0℃, A and B represent the linear coefficient and quadratic coefficient respectively, T th Indicates the temperature deviation threshold.

[0114] Preferably, in actual application, in order to save storage space, the resistance value determination module and the platinum resistance temperature measurement module are set in a single chip microcomputer.

[0115] In summary, the above method embodiments and device embodiments are based on the same principle, their related aspects can be referenced from each other, and can achieve the same technical effects.

[0116] Those skilled in the art will appreciate that all or part of the processes of the methods and apparatuses of the above embodiments can be implemented by instructing related hardware through a computer program, and the program can be stored in a computer-readable storage medium, such as a magnetic disk, an optical disk, a read-only memory, or a random access memory.

[0117] The above description is only a preferred specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by any technician familiar with this technical field within the technical scope disclosed in the present invention should be covered by the scope of protection of the present invention.

Claims

1. A platinum resistance temperature measurement method, characterized in that: The temperature measurement method comprises: Get the resistance value R of the platinum resistance temperature sensor in the platinum resistance temperature measurement circuit t ; According to formula (1), the resistance value R is obtained t The corresponding temperature approximation T0 is: T0=(R t / R0-1) / A (1) Perform regression correction on the temperature approximation T0; the regression correction process includes: Set the initial value of i to 0, According to formula (2), the quadratic term value δ of the i-th regression correction is obtained i : d i =B|T i | 2 (2) According to formula (3), the temperature value T obtained by the i+1th regression correction is obtained i+1 : T i+1 =(R t / R0-1+|δ i |) / A (3) If |T i+1 -T i |≤T th If the regression correction process is completed, the resistance value of the platinum resistance temperature sensor R t The corresponding temperature measurement value is T i+1 Otherwise, i=i+1, and jump to the formula (2) to obtain the quadratic term value δ at the time of the i-th regression correction i Steps; Among them, R0 represents the resistance value of the platinum resistance temperature sensor when the temperature is 0℃, A and B represent the linear coefficient and quadratic coefficient respectively, T th Indicates the temperature deviation threshold.

2. The platinum resistance temperature measurement method according to claim 1, wherein: The platinum resistance temperature sensor is PT1000 or PT100.

3. The platinum resistance temperature measurement method according to claim 2, characterized in that: The maximum temperature measurement range of the temperature measurement method is 0°C to 850°C.

4. The platinum resistance temperature measurement method according to claim 2, characterized in that: When the platinum resistance temperature sensor is PT1000, A=3.9083×10 -3 , B=-5.775×10 -7 .

5. A platinum resistance temperature measuring device, characterized in that: The device comprises: A platinum resistance temperature measurement circuit is used to output a voltage related to the temperature change of the platinum resistance temperature sensor; a resistance value determination module, configured to obtain the resistance value of a platinum resistance temperature sensor in the platinum resistance temperature measurement circuit based on the voltage output by the platinum resistance temperature measurement circuit; A platinum resistance temperature measurement module, configured to calculate an approximate temperature value corresponding to the resistance value, perform regression correction on the approximate temperature value, and use the temperature value after regression correction as the temperature measurement value corresponding to the resistance value; In the platinum resistance temperature measurement module, the following steps are performed: According to formula (1), the resistance value R of the platinum resistance temperature sensor is obtained t The corresponding temperature approximation T0 is: T0=(R t / R0-1) / A (1) Perform regression correction on the temperature approximation T0; the regression correction process includes: Set the initial value of i to 0, According to formula (2), the quadratic term value δ of the i-th regression correction is obtained i : d i =B|T i | 2 (2) According to formula (3), the temperature value T obtained by the i+1th regression correction is obtained i+1 : T i+1 =(R t / R0-1+|δ i |) / A (3) If |T i+1 -T i |≤T th If the regression correction process is completed, the resistance value of the platinum resistance temperature sensor R t The corresponding temperature measurement value is T i+1 Otherwise, i=i+1, and jump to the formula (2) to obtain the quadratic term value δ at the time of the i-th regression correction i Steps; Among them, R0 represents the resistance value of the platinum resistance temperature sensor when the temperature is 0℃, A and B represent the linear coefficient and quadratic coefficient respectively, T th Indicates the temperature deviation threshold.

6. The platinum resistance temperature measuring device according to claim 5, characterized in that: The platinum resistance temperature measurement circuit includes: a resistor R15, a resistor R16, a resistor R17, a resistor R18, a resistor R20, a resistor R21, a capacitor C19, a capacitor C20, a capacitor C21 and a differential amplifier U1; wherein, one end of the platinum resistance temperature sensor J5 is grounded and the other end is connected to one end of the resistor R16, and the other end of the resistor R16 is connected to the power supply VCC_2V5; one end of the resistor R17 is connected to VCC_2V5 and the other end is connected to one end of the resistor R18, and the other end of the resistor R18 is grounded; One end of the resistor R16 is connected in series with a resistor R20 and then connected to the non-inverting input of the differential amplifier U1. The other end of the resistor R17 is connected in series with a resistor R15 and then connected to the inverting input of the differential amplifier U1. A capacitor C19 is also connected in parallel between the inverting input and the non-inverting input of the differential amplifier U1. The -Vs pin of the differential amplifier U1 is connected to the REF pin and grounded. The Vs pin of the differential amplifier U1 is connected to the power supply VCC_3V3. Capacitors C20 and C21 are connected in parallel between the power supply VCC_3V3 and ground. A resistor R21 is connected in series between the RG pin and the -RG pin of the differential amplifier U1. A voltage related to the temperature change of the platinum resistance temperature sensor is outputted through the output terminal of the differential amplifier U1.

7. The platinum resistance temperature measuring device according to claim 6, characterized in that: The resistance values ​​of resistors R16 and R17 are equal, the resistance value of resistor R18 is equal to R0, the resistance values ​​of resistors R15 and R20 are equal, and resistor R21 is the amplifier gain resistor; The resistors R15 , R16 , R17 , R18 , R20 , R21 and the differential amplifier U1 are selected to match the temperature measurement range of the platinum resistance temperature sensor.

8. The platinum resistance temperature measuring device according to claim 6, characterized in that: In the resistance determination module, the resistance value of the platinum resistance temperature sensor in the platinum resistance temperature measurement circuit is calculated based on the voltage output by the platinum resistance temperature measurement circuit and the voltage division relationship between the resistors in the platinum resistance temperature measurement circuit.

9. The platinum resistance temperature measuring device according to any one of claims 5 to 8, characterized in that: The resistance value determination module and the platinum resistance temperature measurement module are arranged in a single chip microcomputer.

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