CN-122016071-A - High-precision calibration-free PT1000 measurement method, device and system

CN122016071ACN 122016071 ACN122016071 ACN 122016071ACN-122016071-A

Abstract

The invention relates to the technical field of temperature measurement and discloses a high-precision calibration-free PT1000 measurement method, device and system. According to the method, a voltage signal and a reference voltage signal of the PT1000 are respectively obtained through a voltage dividing branch and a reference voltage branch which are formed by a high-precision reference source and a precision resistor, and after differential amplification and analog-digital conversion, a real-time resistance value of the PT1000 is calculated by a processing unit. Finally, a pre-stored PT1000 standard graduation table is inquired, and an interpolation algorithm is adopted to obtain a high-resolution temperature measurement value. According to the scheme, complicated on-site calibration procedures are avoided through high-stability hardware design and a standard table lookup algorithm, and high-precision and high-stability temperature measurement in a wide temperature range is realized.

Inventors

HUANG PAN
SUN YAN
WANG GUOYU
CHEN GUIFEI
CHEN YOUFENG
YU FENG
LIU GUOPENG
WANG HUIYAN

Assignees

南京米特科技股份有限公司

Dates

Publication Date: 20260512
Application Date: 20260415

Claims (9)

1. A high-precision calibration-free PT1000 measurement method, comprising: A first voltage signal at the upper end of the PT1000 platinum resistance sensor is obtained through a voltage dividing branch formed by connecting a first reference voltage source, a first voltage dividing resistor and the PT1000 platinum resistance sensor in series; Acquiring a reference voltage signal through a reference voltage branch formed by connecting a first reference voltage source, a second voltage dividing resistor and a reference resistor in series; Amplifying the difference value between the first voltage signal and the reference voltage signal by utilizing a differential amplifying circuit to obtain a conditioned second voltage signal; Li Yongyi the second reference voltage source is an analog-to-digital converter for converting the second voltage signal into a digital signal; Based on the digital signals and circuit parameters, calculating the real-time resistance value of the PT1000 platinum resistance sensor; comparing the calculated real-time resistance value with a pre-stored PT1000 standard graduation table, directly outputting a corresponding temperature measurement value when the real-time resistance value is equal to the standard resistance value in the PT1000 standard graduation table, and obtaining the temperature measurement value through interpolation calculation when the real-time resistance value is not equal to the standard resistance value in the PT1000 standard graduation table.
2. The method of claim 1, wherein the reference voltage signal is a voltage division point voltage of the first reference voltage source on a branch of the second voltage division resistor and the reference resistor in series.
3. The method of claim 2, wherein the reference voltage signal is buffered by a voltage buffer and then input to an inverting input terminal of the differential amplifier circuit.
4. The method of claim 1, wherein the circuit parameters include a voltage value of the first reference voltage source, a voltage value of the second reference voltage source, a resistance value of the first voltage dividing resistor, a resistance value of the reference resistor, and an amplification factor of the differential amplifying circuit.
5. The high-precision calibration-free PT1000 measuring method of claim 4, wherein the pre-stored PT1000 standard graduation table is a temperature-resistance correspondence table generated according to IEC60751 standard at intervals of 0.1 ℃.
6. The method of high accuracy calibration-free PT1000 measurement of claim 5, wherein interpolating the calculated temperature measurements comprises: When the real-time resistance value is between the first standard resistance value and the second standard resistance value corresponding to the adjacent first standard temperature point and the second standard temperature point in the standard graduation table, calculating a temperature measurement value according to the first standard temperature point and the second standard temperature point by adopting a linear interpolation formula.
7. The high-accuracy calibration-free PT1000 measurement method of claim 6, wherein the linear interpolation formula is: Wherein, the As a measure of the temperature of the material, 、 Is a first standard temperature point and a second standard temperature point, 、 The first standard resistance value and the second standard resistance value corresponding to the first standard temperature point and the second standard temperature point, Is the real-time resistance value.
8. A high-precision calibration-free PT1000 measurement apparatus for implementing a high-precision calibration-free PT1000 measurement method as claimed in any one of claims 1 to 7, comprising: The voltage dividing and exciting unit comprises a first reference voltage source, wherein the first reference voltage source is connected with the PT1000 platinum resistance sensor in series through a first voltage dividing resistor to form a voltage dividing branch; The signal conditioning unit comprises a reference voltage generation branch and a differential amplification circuit, wherein the reference voltage generation branch is formed by connecting a first reference voltage source, a second voltage dividing resistor and a reference resistor in series, and the differential amplification circuit is used for amplifying the difference value between the voltage at the upper end of a PT1000 platinum resistance sensor in the voltage dividing branch and the voltage of the voltage dividing point of the reference voltage generation branch; The input end of the analog-to-digital conversion unit is connected with the output end of the signal conditioning unit, and the reference voltage of the analog-to-digital conversion unit is provided by a second reference voltage source; The intelligent calculation processing unit is connected with the analog-to-digital conversion unit and is used for calculating the real-time resistance value of the PT1000 platinum resistance sensor according to the digital signals and the circuit parameters output by the analog-to-digital conversion unit and obtaining a temperature measured value through interpolation calculation based on a pre-stored PT1000 standard graduation table.
9. A high-precision calibration-free PT1000 measurement system comprising a high-precision calibration-free PT1000 measurement device as set forth in claim 8, and a host computer or management system communicatively coupled to the measurement device.

Description

High-precision calibration-free PT1000 measurement method, device and system Technical Field The invention relates to the technical field of temperature measurement, in particular to a high-precision calibration-free PT1000 measurement method, device and system. Background In the field of industrial temperature measurement, platinum resistors (such as PT100 and PT 1000) are widely used due to the characteristics of good stability and high precision, such as charging piles, which are commonly used for temperature measurement by PT1000, and the difference between the requirements of some standards on the temperature measurement of the anode and the cathode in the gun head is less than 5 ℃. Although the temperature-resistance relationship of PT1000 follows the CALLENDAR-Van Dusen equation defined by the IEC 60751 standard, the equation is computationally complex. The invention constructs an ideal measuring hardware system with negligible error by adopting a reference source, an operational amplifier and a resistor with ultra-high precision and low temperature drift. The system directly measures the accurate resistance value of the platinum resistor, and obtains the temperature value by inquiring an IEC standard graduation table completely consistent with the formula and combining an interpolation algorithm. The method avoids the real-time calculation of complex formulas, avoids the complicated procedures of calibrating the field temperature points of the whole system, and realizes the unification of high precision and calibration-free in principle. In order to accurately and reversely derive the temperature value from the measured resistance value, the prior art mainly relies on a calibration procedure: 1. the two-point calibration method is to measure the resistance of the platinum resistor at two known temperature points (such as 0 ℃ for ice-water mixture and 100 ℃ for boiling water) and establish a linear equation. This approach ignores the nonlinearity of the platinum resistance characteristics and introduces significant errors over a wide temperature range. Calibration is essentially compensation for the overall systematic error of the sensor and measurement circuitry. 2. The multipoint calibration method is to measure at a plurality of temperature points and approach the real characteristics through piecewise linear fitting or higher order curve fitting. The method has higher precision, but requires complex calibration flow and more calibration time, which results in increased production cost and reduced production efficiency. In either method, calibration of the physical temperature point needs to be performed on the production or use site, the process is complicated, and the calibration accuracy is affected by the calibration equipment and the environment. Therefore, there is a strong need for a technical solution that can achieve high-precision measurement in a wide temperature range without performing complex calibration on site. Disclosure of Invention Aiming at the technical defects, the invention aims to provide a high-precision calibration-free PT1000 measuring method, device and system, and solves the problems of limited precision, low efficiency and high cost caused by the fact that the traditional PT1000 temperature measuring technology depends on a field physical calibration procedure. In order to solve the technical problems, the invention adopts the following technical scheme: In a first aspect, the present invention provides a high-precision calibration-free PT1000 measurement method, including: A first voltage signal at the upper end of the PT1000 platinum resistance sensor is obtained through a voltage dividing branch formed by connecting a first reference voltage source, a first voltage dividing resistor and the PT1000 platinum resistance sensor in series; Acquiring a reference voltage signal through a reference voltage branch formed by connecting a first reference voltage source, a second voltage dividing resistor and a reference resistor in series; Amplifying the difference value between the first voltage signal and the reference voltage signal by utilizing a differential amplifying circuit to obtain a conditioned second voltage signal; Li Yongyi the second reference voltage source is an analog-to-digital converter for converting the second voltage signal into a digital signal; Based on the digital signals and circuit parameters, calculating the real-time resistance value of the PT1000 platinum resistance sensor; comparing the calculated real-time resistance value with a pre-stored PT1000 standard graduation table, directly outputting a corresponding temperature measurement value when the real-time resistance value is equal to the standard resistance value in the PT1000 standard graduation table, and obtaining the temperature measurement value through interpolation calculation when the real-time resistance value is not equal to the standard resistance value in the PT1000 standard grad