阅读说明：本技术 高精度测温方法及装置 (High-precision temperature measuring method and device ) 是由 徐斌阳 张彭朋 于 2021-08-05 设计创作，主要内容包括：本发明涉及测试计量技术领域,具体涉及一种高精度温度测量方法及装置,包括温度测量模块,由温度传感器和温度信号变换调理电路组成,用于将待测对象的温度物理量转换为可运算处理温度数据；存储器,用于存储历史温度测量数据以及测量设备的各种工作参数和运算参数；通信模块,用于将获取的温度数据传输至上位机或远端服务器,并从上位机获取设备工作及配置参数；主控制器,用于对所述温度测量模块、存储器及通信模块进行集中控制。本发明可以应用于宽量程温度监测装置和仪表中,通过预先设置多个不同的温区,每个温区使用适合本温区的多项式拟合,显著提高温度测量精度。(The invention relates to the technical field of test measurement, in particular to a high-precision temperature measurement method and a high-precision temperature measurement device, which comprise a temperature measurement module, a temperature signal conversion and conditioning circuit and a temperature signal conversion and conditioning circuit, wherein the temperature measurement module consists of a temperature sensor and a temperature signal conversion and conditioning circuit and is used for converting a temperature physical quantity of an object to be measured into temperature data capable of being operated; the memory is used for storing historical temperature measurement data and various working parameters and operation parameters of the measuring equipment; the communication module is used for transmitting the acquired temperature data to an upper computer or a remote server and acquiring working and configuration parameters of equipment from the upper computer; and the main controller is used for carrying out centralized control on the temperature measuring module, the memory and the communication module. The invention can be applied to wide-range temperature monitoring devices and instruments, and obviously improves the temperature measurement precision by presetting a plurality of different temperature zones, wherein each temperature zone uses polynomial fitting suitable for the temperature zone.)

1. A method of high accuracy temperature measurement, the method comprising the steps of:

s1 initialization, extracting N temperature sampling points at equal intervals in the measuring range of the temperature measuring equipment, and reading to obtain N groups of F-T temperature response characteristic values, wherein N is a positive integer;

s2, generating a characteristic curve from the N groups of F-T temperature response values, and dividing the characteristic curve into K +1 temperature zones according to the critical temperature points of K characteristic curves, wherein K is a positive integer;

s3, selecting a proper fitting function, and respectively performing parameter fitting on the characteristic curves of the K +1 temperature zones to obtain parameters of each fitting function;

s4, storing the fitting function and the parameters of each subarea into a temperature measuring equipment memory to complete the configuration of the working parameters of the temperature measuring equipment;

and S5, calling a corresponding fitting function according to the actually measured temperature response characteristic value during actual measurement, and calculating to obtain the accurate temperature value of the measured target.

2. A high accuracy temperature measuring method according to claim 1, wherein in S2, when the temperature region of the characteristic curve is divided, the monotone interval of the characteristic curve and the linear/nonlinear principle of the characteristic curve are used.

3. A high accuracy temperature measuring method according to claim 1, wherein the range of the temperature measuring device is set as T₀～T_mWherein m is a natural number, dividing the characteristic curve into K +1 temperature regions of (T)₀～t₁)，(t₁～t₂)…(t_k～T_m) At (t)_x,t_x+1) The fitting function for the interval (x ≦ K) is expressed as a polynomial function:

F(t)＝a_x0+a_x1·t+a_x2·t²+Λa_xn·tⁿ,t∈(t_x,t_x+1)。

4. a high accuracy temperature measurement method according to claim 3, characterized in thatIn the above method, for (t)_x,t_x+1) The other temperature regions are treated similarly, and the whole characteristic curve is expressed as a piecewise polynomial function

5. A high accuracy temperature measurement method according to claim 4, characterized in that in the method, the characteristic curves of K +1 temperature zones are subjected to parameter fitting to obtain parameter matrices of each fitting function as:

6. a high-precision temperature measuring apparatus for carrying out the high-precision temperature measuring method according to any one of claims 1 to 5, comprising

The temperature measuring module consists of a temperature sensor and a temperature signal conversion conditioning circuit and is used for converting the temperature physical quantity of the object to be measured into temperature data capable of being operated and processed;

the memory is used for storing historical temperature measurement data and various working parameters and operation parameters of the measuring equipment;

the communication module is used for transmitting the acquired temperature data to an upper computer or a remote server and acquiring working and configuration parameters of equipment from the upper computer;

and the main controller is used for carrying out centralized control on the temperature measuring module, the memory and the communication module.

7. A high accuracy temperature measuring device according to claim 6, further comprising a power module for providing a smooth power supply to the measuring device parts.

8. A high-precision temperature measuring device as claimed in claim 6, wherein the communication module adopts wired or wireless communication, wherein the wired communication interface is RS485 or Ethernet; the wireless communication uses a wireless local area network WLAN, and a cellular network 2G, 4G, 5G, or NB-IoT.

9. A high accuracy temperature measuring apparatus according to claim 6, wherein said temperature sensor is configured to convert a physical quantity of temperature of the measuring object into a voltage or current signal;

the signal conversion conditioning circuit amplifies the voltage or current small signal output by the temperature sensor, converts the voltage or current small signal into digital data which can be processed by the main controller through an analog-to-digital converter, and feeds the digital data back to the main controller.

10. The high-precision temperature measuring device according to claim 6, wherein the main controller is a microcontroller MCU, and is used for processing the temperature data collected by the temperature measuring module, storing the temperature data in the memory, and uploading the temperature data to an upper computer, a remote server or a cloud platform through the communication module.

Technical Field

The invention relates to the technical field of test and measurement, in particular to a high-precision temperature measurement method and device.

Background

With the progress of industry and the development of high technology, more and more industry organizations have higher requirements on the accuracy and reliability of the temperature measurement of the target environment, and the application of high-accuracy temperature measurement equipment is more and more extensive. Typical applications include, for example, precision instrument manufacturing, aerospace, military manufacturing, quality supervision/quality inspection, medical and high-tech scientific research, and the like, and in order to ensure the quality of raw materials in storage, circulation, and product manufacturing processes, high requirements are placed on the stability and accuracy of temperature measurement and control of a target environment/object. Inaccurate or unstable temperature measurement easily causes production quality problems because actual target temperature cannot be truly reflected.

Temperature sensors in mainstream temperature measuring equipment in the market generally adopt thermistors, thermocouples or infrared thermoelectric induction and the like, and the temperature range which can be measured is wide. Common probe-type thermometry devices can measure a wide temperature range from-200 ℃ to 200 ℃. However, due to the nonlinearity of the physical characteristics (such as thermal resistance, light sensitivity, etc.) of the temperature sensing material used in the sensor and the nonlinearity of the signal detection conditioning circuit, the conventional temperature measurement equipment is difficult to measure with high precision in a wide temperature range. Thus, it becomes critical to be able to realize a wide temperature range high-precision temperature measurement technique.

Disclosure of Invention

Aiming at the defects of the prior art, the invention discloses a high-precision temperature measuring method and device, which are used for solving the problem of production quality easily caused by the fact that the actual target temperature cannot be truly reflected due to inaccurate or unstable temperature measurement in the prior temperature measuring technology.

The invention is realized by the following technical scheme:

in a first aspect, the invention discloses a high-precision temperature measuring method, which comprises the following steps:

s1 initialization, extracting N temperature sampling points at equal intervals in the measuring range of the temperature measuring equipment, and reading to obtain N groups of F-T temperature response characteristic values, wherein N is a positive integer;

s2, generating a characteristic curve from the N groups of F-T temperature response values, and dividing the characteristic curve into K +1 temperature zones according to the critical temperature points of K characteristic curves, wherein K is a positive integer;

s3, selecting a proper fitting function, and respectively performing parameter fitting on the characteristic curves of the K +1 temperature zones to obtain parameters of each fitting function;

s4, storing the fitting function and the parameters of each subarea into a temperature measuring equipment memory to complete the configuration of the working parameters of the temperature measuring equipment;

and S5, calling a corresponding fitting function according to the actually measured temperature response characteristic value during actual measurement, and calculating to obtain the accurate temperature value of the measured target.

Further, in S2, when the temperature region of the characteristic curve is divided, the monotone interval of the characteristic curve and the linear/nonlinear principle of the characteristic curve are used.

Furthermore, in the method, the range of the temperature measuring equipment is set as T₀～T_mWherein m is a natural number, dividing the characteristic curve into K +1 temperature regions of (T)₀～t₁)，(t₁～t₂)…(t_k～T_m) At (t)_x,t_x+1) The fitting function for the interval (x ≦ K) is expressed as a polynomial function:

F(t)＝a_x0+a_x1·t+a_x2·t²+Λa_xn·tⁿ,t∈(t_x,t_x+1)。

further, in the method, a pair (t)_x,t_x+1) The other temperature regions are treated similarly, and the whole characteristic curve is expressed as a piecewise polynomial function

Furthermore, in the method, the characteristic curves of the K +1 temperature zones are subjected to parameter fitting, and a parameter matrix of each fitting function is obtained as follows:

in a second aspect, the present invention discloses a high-precision temperature measuring device for implementing the high-precision temperature measuring method of the first aspect, comprising

The temperature measuring module consists of a temperature sensor and a temperature signal conversion conditioning circuit and is used for converting the temperature physical quantity of the object to be measured into temperature data capable of being operated and processed;

the memory is used for storing historical temperature measurement data and various working parameters and operation parameters of the measuring equipment;

the communication module is used for transmitting the acquired temperature data to an upper computer or a remote server and acquiring working and configuration parameters of equipment from the upper computer;

and the main controller is used for carrying out centralized control on the temperature measuring module, the memory and the communication module.

Furthermore, the measuring device also comprises a power supply module which is used for providing stable power supply for each part of the measuring device.

Furthermore, the communication module adopts wired or wireless communication, wherein a wired communication interface is RS485 or Ethernet; the wireless communication uses a wireless local area network WLAN, and a cellular network 2G, 4G, 5G, or NB-IoT.

Furthermore, the temperature sensor is used for converting the temperature physical quantity of the measuring object into a voltage or current signal;

the signal conversion conditioning circuit amplifies the voltage or current small signal output by the temperature sensor, converts the voltage or current small signal into digital data which can be processed by the main controller through an analog-to-digital converter, and feeds the digital data back to the main controller.

Furthermore, the main controller is a microcontroller MCU and is used for processing the temperature data acquired by the temperature measuring module, storing the temperature data in the memory and uploading an upper computer, a remote server or a cloud platform through the communication module.

The invention has the beneficial effects that:

the invention can be applied to wide-range temperature monitoring devices and instruments, and greatly improves the temperature measurement precision by presetting a plurality of different temperature zones, wherein each temperature zone uses polynomial fitting suitable for the temperature zone. The finer the subsection is, the smaller the temperature zone interval is, and the higher the obtained measurement precision is. Compared with the traditional temperature measuring device, the method can achieve high-precision measurement superior to 0.01 ℃ at lower cost; a solution for improving the measurement accuracy is provided for the wide-range temperature monitoring device. The method has the advantages of easy hardware realization, low power consumption and easy mass production and maintenance.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the drawings without creative efforts.

FIG. 1 is a temperature resistance characteristic curve of a thermistor sensor according to an embodiment of the invention;

FIG. 2 is a functional block diagram of a wide temperature range high-precision temperature measuring device according to an embodiment of the present invention;

FIG. 3 is a diagram illustrating an example of dividing temperature measuring regions of a PT100 wide temperature range according to an embodiment of the present invention;

FIG. 4 is a flowchart of an implementation of the wide temperature range high-precision temperature measurement method according to the embodiment of the present invention.

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are some, but not all, embodiments of the present invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

Example 1

The embodiment discloses a high-precision temperature measuring device as shown in fig. 2, which comprises a main controller, a memory, a temperature measuring module, a communication module and a power module.

The main controller is responsible for centralized control of other components, controls the temperature measuring module to collect target temperature and store measured temperature data, and controls the communication module to upload the collected data to an upper computer or a remote server in a specific communication mode.

The memory of the embodiment is used for storing historical temperature measurement data and various working parameters, operation parameters and the like of the measuring equipment. The power supply module provides stable power supply for all parts of the temperature measuring device.

The temperature measuring module of the embodiment comprises a temperature sensor and a temperature signal conversion and conditioning circuit, and is responsible for converting the temperature-related physical quantity of the object to be measured into data which can be processed by the main controller in an operation way.

The communication module of the embodiment is responsible for transmitting the acquired temperature data to an upper computer or a remote server and acquiring working and configuration parameters of equipment from the upper computer.

The communication module as a further implementation of this embodiment may be implemented by using a wired or wireless communication technology, and the wired communication interface may be RS485, ethernet, or the like; the wireless communication may use a wireless local area network WLAN, as well as cellular networks 2G, 4G, 5G, or NB-IoT, among others.

The main controller is a microcontroller MCU (microprogrammed control unit) which processes collected temperature data, stores the temperature data and uploads the temperature data to an upper computer, a remote server or a cloud platform in a specific communication mode.

The temperature measuring circuit comprises a temperature sensor and a temperature signal conversion and conditioning circuit, wherein the sensor is responsible for converting a temperature physical quantity of a measuring object into a voltage or current signal; the signal conversion conditioning circuit amplifies the voltage or current small signal output by the sensor, converts the voltage or current small signal into digital data which can be processed by the main controller through the analog-to-digital converter and feeds the digital data back to the main controller.

The communication circuit preferably implemented adopts a 2G/4G wireless communication mode, is connected with an upper computer and acquires various parameters required by the normal work of the temperature detection device; and uploading the obtained accurate temperature value to an upper computer or a remote server.

Example 2

In the embodiment, for the requirement of high-precision temperature measurement of a wide temperature zone, a temperature zone segmentation and data fitting method is adopted, and for temperature measurement equipment of the wide temperature zone, the physical characteristics of a temperature sensor of the temperature measurement equipment are usually nonlinear functions of temperature. And the linear characteristics presented are not consistent in different temperature sections. For example, a conventional thermistor sensor has a temperature-resistance (R-T) characteristic curve that is a non-linear complex curve, as shown in fig. 1.

For convenience of description in this embodiment, the physical characteristic of the temperature change of the temperature measuring device is denoted by F. The characteristic value can be resistance, voltage, current, light intensity, infrared radiation energy and the like of the temperature measuring sensor.

In response to the requirement of high-precision temperature measurement in a wide temperature range, the present embodiment further provides a high-precision temperature measurement method, including the following steps:

s1 initialization, extracting N temperature sampling points at equal intervals in the measuring range of the temperature measuring equipment, and reading to obtain N groups of F-T temperature response characteristic values, wherein N is a positive integer;

s2, generating a characteristic curve from the N groups of F-T temperature response values, and dividing the characteristic curve into K +1 temperature zones according to the critical temperature points of K characteristic curves, wherein K is a positive integer;

s3, selecting a proper fitting function, and respectively performing parameter fitting on the characteristic curves of the K +1 temperature zones to obtain parameters of each fitting function;

s4, storing the fitting function and the parameters of each subarea into a temperature measuring equipment memory to complete the configuration of the working parameters of the temperature measuring equipment;

and S5, calling a corresponding fitting function according to the actually measured temperature response characteristic value during actual measurement, and calculating to obtain the accurate temperature value of the measured target.

The embodiment is applied to a wide-range temperature monitoring device and an instrument, and each temperature zone is fitted by a polynomial suitable for the temperature zone by presetting a plurality of different temperature zones, so that the temperature measurement precision is greatly improved.

Example 3

In a specific implementation level, the present embodiment provides a temperature zone segmentation and temperature change characteristic curve fitting process with reference to fig. 4 as follows:

at the measuring range (T) of the thermometric apparatus₀～T_m) Uniformly extracting N temperature sampling points at equal intervals, and reading a temperature response characteristic value F of temperature measuring equipment in a temperature environment corresponding to each temperature sampling point to obtain N groups of F-T temperature response values of the temperature measuring device;

generating a characteristic curve according to the measured N groups of F-T characteristic values, and carrying out temperature zone segmentation on the temperature resistance F-T characteristic curve in the temperature measurement range according to the following principle: monotonic interval of the F-T characteristic curve and linearity/nonlinearity of the F-T characteristic curve;

according to the principle, K critical temperature points of the characteristic curve are obtained, and the F-T characteristic curve can be divided into K +1 temperature regions (T)₀～t₁)，(t₁～t₂)…(t_k～T_m)；

Selecting a suitable fitting function according to the characteristics of F-T curve of each target temperature zone, such as (T)_x,t_x+1) The fitting function of the interval (x ≦ K) may be expressed as a polynomial function

F(t)＝a_x0+a_x1·t+a_x2·t²+Λa_xn·tⁿ,t∈(t_x,t_x+1)

Similar treatment is carried out on other temperature areas, and the whole F-T characteristic curve can be expressed by a piecewise polynomial function as follows:

and respectively performing parameter fitting on the F-T curves of the K +1 temperature zones to obtain a parameter matrix of each fitting function:

the temperature measuring device calls a corresponding fitting function according to the actually measured sensor output F value, and the accurate temperature value of the measured target is obtained through calculation.

Example 4

In a specific implementation aspect, the embodiment provides a specific implementation of the high-precision temperature measurement method as follows:

in the embodiment, the PT thermistor is used as a temperature measuring sensor, and the wide temperature zone temperature measuring equipment with the target temperature measuring working range of-80 ℃ to +60 ℃ is realized by the following steps:

uniformly extracting 100 temperature measuring points at equal intervals in a temperature range of-80 ℃ to +60 ℃, recording resistance values R measured by equipment at each temperature point, and drawing an actual temperature measuring change curve R-T of the equipment, as shown in figure 3.

And step two, selecting temperature zones in a segmented manner. And C, dividing the temperature zone according to monotonicity and linearity/nonlinearity of the characteristic curve obtained in the step I. As in fig. 3, the full range can be divided into: five temperature zones of (-80 to-40 ℃), - (40 to-20 ℃), - (20 to 0 ℃), (0 to +20 ℃), and (+20 to +60 ℃).

And thirdly, selecting a proper characteristic function according to the characteristics of the R-T curve of each target temperature zone, and fitting and calculating a function coefficient. And (3) actually measuring 10 temperature points at equal intervals in each temperature zone, and selecting a proper curve equation according to the change trend of the actually measured temperature points. The present exemplary calibration method selects a first or second order polynomial equation.

In the embodiment, the temperature point is basically linearly changed in the temperature range of (-20 ℃ -0 ℃) and (0 ℃ -20 ℃), and a first-order polynomial is selected as a matching characteristic function;

in the embodiment, the temperature point basically accords with the change of a quadratic curve in the temperature range of (-80 ℃ to-40 ℃), (-40 ℃ to-20 ℃), and (+20 ℃ to +60 ℃), and the matching characteristic function adopts a quadratic polynomial;

in the embodiment, the R-T characteristic curve of the whole temperature zone from-80 ℃ to +60 ℃ can be expressed by a piecewise binomial function as follows:

step four, fitting and calculating by using a least square method to obtain a parameter matrix of each fitting function:

i.e. the fitted R-T characteristic function is

In this embodiment, the fitting function and the parameter of each partition are stored in the memory of the temperature measuring device, so as to complete the configuration of the working parameters of the temperature measuring device.

The initial configuration of the equipment in a wide temperature range of-80 ℃ to +60 ℃ is completed through the processes. During actual measurement, the equipment calculates according to the measured R resistance value and the fitting function of the interval corresponding to the R resistance value to obtain an accurate temperature value. Compared with the standard temperature measuring equipment, the measurement precision of the equipment in the temperature measuring range reaches +/-0.2 ℃.

In practical application, the number of the temperature zone segments and the order of the fitting function can be selected according to the measurement accuracy requirement. Generally, the performance of a processor of the temperature measuring equipment, the consumption of computing resources and the like need to be comprehensively considered.

In conclusion, the invention can be applied to wide-range temperature monitoring devices and instruments, and the temperature measurement precision is greatly improved by presetting a plurality of different temperature zones, wherein each temperature zone uses polynomial fitting suitable for the temperature zone. The finer the subsection is, the smaller the temperature zone interval is, and the higher the obtained measurement precision is. Compared with the traditional temperature measuring device, the method can achieve high-precision measurement superior to 0.01 ℃ at lower cost; a solution for improving the measurement accuracy is provided for the wide-range temperature monitoring device. The method has the advantages of easy hardware realization, low cost and easy mass production and maintenance.

The above examples are only intended to illustrate the technical solution of the present invention, but not to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; and such modifications or substitutions do not depart from the spirit and scope of the corresponding technical solutions of the embodiments of the present invention.