The platinum resistance temperature sensor measures the temperature by using the characteristic that platinum resistance changes with the temperature. The display instrument will indicate the temperature value corresponding to the platinum resistance value.When there is a temperature gradient in the measured medium, the measured temperature is the average temperature in the medium layer within the range of the temperature sensing element.

Range of application

Platinum resistance temperature sensors are temperature sensors used to measure air, soil and water.The sensor is composed of a precision platinum thermal resistance element and a specially processed protective sleeve, and a four-core shielded signal cable is drawn from the sensing element for measurement. Usually, the four-wire measurement method can be adopted to reduce the measurement error caused by wire resistance.Platinum resistance temperature sensor with excellent interchangeability and long-term stability, widely used in meteorology and environmental protection departments.

Wide range of temperature measurements: Platinum is stable and does not cause physical or chemical changes due to high and low temperatures.

Platinum resistance temperature sensor is a temperature sensor made by using its resistance as a function of temperature.Since the characteristic curve of platinum resistance is nonlinear, the standard resistance and temperature relationship is given in the form of the scale table, and expressed by the resistance - temperature polynomial function R (t).But in the actual measurement, the temperature - resistance function T (r) is more convenient for measurement and calculation.This paper introduces a method to obtain the temperature resistance polynomial function T (r) by using cubic basic spline curve fitting.The practical application shows that this method can improve the operation speed and control precision of the temperature measurement and control system.

The main advantages

Platinum resistance sensor has good long-term stability. Typical experimental data are as follows: it lasts for 300 hours at 400℃, and the temperature drift at 0℃ is 0.02℃.

Platinum resistance temperature sensors are often used in protective equipment.

Measures taken to avoid errors

1. Reduce the radiation coefficient of the platinum resistance temperature sensor protection tube;

2. Increase the circulation of the measured medium, and increase the convective heat transfer between the platinum resistance and the measured medium as far as the working pressure permits;

3. Reduce the outside diameter of platinum resistance protection tube as much as possible;

4. Increase the insertion depth of platinum resistance and lengthen the heated part;

5. If the response time is not required to be high, the protective tube with small heat conductivity coefficient can be used as far as possible;

6. If the requirement of thermal response time is relatively high, the protective tube with large thermal conductivity shall be selected as far as possible and the choice shall be made according to the actual use situation.

In addition to the above, when using the platinum resistance temperature sensor, it should be noted that there should be good insulation between the temperature sensing elements (two-branch structure) and between the temperature sensing elements and the ground, otherwise it will directly affect the accuracy of the measurement results, and even affect the normal operation of the instrument.In a word, in the application of platinum resistance temperature sensor for temperature measurement, first of all, it must be correct selection, reasonable installation and use, try to eliminate all kinds of external influences as far as possible, reduce additional errors, to achieve accurate measurement, simple and durable purpose.

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