Multi-range platinum resistor temperature measurement circuit and method

Abstract

The invention discloses a multi-range platinum resistor temperature measurement circuit and a temperature measurement method. The circuit comprises a constant current source, a single-pole double-throw switch, a reference circuit, a to-be-measured circuit, a temperature measurement chip and a microcontroller, wherein the reference circuit comprises a constant resistor and a variable resistor; theto-be-measured resistor comprises a platinum resistor and a variable resistor the same as the reference circuit, wherein the maximum resistance value of the variable resistor is greater than the resistance value of the platinum resistor at the maximum temperature measurement point by changing the size of the variable resistor, and the minimum resistance value of the variable resistor is greater than the resistance value of the constant resistor; through internal calculation of the temperature measurement chip, input voltage at two ends of the constant resistor and input voltage at two ends ofthe platinum resistor are respectively read, the resistance value of the platinum resistor is calculated by utilizing the same current provided for the constant resistor and the platinum resistor by the constant current, and a temperature value corresponding to the platinum resistor at the moment is further obtained. During the solving of a small-range problem, the temperature measurement method can be used for effectively avoiding the problem that the difference between the platinum resistor and the variable resistor is too large, so the temperature measurement precision is improved.

Description

technical field [0001] The invention relates to the field of temperature measurement, in particular to a multi-range platinum resistance temperature measurement circuit and a temperature measurement method. Background technique [0002] Temperature is one of the basic physical quantities of the International System of Units. Temperature detection is widely used in the fields of industrial automation and scientific research. Thermal resistance temperature measurement is based on the characteristic that the resistance value of metal conductors increases with the increase of temperature. Yes, most thermal resistances are made of pure metal materials. Platinum is the most widely used temperature measuring element at present; due to the stable characteristics of platinum, it will not cause physical or chemical changes due to high and low temperatures, and the measurement range is large, which can be It can reach -250°C to 850°C, with high temperature measurement accuracy and high...

AI Technical Summary

Problems solved by technology

[0004] Aiming at the problem of low accuracy in small and medium ranges of multi-range platinum resistance temperature measurement, the present invention proposes a multi-range platinum resistance temperature measurement circuit and measurement method

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