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Temperature was a basic physical quantity, the most common and importantprocess parameter. Industrial and agricultural production, scientific research ornational defense modernization, they were all inseparable from the temperaturemeasurement. Currently in aerospace, material, metallurgy, energy and other fields,high temperature measurement was more important, and in these fields, the feature ofthe work environment was high-temperature, strong interference, corrosion, and so on.For the poor conditions and special environment, the work met rapid change, hightemperature, nonrepeatability. For those special requirement, although some commontechniques such as the mocouple, thermal resistance and radiation thermometers, etc.were technically mature, just can get good effect in the general application site, cann’tmeet requirements in exceptional circumstances. In this paper, for the industrialmetallurgical features, we designed the high temperature thermometer based oncolorimetric principle. The temperature measuring instruments had high accuracy,high anti-interference ability, and because of low power, small cubage，it wasportable and can be fixed in confined space.In the first, this paper gave the overview of the development of high temperaturemeasurement and internal and overseas research status, compared the monochromaticand multi-spectral thermometry, described the principle of colorimetric thermometerin detail, and proved the unique advantages of it. Then, the paper gave the design ofcolorimetric thermometer after analyzing the characters of target signals andbackground. Throgh the optical fiber, radiation was detected by the photodiode whichcan convert the light signals into electrical signals. We chose the low noise I/V OPA tochange the current into voltage, and a filter to remove the noise. After that, the analogsignals came into the24-bit precision ADC, and they were converted into digitalsignals. The MCU would process those signals using the colorimetric principle, anddisplayed the temperature result. This paper described the hardware system of thecolorimetric thermometer according different modules in details. It included how todesign each module’s function, to select chips, to be anti-interference and so on. After that, the Software design was completed in the integrated development enviroment—keil uVision3according modular design. The least square method and the temperaturecurve ratio method were also introduced. Finally, the paper described the debuggingprocess of this system and expermental programs.From the experimental results, this thermometer had good performance. It workedstably, achieved the design target.
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