DOI: 10.14489/td.2022.03.pp.052-057

Shilin А. N., Mac B. V., Koptelova I. A.
DIGITAL PYROMETER OF SPECTRAL RATIO
(pp. 52-57)

Abstract. The article provides a comparative analysis of the main optoelectronic pyrometers: radiation and spectral ratio. The main error of optoelectronic pyrometers is a methodological component, which is due to the inconstancy of the radiation coefficient of the surface of the material of the product, which depends on the material, the state of the surface of the material and temperature. When measuring temperature, it is difficult to take into account this dependence, since there are no analytical expressions. In practice, the radiation coefficient of the surface of the material of the product is determined approximately using reference books. From the analysis of the two main optoelectronic pyrometers, it follows that the methodological error of spectral ratio pyrometers is less than that of radiation pyrometers, and when measuring the temperature of gray bodies, this component of the error is absent. To substantiate the technical implementation, the analysis of existing information processing schemes of spectral ratio pyrometers - ratiometric converters was carried out. The analysis revealed that it is advisable to use a converter with push-pull integration to implement a digital pyrometer of spectral ratio. This digital pyrometer of spectral ratio, in comparison with the known implementation scheme, performs three functions, namely the functions of two analog-to-digital converters (ADC) and a digital ratiometric converter of the unit. In addition, such a digital pyrometer of spectral ratio has good protection against network interference and can significantly reduce the influence on the measurement error of factors having a multiplicative nature. A technique for selecting the wavelengths of light filters and radiation detectors with the required spectral characteristics for a given range of measured temperatures is presented.

Keywords: radiation from heated bodies, radiation coefficient, pyrometry, spectral ratio pyrometers, optoelectronic devices, converters with push-pull integration.