Dynamic compensation method on temperature drift in Pt-resistance temperature online measuring system

摘要

The Pt-resistance temperature online measuring circuit is described in detail in the paper. Four-wire connection mode is introduced to improve effectively measurement precision of system. This paper analyses the causes of temperature drift in Pt-resistance temperature online measuring system, and puts forward a dynamic compensation method on temperature drift during the period of measuring process to solve the problems of traditional measuring methods, which are complicated to operate and has low reliability. Combined with this compensation method, a micro-controller is embedded in the online measuring system. Programs are compiled to realize automatic calibration and zero adjustment. In this method, two ordered precise standard resistors (temperature coefficient is much less than 1/spl times/10/sup -6//spl deg/C) are employed as intermediate transfers. Without measuring environmental temperature and pre-calibration, the measured variables can be compensated dynamically during measurement process. Experimental results show that the relative error of a measuring system that has adopted this dynamic compensation method is less than 0.2%.