Research of a cold end temperature compensation for thermal couple

The performance of the cold end temperature compensation for the thermal couple was investigated. The cold end temperature compensation errors of two typical thermocouples were calculated point by point, based on that the error tables were arranged in order to visually display the defect of the conventional compensation. The bi-bridge of the compensation solution was recommended in the paper as contrast. The improved compensator was composed of main bridge and assistant in series connected. The main was designed according to the traditional method while the assistant was designed equilibrium at the point of the main bridge perfect compensation. The voltage output of the assistant could be changed by adjust the current-limited impedance, in order to the input-output characteristic curve of the improved compensator, approach the curve of the matched thermal couple's. Calculation and analysis shows that the error of cold end temperature compensation was reduced distinctly and the accuracy of the temperature measurement was enhanced remarkably.