For the derivation of the coefficients of the deviation function in the range from 0 to 400 C, we used the data obtained by comparison with a SPRT in water, oil, and salt baths which are given in Table 3.
The coefficients of the deviation function derived by the method of least square were added to those of the reference function to give the coefficients of the calibration function for the thermocouple when used in the range 0–400C.