Thermocouple Calculations

Example:

A T type thermocouple has linear calibration between 0 and 500 oC with emf at maximum temperature (reference temperature oC) equal to 21.5 mV.

Determine the correction to be made to the indicated emf, if the cold junction temperature is 25 oC. If the indicated emf is 9.0 mV, determine the temperature of the hot junction.

Solution:

Sensitivity = 2.15 / 500 = 0.043 mV/ oC

E correction = 0.043 x 25 = 1.075 mV

Difference of temperature between hot and cold junction = 9.0/0.043 = 209.30 oC

The reference junction temperature = 25 oC

The hot junction temperature = 209.30+25 = 234.3 oC