Calculate the Thermocouple’s Measurement Junction Temperature

Type K thermocouple

A type K thermocouple is inserted into a process, with a digital multimeter connected to its terminals.

The ambient temperature at the DMM’s test lead connections is 84 ^oF.

Calculate the thermocouple’s measurement junction temperature at the following millivolt measurements (rounding to the nearest degree Fahrenheit):

• 2.55 mV ; T = ______ deg F
• 6.21 mV ; T = ______ deg F
• 10.93 mV ; T = ______ deg F
• 18.83 mV ; T = ______ deg F

Answer :

All answers based on ITS-90 thermocouple table values:

• 2.55 mV ; T = 195 deg F
• 6.21 mV ; T = 357 deg F
• 10.93 mV ; T = 567 deg F
• 18.83 mV ; T = 904 deg F

Type J thermocouple

A type J thermocouple is inserted into a process, with a digital multimeter connected to its terminals.

The ambient temperature at the DMM’s test lead connections is 17 ^oC.

Calculate the thermocouple’s measurement junction temperature at the following millivolt measurements (rounding to the nearest degree Celsius):

• 5.05 mV ; T = ______ deg F
• 17.82 mV ; T = ______ deg F
• 31.44 mV ; T = ______ deg F
• 40.29 mV ; T = ______ deg F

Answer :

All answers based on ITS-90 thermocouple table values:

• 5.05 mV ; T = 112 deg C
• 17.82 mV ; T = 346 deg C
• 31.44 mV ; T = 586 deg C
• 40.29 mV ; T = 732 deg C