Type S thermocouple table: mV vs °C (−50 to 1768.1 °C)

A type S thermocouple (platinum with 10% rhodium (+) and platinum (−)) produces a voltage that depends on the temperature difference between the measuring junction and the reference junction. The table follows the NIST (ITS-90) reference functions, with the reference junction at 0 °C.

Types R and S have close values and the same cable colors; confirm the type configured in the instrument before using the table.

Type S thermocouple, reference junction at 0 °C

What about the cold junction?

In the field the reference junction sits at the transmitter or instrument terminals, almost never at 0 °C. So the voltage measured at the terminals is not the table value: the instrument compensates the cold junction. To check a mV reading, take the terminal temperature into account.

Calculated reference values, not measurements. The thermocouple tolerance depends on its class (IEC 60584-1) and is not in the table.