Thermocouples – Part 1: EMF specifications and tolerances
|Publication Date:||1 August 2013|
|ICS Code (Temperature-measuring instruments):||17.200.20|
This part of IEC 60584 specifies reference functions and tolerances for letter-designated thermocouples (Types R, S, B, J, T, E, K, N, C and A). Temperatures are expressed in degrees Celsius based on the International Temperature Scale of 1990, ITS-90 (symbol t90), and the EMF (symbol E) is in microvolts.
The reference functions are polynomials which express the EMF, E in μV, as a function of temperature t90 in °C with the thermocouple reference junctions at 0 °C. Values of EMF at intervals of 1 °C are tabulated in Annex A.
For convenience of calculating temperatures, inverse functions are given in Annex B which express temperature as functions of EMF within stated accuracies.
This International Standard specifies the tolerances for thermocouples manufactured in accordance with this standard. The tolerance values are for thermocouples manufactured from wires, normally in the diameter range 0,13 mm to 3,2 mm, as delivered to the user and do not allow for calibration drift during use.
Annex C gives guidance on the selection of thermocouples with regard to temperature range and environmental conditions.