IEC 60751:2022

IEC 60751:2022 specifies the requirements, in addition to the resistance versus temperature relationship, for both industrial platinum resistance thermometers (later referred to as "thermometers") and industrial platinum resistance temperature sensors (later referred to as "platinum resistors") whose electrical resistance is derived from defined functions of temperature.
Values of temperature in this document are in terms of the International Temperature Scale of 1990, ITS-90. A temperature in the unit °C of this scale is denoted by the symbol t, except in Table A.1 where the full nomenclature t90 /°C is used.