These equations are called ITS-90
inverse polynomials because they determine temperature from voltage.
Three different water triple point cells (Table 3) are used at METROSERT to represent the temperature of the triple point of water (TPW) according to the ITS-90
as the national reference.
General information: New standard reference tables for thermocouples are necessary as a result of the introduction of the new international temperature scale, ITS-90
, which interpolates between fixed points by means of a standard platinum resistance thermometer instead of thermocouples.
The thermometer conforms to ITS-90
International Temperature Standard.
005 % from the corresponding ITS-90
is based on 17 temperature fixed points, to which certain temperatures are assigned.
pp] include a contribution associated with the ITS-90
thermocouple inverse polynomials (e.
Hart adds that Met/Temp II also enables users to perform ITS-90
coefficient and residual calculations and generate corresponding tables and reports.
PRTs may be read using the standard DIN curve or individually calibrated probes may use ITS-90
coefficients for higher accuracy.
These databooks are denoted as: 1 - Realising ITS-90
, Primary Laboratory; 2 - Secondary Laboratory Equipment; 3 - Industrial Laboratory Equipment; 4 - Blackbody and Thermocouple Reference Equipment; and 5 - Training and Services.
IF97 is based on the latest standard temperature scale, ITS-90
, which is a small improvement toward better representing physical reality.
Each probe comes with a NIST-traceable certificate of calibration and specific ITS-90