SPRT is a standard reference, which is used to define temperature as per ITS-90. The ITS-90 extend defines upwards from 0.65 K to the highest temperature practically measurable in terms of the Planck Radiation Law using monochromatic radiation.
The range from The Triple Point of Equilibrium Hydrogen (13.8033 K) to the Freezing Point of Silver (961.78ºC) Platinum Resistance Thermometer is used as a defining sensor.
This SPRT calculator is used to provide the ITS-90 coefficients for the set of resistance readings provided on the fixed point cell.
For the range 0ºC to 961.78ºC the following reference function is defined:
An inverse function, equivalent to equation (10a) to within 0.13 mK is equation (10b)
The values of the constants Co, Ci, Do and Di are given in Table 4.
A thermometer may be calibrated for use throughout this range or, using fewer calibration points, for ranges with upper limits of 660.323ºC, 419.527ºC, 231.928ºC, 156.5985ºC or 29.7646ºC, all are having a lower limit of 0ºC.
This free software has been specifically designed to provide the ITS90 parameters for temp range 0 to 660 deg C. For this the user has to provide the resistance values at TPW, FP Sn, FP Zn and FP of Al. This software shall calculate and provide the ITS90 coefficients and shall also generate a report for every 1 degree of interpolated readings for the sensors.
Other specific software for larger range can be provided on request.
This software is “FREE” and can be distributed to other users. It has been designed for the internal use at Tempsens, please double-check before use. Tempsens stand no guarantee for the output. We are open to your feedback for improvement in the program, if any.