The Fluke 8846A gives users the ability to measure temperature with an RTD, according to the Callendar-Van Dusen equation, automatically calculating the corresponding temperature for the resistance value measured by the meter.
The Callendar-Van Dusen equation is a complicated mathematical model used to correlate the resistance-to-temperature relationship of RTD devices. It relies on three coefficients: a, ß, and d.
When using industrial grade PRTs, ß and d are defined by EN 60751:1995, leaving a as the only coefficient that is entered by the user in measurement devices.
The Fluke 8846A assumes the use of industrial grade PRTs, and thus only the a coefficient can be changed.
ß is fixed at 0.1086 and d is fixed at 1.500 °C.
For more information about the Callendar-Van Dusen equation and industrial grade PRT coefficients, visit the following link: http://www.wikapolska.pl/upload/DS_IN0029_en_co_59667.pdf