http://ww1.microchip.com/downloads/en/AppNotes/00687c.pdf
  RTD(T) = RTD_0 * (1 + T * alfa)

  RTD(T) = the RTD element's resistance at T
  RTD_0  = the RTD element's resistance at 0 C
  T = the RTD element's temperature (in C), -100 till 200 C
  alfa = 0.00385 1/C

//

 RTD(T) = RTD_0 (1 + A T + B T^2 + C T^3 (T - 100))

The ITS-90 standard values are:

   RTD_0 = 100 Ohm
   A = 3.9083 10^-3  C^-1
   B = -5.775 10^-7 C^-2

   C =
     -4.183 10-12 C^-4, T < 0C
     0, T >= 0C

///
John P. Bently / Principles of Mesaurement Systems / 3rd edition

The resistance of most metals increases reaasonably linearly with temperature in the
range -100 to +800 °C.
R(t) = R_0 * ( 1 + a t + b t^2 + c t^3 ...)

Platinum
 R(0)   = 100 Ohm
 R(100) = 138.50
 R(200) = 175.83
 a =  3.91 e-3
 b = - 585 e-7
 R(100) - R(0) is called the fundamental interval (38.5)
10mW => + 0.3 temperaturökning

///

possible input filter
. simple rc
  f_c = 1/ ( 2 pi R C )

. Butterworth
  a_i    b_i   f_gi/f_g Q_i
  1,4142 1,000 1,000    0,71
. Bessel
  1,317 0,6180 1,000    0,58

f_c could possible be 10 Hz depending on the context

///

 Two tables:
https://www.emory.edu/NMR/mysite06/My Stuff/My Notes/pt100_table.pdf
https://www.tnp-instruments.com/sitebuildercontent/sitebuilderfiles/pt100_385c_table.pdf

program in ../bin/pt100.pl