wow nearly 7 weeks (continously?) measurement.
Yes, almost continuously. There was only a small break of a few hours in between, where I couldn't measure the reference, but that's it.
how much of the coefficients belong to the LM399 and which part is for the 3458A?
And how much do they add or compensate?
I can't tell you. One sad thing is, that there is now multiplexer inside the 3458A and damn, I once sold my Prema 2080 when I got my Prema 5017 SC. That gear would have been perfect to compare multiple references on the 3458A.
Here are the real calculated coefficients instead of reading them out of a diagram using a linear fit:
Temperature sensor inside my styrofoam box with the reference:
TMP112 = 782.2192909802102e-09 10.00175078714701
Ambient conditions:
SHT25_Temp = 702.0809476528713e-09 10.00175529680888
SHT25_Hum = 252.2596185775486e-09 10.00175926263134
SHT25_Dew = 874.2006798035875e-09 10.00176195005415e+01
MS5611_Temp = 649.5007437887549e-09 10.00175629266645
MS5611_p = -252.3944060096974e-09 10.00201462316427
Next step, compensate for temperature, humidity and pressure.
-branadic-