search

bkubicek / Marlin

Reprap FW optimized for gen6
17 stars 1 forks source link

thermistor table values #24

Closed hurzl closed 12 years ago

hurzl commented 12 years ago

what are the "*16"s in thermistortables.h for? I have a 100k thermistor and the values are only correct when I take the 16s out.

bkubicek commented 12 years ago

i have asked the guy who designed the first thermistor table ever, and he does not know. you need to ask zalm, maybe he knows

bkubicek commented 12 years ago

I had actually the same problem, for a reprap with a 10k thermistor. Its not in sprinter, i think zalm actually changed it. Should i use the thermistor tables of sptrinter instead?

bkubicek commented 12 years ago

i know the reason, and know how to fix it.

hurzl commented 12 years ago

delete the "*16" fixed it for me. I just would like to have it in the repo, so I don't have to fix it every time ;-)

bkubicek commented 12 years ago

I made it configurable. The magic 16 was the number of temperature measurements that were added, before they were translated to temperature.Oversampling basically for additional numerical accuracy. I rewrote the temperature code to be useful for the AD595 chip, and took the code from sprinter where no oversampling occurs. That was the reason for the failure. However, I am not really for that concept, because if you would use PID, the "I" would actually do some averaging already, as far as I understand.