CLT/MAT curve generation issue

[Keithg]

I have been running my Bosch MAT and CLT sensors for years. I used to use Easytherm to generate the inc files and recompile. With MS2, I received a spreadsheet that would develop the values based on a Steinhart-hart equations. For all of these, I used the data points at 32F,176F,212F. I always got reasonable temperatures reflected in MT and would come out of WUE where expected. I did not think to check this in MS3 until it got cool, recently and noted that it would not come out of WUE with MS3. I thought the thermostat was OK, but replaced it anyway. Same result, it would not get any warmer than 160F. Hmmm. So I wondered if TS/MT actually knew what the temp was. I checked against a thermometer and it was off by 10-20F. So, I searched around for a better calibration for the bosch sensors. The values I had were close, but I tried the more accurate values at the same temperatures. Still off... So I put in values at the temps that are listed for the GM sensors. -40C,30C, 100C with 45313,1707,187 ohms respectively and voila, the temps reported by the CLT and IAT appeared correct. It now goes out of warmup.

So, it appears that the math used to generate the values are dependent on using temp values close to the end of the range.

I received the steinhart-hart excel sheet from a MSExtra forum member and it generated a very close set of values even though I was using values closer to the mid points of the range.

KeithG

[LT401Vette]

Interesting... You probably already saw that TS outputs a log of the generated values in the project dir.

I'll compare the math I am using in TS to what is in the spreadsheet, maybe I can improve it if this works better.