Oat Survey

[landar]

I have noticed that the OAT on my '02 always seems to jump by 2 degrees F when it does change. So, I pull out of a warm(er) garage and the readout is 35. As I proceed on my way, the readout goes down due to the frigid winter temps...35, 33, 31, 29, 27, 25, 23. What?? Doesn't it like even numbers? Same thing on the way back up.

Now, I would think that as the temp sensor cooled it might hit consecutive numbers, but no. I mean, I can see a long sampling period to filter(average) out the changes but this is "redikerus".

If you have an OAT on your LS can you do a check next time out and report back your readout results/behaviour? Tnx

[landar]

I think I "fingered" it out. The temperature reading is all done natively in degrees Celsius THEN converted to Fahrenheit. Since Fahrenheit readouts are just a conversion, the ratio is 9/5 or almost 2x. Therefore, the micro is just converting the Celsius and rounding, hence the apparent jump by 2 degrees F. When the rounded C reading is close to an even F reading, the display shows an even value and it jumps by 2 until it gets to a rounded C value close to an odd F integer number and it goes odd for a while.

Lika so:

-2 C = 28.4 F = 28 F

-1 C = 30.2 = 30 F

0 C = 32 F

1 C = 33.8 = 34 F

2 C = 35.6 = 36 F

3 C = 37.4 = 37 F

4 C = 39.2 = 39 F

5 C = = 41 F

That is what is going on. Whew, I can sleep tonight! ;) :whistles:

[Micah.Berry]

Interesting!

[xrayangiodoc1]

I see the same thing in a wide variety of electronics with temperature readouts. The ones that show tenths of a degree will jump by 0.9 degrees F (0.5 degrees C).