[Novalug] Calibrating temperature settings

Nino Pereira ninorpereira@gmail.com
Sun Apr 10 10:29:27 EDT 2011


I've always wondered: are those temperature measurements done with a
resistive thermometer, or do they do it with a silicon thermometer,
that is, from the way the current through a silicon diode changes with
temperature?,
(IIRC, the current is exponential with temperature T, ~exp(-kT/E),
with E silicon's
band gap.

Nino




On 4/9/11, steve zamory <zemo@safe-mail.net> wrote:
> With a separate contact thermometer mounted as close as possible to the
> point of interest, make two measurements. The first serves to correct the
> offset. The second, at a distinctly different temperature, is used to
> correct the slope. Only two reference points are required because, in the
> range of interest, common resistive thermometers respond in a linear
> fashion. The most difficult part is getting the thermometer on the hot spot
> which is under a big, possibly permanently attached, heat sink.
>
> Referencing the BIOS at boot time is not useful. The temperature can change
> too drastically in very short order.
>
>
> On Sat, Apr 9, 2011 at 3:58 PM, Jon LaBadie <novalugml@jgcomp.com> wrote:
>
>> There are several apps to display the various temperature
>> sensors eg. cpu, gpu, mb, disk, etc.
>>
>> Typically these apps let you tune the display with an
>> by specifying an offset and slope.  By adjusting these
>> I can make it look like the sensor is about to melt or
>> is sitting in a puddle or liquid nitrogen.
>>
>> Is there a way to determine the proper settings for
>> the offset and slope?
>>
>> An approach I've taken is to match the temps to those
>> reported in the bios at boot.  I leave the box idle
>> for a while.  I then note the temps and reboot.
>> During reboot I check the readings in the bios and
>> upon logging in, adjust the offsets to match the
>> sensors to the bios readings.
>>
>> Right now my cpu reading says 42C and my gpu 62C.
>> But what are the correct values I have no idea.
>>
>> --
>> Jon H. LaBadie                  novalugml@jgcomp.com
>>  JG Computing
>>  12027 Creekbend Drive          (703) 787-0884
>>  Reston, VA  20194              (703) 787-0922 (fax)
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>



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