Exact match. Not showing close matches.
PICList
Thread
'[EE]: Why SteinhartHart equation...?'
2001\04\19@095713
by
Jose S. Samonte Jr.
Hello to all! =)
In my project, I've used the SteinhartHart equation to linearize the output
of the thermistor, because I have found out that it is the most commonly used.
But my professor wants a much better reason why I used
SteinhartHart equation. What could be much better reasons, why SteinhartHart
equation? He said that there are other equations that could be used. Are
there? Please help me.
Thank you very much and God Bless.
Best regards.
____________________________________________________________________
Get free email and a permanent address at http://www.netaddress.com/?N=1

http://www.piclist.com hint: The PICList is archived three different
ways. See http://www.piclist.com/#archives for details.
2001\04\19@101627
by
Eisermann, Phil [Ridg/CO]
The SteinhartHart equation DOES NOT linearize the the output of a
thermistor. It is really a curvefitting function for resistance vs.
temperature. Put another way, it is a mathematical model of the thermistor's
behavior in response to temperature. The reason that people like to use it
is because it is an extremely accurate model over a very wide range of
temperature.
{Original Message removed}
2001\04\19@105108
by
Scott Dattalo

On Thu, 19 Apr 2001, Jose S. Samonte Jr. wrote:
> Hello to all! =)
> In my project, I've used the SteinhartHart equation to linearize the output
> of the thermistor, because I have found out that it is the most commonly used.
> But my professor wants a much better reason why I used
> SteinhartHart equation. What could be much better reasons, why SteinhartHart
> equation? He said that there are other equations that could be used. Are
> there? Please help me.
Tell your professor that you use SH because everyone else does, but after
becoming an experienced PIC programmer you've discovered that a look up table
with first order interpolation is the best way to "linearize" a thermistor with
a microcontroller.
He'll say , "True, but why?"
And you'll say, "Well Sir, it's obvious. With the SH approach you have to
compute these really nasty logarithms and arithmetic operations. All of that
just to get 1 or 2% accuracy. However with a lookup table it only takes about 20
CPU cycles to get an answer that's accurate to with in a 0.5%. However, I found
that the look up table can only give you this accuracy after the thermistor has
been carefully calibrated. In other words, with the SH equation I found my
compuatations suffered from cumulative round off errors but the lookup table is
accurate as the data in the table."
"Hmm. 20cycles for 0.5% accuracy? Amazing! How did you do that?"
"Sir, I only tell you if you give me an A+."

What do you think, Jose? Will he like that?
Scott

http://www.piclist.com hint: The PICList is archived three different
ways. See http://www.piclist.com/#archives for details.
2001\04\19@105925
by
Alan B. Pearce
More... (looser matching)
 Last day of these posts
 In 2001
, 2002 only
 Today
 New search...