nuckolls.bob(at)aeroelect Guest
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Posted: Tue Feb 16, 2010 10:05 pm Post subject: Temperature Probes |
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At 04:14 PM 2/16/2010, you wrote:
Quote: | Hi Bob and Ira
I am not at the hangar at the moment but took a look at data sheet:
http://www.st.com/stonline/books/pdf/docs/2158.pdf
TO-92 looks like what Ilec is using, you can see the adjustment on the datasheet I speak about, thus can match all senders so they are equal, then i can adjust my Ilec to read correctly from any sender. |
Yeah . . . that's the LM135 series devices I was talking
about. They have an initial accuracy of 1C or about 2F.
Doing the 'adjustment' means adding components at the
temperature sensor location or bringing the third wire
back to the instrumentation package.
Consider carefully if you need better accuracy and
how hard you're willing to work to achieve it.
Quote: | We are all on the same page. I may have confused speaking how Ilec does things, since they are only meant for 1 sender, they do hocus pocus in their unit to adjust and compensate for any tolerance error on senders part. |
Yup, that's the offset and scale factor constants that
I mentioned for the software that reads my DAS . . .
Quote: | In my case forcing the unit that is already installed to read correctly off of multiple senders, i will just adjust all senders to be equal, then adjust unit. |
That will get your offset covered but see how
close they are without fiddling. If you need tighter
accuracy, then it might be worthwhile to consider
the LM135Z with an out of the box initial accuracy
of 0.5C or about 1F.
Even off the spool thermocouple wire is only +/-
2C stuff. The thermocouple signal conditioners add
another couple degrees uncertainty. I can't ever recall
a situation where we needed more temperature accuracy
than the unadjusted products offered.
Bob . . .
[quote][b]
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