At 11:17 PM 5/18/00 +0100, you wrote:
>>If I understand your question, you wish to use a thermocouple to measure
>>a temperature from 0 ~ 70'C, using a preamplifier designed for 0 ~ 900'C.
>>I would dissuade you from attempting this.
>
>No, I am wanting to use the entire 0-900oC range to measure temp on a jet
>engine.
>I need to be able to use this info as part of a loop-back control system -
>this is why i need to get this into a pic with usable figures.
>
>Aaron

Hi, Aaron, where does the 0.28 volt in your original post come from?
I thought you might be using (0.28/3.6) of the span for 70'C.

Anyway, if you use an external 12-bit A/D you will get around 0.2'C
resolution. If you use one of the 20+bit delta-sigma converters, say
from Linear technology you can get more resolution and also the noise
level will probably be a lot less.

Once you have it in 0-3.6V form the rest is relatively easy. Of course
it won't be linear, and you may have to deal with that. I assume your
circuit is taking care of the cold-junction compensation.

Does this answer your question? I'm a little hazy on what you need.

Best regards,
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