high-precision temperature and voltage logger

Hello again,

I sent an email earlier about thermocouples and got a few responses.
Some suggested to use any type of ADC, but the specs I have are very
tights.

1/ Reading accuracy as close as possible to 0.01 deg C
2/ Compact solution (PCI preferred)
3/ Should work on linux.
4/ Low cost ;-)

As far as the hardware goes, I found that only the NI PCI-4351 is
getting close to my requirements. Indeed its accuracy is 0.03 C when
connected to thermistors. Price is also reasonable ($795).

This ADC was specifically designed for temperature measurement.
Any ADC could not do as thermistors need a stable current source. This
ADC provide the current source.

For those who do not know, thermistors are resistances that change
according to temperature. But since the ADC measures the voltage (V=R*I)
and not the resitance, then the supplied current intensity needs to be
very stable.

It is clear to me that for my tight requirement, I need 24 bits ADC and
thermistors.

Earlier this afternoon, I spoke with my manager and we commonly decided
that we could pay a consultant to develop the NI PCI-4351 driver. 
Now the issue becomes where to find the expertise. Our need is somewhat
urgent.

If anyone of you is capable of writing this driver in a timely manner,
then please contact me directly at 650/793-0626 or at emmanuel_mayssat
(at)lynceantech.com. Hefty compensation and fame is just around the
corner. ;-)

PS: Of course, if this driver is ever developed, it will be open-
sourced. Viva comedi!

-- 
Emmanuel Mayssat
Cell: 650/793-0626
Lyncean Technologies, inc.
"See the invisible"

Received on 2005-09-09Z22:16:16