Multichannel Acquisition:Problem

[Dmitri Eskine]

Dear All!

I have a problem. I am using a Keithley KPCI-1801HC card in a
32-differential mode. Three inputs are in action: K-thermocouple, LVDT
(+-5V) and pressure sensor (0-10 V). In the Labview VI I use three
Scan-One-Channel.VI in the while loop (about 50 points per sec per ch). I
have huge effect of voltage coming from LVDT and/or pressure sensor on the
temperature reading. At the same time, the independent Keithley Analog I/O
panel shows correct and stable readings.

What is the problem: is it the problem of LabVIEW drivers of subVI provided
by Keithley or I am using wrong subVI for data acquisition.

Can somebody give me a program for multichannel acquisition where is would
be possible (1) to simultaneously write the
time and data and (2) to process
data from different channels prior to writing in a file.

With many thanks in advance.

Dmitri


--
Dmitri Eskine, PhD
Laboratory of Materials Science
NIMR, Rotterdamseweg 137,
2628 AL Delft, NL
tel: +31 ( 0)15 278 4463
fax: +31 (0)15 278 6730
e-mail: D.Eskine@tnw.tudelft.nl

[Ronald]

Looks to me if you're using the wrong data-acquisition vi. Take more samples
per second and do some simple averaging. For instance. Instead of scanning
50 points / sec. Try 500 points per second and average every 10 points.

Ron@ld

Dmitri Eskine schreef in berichtnieuws
99psjj$ai8$1@news.tudelft.nl...
> Dear All!
>
> I have a problem. I am using a Keithley KPCI-1801HC card in a
> 32-differential mode. Three inputs are in action: K-thermocouple, LVDT
> (+-5V) and pressure sensor (0-10 V). In the Labview VI I use three
> Scan-One-Channel.VI in the while loop (about 50 points per sec per ch). I
> have huge effect of voltage coming from LVDT and/or pressure sensor on the
> temperature reading. At the same time, the independent Keithley Analog I/O
>
panel shows correct and stable readings.
>
> What is the problem: is it the problem of LabVIEW drivers of subVI
provided
> by Keithley or I am using wrong subVI for data acquisition.
>
> Can somebody give me a program for multichannel acquisition where is would
> be possible (1) to simultaneously write the time and data and (2) to
process
> data from different channels prior to writing in a file.
>
> With many thanks in advance.
>
> Dmitri
>
>
> --
> Dmitri Eskine, PhD
> Laboratory of Materials Science
> NIMR, Rotterdamseweg 137,
> 2628 AL Delft, NL
> tel: +31 ( 0)15 278 4463
> fax: +31 (0)15 278 6730
> e-mail: D.Eskine@tnw.tudelft.nl
>
>