A problem about lowpass filter of Scxi-1102

[hanwei]

Hi all:

 I meet a serious problem about lowpass filter of SCXI-1102.

Actually, I want to use PCI-6040E + SCXI-1102 + SCXI-1300 to test rising edge of pressure signals. Now the problem is that I can not get the right rising edge signals. The corresponding screen capture pic are attached below. The first pic is showing the rising edge measured by other two DAQ equipment (Dactron and HP oscilloscope). the second pic is the signals from NI DAQ equipment.

It seems, the oscillation of signals are realized as noise by low pass filter of SCXI-1102??

In the Pic, the frequence of oscillation is less than 100hz, and the cut-off frequency of Scxi-1102 is 2HZ, (to reject 60HZ).

Is my problem is this??

Thanks s lot

Wei

[AnalogKid2DigitalMan]

Wei:

Your pics did not attach to your post.

-AK2DM

[hanwei]

sorry about that, I forgot to post.

here I post a detailed comparision between NI and another DAQ equipment. and screen capture pic

thanks so lot

[hanwei]

sorry to bother, but it is really a problem of great urgency.

 I just want to make sure this probram is something about lowpass filter and whether I need a another 1102 module (B or C) with high cutoff frequency, or can I switch off the lowpass filter for SCXI1102.

Thanks again

Message Edited by hanwei on 12-12-2008 12:36 PM

[Jason_D]

Hi hanwei,

The pictures you have provided here show a signal on each, but are of different amplitudes?  Are these the same signals?  Are you doing some sort of scaling?   What is the specific model of the Dactron scope you are comparing the 1102 with, or can you provide me with a link to their specifications?  Are you expecting to see the oscillating signal?  What kind of pressure gauge do you have what is its model number and specs?

Message Edited by Jason_D on 12-15-2008 01:03 PM