Noise with NI 9201

[ZacReeves]

I read other questions about similar problems, but there is certain things that seem different in our situation.  I am using a NI 9201, connected to a signal conditioner and then to an accelerometer.  There is always a lot of noise but our current concern is that there is a constant 150Hz spike on the power spectrum.  This is there no matter what location the accelerometer is in, even if it is just laying on the table.  This is the case even if the beam we are testing is being excited at any range of frequencies, the 150Hz is still the dominant spike.  The main thing we realized today was even with the 9201 unplugged from the signal conditioner, that 150Hz is still there, so without even an input its still prevelant.  We tried different ground techniques but nothing seemed  to change it.  The following is a picture of what I am getting from the 9102 with nothing hooked up to it.

http://i10.photobucket.com/albums/a119/z4cr33v35/signalunplugged.jpg

[muks]

Have you seen this?

Also I am not able to see your jpg image.

[ZacReeves]

Thanks for the suggestion, I did find that thread previously but still could not fix the problem.  Today we decided to just try another device and switched over to a NI USB-6216.  This gave wonderful results, very low noise, no 150Hz spike and the recorded signals show exactly what we have been looking for. Here is the picture I tried to post a link to.

[Efrain_G]

If you connect a battery directly to the NI 9201, do you still get that noise?