new 6210 gives me strange waveforms

[gliangdu]

just got a new 6210, used to use 6008 but needs higher sampling rate. Use the same setup as our 6008 (connections, software, etc) The device was fine in the lab (tested in both XP and win7), no load test gives the sin wave.

We take this device to peoples' houses,doing the no-load test, which should give the household voltage waveform, which is sin, but the result is attached.

sampling rate is 30.72k, using Labview 8.5 professional, device is OK in Measurement & Automation

does anyone have idea why is this? 

[HeatherBaker]

Hi gliangdu,

What are you physically connecting to?  Are you using an external circuit?  The front end circuitry for the 6008 will be different than the 6210.  What is different in the lab tests compared to the home test?  Since all of the values are cut-off above approximately 2.5V, then I would try a known signal that is higher than 3V.  Do you see the same behavior?