Hi yangshanglu,
In your LabVIEW VI, are you displaying the waveform on a
graph or on a
chart? A
chart will put the real time on the x-axis, whereas a
graph will put the relative time.
To put a Waveform Chart on your Front Panel in LabVIEW 7.1, right-click and select Controls » All Controls » Graph » Waveform Chart. A Waveform chart should show the absolute time.
I hope this helps!
Regards,
Erik