Phase lag of analog input with NI USB 6009

[iygu]

Hi,

I'm trying to aquire analog signal with NI USB 6009 using LabVIEW. (The signal is 50Hz from functional generator.)

However, the aquired singnal has dynamical phase shifting which is NOT observed by my oscilloscope.

I have no idea why this phase shifting happens.

Any information is welcom. Thank you for reading.

[Blokk]

If you post your VI here (as attachment, or a png snippet), there is a bigger chance you get help.

[iygu]

Thank you for your reply.

Here is the image of the test VI.

 (Somehow I can not post my VI file...)

[Blokk · Accepted solution]

An image file will not help. Post your actual VI. If Firefox does not work, use Explorer or Chrome to attach your VI(s)!

You have here a subVI, I cannot see what is inside and how it is configured. Besides, this while loop is silly: there is no control button to stop it running. Never use the red abort button for normal stopping of a VI!

Why did you configure NChan NSample ? You are talking about measuring a single signal, yes? So use 1 Channel only.

edit: why do not you play first with a given example shipped with LabVIEW?

From your LabVIEW, go to Help menu --> Find Examples --> Hardware input and output --> DAQmx --> Analog input --> and open the "Voltage - Continuous Input.VI" !

Use this VI to sample your analog signal.

[iygu]

Ahh, still I cannot post my VI file with Chrome, IE, Firefox...

Anyway, because I wanted to check continuous waveform, I used while roop. And I used to use the red button for nomal stop... I'll never do that, thank you.

I used NChan NSample to check multiple input signals, but in this case it should be used as single signal. So the answer is yes.

And, you're right. First of all, I try to use the example.
If the problem is still not solved, I gonna post again.
Thank you again, Blokk!

EDIT: The example seems to be fine! Input signal's phase is much more stable.

Thank you Blokk. If there is problem, I will ask here again.