Generate single sine pulse waveform

[lrallen]

Chan,

Have you measured across the AO and GND pins without the output on to see if there is an offset there?  There may be a problem with your card.  Also, what if you apply -3V offset to your output waveform?  Does the signal then look ok?  I realize that this is not an acceptable final solution.  I am just curious as to what would happen.  Maybe even try another output to see if you get the same results.  Let me know your results.

Regards,

Lon

[Jason_Chan]

Hi Lon,

Below are the results for the measuremenrt:

Measure the AO channel without any output signal

AO 0

DC = 251 mV

AC = 0.4 mV

AO 1

DC = 251 mV

AC = 0.4 mV

What should i do? Is my PCI 6120 card, ok?

Generate waveform using 1000Hz with amplitude 4V and -4V

Please see the attachment for the result

When waveform generated using amplitude 4V, the waveform offset to the top.

When waveform generated using amplitude -4V, the waveform offset to the bottom.

What is the problem? Is the problem cause by the vi? I also attach my vi here.

Please advise me. Thank you.

Best wishes. Chan

[Jason_Chan]

Hi,

When i tried with AO 1, the generated results are still the same with the results generated using AO 0. Thanks.

Best wishes. Chan

[Otis]

Hi Chan,

Could you try reading the AO voltage into one of the AI channels and see if you get the same behavior? 

It almost looks like the scope that you are using is doing some offsetting based off of the initial measurement direction.  If you can confirm it with the same board, then I think that would help.

Thanks,

[Jason_Chan]

Hi,

Thanks. Actually the measured value of the AO channel without any signal generated was done by a AI channel (with multimeter.vi). This offset behaviour only observed when 1 cycle sine waveform generated. No offset of the waveform when i generated continuous sine waveform. I wonder why? I need to solve the offset problem. Please do help me. Thank you.

Best wishes. Chan 

[Otis]

Do you get the same behavior when you do 2 cycles?  1/2 a cycle?

I've never seen a board do that before, and cannot make mine act the way yours is.  Do you have a different board that you could test it with.  Any M, E, AO, or S Series board should be fine to attempt to replicate this behavior.