05-19-2015 08:45 AM
Hi there, i'm nex to LabVIEW and encounter a matter testing my software.
I'm trying to generate a simple signal (Sinus Waves) read on a Tektronix (TDS 3012). The matter is that the number of sample per second doesnt seem right.
What i mean is that when i display : Sample/second = 2000 and a total of 1000 Samples, for a default signal (Frequency = 10 Hz / amplitude = 1V), it should last 0.5s ?
Instead, it last 1s and only display a 5Hz signal.
If you had any hint to help me, i would be glad to hear those !
05-19-2015 10:05 AM
Your example code shows Frequency = 1.00k (infos sur l'éch.). Did you see 10 cycles on your display? [Maybe it is doing what you told it to do, rather than what you want it to do ...].
Bob Schor
05-19-2015 11:32 AM
Thank you Bob Schor for your attention.
I'm bad at english so i might have made a mistake explaining my problem.
It's on the value "Sample per second" in the sample info.
For example, for those condition :
Sample infos :
_Sample per second : 2000
_Sample : 1000
_Frequency : 10 Hz
(_Amplitude : 1 V)
I though it would display 10 cycles in 0.5s, but it displays 5 cycles in 1s.
I tested it numerous times, and always get the same result. I think the matter comes from my card (NI 9263) that use and other "Sample per second" with 1000 by default (but its only a guess).
(An other exemple so that you might have a better understanding.
_Sample per second : 10000
_Sample : 2000
_Frequency : 10 Hz
(_Amplitude : 1 V)
I though it would display 10 cycles in 0.2s, but it displays 2 cycles in 2s.
Again, thanks a lot for your time.
05-19-2015
11:42 AM
- last edited on
11-16-2024
03:05 PM
by
Content Cleaner
You should set the sample rate of the DAQmx task, by default it will not use the sample rate of your waveform!
There also is the option to use the sample rate of the waveform - but you have to enable that behaviour…
Do you ever read the help for those functions - or do you read AppNotes provided by NI?
05-21-2015 01:48 AM
Thanks for the advice, i did not know of that page.
My matter isnt solve yet, but i now i will find the solution now.