generation train of alternative impulse with USB 6251

[rostov]

Hi all

My goal is generation on the output of USB6251 signal like:

<a href="http://s232.photobucket.com/albums/ee262/rusian24h/?action=view&current=formofsignal.jpg" target="_blank"><img src="http://i232.photobucket.com/albums/ee262/rusian24h/formofsignal.jpg" border="0" alt="Photobucket"></a>

The first, I maked VI "generating signal"(fllowing attached), after that I replaced sub VI "Basic fuction generator" in the VI "Multi-Fuction-Synch AI-AO" (in the library of examples of Laview) with VI "generating signal".

<a href="http://s232.photobucket.com/albums/ee262/rusian24h/?action=view&current=Outputanalogsignal.jpg" target="_blank"><img src="http://i232.photobucket.com/albums/ee262/rusian24h/Outputanalogsignal.jpg" border="0" alt="output signal"></a>

When program runs, signal on the output is only last 6 periods of signal. 

How can I output the whole of the signal?

Plz help me

Thank so much!

Message Edited by rostov on 05-24-2009 02:30 PM

[Aaron_W. · Accepted solution]

Rostov,

Thank you for using the NI Forums. I was able to see the same behavior that you are experiencing when you place your custom VI in the Multi-Function-Synch AI-AO. This behavior is because your custom VI was not outputting the data that you were expecting. When you wrote your data out you were placing it in a Waveform Chart and Charts have memory. So it was combining all of the data in the same chart even though it was only being written out in pieces. This is why when you place your VI in the other program you were only seeing the last couple periods. I have attached a VI that I made that will output the step that you are wanting, and I used a "Append Waveforms" VI to make sure all of the data is saved correctly.  If you place this VI in the code you should see everything correctly. Let me know if you have questions.

I have attached the VI in version 8.6 and 8.0, if you need a later version than 8.0 let me know. 

[rostov]

Thank Aaron W

Your VI runs very well.