Waveform generation VIs

[MogaRaghu]

When a waveform generation VI is used in code, will it not keep generating as long as the code is active,  till the Reset node ( if available ) is pulled high ?

But it appears that to do so, the waveform VI has to be inside of a  while loop. I tried to run a while loop and a function generator VI outside of it as a trial . But found that, after the first call, the waveform VI was idle and it was only the while loop that was executing. Can someone clarify on this.

I would have expected that the function generator VI  to start and continue till the whole code containing it is stopped. Is that too much to expect

Raghunathan

[Dennis_Knutson]

I think you're totally confused about the purpose of the function generator. It outputs a waveform of a specified signal type, at some sampling rate, and the number of samples you ask for. It does not do continuous generation unless you put it inside a while loop. I don't know how else a software function would work.

[MogaRaghu]

When under time pressure, there are occassions that even some fundamental items fail to register.  I guess this query of mine was borne out of one such  incident.

I tried out some basic code  using the function generator  with a chart and now its quite clear. In fact had I mot missed  this  line in the  help  document of the basic Function Generator .vi, things would have been quite clear :

" This VI remembers the time stamp of the previous waveform generated and continues to increment the time stamp from that point."

Raghunathan

[craige]

Along the same line, I noticed the same comment in the help file:

"This VI remembers the time stamp of the previous waveform generated and continues to increment the time stamp from that point"

Seems to me that the VI should be keeping track of the Number of Samples and the Sample's Per Second based on the last time the VI was run (whether in a loop or not) So why is it that this VI seems to rely on the sampling rate of the loop itself? If I increase the Millisecond Wait Time my generated signal slows and when I decrease my millisecond wait time my generated signal updates much faster.

 Run the attached VI (LV 8.2.1)

Message Edited by craige on 10-27-2008 11:22 AM