Waveform Problem

[Tebefia]

Folks, for two weeks I have been having problem with the use of waveform chart, and no one has been able to help me figure out what could be wrong.  Here is the summary again:

My application is continously acquiring/logging waveform data, and am using USB 6218.  I have my number of samples per channels as 4096, and sampling rate as 13000.  When I set my X axis scale as from 0 to 20000, and Y scale as from 0 to 200, I do not see any plot on my Waveform chart, unless I set my Waveform Chart  X and Y axis as Auto Scale.  My repeated question is that why must set my Axis as Auto scale before I can see my plots, given the situation I just described, and what could I do to have my waveform chart set at the desired range?

I would be most grateful if anyone could just help me with a solution that has lingered on for three weeks as I try to develop my application.

Thanks in advance.

[camerond]

Actually, looking through your posts on your profile, you first asked this question on 10/23 (5 days ago, counting the weekend), not 2 (or 3) weeks ago in another thread. Thomas-B answered you a couple of times with what sounded like quite relevant advice. Do you understand how a waveform chart works? How long is your history setting? If you would post your code instead of jjust describing your situation, it might be much easier to help you.

Cameron

[Tebefia]

Cameron, thanks for your response.  I don't understand what you meant by Thomas-B answered me a couple of times>  You might want to read that thread again, please.  As a novice, I would say I know to an extent how a waveform works.  My history setting is set to 20001, since I wanted my X scale to range from 0 - 20000.

Thanks again.

[camerond]

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@Tebefia wrote:

Cameron, thanks for your response.  I don't understand what you meant by Thomas-B answered me a couple of times>  You might want to read that thread again, please.  .

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Well, in the thread, "Problem with Splitting my Four Channels and Amplitude Control," there were two (now three) posts by him to try to answer your question which you posted at the top of the current thread. That's what I meant.

I guess you decided to post your VI in that thread (for others who might be interested in the topic later).

Cameron

[Tebefia]

Camerond, thank you for your response.  Still on the same issue of waveform problem that I seem not to understand, and luckily for me , I found an example on NI website which I tried to modify and play with.  I have attached the vi to this thread and I would be happy if you could open it and run it with X axis set to 0-20000, and y axis set to 0-200.  You could modify it to have three channels, and 4000 samples per channel, at a rate of 13000 samples per second.  If you don't see a plot, then let me know what could been done in such a situation.  Believe me that would put a stop to all my questions concerning waveform.

Yes, I decided to attach my other vi to that thread, because Thomas-B responded immediately after you and exchanged message on this thread.  ALthough, he asked for a snippet, I decided to attach the vi for proper understanding of what am trying to know.  You can also be kind to respond on that thread.  Either way.

Thanks again.

[Tebefia]

Camerond, sorry I forgot to attach the vi few minutes ago. Here it is!