plot the figures in the same chart

[dapeng]

Hello everyone,

Now I am doing the analysis with FFT. I get different power spectrums of the signal when I change the conditions. From one chart I just get the latest figure of power spectrum (it means that this chart will refresh every time). 

To compare figures easily, I hope that these figures are shown in the same chart. How can I make it like this? Because I use the same sampling rate (N Samples style), so the x-axis of these figures are the same.

I have read something about XY-graph, but in my case I can not plot these figures (at different conditions) at the same time.

Any suggestion will be so appreciated!!!

Thank you!

Dapeng

[Norbert_B]

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@dapeng wrote:

Hello everyone,

[...]

 From one chart I just get the latest figure of power spectrum (it means that this chart will refresh every time). 

[...]

Dapeng

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Dapeng,

from this sentence, i asume that you are working inside a loop. So just a little hint: What, in general, do you need in order to know the past?

hope this helps,
Norbert

[dapeng]

Hi Norbert,

Thanks for your reply.

I don't use any loop and as you said I want to get all of the figures in the same chart. I have attached my vi and hope you can help me!Thank you.

Dapeng

[Norbert_B]

---

@dapeng wrote:

Hello everyone,

 [...]

I get different power spectrums of the signal when I change the conditions. From one chart I just get the latest figure of power spectrum (it means that this chart will refresh every time). 

 [...]

Dapeng

---

Dapeng,

looking into your VI and reading the quoted text, i asume that you re-run the VI several times. In each run, you get 250k samples and make your FFT on them. The result is displayed in the graph. When you rerun the VI, you want to keep the old "graph" and add the new result. Is that true?

If yes, you have to create a loop in your VI, use some kind of memory (e.g. shift register) to store the results from previous iterations and add the new result before displaying the result-collection on the graph.

hope this helps,
Norbert

PS: DO NOT use the run continuous button. NEVER!

[dapeng]

Hi Norbert,

Your suggestion is very helpful. Now it works. Thanks a lot!!

Dapeng