calling an event structure via a LED?

[Vsh]

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johanneshoer wrote:

@Vsh:

1. and 3.: Better like this?

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I dont see much difference in the latter image except for the shift register wires are straightened a bit  

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2. How can I overgive a value to an event structure if the terminal of that value is already used somewhere else in the VI?

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Like altenbach has already mentioned you can use the entire False case (Pause) inside the event structure. You just have to add a value change event for Pause boolean. You can eliminate locals, and value signaling property also wouldnt be necessary.

[johanneshoer]

@Gerd,
all right, now I understand. Thank you again.

@altenbach:
My intention for using the event structure was the following:
If I have lots of data and because of that the change of X-scale minimum and maximum takes some considerable time. So I put it in an event structure to achieve parallel code execution, so that the modification of the X-scale does not slow down the rest of the program. Unfortunately the performance did not become better with the event structure, it semms to make no difference.

I already suspected that the continuously change of the array size would be a bottleneck. Thanks for the hint, I will change that, like you said. I try to keep the array size constant.

Greetings

Johannes

LabVIEW 7.1

[johanneshoer]

@altenbach:

It just came into my mind, the reason for modifying the array size or better say for adding and deleting data from the array was to obtain a "scrolling graph".

You understand what I mean?

By adding new data at the end of the array and deleting the oldest data in the first row, the graph in the chart moves from right to left.

How can I achieve a moving graph without excessive array operations?

Let me guess, I simply place a waveform chart and let it scroll? Am I right that I do not need any arrays any more?

Uh, if I had know that before, it would have saved me some work  

[johanneshoer]

Hmm.... Waveform Chart will probably not work, because I need the current time in the x-axle....

[elset191]

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johanneshoer wrote:
Hmm.... Waveform Chart will probably not work, because I need the current time in the x-axle....

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This thread may be useful to you.

[johanneshoer]

Thanks Tim,

but as you can see, I have an unsteady cycle time. I doubt, that a maveform chart would be the right chart in this case. Stil I would be happy, if I can avoid the array modifications somehow.

Message Edited by johanneshoer on 11-13-2009 08:22 AM

[johanneshoer]

Ok,

now I tried something different:

I do no longer add new data in a new element and do no longer remove old elements, but I simply replace existing elements in the data array with the new data. The graph does not depend on the index of the element, because the x scale of the chart is the data-time and not the index of the array 🙂 I also change the array size only if neccessarry, e.g. if the user zooms in or out in the chart.

I think this method is more efficient. Right?

But there is stil a bug:  

If I enlarge the data array (by changing the x scale time), new elements are added and filled with "0" and you can see that in the chart

Later these elements will be overwritten with new data.

With what should I fill the new elements so that the chart does not display them?

Message Edited by johanneshoer on 11-13-2009 09:52 AM

[johanneshoer]

Sorry there are some other bugs.

Please do not use the vis attached to this message. Somehow I can not remove them...

Message Edited by johanneshoer on 11-13-2009 10:06 AM

[altenbach]

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johanneshoer wrote:

With what should I fill the new elements so that the chart does not display them?

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Use NaN. 🙂

[Alain_S]

Using the help you could have found the "XY Chart.vi" that handles all the array stuff for you.