filtering waveform data

[bgeist]

Hi, I am fairly new at LabVIEW and have the following question:

I have an 8 channel waveform data  that I would like to filter out all of the times the channel 8 is below a user specified value.  When I use a Build Table VI, it bogs the program down.  When I do a simple conversion to an array, I lose my time values for the waveform.  Is there any way I can sort the data without losing the time value for each sample set or having the program bog down?

[Cory_K]

How about something like this

Get the components of your old waveform. Use in range and coerce to check if it is in the range you want.

If it is, add it to the new array. If not, ignore it.

Lastly, build a new waveform, with only the points that were in the range.

I attached this VI if you would like to use this code.

[Ben]

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Cory K wrote:

How about something like this

Get the components of your old waveform. Use in range and coerce to check if it is in the range you want.

If it is, add it to the new array. If not, ignore it.

Lastly, build a new waveform, with only the points that were in the range.

I attached this VI if you would like to use this code.

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Please note that the approach posted by Cory will remove the values that are out of range

AND

subsequent values will be shifted (left) into the time-slot where the out- of range value WAS located. If the shifting is un desirable, use a vairation of Cory's code that replaces the out of range value with a "NaN". This will maintain the timing AND will give you a gap in plot where the deleted element was.

Just trying to hlep,

Ben

[bgeist]

One more problem.  Since it is eight waveforms, it is a dynamic data type.  How do you convert the VI?

[bgeist]

I do need to maintain timing and I will have potentially a million values to filter out between reads.  How do I completely throw out the unnecessary rows?