Peak detection (threshold detector) from spreadsheets.

[Ivan899]

"According to them" - according to datasheets I mentioned above. "System" - is VI we are trying to optimize.

Thank you very much! I am going to try  to find the reason why we interpret the same datasheets in different way and why graphs differ so significantly.

[Omar_II]

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@johnsold wrote:

Do you want peaks or thresholds? You seem to be using the terms somewhat interchangeably while they actually refer to different things.  From the way you seem to be using the results I think you want thresholds.

I had composed a reply going into great detail about the differences between peak and threshold and how the numbers would be different, but stepped back, took a deep breath and deleted it.

[Ivan899]

Okay, I have two waveforms. I need to detect the moment when signal exceeds a certain threshold (e.g. 0.2V). Then to do so with another channel waveform and finally compare them to find time difference. I am interested only in first rising edges.

Yes, I have read the white paper.. I think it worths to try Threshold Detector.vi as well.

I do understand difference between a threshold and a peak. I need a threshold, you are absolutely right.. 

[Omar_II]

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@Ivan899 wrote:

"According to them" - according to datasheets I mentioned above. "System" - is VI we are trying to optimize.

Thank you very much! I am going to try  to find the reason why we interpret the same datasheets in different way and why graphs differ so significantly.

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There is no differance between your datasheets ("them") and the LabVIEW VI (System)

They both agree.

From Datasheet S2a CH2.CSV

4048	1.60E-09	0.088125
4049	1.80E-09	0.179156
4050	2.00E-09	0.299187
4051	2.20E-09	0.44675

Cross over 0.2 between 4049 and 4050

LabVIEW VI reports 4049.17 (interpolation)

From Datasheet S2a CH4.CSV

4041	2.00E-10	0.051781
4042	4.00E-10	0.1165
4043	6.00E-10	0.37675
4044	8.00E-10	0.859969

Cross over 0.2 between 4042 and 4043

LabVIEW VI reports 4042.32 (interpolation)

[Ivan899]

Probably I received different results because of interpolation that I did not apply.

[johnsold]

I only wanted to clarify your requirements. I did not intend to be critical. Many times it is difficult to tell what someone understands.

First edge and threshold is more straightforward than many of the other combinations.  Here is the way I would do it using Threshold 1D Array.

Lynn

[Ivan899]

Lynn, thank you!

Probably I need to run this VI on another PC because again there is something wrong with graphs or their settings and results are zeroes. 

[johnsold]

I have no idea what is going on when you run the VI. Here is what I get with the files you posted earlier.

I noticed that the subtracts in the dt calculations have their inputs reversed.  dt is not really negative.

Lynn

[billko]

Hey, I see that several people are helping you now.  Excellent!  🙂

[Ivan899]

Thanks very much!  It all works on another PC!