peak detection/DAQ

[Alex_Polyakov]

Hi! I am new in LabView.

I try to solve a problem with a peak detection in signal. I use BNC-2110.

This is my input signal - graph above show just digitized signal, and graph under - signal with "mean".

I have found 2 suitable .VI. They found peaks, but in simulate signal. I have try to change this program for using DAQ-Date as input signal. But it was not successful, I have become many errors etc.

Can you advise me, where is a problem?

With best regards, Alex

[johnsold]

Alex,

First, the BNC-2110 is just a connector package, not a DAQ device.  The actual DAQ device may be a card installed inside the computer.

Are you able to acquire a signal? If so, just use the Peaks_ermitteln2.vi as a subVI.  Wire the data acquired to the "amplitude" control.

To use your VI as a subVI, you must define a connector pane (sometimes called a conpane), and assign controls and indicators to it.  That is the way data moves in and out of subVIs.

If you are not able to acquire a signal, please post your DAQ VI along with an explanation of the errors you see.

The sliding cursor and the beeps when a peak is found are nice user interface touches.

Lynn

[Steve'O]

Hi Alex_Polyakov,

Lynn is absolutely right. The best way is to use the examples in the example finder and his VI's.

Post your VI if you have problem with it.

Regards,

Stefan

[Alex_Polyakov]

Hi Lynn and Stefan!

Thanks for the answer!

But I have one dummy question - how can I use in this Example a Date from DAQ(PCI 6023E) instead of Simulated Signal?

With best regards, Alex

[Alex_Polyakov]

In this Example )

[Steve'O]

Hi Alex,

look for "peak" in the search window and now you can find the "Peak Detector.vi" or the "Waveform Peak Detection.vi".

Click on drop and then you can wire it with your DAQ Assistant VI or s.th. else.

Hope i've solved your problem 😉

Regards,

Stefan

[Alex_Polyakov]

🙂 I now about this peak detectors, but they show very many peaks instead of 1 😞

And in this Program (peaks_ermittlen) it was very good realized. But I don't understand, how can I change the type of Input Signal.

In this pic I have to draw, what i measure must - Time between 2 peaks 🙂

With best regards, Alex

[johnsold]

Alex,

Increase the threshold to about -0.84 and perhaps the width parameter.  There are many kinds and shapes of peaks.  The signal you are showing is rather complicated so the default parameters may not work well for that signal.  You have to make adjustments based on your signal and your requirements.  No one can really do that for you because you are the only one who knows what is important about your signals.

The valleys (negative peaks) below -0.847 seem to be relatively clean and consistent. (With one exception).  Perhpas you find the big valley then find the first peak after that.  This would eliminate the little peaks after the plateaus near -0.842.  This is a two step process but may be much more robust.

Lynn