waterfall plot

[Duc]

Hi all,
I am using the AmplitudeAndPhaseSpectrum.vi to analyse waveforms for a vibrating shaft. What I really need is a waterfall plot of the spectrum with changing shaft speed (shaft speed being on the Z-axis). I looked at PictureWaterfallSpectrum.vi, but not sure if it is the right one to adopt. Please can you advise me where I can find a another/better example. Thanks in advance.

[chutla]

You can also use the intensity chart. Since shaft speed is your independent variable, I wouldn't use that as the Z axis. Z should always be used as a dependent variable, in your case amplitude of vibration. X and Y can be shaft speed, and sample. (I assume you are changing some configuration, such as thickness of the shaft, as well.)

Eric

[chutla]

You can also use the intensity chart. Since shaft speed is your independent variable, I wouldn't use that as the Z axis. Z should always be used as a dependent variable, in your case amplitude of vibration. X and Y can be shaft speed, and sample. (I assume you are changing some configuration, such as thickness of the shaft, as well.)

Eric

[chutla]

You can also use the intensity chart. Since shaft speed is your independent variable, I wouldn't use that as the Z axis. Z should always be used as a dependent variable, in your case amplitude of vibration. X and Y can be shaft speed, and sample. (I assume you are changing some configuration, such as thickness of the shaft, as well.)

Eric

[alipio]

Hi Duc
I found an example in my vis library. I don´t know where I got it or who is the author.
Hope it helps you
Alipio

[Kianoosh Motallebi]

Hello

I'm new to labview and I'm having problems with waterfall displays. I need to acquire samples from two channels of a pci mio 6014e with bnc block 2010, and display them simultaneosly on different waterfall graphs? When I use any of the examples in labview I get an error stating that the application is already in use. Any idea's?

Kianoosh

[Coal_Man]

Kianoosh,

How are you acquiring the data?  Are you using Traditional DAQ or DAQmx?  It sounds like the device is already acquiring data when you run your code, so make sure that you are not running another acquisition on the same board at the same time.  Also note that you can only create a single virtual channel to acquire data on that board at one time.  You cannot create two channels on the same board and run them at the same time.  To acquire data on two channels, use a single virtual channel with two physical channels being acquired.  Would you mind posting some of the code you have written, or a screenshot of the error?

[Kianoosh Motallebi]

Hi and thanks for you help. I however don't understand what you mean. I use MAX with daq assistant and When I acquire signals on two channels ( differential ) it simply works. My signal is differential voltage. I can plot all the channels on my pci mio 6014e. Can you explain what you mean when you say "You cannot create two channels on the same board and run them at the same time". I can graph two channels at the same time, with a waveform graph indicator,  it just doesnt seem to work waterfall displays.

[Coal_Man]

Ok, so the problem is not the data acquisition.  I was confused as to what the error you were referring to was.  Have you looked at the example on waterfall graphs located here?:

http://zone.ni.com/devzone/cda/epd/p/id/1425

It is very similar to what you are trying to do I think.  In fact, I set up a similar VI with 2 waterfall graphs with just a few minor edits.