Averaging XY plot for hysteresis loop

[Benjosaur]

Hello,

I'm new to Labview, so sorry if this is a bit of a simple question.

I am working on a project that requires a hysteresis loop of a sample. The output from the reflected laser beam is plotted against the varying magnetic field in an xy plot, and is looped 'n' times. (Each loop lasts a period 't' and has a fixed 'i' number of points)

The thermal drift of the laser and magnet cause drifting overlayed plots and the whole hysteresis loop looks a mess (see picture). I need a way to average the XY-plot to leave me with one overall average loop to analyse.

One way I thought is to bin the value of each channel for each point in the loop, then to take an average of the bins to get an average xy plot. Another way could be to somehow plot each channel over period 't' and get the moving average of each, and plot those together?

I'm not overly confident with arrays etc in Labview, and so was wondering if anyone had a VI that I could use as a reference point, or could suggest another angle of attack?

Any help would be appreciated!

Thanks,

Benji

[DanBrowne]

Hi Benji,

I'm willing to put together a small example for implementing averaging using the array functions within LabVIEW. However, I was wondering if you could also post your code that you're working with, as I'd like to architect it properly for your code, so that you can add it to your code easily?

Regards,

Dan - Applicatons Engineer
NIUK

[CoastalLabVIEWER]

I have a somewhat related quandry to this.  I have a ehv controlled linear actuator that I am commanding over it's entire stroke and measuring the LVDT output for following error.  This curve will generate a hysteresis-like plot in that when extending the actuator there LVDT output will be slightly different than from when retracting the actuator.

From one channel I'm measuring the commanded set point and the other I'm measuring the LVDT output.  I'd like to know the maximum width of this plot and I have been looking through all the pallettes trying to find something that will do this comparison for me but nothing is jumping out at me that can do it.

[Christian_Hartshorne_NIUK]

Hi SmokeMonster,

A general word of advise - You will probably see a much better response if you post this question as a new thread since this thread is fairly old.

I hope this helps,

Christian Hartshorne

NIUK