02-15-2017 05:06 PM
I have been working with the VIs from this thread:
http://forums.ni.com/t5/LabVIEW/Problem-Fitting-Lev-Mar-with-Error-Function/m-p/2716045
My modified VIs are attached.
It functions correctly for good data, but I'm confused how to modify the code so that I can fit low threshold data. For example:
I've attached a fit for data taken at a 20mV charge injection & 5mV. There are 1000 reads, & so 1000 hits means the transistor is reporting 100%. For 20mV, below the threshold transition there's 100% hit. But for 5mV, the transistor is only marginally working below threshold, and so the fit calculates the 50% hit crossing point out of 750 hits instead of the real 1000.
How can I modify the fit so that the range parameter doesn't change (1000 no matter what the data)?
02-16-2017 04:38 PM
Hi bbentelin,
Have you tried turning off the autoscale for the y-axis? If you right click on your graph and click properties, you can go to the Scales tab. There is a dropdown list at the top of the page where you select your axis, so in your case the y-axis. Beneath it is an Autoscale checkbox, and if you unselect that and select the range you would like to appear, I think that should work.
Let me know if this is what you're looking for.
02-16-2017 05:31 PM
No no, It's the fitting calculation I'm asking about.
There are 3 parameters --- range, 50% crossing & slope. I'd like to set the range as a constant so that the fitting calculation only varies the slope & crossing point.