How to enlarge the range of Y scale set by auto scaling?

[jingliu]

Hi, there,

When I enable the auto scaling of Y axis of a waveform chart, the extremums of Y scale equal to those of the curve displayed in the chart, i.e. maximum of Y scale = highest point of the curve, minimum of Y scale = lowest point of the curve. Is it possible to enlarge the range of the Y scale when auto scaling is enabled? Say, set  |Ymaximum -Yminimum|*80% = |Value of highest point - value of lowest point|

Thanks in advance!

[Graziano]

Hi!

   I think you're talking about Loose fit property. If you enable "loose Fit" in your "edit axis settings" window, you can change the llose fit factor. Actually I never used it, but it should be what you're looking for!

  I hope this helps! Have a nice day!

graziano

[jingliu]

Hi, graziano,

Thanks.  I've already tested it.  I found that when curve went up, the maximum of the scale was really a little higher than the highest point of the curve, but when curve began to go down, the maximum of the scale then became the same of the highest point of the curve. My problem is still unsolved.

By the way, how can I change the loose fit factor? I read in the labview help that If loose fit is set to be TRUE, LabVIEW rounds the end markers to a multiple of the increment used for the scale. Do you mean that I need to change YScale.Increment?

Jing

[Graziano]

Hi!
   Are you using LabWindows or LabVIEW?

   In LabWindows, when you check "Loose fit" flag, a numeric control becomes active: there you set "loose fit units".  For a detailed description, look in help pages.

   Hope it helps!  Have a nice day!

graziano

[jingliu]

Hi, graziano,

Thank you! But I use LabVIEW. I think this requirement is not a very proper one for a dynamically updated chart. Maybe I'd better use a static chart to show the long-time history, then I can set the parameter of the chart according to the existed data.

Cheers, Jing

[RobertoBozzolo]

"Loose fit" is available as a property of the graph: you can select either at design time right-clicking on the graph and selecting Y axis >> Loose fit in the context menu or at run-time via a property node (property Yscale.LooseFit).

[jingliu]

Hi, Thanks, But I'v already did this. I have no problem to do with Loosefit. but It seems loosefit is just not a final solution to my original requirement.