Waveform Chart - Polar Coordinates

[Phil747]

Hi,
I'm building an application to read a sensor called Double BallBar (DBB). It's used to measure radial error on machine tools. It uses a serial port and for now, I'm displaying this radial error on a waveform chart (Radial error amplitude vs time). What I'd like is to get exactly the same chart, but instead of having a flat line, I'd like to get a circle one. It's 'cause my DBB makes circular interpolation and it would be more significant to have its measurement on a circle chart. I'd define a nominal radius, then trace a circle as one extremity of the DBB moves around the other and measures radial displacement. In fact, it's just to change my actual chart that "opened" the circle to a polar coordinates one that would be more signif
icant. Is there a kind of chart I can use to do so?
Thanks for any help

Philippe

[Christian_L]

By converting your polar coordinates into carteesian coordinates you can plot your plot your data on a XY graph

Check out the XY Chart example in LabVIEW for some ideas.

..\National Instruments\LabVIEW 7.1\examples\general\graphs\charts.llb

Christian L
NI Consulting Services

[Phil747]

That's a good idea. My problem is that I don't know how to "catch" the time displayed by my waveform chart on X. What I could do, if I'd be able to use the time, is to use my 1D array of data (coming from the Double Ballbar) and to construct an other array with the time corresponding to each Y point. With that, I'd be able to build my XY chart with simple formulas as Rcos(t) and Rsin(t). I've studied a little the example "Real-Time Chart.vi" 'cause it's close to what I'm trying to do, but I'm not sure I understant how they get their time, and I and wondering if there's a simplier way to get that time, as the waveform chart easily do it. Thanks again for your help, I appreciate.

Philippe