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two polar plot in same program

Hi All,


I am having some problem two polar plots inside one program. I am going to have two systems running at the same time but each of them will have their own Speed & Vibration signals and then will create two polar plot for balancing reference. Here somes my problem, program is not giving any error message but one of my polar plot is not showing up anything at all. Is it possible to plot two polar plot in same program? Or can we plot two different system (each of them will have 1 vibration signal, 1 speed signal (total 4 signals) within one polar plot?


I am attaching two files please have a look. You will need with the main vi. Thank you very much in well advance.





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I tried to run the code on my machine and neither polar plot gave any output.


As far as I am aware there should be no reason why you cannot have two polar plots within the same VI.


Have you made any progress with this since your initial post?



Best regards,

Stephen C
Applications Engineer
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Hello Stephen,


If you zoom in first polar plot to 5E-3 then you will see something on the first polar plot. But second polar doesn't seem to show anything at all. I have been trying tto find the problem in between I found one more problem thst is, the whole Bode & Polar plot Function in LabVIEW is taling too much time to generate magnitude and phase output which leads to not getting any data in low RPM for Speed up or Speed Down. As you know we can get magnitude & phase output from Bode & Polar function but sometimes it does take near about 30 seconds to generate any output for magnitude & phase indicator till then it just show zero in both fields. I checked the analog speed signal input was fine but speed output from Bode Function indicator was showing NaN.


As far I think if we got any speed signal and any amount of vibration signal it should show us the magnitude & phase output or do we need any specific amount of signal for both of them?? I tried plotting Bode plot (Magnitude/RPM) for Speed down, somehow I am not getting any magnitude output between 0-9000 RPM & 55K-60K RPM, I am getting nice output between 9K to 55K.





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In answer to your initial question, yes it is possible to output two polar plots within the same program, although your code has been edited to allow this.


Regarding the code you attached, the arrays shown in the .png attachment have been removed.

Using data from the simulate signal express VIs, you have built an array with elements 1&3; and also 0&2, coming from the same signals.
Using this built array, you then extracted elements 1&3 before merging them back together and therefore have counteracted the previous actions. What were
you trying to achieve by this?


Other amendments made to the code were to increase the number of samples taken, and therefore allow the necessary amount of points that the polar plot needs. What I also changed was to go into the "Bode & Polar" Express VI and click on details of the warning (which said that we didn't have enough samples) and select the "on errors, show details immediately".


The speed of excecution was also improved.

In the "Polar Plot" vi, double click on the "Simulate Signal" Express VI (to bring up a menu) -> Timing -> select "Run as Fast as Possible".


Hope the attached VI solves your issues!


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