Center of pressure graph

Question

Hello,
Currently, I'm trying to create the COP graph to show the position of food steps. I have 3 channels, channel 3 is the Fz( Force in z direction), Channel 4 is Mx( Moment in x direction), and Channel 5 is My( Moment in y direction). To calculate X position, I do -My/Fz, and for Y position, I do Mx/Fz. According to these formula, when Fz is zero( no force in z direction), the output value should be undefined. Right now, I put those two output values into a XY graph with the "select" function, so when the output value is undefined, show 0 in the graph, if the output value is a number, show that number in the graph.
As you can see in my block diagram screen shot, I have everything wired correctly, no error appeared. The graph did show nothing when no z-force. However, when I have a force, the graph still not showing anything, the graph is changing the size( I have auto scale on) but nothing appeared in the graph. I'm wondering if there anyway to fix this problem. I dont know if theres any icon can tell u this number is undefined, so I use "Not a number/path/Renum" icon.
Thank you,
CKH
Attachments:
COP error.jpg ‏79 KB

Answer 1

CKH,
That code may qualify for the Rube Goldberg thread.  You just have to live with it.  Sorry.
If you follow the data lines back, you see that the GET DATA VI produces a 1D array for each packet received. Then the 2D array from the for loop goes through what appears to be a Reshape Array function to convert it to a different 1D array which is placed in a buffer then converted back to a 2D array.  Some complicated code appers to index out six columns and makes a new 2D array from those. Those are converted row by row to an array of waveforms (in two places) ...
I suspect that if we knew what all that was supposed to do, it could be done with about one third the code. You can certainly build an XY graph directly from the arrays with much less effort. The code following the Gen 5 Displayed1 and 2 appears to be identical. Therefore, Output Graph 2 has the same data as is fed to the Wavefrom Array Decimator above.  Just branch the wire rather than duplicating code.
Lynn