You need to remember most ppl are not able to reproduce your setup. You need to describe what your pde does. First question: Are you getting your data? As suggested by @erwrow, you can send the data in the same stream. Check this recent post to see the concept: [SOLVED] ArrayIndexOutOfBoundsException: 1 - #4 by racs and follow the discussion there.
Also relevant:
error with serial - Processing 2.x and 3.x Forum
Two sensors trigger same part of code - Processing 2.x and 3.x Forum
After you get this part ready, then you can check this post to have an idea for plotting data: real time graph plotting using processing - Processing 2.x and 3.x Forum
Also check this as it displays one way to do it and it focus in the concept: Sine Wave / Examples / Processing.org
Last, you can indent your code in the PDE before you post it here. To indent, select your code in the PDE and press ctrl+t. It makes your code easier to read after you paste it and format it here.
Kf