SubVI Re-entrant Option

[Iaquinto.Joe]

Our team is using a subvi to take an encoder and our optimal speed in in/s to control our drivetrain with 4 custom PID controls. We had 4 of these SubVIs (One for each wheel) and we were running into an issue where all of the PIDs were all tied together (When you manually twisted a wheel, all of them moved to compensate). We searched for awhile and we learned that when you have multiple instances of the same VI, their IO is shared on the same memory. This can be stopped by going to the front panel of the SubVI, right clicking the icon in the top right, going to VI Options, going to Execution in the drop down, and checking the radio button under "Preallocated clone reentrant execution". This allows you to call the same subvi on your crio multiple times. You will most likely need this for any custom VIs you create. I just thought this was a little obscure and deserves a thread for clarity. Good luck!