LabVIEW
TO rotate a shaft
I haven't looked at the FPGA code, just wanted to point out a serious race condition in host.vi. (there is no guarantee that the case structure at the bottom actually executes when stopp is pressed, so why is it even there? What's the purpose of the "x+1" indicator?
Under what conditions should the two left FPGA loop stop while the two timed loops continue.
@krupa wrote:1, The case structure works,i checked it many times.That is to stop the motor rotation when stop is pressed.
No. It might occasionally work, but there are no guarantees. For example if you would press the Stopp button while the local variable has already been read as FALSE but the terminal has not been read in the current iteration, the loop will stop without executing the case structure.
Even if the case structure would execute, the two terminals of the local variables inside the case will get written after the controls have been read, so the new values will not get relayed to the hardware, just to the local controls.
You have a prototypcal texbook race condition due to blatant overuse of local variables!
Here's one possibility to do it correctly. (The booleans are wired across in the FALSE case.)
The x+1 only gets written for one possible value, because it is inside a case. Once it has been written once, it can never change again to a different value.
Sorry, that's not my area of experise. Did you write the code from scratch or is it based on some example?
