DAQmx Read Loop only reaches speed of serial Communication

[jannik1810]

Hello everybody,

this is my first post in this Forum. I have a program with 4 loops, 2 seperate and 2 connected by a queue. The first loop (see attachment PID Loop) runs at maximum speed, the second one (serial communication) runs at maximum speed (very slow because of serial speed).

To find the error I deleted the queue to get 4 seperate loops. The loop with the calculations (Calculate Loop) now also runs at maximum speed, but the analog read loop just runs at the speed of the serial communication loop. Inside the subVI is just the setup for the DAQmx with internal sampling. I have no connections between the serial communication loop and the analog read loop. Is it possible that the DAQmx is slowed down because of the serial communication? The serial communication also uses a DLL of windows.

I hope you can help me.

Best regards,

Jannik

[GerdW]

Hi jannik,

as all subVIs are missing we cannot tell much about your VI…

All I can say is you are misusing local variables in your "calculate loop", enforcing race conditions…

[jannik1810 · Accepted solution]

Thank you for your fast answer. I found the answer I guess: I deleted the SubVI and use the DAQmx in the loop directly, than it worked. I think the SubVI took to much time because of extra options to execute at 1kHz.