Hi sofia,
as jbm mentioned i used a separate thread to determine the velocity each time the thread is called (125Hz).
in the same thread i opened up an tcp socket and pushed out the velocity values (later on some other values) to a separate
stepper controller that was able to receive the tcp packets at the same speed (in my case linux with real time kernel, but every other
RTOS on arm like cpu should work). I validated the transmitting of the values with wireshark to be shure.
i hope that helps, kind regards
seb