Hi,

I would like to know if it's possible to send an instruction to the cortex during the execution of the program.
For example, the robot goes forward and I sends an instruction "stop" to stop it.

Thank you

Every time you download a program to the robot, you'll notice that a small Program Debug window pops up. On that window, you'll see a "Start" button that allows you to run the program while the robot is connected over USB or VEXnet. Once the program is running, the button changes to "Stop", which you can press to stop the robot.

Thank you for your answer. I already saw this windows but the "stop" was just an example. I give you others exemples :
- The robot goes forward and I send an instruction "turn left"
- The robot finds an obstacle and sends me message to tell me this

You would need to program that behavior yourself. You could use the Remote Control to do it, assigning a different behavior (turn right, left, etc) to different buttons.

And the other way (robot send to PC) is possible or not ?

I'm not sure what you mean. ROBOTC and the Cortex communicate back and forth.