[SOLVED] How about preventing a animation from rotating a Motor6D?

Currently, i have a code that rotates player's arm up. The thing is that before, while and after the rotation, if you walk, the animation will increment rotations, which is not i what i mean't. How could i prevent the Motor6D from rotating or locking it into a single angle?

I'm ran out of ideas from trying to fix, if you can help, please post an answer.