The one DC moto GFM 925AL, what is the standard price include installation in klang area?

Hi guy, I got this sliding gate issue.
Basically when open to end, can hear the huming motor sound before it was click cut off.
When close it will also reach the close and huming sound as well.
the huming sound goes about 6s before was cut off.
My sliding gate dun have any switch trigger it stop. I wonder how the system knows when it need to stop the motor.