To setup the bottom limit, close the drape/shade.
Press the back [button] plus the down [button] at the same time for 4 seconds, the motor will quiver or the light comes on.
Press the down [button] to make the curtain moving downwards, and stop at the needed lower position.
Press Slight up or Slight down buttons to set upper limit position with slight rotation of the motor.
Press the back button for 4 seconds, the motor quivers.