Various methods and systems are provided to control a probe moving towards fluid held in a container. The probe is moved towards the fluid to take a sample of the fluid in the container. To take a sample, probe is actuated to hit the fluid surface and to pass the fluid surface by a predetermined distance. Capacitive sensing which incorporates the probe itself is used to support an approach engine for controlling the motion of the probe. The approach engine determines the speed of the probe based on capacitance measurements, and in some cases based on position information of the probe. The approach engine ensures the probe hits the surface of the fluid in the container in order to take a sample while ensuring the probe does not hit the bottom of the container.