A system for placing sample tubes into tube receptacles, comprising: a sample handling device configured to position a sample tube and to provide at least one electrical signal relating to an operating condition of the sample handling device; at least one tube receptacle configured to receive the sample tube from the sample handling device, the at least one tube receptacle comprising a bottom and at least one spring device configured to apply a holding force to the sample tube when placed in the tube receptacle; and at least one processor configured to control the sample handling device and receive the at least one electrical signal, wherein the at least one processor is configured to: - determine an expected location of the tube receptacle, - subsequently determine from the at least one electrical signal that the tube has encountered the bottom of the tube receptacle, to verify proper placement of the sample tube, and - control the motion of the sample handling device in substantially real time, in response, characterized in that the at least one processor is further configured to - determine, during placement of the sample tube, from the at least one electrical signal, that the tube has encountered the spring device, - and wherein the at least one electrical signal indicates a deviation of at least one of an acceleration, a velocity, and a position, from an expected trajectory of the sample handling device. a sample handling device configured to position a sample tube and to provide at least one electrical signal relating to an operating condition of the sample handling device; at least one tube receptacle configured to receive the sample tube from the sample handling device, the at least one tube receptacle comprising a bottom and at least one spring device configured to apply a holding force to the sample tube when placed in the tube receptacle; and at least one processor configured to control the sample handling device and receive the at least one electrical signal, wherein the at least one processor is configured to: - determine an expected location of the tube receptacle, - subsequently determine from the at least one electrical signal that the tube has encountered the bottom of the tube receptacle, to verify proper placement of the sample tube, and - control the motion of the sample handling device in substantially real time, in response, - determine an expected location of the tube receptacle, - subsequently determine from the at least one electrical signal that the tube has encountered the bottom of the tube receptacle, to verify proper placement of the sample tube, and - control the motion of the sample handling device in substantially real time, in response, characterized in that the at least one processor is further configured to - determine, during placement of the sample tube, from the at least one electrical signal, that the tube has encountered the spring device, - and wherein the at least one electrical signal indicates a deviation of at least one of an acceleration, a velocity, and a position, from an expected trajectory of the sample handling device. - determine, during placement of the sample tube, from the at least one electrical signal, that the tube has encountered the spring device, - and wherein the at least one electrical signal indicates a deviation of at least one of an acceleration, a velocity, and a position, from an expected trajectory of the sample handling device.