This information is part of the Modelica Standard Library maintained by the Modelica Association.

These sensors measure

force f in N
position s in m
velocity v in m/s
acceleration a in m/s2

In this example, the measured velocity and acceleration is independent of the flange the sensor is connected to. In contrast, the measured position depends on the flange (flange_a or flange_b) and the length L of the component. Plot positionSensor1.s, positionSensor2.s and mass.s to see the difference.