when measuring the length of a path travelled.
For path or position measurement, the location of a point is measured in relation to a fixed point of reference.
In measurement technology position measurement has a special significance, as it is also used to determine other variables, e.g. by differentiation for velocity and acceleration measurement.
A distinction is made between position measurement for
- feedback control (e.g. as an actual signal for position or speed control);
- location/velocity monitoring (e.g. measurement limit values of position and speed);
- for display (e.g. control display of the current position of a cylinder).
These different tasks place different requirements on accuracy, resolution and dynamic performance.