A distinction is made between analogue and digital processes (Figure W 6). In analogue position measurement processes, the resistance position measurement (with potentiometer) is commonly used for lengths of up to around 1 m and inductive position measurement is used for lengths of up to around 500 mm. In contrast capacitive position measurement is only used for very small distances.
Digital measurement processes work either with coded rulers or with ultrasound.For processes with rulers (e.g. graded glass rulers) a distinction is made between incremental and digital absolute systems.
For cylinder drives with position measurement, the processes which can be integrated in the cylinders are particularly interesting as they eliminate several difficulties when installing the measuring system in the working space. The pressure-tight designs of inductive and resistive sensors and ultrasonic processes are suitable here.
Figure W 6: Order of position and angle measurement processes