The semi-rotary drive DSMI with integrated displacement encoder has the same design as the pneumatic semi-rotary drive DSM, but has a displacement encoder that measures absolute values based on a potentiometer. 
Swivel range: 0 ... 270° 
Size: 25, 40, 63 
Max. torque: 5 ... 40 Nm 
The semi-rotary drive DSMI is used with Soft Stop and pneumatic positioning for mass moments of inertia of 15 ... 6,000 kg/cm2. 
The advantages are: 
Complete drive unit, compact, ready for immediate use, high angular acceleration with adjustable fixed stops for fast and precise positioning of up to ±0.2° (only with axis controller CPX-CMAX)