HEIDENHAIN angle encoders are characterized by high accuracy values in the arc second range and better.
Examples for application:

There are three different mechanical design principles:

Angle encoders with integral bearing, hollow shaft and integrated stator coupling
 
Because of the design and mounting of the stator coupling, it must only absorb that torque caused by friction in the bearing during angular acceleration of the shaft. RON, RPN and RCN angle encoders therefore provide excellent dynamic performance.
With an integrated stator coupling, the stated system accuracy also includes the deviations from the shaft coupling.
Further advantages:

• Compact size for limited installation space
• Hollow shaft diameters up to 100 mm for leading power cables, etc.
• C axes on lathes
• Simple mounting

Angle encoders with integral bearing, for separate shaft coupling
 
ROD angle encoders with solid shaft are particularly suited to applications where higher shaft speeds and larger mounting tolerances are required. The shaft couplings allow axial tolerances of ± 1 mm.

Angle encoders without integral bearing

The ERA and ERO angle encoders without integral bearing (modular angle encoders) are intended for integration in machine elements or apparatuses. They are suited for the following requirements:

• Large hollow shaft diameter (up to 10 m with a scale tape)
• High shaft speeds up to 40000 rpm
• No additional starting torque from shaft seals
• Segment solutions