With the ECI 4000/ EBI 4000 rotary encoder series, Heidenhain is expanding its existing range of inductive position encoders. The modular devices without integral bearing have a hollow shaft dimension of 90 mm. They can replace the conventional toothed belt drives for coupling a motor feedback system to torque motors. The "ECI 4000" singleturn version has a resolution of 20 bits. "EBI 4000" is a multiturn version that has a revolution counter option with a resolution of 16 bits and is buffered by an external battery. The inductive encoders consist of a scanning unit and scale drum and have an overall height of 20 mm. The scanning is designed as all-round scanning: The complete graduation structure of the scale drum (rotor) with the associated scanning strip of the scanning unit (stator) is involved in obtaining the position signal. The rotary encoder thus evaluates two incremental scanning tracks of different periodicity. According to the manufacturer, this scanning principle has a positive effect on mounting tolerances and position accuracy. It also compensates for position deviations as far as possible over the entire speed range up to 6000 rpm. The encoders are equipped with the digital EnDat 2.2 interface and have an operating temperature range of up to +115 °C. The vibration resistance is 400 m/s² for the stator and 600 m/s² for the rotor in accordance with EN 60068-2-6.