Rotary Encoders Couple Motor Feedback Systems to Torque Motors

Heidenhain supplements its line of inductive position encoders with the ECI 4000/EBI 4000 rotary encoder series. The new encoder variants are modular devices without integral bearing and with a 90-mm hollow shaft, enabling the user to replace the conventional toothed-belt drive for coupling a motor feedback system to torque motors. Containing fewer components, these rotary encoders provide increased performance and guaranteed wear-free operation, Heidenhain says. The encoders open up new applications for inductive rotary encoders, for example on highly dynamic motors, drive modules and machine components that require a corresponding hollow shaft in the encoder.

The single-turn version of the ECI 4000 features a resolution of 20 bits. As an alternative, the EBI 4000 provides a multi-turn variant that features a revolution counter option with a resolution of 16 bits and that is backed up by an external battery buffer. The inductive rotary encoders consist of a scanning unit and the scale drum.

The encoders are equipped with the digital EnDat 2.2 interface. In addition to noise-free transmission, the EnDat 2.2 interface also supports further encoder-specific functions, such as the data transfer from one temperature sensor inside the encoder and one outside of it, or the allocation of standardized valuation numbers for signal diagnostics. The output of these operating parameters in the closed control loop allows permanent monitoring of the encoder status. The encoders’ operating temperature ranges to over 115°C. Vibration resistance is 400 m/sec.² for the stator and 600 m/sec.² for the rotor. This ensures robustness as a motor feedback system—particularly when the motor is designed for high performance.