The Fanuc Serial Encoder Converter commands the Fanuc Serial Encoder to report position 8000 times a second, and converts the change in position to quadrature counts at a switch-selectable maximum rate. Also, it produces commutation (Hall) signals so a servo drive knows which coils to activate. Fanuc absolute encoders, such as the αA64, provide low-res absolute position information immediately at power-on, so no battery backup is needed as long as it is permitted to perform a homing procedure on the axis. Fanuc Incremental encoders such as the αI64 do not provide this info, so the converter cannot provide commutation signals to the drive until the motor has passed the index position. For these encoders, your choice is to keep the encoders powered at all times, or provide a backup battery for the encoder's memory.