I have build a rotary axis with a direct drive motor. To control this motor I use a high resolution TTL encoder (629760 ppr after quadrature and interpolation). For the application it would be beneficial to have an absolute encoder, because homing is not always possible and I don't want to make a 360 degrees mistake, in the present situation this is possible. I solved it for now by performing a defined homing procedure at machine startup and after that never home again, even after emergency stop. This is possible because the controller/encoder remains powered. Only when the power is down, homing is necessary.
I was thinking of the following situation: Is there a counter on the market that reads the encoder TTL signal and counts the absolute position. This device should be battery packed and when I startup the machine, I want to ask the counter the absolute position (eg RS232) and than I am able to sent this offset to the controller.