g-rex and encoder feedback

I read from the specs that the g-rex can use feedback from encoders, and this seems to be its strength. Does the g-rex assume the encoder is a rotary device? Can the encoder be a linear device? The question is based on my limited knowledge of backlash compensation.

The compensation steps when applied in a given direction must be matched by an equal (or similar) change in encoder position for a rotary encoder before machine movement will result. In a linear system no encoder feed back is recorded for the amount of compensation change, but the next step (or micro step) will produce a corresponding amount of positional change.

I am looking at a system which needs to work with shallow arcs (8 feet/2.44mtrs radius in 11"/275mm overall travel) and am trying to visualise what will happen at the direction change in one axis. An incorrectly applied compensation will produce a step in the profile.

Comments?

Regards
Davidp