servo or stepper?

If I had a linear encoder and i wanted to use the position data from that to
control the movement of a rotary axis what is the best way. I need to have
the rotary do about one rev for every foot of linear travel. I can't CNC the
linear axis. I need it to position the rotary very accuratly along a path no
matter what direction the linear is traveling in. That is so the it can
reverse on the exact path it came down the first time. From what I have read
so far a servo loop is the best way to control such things but can it use the
feedback from a seperate and NOT controlled axis for it's position? I hope
you can understand what the heck I am talking about. Feel free to contact me
off list.


Brad


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