Servo encoder placement

If you were setting up a backlash compensation would you use dual loop or
not? I don't really see the need to have an encoder on the motor and an aux
encoder on the actual moving part. Why wouldn't you just skip the one on the
motor since the load position is all that matters?

Has anyone read the book "step by step design on motion control systems" by
Jacob Tal........... ie Galil motion control president. Well I was hoping for
some good information but it's like 10000 formulas with not much text. Is
there any better books?

Why does the little "break out box" or whatever you want to call the box that
breaks out the 60 pin connector cable to screw terminals $750 for the
ACS-Tech 80 PCI servo card?

Brad


[Non-text portions of this message have been removed]