Brian wrote:
> Jon,
>
>   You idea would work, along with a number of others, so long as I
> never disable the motors.  The problem occurs when I disable the
> motors and move the table manually.
>
>   
I think there is a stepper-driven system that works like this, using my 
Universal Stepper Controller.  I know that this is trivial with my 
Universal PWM Controller.  You can disable, move manually and then 
re-enable, and the coordinates are kept all the time.
>   The problem occurs because the only place to feed position feedback
> that will work when the motors are disabled is through
> axis.0.motor-pos-fb.
>   This value is then subject to inverse screw
> compensation.  The only way to make this work accurately is to zero
> out all the screw and backlash comp.  Theoretically, it will calculate
> the screw comp and backlash in real time, but on my machine, I need a
> feed forward component for accuracy.
>   
OK, that is a different problem, and I guess the screw compensation has 
been put at the wrong place in the logic.
And, I don't use the screw compensation, so I am blissfully unaware of 
the problem.

Jon

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