Re: [CAD_CAM_EDM_DRO] Re: A Z80 guy needs help!

> I'm not quite sure what you want to end up with, but wouldn't fixed, time
> dependent, moves that might not get to where you want them to be before feedi
> ng
> new positional data be self defeating? Wouldn't a closed loop system be bett
> er?
> In other words a:
>
> go to start point
> move to XY (wait till arrival is announced by encoder)
> continue
>

Bill,

I would have thought it would, but I've never seen a motion control
system that actually works that way. Rather, they usually have one
part that calculates where they want to be at each instant in time
based on the commanded motion and resonable acceleration profiles,
then another part (the position servo loops) that is charged with
making sure they actually get there, or close enough. The only error
reporting from the servo loop back to the motion planner is a shutdown
if the fatal following error limit is reached....

Generally this seems to work pretty well. Where it gets tricky is if
you want to move in coordination with something external, such as an
encoder on a non-servo spindle.

Chris Stratton

-------------------------------------------------
Christopher C. Stratton
Engineer, Instrument Maker, and Horn Player
ccs@... 617 628 1062
http://web.mit.edu/~stratton/www/brassbuild.html