Re: CNC API
- --- In SherlineCNC@yahoogroups.com, "Carol & Jerry Jankura"
> > Or the lesson could be that you can never be certain that a
> > has not lost steps until you re-home the machine after running aits zero
> > program, and then only if you have a 1 step threshold (or less)
> > homing routine (like with an optical switch, ... or an encoder).
> Actually, you don't want to rehome the systen, You should "zero" the
> location after homing. Then run your part and move the system to
> location, which should be the same as home if you haven't lost anysteps.
Returning to zero is not the same as homing. Homing is usually
defined as moving to a location that is repeatable with respect to
the mechanical machine and zeroing the machine coordinate system. It
is usually a required first step on a commercial controller after
turning on the power.
For a stepper system, you need to hit the switch and visually check
the readout, without re-zeroing to verify that your zero is still the
same. Any difference from zero at home position is the lost steps
Re-home is not really the correct word for what I was describing. A
better term would be "step loss check".
For efficiency a "step loss check" sensor could be located in middle
of the travel, rather than on the ends. It's more difficult to
protect it, the closer it gets to the cutting action
Fred Smith - IMService