Re: Newbie has some questions

[Ray <rehenry-at-up.net>]

On Sunday 28 October 2001 00:01, you wrote:
> On Saturday 27 October 2001 04:28 pm, Ray wrote:
> > The probe features were migrated into the emc code from a parallel
> > NIST project with CMM.  Will Shackleford wrote the probe access script
> > to test and demonstrate it there.  It simply takes a linear move and
> > sees if the probe switch trips.  If it does, the motion is interrupted
> > and the location along the path reported.  With a bit of modest
> > hacking that script could be made to probe a grid pattern like you
> > describe.
>
> I assume this probe move is accomplished through a G-code?
> Is there a way to get the coordinates into a file?  Can I execute
> an external program from G-code or script?

There are g-codes available for probing but the probe script is direct to 
and from Tcl/Tk which means that you can do anything with them that you 
want to do.  This script uses an extended wish shell with emc commands 
available.  

These first two commands set the number of the probe pin and the polarity 
of the trip switch.

emc_probe_index
emc_probe_value

These commands run the probe through its routines and get the values 
associated with a trip.

emc_probe_move <toX> <toY> <toZ>
emc_probe_clear
emc_probe_value
emc_probe_tripped
emc_probed_pos0
emc_probed_pos1
emc_probed_pos2

Using these and some mdi commands to move the probe to the next location 
would rather easily create the cloud of tripped points. 

> > I would think that you could begin in manual and teach the corners of
> > the pattern, enter a repeat value and let it go.  It might also be
> > possible to speed up probing by teaching some sort of envelope within
> > which the pattern lies.
>
> Yea, that would be good, and manually show it where the workpiece
> is as well.  Ideally, one would like to put the item to be probed, as
> well a as the workpiece on the same table, mark the extents, and click
> "duplicate". I am sure there is much work to do to get to that point.

This side by side arrangement is an ideal place for the coordinate systems 
that are available with the EMC.  Probe the pattern using one coordinate 
system, change to the coordinates that describe the workpiece and switch 
from probing to milling.

> I have to walk before I can run.  My table is complete, but I need to
> mount limit switches and hook up all the wires.  Then do the BDI install
> on an old PC and get it configured.   It'll be some time before I am
> writing scripts/code.

We all do.  I fumbled with the system for months.  It is easier now with 
the BDI and the run scripts.  When I started you had to, load linux, patch 
the kernel for real-time (Tim's script really helped that process), 
compile the new kernel, compile the EMC, and start four terminals and run 
a module from each one.  And I'm not one of the pioneers with it by any 
means.

Ray