Re:DIgitizing a part with no probe

I posted this on CNCzone a while back with no avail so ill try it here

Back when I used to program CNC routers for my job we had a router that we could lay a cardboard template down, drive the machine manually and place the axis where we wanted and hit a button and create a point. The software that drive the machine (windows based if I remember right,this was 7ish years ago and it was old then though) would output a dxf which we could open in autocad and create curves off the point cloud.

Im looking to something similar with my router and Emc. Im currently using ubuntu vs 8.04 and I think EMC 2.3. I dont currently have anything special set up in my config file, I dont even have my limit switches wired in yet Im using the probotix stepper drivers and breakout board for my electronics.

Im not at a point where I want to create a probe sequnce or even really make a probe, I would be happy with manually jogging the machine with a fine point bit and pushing a button when I get where I want to be. Really I would be perfectly happy with EMC creating a text file with the coordinates I need. So jog to a point, click a button, Coordinate output. Anyone have any ideas, I need to do this tonight, so simple is great

Jog to your point copy the numbers from the DRO into your g-code program... simple, tonight.

John

One way might be to create a PyVCP button that calls an MDI_COMMAND calls a subroutine which logs the current XY
I combination of
linuxcnc.org/docs/html/gcode_main.html#sub:Probe-Logging
linuxcnc.org/docs/html/gui_halui.html#sub:MDI
linuxcnc.org/docs/html/hal_pyvcp.html

The docs say that the behaviour is to truncate the log file if it is already open. But I am not entirely sure if this is true, or even what it means.
Experimentation might be needed. You might need a separate button to open a new logging file.

You will probably need something like

(.ini file)
MDI_COMMAND o<logpoint> CALL.

Then in your PROGRAM_PREFIX directory (probably home/emc2/nc_files)

a file called logpoint.ngc containing

o<logpoint> sub
(logopen, logfile.txt)
G92 x0 y0 (store position)
g92.2
(log, #5211 #5212)
g92.1
o<logpoint> endsub
m2
The above work with any EM2 version. With the unrleased 2.5 version you could use this variation as current position is available as a parameter
o<logpoint> sub
(logopen, logfile.txt)
(log, #5420 #5421)
o<logpoint> endsub
m2
And in the even more unreleased 2.6 version:
o<logpoint> sub
(logopen, logfile.txt)
(log, #<_X> #<_Y>)
o<logpoint> endsub
m2

THANK YOU!!

That is exactly the kind of info Im looking for. write now im jogging to a location, then writing down the coordinates by hand. Not exactly the best method. This could be useful for a ton of reasons. Ill post up when I make some progress.

I am looking to use Axis 2.5.4 to digitize a paper plot or 2D template on a small gantry router.

Is there a simple to implement (my programming skills are weak) solution for writing current machine XY or XYZ position to a file? I am imaging a small pointed probe, aligning it visually, and a keystroke or GUI button to log data.

Thanks!

2.5 is quite ancient. Maybe have a look at
github.com/jethornton/position-logger


Or simply the subroutine posted above: