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Recall / Return to previous Home

4 hours into a 5 hour cut and I had a small issue. I paused, fixed the issue and BOOM… my dumb a$$ hit the ‘Define Home’ button.

Is all lost or is there a way to recall the previously set home?

Unfortunately not without knowing where it was :sob:

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I was hoping it might be in a log file or something. :frowning:

Is it possible to add this as a feature request for future versions?

This would be a nice feature to have. I usually screenshot webcontrol from my phone before starting a big job. On this last one that was giant, I oriented everything at absolute home 0,0 so no way to screw that one up unless a chain jumped.

getting on a soapbox here

we really should replace the define home in GC (which has GC re-write the gcode
sent to the firmware) with firmware managed home and the g54 family of offset
options (and make it a little harder to redefine them so it’s not done
accidently)

David Lang

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Being a noob who hasn’t quite figured out how to set home before generating gcode its handy to be able to easily orient the print in WC but what just happened really bites. 4x8 of Baltic waste by my fat finger…

Exactly, as per the spec:

3.2.2 Coordinate Systems
In the RS274/NGC language view, a machining center has an absolute coordinate system and nine program coordinate systems.
You can set the offsets of the nine program coordinate systems using G10 L2 Pn(n is the number of the coordinate system) with values for the axes in terms of the absolute coordinate system. See Section 3.5.5.
You can select one of the nine systems by using G54, G55, G56, G57, G58, G59, G59.1, G59.2, orG59.3 (see Section 3.5.13). It is not possible to select the absolute coordinate system directly.
You can offset the current coordinate system using G92 or G92.3. This offset will then apply to all nine program coordinate systems. This offset may be cancelled with G92.1 or G92.2. See Section3.5.18.

So fling a G10 at it (to redefine home for one of the coordinate systems), and then G54+ to the relevant one.

@md8n

I’ve spent a few days trying to comprehend this and I have to admit that I’m just not as smart as I had hoped. :pensive:

I believe you’re saying that there is a way to continue if I can define a new home and then identify where the starting point is and apply an offset but I’m going to need a bit more by way of procedure.

If you can identify a known point that has been cut, then you can move your sled to that point. Carefully lower the bit (with power off) and joggle the sled until the bit is exactly in the cut. Then read the current x and y location. Call that point (xc, yc). From the g-code, there is an instruction moving the sled to that point, it has some different x and y value, (xg, yg). The original origin is (xc-xg, yc-yg).

Many g-code generators start at the top-right of a cut. This can be a relatively easy point to find. Good luck.


As a UI issue, the define home button should be moved to the left of the “distance to move” input box to make it harder to click accidentally. It is probably should also have a confirmation dialog, since this is an action that is infrequent and difficult to recover from.

Hi Chad,

My apologies, that was me replying to @dlang about what would be needed in GC so it could define more than one set of ‘home’ coordinates, and do that according to the GCode specification.

As regards how I fixed this problem in the past whenever I’ve done it, then @Jim_Penny’s answer was pretty much the procedure I followed.

The other thing is a little change to your process whenever you start a new cut:

  • Once you have defined your new home, take a note of the X and Y coordinates before you actually start cutting.
  • If it won’t affect what you’re are cutting you could also turn your router on and ‘drill’ out that point by lowering and re-raising Z. That way you’ll have a mark where ‘home’ is for that piece of work.

This will only really help you in future projects, but I have drilled a reference hole at the home position before just so that I have something I can line up to if I mess up. I’ve definitely done that more than a few times myself :wink:

Hey,
I maybe to late to the party but this may help someone in the future. When I am setting up a cut and after I zero the z axis I hit the plunge to -0.2. by doing that I always have a mark at home location. I also use that mark to ensure I have the positioning on the work material correct. I often only have a few spare inches to either side of the material, so I have to ensure that my starting location is correct.
Cheers
Rufino

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