[solved] Rehoming Lathespidle / Rotary-Axis from inside GCode

excellent thread guys, I'll look at caxis.comp and see if i can figure it out

Aciera wrote:

@spumco
Thanks, actually that is probably what made me think that there was a component to switch between rotary and spindle. Seems it's not really as simple as recycling a component though.
I think NoJo ended up doing a fair bit of customizing in the source code that was not shared at the time.
 

Nothing is ever simple with LCNC, is it?

From what I gathered, I think the backstage fiddling he had to do was because he wanted switchable kinematics (Polarkins) available via m-codes.

Plowing back through some of the comments I made to him when he was starting out I was reminded of something I wrote earlier... I don't think we need polar interpolation.

When I look at the code Fusion 360 outputs for my commercial C-axis live-tool lathe, there's no polar interpolation.  It's all done in the post processor.  My control has polar interpolation internally, but my post processor doesn't use it - it just outputs X/Z/C moves, having done the Y->C  gymnastics inside the post.

I've no intention of hand-coding a radial cam groove on a shaft - the sort of thing you really want polar interp for in a control.  F360 can handle that one as far as I'm concerned.

If NoJo's implementation was that fussy, I don't think it's necessary, at least for my use-case.  What I'm interested in is C-axis indexing (at the moment) as well as a dual-purpose velocity/positioning spindle.  And his caxis.comp plus HAL config appears to accomplish that without anything seiously 'advanced'.

-R

smc.collins wrote:

excellent thread guys, I'll look at caxis.comp and see if i can figure it out
 

NoJo's responded in his original thread I drug up... I suspect he will be able to shed some light on the whole shebang.  Might want to pay attention to that one, too.

Your insights are also, as usual, most welcome.  I tend to grab my popcorn and thinkin' cap when I see you post something.

I am thinking about handling the c axis and spindle by controlling the encoder signal by using the enable for each, and then using macro's to force the rehoming of the axis or spindle orient on each enable. IE if spindle is enabled, call orient from a macro and  then have the output sent to the spindle encoder , when in c axis, the encoder output is sent out to C axis then macro calls home and resets encoder. at least, that what I have worked out in theory. This functionality really needs to be integrated into linuxcnc at it's core.

smc.collins wrote:

 IE if spindle is enabled, call orient from a macro and  then have the output sent to the spindle encoder , when in c axis, the encoder output is sent out to C axis then macro calls home and resets encoder.
 

Do you think you need to orient the spindle?  I gather the C-axis homes every time it's enabled (like my Fanuc), but I don't see the need for spindle orient once a C-axis is available.

And, looking back through NoJo and Andy Pugh's discussion while they were working out the bugs, resetting the encoder on C-axis enable results in the C-axis immediately homing. 

I think this takes place in caxis.comp.

Maybe.

well, the index iirc is used by c and spindle, for m19 etc.

I'll try to get to testing in near future, busy working on my slv40 mill currently.