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  5. CSS/G96 for other than X-axis?

CSS/G96 for other than X-axis?

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30 Mar 2026 18:46 #344965 by spumco
Replied by spumco on topic CSS/G96 for other than X-axis?
Lets see if I've got everything now that I've had a good think:
  • INI
    • V-axis
      • change HOME/HOME_OFFSET to "0" (to match X-axis/Joint0)
    • X-axis
      • add min/max limit entries for switched state
      • add max_vel & max_accel for switched state
    • Remap M-codes
    • [KINS]
      • KINEMATICS = parting_slide (yes/no?)
  • M-CODES
    • M300 - normal mode;  set #<kinstype> = 0, call M100
    • M301 - switched mode;  set #<kinstype> = 1, call M101
    • M100 - set V-axis min/max limits and vel/accel to normal
    • M101 - set V-axis min/max limits and vel/accel to switched values
  • HAL
    • net KINSTYPE-SEL <= motion.analog-out-01 => motion.switchkins-type
    • (analog-out-01 verified to be free)
  • COMPONENT
    • parting_slide.comp created from millturn.comp.
    • substituted @Aciera's suggested edits and added comments
    • compile/install
  • OPTIONAL?
    • Add G53 G0 V0 initial move to M301 so V and X are both at "0" before switching anything
    • Some sort of safety so joint0 jogging is inhibited when switched?  Don't want to accidentally jog joint0 (actual X) when sub-spindle is clamped on to a part.
      • I will probably also add an X jog-inhibit to my spindle/sub synch sequence.
    • Some sort of safety so everything switches to normal on an abort/estop/similar
Assumptions:
  1. I won't need new stepgen settings when switch is active because I'll be commanding the X-axis - which is now joint3.  And nothing about joint3 will have changed.  Millturn example M128/129 only changed the axis settings, not the joint settings.
  2. I won't need the G10 home offsets adjustments in the millturn example since I will be setting V and X home to 0.
Still unclear:
  • Is the INI [KINS] change, along with HAL file loadrt [KINS]... what calls up parting_slide.comp?
  • what connects motion.switchkins-type to the Case0/Case1 settings in parting_slide.comp?

Comments/critique welcome as usual.

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30 Mar 2026 19:09 #344967 by spumco
Replied by spumco on topic CSS/G96 for other than X-axis?
On second thought, I will need to include the G10 offset stuff.

Just because I set HOME = 0 for both axes doesn't mean the HOME_OFFSET is the same for both.  And if I plan to use G54 offset to get the parting tool tip at spindle centerline I need the switched X-axis G54 values to be the same as V's.

Hmm...
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02 Apr 2026 04:50 #345054 by spumco
Replied by spumco on topic CSS/G96 for other than X-axis?
UPDATE

I have switchkins working.  I have not yet tested CSS, but the axis/joint swap works with a couple of M-codes.
  • Normal mode:
    • jogging/g-code/MDI axis "V" moves the parting slide (joint-3)
    • jogging/g-code/MDI axis "X" moves the real X-axis (joint-0)
  • Switched mode
    • jogging/g-code/MDI axis "X" moves the parting slide
    • jogging axis V and joint-0 is disabled
    • Pre-switch V-axis G54 offsets are written to the virtual X
    • Appropriate max/min limits and accel/velocity are written to the virtual X
  • Switched back to normal
    • All jogging/g-code/MDI work normally
    • X-axis position goes back to pre-switch position (G53 X0)
    • Same for V-axis
Remaining issues
  • Axis GUI screen buttons can still jog joint-0/V-axis when in switched mode
    • I don't plan to use Axis once I'm done configuring & sorting out the lathe, but I don't know how to stop NML background messages from a GUI from moving the true X-axis.  Any ideas how to no-kidding stop an axis from being moved without disabling the drive? like DEACTIVATE_JOINT or something?
    • Bad Things will happen if the real X-axis moves when I've got the main and sub-spindles both clamped on a part.
  • Jogging the slide while in switched mode results in half the motion I'd expect.
    • i.e. the DRO doesn't match the physical distance the slide moves.
    • This may be due to a scale component I've got in the X-axis jogging logic so I can jog in diameter mode.  Maybe I need to get rid of that and change the joint-0 scale.

Not posting config or other files until I've tested CSS and sort out the jog motion issue.

Big thanks to @Aciera for the help.
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02 Apr 2026 12:47 #345060 by Aciera
Replied by Aciera on topic CSS/G96 for other than X-axis?

Any ideas how to no-kidding stop an axis from being moved without disabling the drive? like DEACTIVATE_JOINT or something?


I'm not aware of a way to block the operator from commanding a move of a particular axis. Would be a handy feature to have.

- I use Gmoccapy where the onscreen jog buttons can be hidden and only physical jogging through hal pins needs to be handled.
- MDI entries are more involved as one would need to parse all commands that an operator enters, still possible without too much effort.
- Rehoming can be handled using 'motion.homing-inhibit'.

Still leaves program execution and any mdi commands that are not coming from the gui entry.
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02 Apr 2026 13:23 #345061 by spumco
Replied by spumco on topic CSS/G96 for other than X-axis?

I'm not aware of a way to block the operator from commanding a move of a particular axis. Would be a handy feature to have.


Appreciate you having a think about it.

I'd like to experiment with that NML message I found (DEACTIVATE_JOINT).  If I can deactivate joint-0 near the beginning of the sub-spindle transfer process I can simplify the parting-slide jogging disable (which happens later in the overall sequence).

Any idea how I can send an NML message to LCNC?

Maybe it's done via python interface, but I don't see anything obvious in the LCNC manual section on python-interface that includes that specific command.
 

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02 Apr 2026 17:44 #345069 by Aciera
Replied by Aciera on topic CSS/G96 for other than X-axis?
Not sure if there is an easier way of trying this but I inserted the the actions of 'EMCMOT_JOINT_ACTIVATE' / 'EMCMOT_JOINT_DEACTIVATE' (ie set/reset 'SET_JOINT_ACTIVE_FLAG' for a specific joint :
 

into 'EMCMOT_SPINDLE_ON' / 'EMCMOT_SPINDLE_OFF':

 
 


Which lets me clear 'joint.1.active' using the spindle control but it does basically the same as disabling the drive as 'joint.1.pos-cmd' is still updated as the axis is jogged or commanded through the interpreter:

 

The problem with the following error when reactivating the joint remains the same as if it was done in hal or the drive disabled. 
 
Attachments:

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02 Apr 2026 17:53 #345070 by Aciera
Replied by Aciera on topic CSS/G96 for other than X-axis?
What would be needed here is to have the _interpreter_ reject the axis word which was disabled. So just like if the operator used an axis letter that was not configured in the ini file. Any MDI or gcode program line containing the disable axis letter would create an error 'Bad character x used'.

Unfortunately I do not know how to dynamically pass the disabled axes to the interpreter during runtime.
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02 Apr 2026 18:14 #345071 by spumco
Replied by spumco on topic CSS/G96 for other than X-axis?
I wonder if this could be done through the switchkins component.

Do you think LCNC would throw an error if I just left joint-0 out while operating under Case 1? 

Instead of this:
case 0:
            pos->tran.x = j[0];
            pos->tran.z = j[1];
            pos->c      = j[2];
            pos->v      = j[3];
            break;
        case 1:
            pos->tran.x = j[3];
            pos->tran.z = j[1];
            pos->c      = j[2];
            pos->v      = j[0];
            break;
    }
    // unused coordinates:
    pos->a = 0;
    pos->b = 0;
    pos->u = 0;
    pos->w = 0;

Maybe this:
case 0:
            pos->tran.x = j[0];
            pos->tran.z = j[1];
            pos->c      = j[2];
            pos->v      = j[3];
            break;
        case 1:
            pos->tran.x = j[3];
            pos->tran.z = j[1];
            pos->c      = j[2];
           break;
    }
    // unused coordinates:
    pos->a = 0;
    pos->b = 0;
    pos->v = 0;
    pos->u = 0;
    pos->w = 0;

And do something similar for the inverse later in the comp.

​​​​​​​

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02 Apr 2026 18:20 #345072 by spumco
Replied by spumco on topic CSS/G96 for other than X-axis?
On second thought it probably wont work like that  I can't have "v" defined in case-0 as well as an 'unused coordinate.'

But maybe there's a way to define the motion math of case 1  pos->v= j[0]; so that no motion results regardless of input.
 

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02 Apr 2026 19:26 #345073 by spumco
Replied by spumco on topic CSS/G96 for other than X-axis?

What would be needed here is to have the _interpreter_ reject the axis word which was disabled. 



So the NML description in the LCNC manual isn't accurate? Or perhaps not exactly clear what happens?
8.10. DEACTIVATE_JOINTThe DEACTIVATE_JOINT command turns off all the calculations associated with a single joint, but does not change the joint’s amp enable output pin.

I would have thought 'turns off all the calculations..." would have removed that joint/axis from the TP calcs entirely.  

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  1. Configuring LinuxCNC
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