Yes, it seems to be the case. I seem to have better luck when deleting position file prior to opening linuxCNC and homing, it works without issue most of the times. The issue i had with the Z motor turned out to be a slight misunderstanding of the process on my side, i still don't have a z axis and I was simulating the homing switch hits triggering the sensor manually, but turns out the process needs the sensor to become hit again on the second pass before it'll attempt to look for the z pulse.

@andrax are you on an XYYZ machine like your posted config suggests? can you respond regarding how the Ys sync up with the absolute encoder? The other thing i'm concerned about is if I should use homing mode 20 instead of 4 for Y, because otherwise the z pulse step becomes something that'll mess up your parallelism without you being able to adjust by adjusting the sensor triggers

Regarding the post above:
Yes, you're right,
CIA homing isn't really well documented yet.

In principle, it works like this:
The CIA-home function triggers the servos' internal homing routine and monitors the status. Once the servos report completion, CIA-home signals to LinuxCNC that homing is finished.

The drive error after homing is normal.
This happens when CIA-home hands control back to LinuxCNC.
Make sure the lowest feed rate is set; the axes will then synchronize without errors.

For plasma and starting with LinuxCNC with stepper motors, I would get a Mesa 7i96s and a Mesa THCAD2 to read the torch voltage. Also get a Meanwell MDR-60-24 24 volt power supply for field power and a Meanwell MDR-10-5 5 volt power supply for logic. When you order your Mesa gear also get some of their DIN rail mounts and a couple of COMMX2 bus bars. That will set you up for a running start.

SoloRev wrote:

The issue seems to be DKMS failing with the latest debian kernel. I couldn’t figure out how to uninstall the kernel but I was able to stop it from being installed on a new system. Before you do a 

Code:

sudo apt upgrade. stop any kernel update with [code]sudo apt-mark hold *6.12* basically wildcard the 6.12 string on both sides to prevent anything related to the kernel from being updated. 

[/code]

Did you try the revised instructions in the first post?

Thanks for the reply, it's all a bit overwhelming the information on the site when you have no Linux experience at all.

Hi,
New to the forum and new to cnc. I am building a CNC plasma cutting table based on plans from Homemade Madness however, I would like to use LinuxCNC instead of Mach3 as in the plan. I have not bought any of the motors or controllers yet so was hoping to get some advice before purchasing anything. I plan to use an old laptop for the install of Linux and LinuxCNC so am also looking for suggestions for the best version of Linux to use. Thanks in advance for any suggestions, help.

Would there be a way for the python handler for the vcp, to call or reference to python remap script that can access the interpreter variables?  With as little python programming skill as i have this seems like it could be possible, I wouldn't know if that is completely impossible, or not any better than writing to an intermediary file.

The issue seems to be DKMS failing with the latest debian kernel. I couldn’t figure out how to uninstall the kernel but I was able to stop it from being installed on a new system. Before you do a  . stop any kernel update with  basically wildcard the 6.12 string on both sides to prevent anything related to the kernel from being updated. 

I'm a little disappointed that there is no way to read/monitor them directly, but I was coming to that conclusion. Now to figure out the best work aroud. I'll probably end up trying to do what you suggest. Thanks for your help.

I don't think any of that is necessary (mapping homing pins to the regular inputs). I'm like 95% there now getting cia402 homing working with the absolute mode disabled. I'm able to home all axis x and y (z spins around looking for the z pulse and doesn't find it), but sometimes a joint will throw an amplifier fault JUST after completing homing (I can see the logging from cia402_homecomp indicating that the process had finished for that axis). I'm not sure why this is and it seems to be random...It'd be nice to figure it out but I guess that all i need is for homing to succeed once and then switch to absolute encoder mode? I'm still not sure how the combined Y+Y2 is supposed to work without homing... Like suppose you move one of the motors when the machine is off, will linuxCNC or something try to correct this deviation when the machine is turned on? If anyone knows what is the aim regarding this topic, please let me know. Below are my steps to getting to this stage:

- This repo is the best one I found for both homecomp implementation and linuxCNC config for these servos github.com/nickstewartroc/linuxcnc-a6-servo , and it is a fork from the one mentioned by @andrax (though the files he posted are not from there or are modified at least). Only one thing from there didn't work for me which is the binding of the di pins to see their state, they didn't reflect the way they are setup there. This is how each servo looks and what worked for seeing the home switches change state ( see<pdoEntry idx="2040" subIdx="05" bitLen="16" halType="complex". Also, I initially had issues halcompiling this homecomp with the additional includes, it was giving me an error on some types, make sure the cloned linuxCNC repo is on the same tag as your installation and not on main.

<slave idx="3" type="generic" vid="0x00400000" pid="0x00000715" configPdos="true">
<dcConf assignActivate="300" sync0Cycle="*1" sync0Shift="300000"/>
<watchdog divider="2498" intervals="1000" />
<sdoConfig idx="2004" subIdx="0a"><sdoDataRaw data="01 00"/></sdoConfig>
<syncManager idx="2" dir="out">
<pdo idx="1600">
<pdoEntry idx="6040" subIdx="00" bitLen="16" halPin="control-word" halType="u32" />
<pdoEntry idx="6060" subIdx="00" bitLen="8" halPin="control-mode" halType="s32" />
<pdoEntry idx="607A" subIdx="00" bitLen="32" halPin="target-position" halType="s32" />
<pdoEntry idx="60FF" subIdx="00" bitLen="32" halPin="target-velocity" halType="s32"/>
<pdoEntry idx="607C" subIdx="00" bitLen="32" halPin="home-offset" halType="s32"/>
<pdoEntry idx="6098" subIdx="00" bitLen="8" halPin="homing-method" halType="s32" />
<pdoEntry idx="6099" subIdx="01" bitLen="32" halPin="homing-high-velocity" halType="u32"/>
<pdoEntry idx="6099" subIdx="02" bitLen="32" halPin="homing-low-velocity" halType="u32"/>
<pdoEntry idx="609A" subIdx="00" bitLen="32" halPin="homing-acceleration" halType="u32"/>
</pdo>
</syncManager>
<syncManager idx="3" dir="in">
<pdo idx="1A00">
<pdoEntry idx="6041" subIdx="00" bitLen="16" halPin="status-word" halType="u32" />
<pdoEntry idx="6061" subIdx="00" bitLen="8" halPin="mode-display" halType="s32" />
<pdoEntry idx="6064" subIdx="00" bitLen="32" halPin="actual-position" halType="s32" />
<pdoEntry idx="606C" subIdx="00" bitLen="32" halPin="actual-velocity" halType="s32"/>
<pdoEntry idx="6077" subIdx="00" bitLen="16" halPin="actual-torque" halType="s32"/>
<pdoEntry idx="60FD" subIdx="00" bitLen="32" halPin="digital-inputs" halType="u32"/>
<pdoEntry idx="2040" subIdx="05" bitLen="16" halType="complex">
<complexEntry bitLen="1" halPin="di-1" halType="bit"/>
<complexEntry bitLen="1" halPin="di-2" halType="bit"/>
<complexEntry bitLen="1" halPin="di-3" halType="bit"/>
<complexEntry bitLen="1" halPin="di-4" halType="bit"/>
<complexEntry bitLen="1" halPin="di-5" halType="bit"/>
<complexEntry bitLen="11"/>
</pdoEntry>
</pdo>
</syncManager>
</slave>

- Wire the home switch per page 26 of the manual. You need to tie either COM- or COM+ to your external PSU's negative output depending on the sensor type (NPN or PNP). I had tied COM- instead of COM+ for PNP and that wasn't working. Make sure DI3 flips when the sensor toggles before proceeding any further.
- Depending on whether your sensor is NC or NO, you need to change your home switch between active low and active high, documentation for this is in page 209. (<sdoConfig idx="2004" subIdx="0a"><sdoDataRaw data="01 00"/></sdoConfig> in my config for NC switch). Also on page 209 is the function selection for DI3. It's set correctly by default, but one of my drives had it wrong and i presume this was the result of debugging changes made via dcConf entries that got removed. Check that all yours drives have it on the correct setting which is 5. You could technically use any of the DI pins that have function selection as the home switch changing stuff around this PDO. By this time the sensor pin should light up in halshow when triggered no matter whether the sensor is NO or NC.
- At this point it should be possible (though i haven't tested, i did have it working with the pins wired to the beckoff inputs though) to configure regular homing using the drive pins as input if you wished to test it out for sanity checking.
- Assuming that works or you skip it, copy the relevant bits of the hal in the referenced repo. I didn't have to change anything there since i dumped my XML (which was already very close but had slightly different property names) so i could just copypaste as it was.
- I used homing mode 4 like @Andrax but that might not be right for you. On Page 74 there's ample documentation for how each home mode works.
- When trying things out you might use low speeds for the 2 speeds involved in homing. Beware homing has a timeout that defaults to 60 seconds on the servo config. Homecomp doesn't catch this timeout and gets stuck forever, leading you to have to close linuxCNC and power cycle the drives (Page 215).
- Presumably once you're happy you'd comment the homing stuff and add HOME_ABSOLUTE_ENCODER to the joints like the initial post suggests.

I hope this helps someone, and please let me know if your know what the amplifier faults i'm getting after homing might be. This is my first time using linuxCNC. My config is attached for whoever finds it useful or can help me with the little bit i think i have left to fix.

I will update the first post so wish me luck!

There was some talk of publishing a new 2.9.x version to fix some bugs. If that is the case, I will send in a PR to update the repos in the installer based on the link above.