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I have read all documents and tried to understand DH parameters and how kinamatics works. And read the documents many times to have good grap of the subject. I tried my best to explain geometry of my DIY arm.
I am attaching photo explaining more about geometry of arm.
 

I hope this might better explain geometry of robotic arm.

I have something to mention. By increasing the Stepgen value on the three axes (from 24 to 30 in maxvel and from 120 to 150 maxaccel) when moving the motors quickly with the arrow keys, it no longer disconnects as easily as before. Could that be the source of the problem? When attempting to create a new configuration with Pncconf, there is some data that I do not know how to configure.

They also mentioned something about ‘isolcpus’ and ‘cpuset’ since my processor is an Intel Core i5-12400 2.5 GHz (new generation) and it could be related to that.

Edit:   I get this error (see attached image) 

Huh, shows what I know - I'll certainly check out Inkscape!

To be clear, I use Alibre for CAD and borrow Vcarve's vectoring feature to convert it to G-code with my own post-processor.

jmp97 wrote:

 With PNCConf, I couldn't get a configuration that would even allow LinuxCNC to exit emergency mode. 

Make a new config, do NOT change or add anything at all except 3 stepgens and scaling.
You can go back and modify it, or make new configs to your hearts content, add switches and sensors and motors and propellers ... but do NOT just chose and change stuff at random.

Not what you asked, but try Inkscape, it is free and it exports ready for use gcode, and more importantly very easy to use and add a line for were you want the cut to start.
Vcarve is really, really not for EDM, as far as i am concerned.

gents,
i would like to get some advise please. i have performed now a 2nd install, i tried APT ansd DEB also. i have an issue that :- the startup of probe basic takes "ages" compared to qtdragon, i mean like 30-40 sec( of course i could live with that, i just saw on my friend install it takes max 5sec.
- i can not reset estop. as i click on it timer froze up to 5-7 sec, nothing happens. the logic in hal was working fine with qtdragon so i assume there is nothing wrong there. 
1 more thing that is still very confusing me, that in the configuration guide, "Step 2: Copy required files" it says "Copy the required files from the probe_basic_machine_config_setup_files folder to the Pncconf config folder." but ther are 2 folders, machine_config_setup_files folder AND probe_basic folder, both contained similar folders and files. From which i should copy the files?
thx in advance

Grounding is a really big subject but here a bit of advice

For standard step/dir drives with opto-isolated inputs, grounding is not
super important as there is little coupling from the drive to the step/dir lines

 It is important however  to keep encoder and step/dir lines away form any motor or power
lines to prevent unwanted coupling ( both inductive and capacitive ) from these noise
sources to the low voltage signal lines.

For encoder, analog, and step/dir lines to non opto isolated connections, a common ground
is vital between the 7I97T and the signal source/destinations. The exact wiring for the common ground
and reference to earth ground depends on the drive design. Typically motor drives will have an earth
ground but may have an isolated input or output common. If the drives have an isolated common input,
this should connect to the 7I97T GND and then be connected at one place to the earth ground.
 

i'm not in linuxcnc yet. i'm testing it on windows. Drive settings are right. Its not receiving any data back of any kind. Feels like a cable thing. hmmm

There is documentation on how to set up genserkins:
www.linuxcnc.org/docs/stable/html/motion/dh-parameters.html

I can't quite tell from the picture how many joints your arm has but genserkins will only work for manipulators with 6 joints.

I have to say I tried every scaling combination in the book for Inkscape i.e. px,mm,in and none of them work. I keep getiing g code for an image of 250 inches for a 3 inch be 6 inch drawing. I find I can use inkscape for handling and ungrouping the svg and then import it into freecad. Freecad is much easier to handle and I get very good results.
Inkscape really has to address the conversion situation much better than it has.

Again, thanks for all your help

Yeah unfortunately that's not going to work.

Not sure what the EStop issue is. It  may be a LinuxCNC 2.9.4 bug,
but the easiest way forward is probably to make a pncconf
configuration (or MesaCT configuration) and if the is a EStop
logic bug, to find and fix it in the hal. file.

Another possibility is to update to 2.9.7 which is available now.
 

Other possibilities:

Make sure you use a pncconf or MesaCT created configuration for Mesa hardware
as these use a number of techniques to minimize timing related  following errors:

1. Using the DPLL to retime the position sampling
2. Using the stepgens in velocity mode with a PID loop
3. Using a small PID max_error value so a dropped packet does not cause a
large bogus correction because of stale stepgen position data

#2 is especially important

To check network latency:

sudo chrt 99 ping -i -q -c 60000 [mesa_card_ip_address]

This will run for one minute and then print timing statistics.

Other possibilities are using a newer Kernel, the default RT kernels used with Debian seem
quite poor latency wise (using 6.17 currently and its decidedly better than earlier kernels)

Pinning the Ethernet IRQ to the last processor also helps (if you also isolate the last processor
on your grub command line, or however you do it on the RPI)
 

Sorry about that. I'm attaching the files. With PNCConf, I couldn't get a configuration that would even allow LinuxCNC to exit emergency mode.    

Did you check that you have 0V at the enables when LinuxCNC is on the power-on and EStop released state?

How are you checking motion? With normal homing setup (with home switches),
you will not be able to jog until the machine is homed.

If the enables are at 0V, anther sanity check to do is to jog in either direction
and check that the DIR pin changes polarity.

It only gave me a blank page, I tried several times all day.

That's very strange as the link should not open a webpage at all since it's a direct file download link.