Linuxcnc requirements for plasma cutting

[acourtjester]

Ok the main thing is to have a post processor that will work with the software. This can be a little tricky as some software will sue different G-code commands to do a function. In SheetCam they have a long list of Post Processors because of that. Example I have used UCCNC electronics on one table and I can use the G31 command for the ohmic sensor operations but QTPlasmaC uses I think G38. Maybe one of the other members can tell you which you should use as to which GUI you use. I know you can use Axis or QTPlasmaC GUIs for plasma and maybe others. Another thing that may come into play is the Mesa board you are using. You can use Pncconf or Stepconf for setting up the card, I have a 7I76E and that uses the Pncconf for the setup. If you are using a parallel port board you may use the Stepconf. I am still learning too so other help will be needed to answer your questions.

[robertspark]

what other hardware do you have?

I can see you have a 5 axis Chinese bob, but how are you intending to connect that to the pc, using a parallel port or using Mesa hardware or something else?

I always recommend new users just install from the linuxcnc iso via usb stick. it's best not to get too smart before you understand how it works..... do you want cut metal or a pretty desktop?

[wiltshire_chris]

Using parallel port, it's all installed but when I open linuxcnc it wants me to select a sim. Axis whichever one I chose get this

[robertspark]

ok for parallel port use have you tested the latency ?

latency is very important for parallel port use as the steps are generated on the pc and output directly to the bob and then in turn to the stepper motors

if you go to the linuxcnc menu there will be latency listed. you need to run it to see what numbers you get, this will tell you if your pc is good or bad for linuxcnc AND parallel port use.

there are some settings that you can change to improve the first numbers you get as I suspect that your machine is still setup (in the bios) for windows (hyper threading, c-states, power saving etc etc)

I have never set up linuxcnc with a parallel port as I never got a pc that was either suitable or what I wanted so do not profess to be an expert at all.

[robertspark]

http://linuxcnc.org/docs/2.9/html/insta ... -test.html

[wiltshire_chris]

I've forwarded this on the test

[wiltshire_chris]

I've played around with the bios setting and ended up with this

[robertspark]

the recommendation is to leave the latency test running for a while and load the PC running glxgears + youtube

something like:



type: glxgears into a terminal and it will pop up.

run it for an hour or 2 and see what you end up with.

it's also best to run the histogram so it shows you what is happening.

open up another terminal window and type: latency-histogram

Again, I am NOT an expert with latency and the parallel port (I use Mesa hardware 7i76E, 7i92 and 7i98 + THC-AD)

[wiltshire_chris]

I gave in with bookworm and installed the last version of buster, all seems to work and the latency test came back as 19800

[robertspark]

there is no need to use bookworm unless you really want to buster will at this time do linuxcnc plus QTPLASMAC

if you want or need to use buster because of your hardware that is fine but it's a choice not a requirement (yet!)

at some point development will move on and bookworm will be the standard but not now

just get it working and making parts

[robertspark]

there is one caveat behind that statement, buster used python 2.7 and you can install python 3.x,

bullseye removed the need for python 2.7 and only used python 3.x. you can install python 2.7 onto bullseye and use it if you or your application needs it but it's native python 3.x


linuxcnc moved from python 2.7 to 3.x about 2 year ago so master branch and 2.9 , shortly to be released is python 3.x


so, I use buster with linuxcnc installed from the building for my lathe. router and mill, so it uses python 2.7 and I need python 2.7 for nativecam which I use.

I also have master branch installed purely for qtplasmac directly from GitHub, all installed and up to date (I use a script to update my entire setup )

I know bookworm will offer some real advantages but I personally don't need it YET as my hardware and software does not require it. if I get an issue with linuxcnc from buildbot or master branch then I will change but there is no need YET as my setup works, and if it works it cuts parts, and creates chips !!!! if it ain't broke don't touch it!