15m Industrial Plasma Cutter

The simplest solution will be to install LinuxCNC + Stretch in one go with the Debian 9 installer image here:
www.linuxcnc.org/downloads/

at that mashine size you need to go with the last stable relaease

then at any time you can update

Thanks for the replies.

I have booted from the Debian LinuxCNC live boot (USB) and run a latency test.

My numbers don't look great:


Max Interval (ns) Max Jitter (ns)


Servothread (1ms): 1045022 45022


Base thread (25μs): 121499 96499


I am concerned that this is too high. I suspect the problem is that the pc I am using does not have a separate graphics card.

If I am using servo motors, do I only need to concern myself with the 45022 number?


Thanks.

That is all good if using Mesa cards, not so good but still usable for parallel port.
It does not matter if servo or stepper, if they are controlled from parallel port they will both have limited speed to an extent. For Mesa cards it also does not matter as the controll and step genration are done in the card.

For a Mesa card, 45,000 is absolutely fine and better than my PC.
For Plasma you really should be using Mesa cards and their THCAD daughterboard.
Machine size has no bearing on what version of Linuxcnc to run.

Gantries are much easier to configure if you use at least Version 2.8 as it has the ability to square the gantry on homing based on offsets in your configuration.

The plasmac configuration for Plasma requires a minimum version of 2.8 which is missing one feature used for error recovery which it uses in v2.9.

Plasmac is by far the least path of resistance for a plasma machine.

In my view the current 2.7 release is just not an option you should consider for this machine and I think error recovery will be important on such large jobs on such thin material.

Therefore I suggest you run the master branch (V 2.9).

Some might tell you that master branch might break as development features are added (and it does occasionally) but I've been using it for about 4 years and that has only happened a couple of times and its usually fixed in a couple of days. Once you have everything working, there is no need to update it again unless there is a feature you really want.

Finally, just use plasmac in its default configuration and if there is something extra that you require in your application, see if Phill will add it first before changing it yourself. The more feedback we get from the real world, the better Plasmac will become.

Thanks guys.

I'm having a bit of trouble trying to install the 2.9 version.

I've been following the instructions here: buildbot.linuxcnc.org/

But I get to the point of running: "sudo apt-get install linuxcnc" (at the bottom of the page),
and I get:

user@debian:~$ sudo apt-get install linuxcnc
Reading package lists... Done
Building dependency tree
Reading state information... Done
Package linuxcnc is not available, but is referred to by another package.
This may mean that the package is missing, has been obsoleted, or
is only available from another source

E: Package 'linuxcnc' has no installation candidate


Does anyone have any experience with this? I saw a thread on this from a month ago but with no conclusive answer.

Thanks