Next steps

jnwinkie wrote:

I must admit I am a bit overwhelmed by the info available and whilst there is a lot to read, it is sometimes hard to know what it is you need, therefore sometimes guidance is useful. As to sheetCAM I have contacted Les, I found part of my problem was due to the fact I am running the linux version and some Gnome 2 rendering issues. Les has indicated there may be a new version coming out in Feb, that may address the issues.
As to E-Stop there was an E-Stop on my BoB card, I also have a diagram from AgentWD40 (Kyle) from his lowrider2 plasma build that I will use as a wiring guide. Out of interest what number of sub-steps are people using on their steppers?
Have taken yr advice and now the CIG unit it provisioning parts and scrap metal for recycle.

Be sure you get the post processor for sheetcam from this thread
forum.linuxcnc.org/plasmac/38438-plasmac-post-processors
I've never had an issue with Sheetcam on Linux. A lot of the postprocessor workarounds you are used to are no longer necessary.

I run 25x microstepping (5000 steps/rev) with mesa hardware.

Re estop, you have absolute control of what pin does what. I suggest you start a table of inputs and outputs and always update it before you add any wirng to allocate the pin.

The estop pins are in halui right at the end.
linuxcnc.org/docs/devel/html/man/man1/halui.1.html

Thanks Tommy; Yes it works OK with Zorin, Mint but not with Ubuntu 16.04 with my config. I run a lot of Gnome 3 stuff.
I will blunder through it but it is good to know Les is updating the libraries.
Cheers
John

Well plasma cutter has arrived and have confirmed a 20:1 voltage divider. Do I mod the thcad 5 card and if so how? or do I go the thcad 10 route?

Also it appears that the swifty table uses same machine torch as I have does anyone have speeds and AMP for different materials? I am still curious as to whether folk build the LinuxCNC environ on a fresh disk or co-habit with an existing version using GRUB to select. Thanks again all.

John

Just go to Jaycar and grab a 3.3 M resistor and put that in line with the +IN input to the THCAD. The Wattage is not important.

That will give you a 170 volt full scale which will be fine for the Unimig. It won't go over about 130 volts while cutting so that will work well and still give plenty of resolution.

Thanks Rod;

I got this sheet from Jasic and yes it seems like 140V is about tops, so I will take that route.

Cheers

John

jnwinkie wrote:

Well plasma cutter has arrived and have confirmed a 20:1 voltage divider. Do I mod the thcad 5 card and if so how? or do I go the thcad 10 route?

Also it appears that the swifty table uses same machine torch as I have does anyone have speeds and AMP for different materials? I am still curious as to whether folk build the LinuxCNC environ on a fresh disk or co-habit with an existing version using GRUB to select. Thanks again all.

John

If you already have a 20:1 divider you can change the range of the THCAD-5 to 10V by adding a 100K 1%
series resistor

Thanks PCW;
So is it the same approach as Rod with the resistor inline with the +IN connection using a 100K rather than a 3.3M?

Cheers

John

Yes, 100K added resistor will change the THCAD-5
scaling to 10V full scale.

You would use a much larger value if you connected to the
plasma voltage directy

jnwinkie wrote:

I am still curious as to whether folk build the LinuxCNC environ on a fresh disk or co-habit with an existing version using GRUB to select.John

Pretty much all Linux distributions support installation to a disk with an existing operating system, with automatic installation and configuration of GRUB to allow dual- (or triple- or whatever) booting.

Here's one article about it: debian.wayoflinux.com/installing/the-installer/dual-booting

It it recommended to backup your existing system first in case something goes wrong with the resize of the existing file system(s) and partition(s).

With one of the installed distros booted, you can mount the other distro's file system to access files between the installed distros.

PCW wrote:

Yes, 100K added resistor will change the THCAD-5
scaling to 10V full scale.

You would use a much larger value if you connected to the
plasma voltage directy

My bad. I was in a hurry and worked off the full raw voltage. 100k would give you a 200 volt range, 70k would give you a 170 volt range. Either or won't make much difference.

Good to see they have cutting charts.