Rod's Spaceship Scratch Built Plasma Table

[asuratman]

To run linux cnc, its only use 2 cards : an ethernet Mesa 7i76e (or the cheaper 7i96) and Mesa THCAD-10 board ?

[asuratman]

an ethernet Mesa 7i76e (or the cheaper 7i96) and Mesa THCAD-10 board

To run linux cnc, its only use 2 cards : an ethernet Mesa 7i76e (or the cheaper 7i96) and Mesa THCAD-10 board ?

[Rodw]

an ethernet Mesa 7i76e (or the cheaper 7i96) and Mesa THCAD-10 board

To run linux cnc, its only use 2 cards : an ethernet Mesa 7i76e (or the cheaper 7i96) and Mesa THCAD-10 board ?

Yes for a stepper based system. The 7i76e has 5 stepgens, 32 inputs and 16 outputs, a spindle encoder, 2 MPG inputs and some analog inputs.
The THCAD board just reads torch voltage and sends a frequency to the 7i76e spindle encoder where its decoded by plasmac back into a voltage. The THCAD voltage to frequency converter makes it highly immune to noise.
All of the THC adjustment is done internally by the Linuxcnc motion controller's servo thread that runs 1000 times a second.
There are other options to run an ethernet Mesa card and servo drives.
One guy is using Ethercat hardware.

[djreiswig]

I don't have a laser, but I have a Mach3 button programmed to align my torch using my air scribe. The fine tip of the scribe is easier to see than the torch.
Activate the slide, move the scribe to where I want 0,0,0 to be and click the button. Slide retracts and the gantry moves to where the scribe was and the DROs zero ready to cut. I even made a button to go the other way, although I haven't used it much.

[Rodw]

I don't have a laser, but I have a Mach3 button programmed to align my torch using my air scribe. The fine tip of the scribe is easier to see than the torch.

That would be pretty cool too! I have bought the parts for a scribe but I'm sure I'll never get around to fit it.

But anyway, today was a momentous occasion!


Ouur plasmac config was pushed to master branch of Linuxcnc!
That means there is no longer any need to compile from source to use this amazing config. You just need to download one of the ISO's from this page to suit your hardware http://www.linuxcnc.org/testing-stretch-rtpreempt/

And use the free win32diskimager to burn it to a USB stick on a windows boxand install Linuxcnc on your hardware.
That will get you the current release version 2.7 but we need the master branch (v 2.9) thos requires a very quick tweak in the Synaptic package manager to get Veriosn 2. 9 as per this page. http://buildbot.linuxcnc.org/
Its been ages since I've done thos but it was honestly a 2 minute job to upgrade from the release version to master branch and then there is a plasmac simulator you can play with without any hardware connected.

[robertspark]

plasmac sounds interesting.

Will there be an idiots guide to how you get to the finished install

I've installed linuxcnc a few times but how do you take to go to the plasmac variant with a appropriate GUI?

[plasma_burn]

I have been wanting to upgrade my old PlasmaCAM DHC, I have messed around with Linux a little, Plasmac looks pretty tempting. Now for the search to find the right servo drives for the PlasmaCAM......

[Rodw]

plasmac sounds interesting.

Will there be an idiots guide to how you get to the finished install

I've installed linuxcnc a few times but how do you take to go to the plasmac variant with a appropriate GUI?

Robert, thanks for your interest.

Once the Linuxcnc Buildbot kicks in, the docs will be included under user guides on the main LinuxCNC documentation page.
http://linuxcnc.org/docs/devel/html/

In the meantime, I've attached preliminary documentation.

I'm just waiting for my graphic artist to complete redrawing a couple of diagrams to avoid any risk of copyright infringement and there will also be a very comprehensive guide to plasma in general which will be published on the same link under General User Information. This is not plasmac specific but talks about all of the things a good plasma controller needs too and relates that back to linuxcnc.

[Rodw]

I have been wanting to upgrade my old PlasmaCAM DHC, I have messed around with Linux a little, Plasmac looks pretty tempting. No for the search to find the right servo drives for the PlasmaCAM......

Well Bob is using some Chinese Steppers (ST80's I think) on this thread. He build routers for a living and he uses them on all his builds....
https://forum.linuxcnc.org/plasma-laser ... smac-build

Because he's using servos, he's using a Mesa ethernet 7i92 that will be connected to a Mesa 7i77 by a 25 pin cable and the THCAD-10 board. The 7i77 has 6 analog servo outputs, 6 encoder inputs and 48 General purpose I/O.

[plasma_burn]

I have been wanting to upgrade my old PlasmaCAM DHC, I have messed around with Linux a little, Plasmac looks pretty tempting. No for the search to find the right servo drives for the PlasmaCAM......

Well Bob is using some Chinese Steppers (ST80's I think) on this thread. He build routers for a living and he uses them on all his builds....
https://forum.linuxcnc.org/plasma-laser ... smac-build

Because he's using servos, he's using a Mesa ethernet 7i92 that will be connected to a Mesa 7i77 by a 25 pin cable and the THCAD-10 board. The 7i77 has 6 analog servo outputs, 6 encoder inputs and 48 General purpose I/O.

Thank you for the link and all the information you have shared and contribution to the Plasmac project.

[Rodw]

Thank you for the link and all the information you have shared and contribution to the Plasmac project.

You are welcome!

[Rodw]

We now have a manual which is accessible from the main Linuxcnc documentation for Master branch V2.9
http://linuxcnc.org/docs/devel/html/pla ... guide.html

One more guide to come.

[Rodw]

And finally, the Linuxcnc primer for plasma table builders I wrote is now available from the main documents for Linuxcnc Version 2.9.
http://linuxcnc.org/docs/devel/html/pla ... rimer.html

One of the Linuxcnc developers asked for a guide about plasma cutting so I volunteered and called on a few experts to put this together.

Its been a long journey but quite exciting to know that my plasma controller is now packaged and available to anybody now.

[robertspark]

And finally, the Linuxcnc primer for plasma table builders I wrote is now available from the main documents for Linuxcnc Version 2.9.
http://linuxcnc.org/docs/devel/html/pla ... rimer.html

One of the Linuxcnc developers asked for a guide about plasma cutting so I volunteered and called on a few experts to put this together.

Its been a long journey but quite exciting to know that my plasma controller is now packaged and available to anybody now.

Nice writeup, a lot of useful info condensed in one location

15.3, is due to parallel resistance and the THCAD looking for 100uA current at FSD (full scale deflection [reading]) Best to work out the parallel resistance of the primary voltage divider and see what the effect of adding the THCAD in as a parallel resistance. The hypertherms have a higher primary current flow through their voltage dividers so the effect of a 100uA parallel current flow over the divided voltage is smaller than maybe some brands which are using higher value of resistors in their voltage divider network.

[Rodw]

Robert, thanks for your feedback. I can't speak for Hypertherm but there is no comparision between the divider board in the Everlast I used to have and the Thermal Dynamics I have now. The TD circuit board is very densely populated. I think most people would be hard pressed (including me) to be able to calculate resistance values for it (if at all).

I did find it was real easy to add an external resistor and run the THCAD on raw arc voltage before eventually testing and adopting the TD 30:1 divider which is perfect for the THCAD. The other thing that stands out is how clean the TD voltage signal is v's the Everlast so the torch voltage is a much better process control on the TD. Some of that may have been my battle to control EMI earlier in the build. There is actually a very good recent thread about EMI in the Linuxcnc plasma forum. https://forum.linuxcnc.org/plasma-laser ... ng-and-emi

[Tautog13]

“Will there be an idiots guide to how you get to the finished install”

I repeat this sentiment......and will go a small step further....recognizing maybe this is better suited for a dedicated thread for those considering PlasmaC....but while I’m here typing:

I assume you must install Linux Ubuntu (or eq. Linux Variant) first as the OS that will “run” PlasmaC. (Correct?)

After successfully installing PlasmaC and collecting all the hardware (motors/controls/etc.) just how difficult is the process for getting everything communicating and working together? (For the average “joe”)

IOW....does this route require a fair degree of experience in electronics and familiarity w/Linux nuances? (Super Geek?)

I ask as it is very tempting to invest some time to get better acquainted......but only if the bar isn’t set too high for “joe”.

My “Joe” definition: Good mechanical abilities, basic electronics experience (read voltmeter/solder),moderate computer knowledge. (has installed OS from disk/swapped out ram/hard drive/video card) Willing to accept setbacks and rely on volunteer support via user forum(s) only. (No help desk ph#)

Thanks for any insight.

Charlie

[Rodw]

Charlie:
Avearge Joe's Idiot guide:
Install Linuxcnc and Linux in one step.
Download one of these ISO files : http://www.linuxcnc.org/testing-stretch-rtpreempt/
You will really need to be using a 64 bit CPU today (AMD64).
There are a couple of versions but grab the latest one with no release number at the end
so probably this one for 64 bit: linuxcnc-stretch-uspace-amd64.iso

Use the free win32diskimager to burn the ISO to a bootable USB
Connect your PC to the internet and boot from this USB. Install
Linuxcnc will appear in the main menus.

So that gets you to the current release version of Linuxcnc (2.7 at the time of writing, but soon to be 2.8) But we want V 2.9
This is a 5 minute job if you follow the instructions here:
http://buildbot.linuxcnc.org/
In the Linux GUI, there is a Package manager called Synaptic. Whilst Buildbot refers to source and configuration files, you can do all that in Synaptic without opening a terminal. Its been a long time since I did this.

Now with 2.9, there will be a plasmac simulator in the main Linuxcnc tree. You can run this with no hardware attached to get the idea.
Build a working machine with XYZ motion
Run the Plasmac Configurator
Optionally import your Sheetcam tools set if you use it.
Cut something!

Idiots guide Yes: http://linuxcnc.org/docs/devel/html/pla ... rimer.html
User Manual Yes: http://linuxcnc.org/docs/devel/html/pla ... guide.html

What else does an average Joe need? A help desk with no phone number https://forum.linuxcnc.org/plasma-laser

Good luck.

[Rodw]

Oops, I forgot, Plasmac comes with a choice of two GUI front ends. One for the old and dated axis screen set which is the standard the LinuxCNC developers use for testing etc and Gmocappy which is touch screen based (And what I use). Try both in the sims and pick the one you like before moving to a live config.

[Tautog13]

Rod,
Install Linuxcnc and Linux in one step
Great.....exactly what I needed to hear.

You will really need to be using a 64 bit CPU today (AMD64)
Got it....was considering using an old Dell Optiplex, I’ll instead use a newer Dell T1600.
Does the AMD in iso name have any significance as to processor mfg.? Or is that just coincidence it is in iso name?
T1600 has intel processor....so maybe iso w/i is what I need?

Build a working machine with XYZ motion
Sounds easy.....ahem......I’ll leave questions about this aspect to another thread.....and just play with the simulator once Linux/PlasmaC is successfully installed.

Thanks for your quick & detailed reply!

Charlie

[Rodw]

Yes your Intel will be fine, Linux seems to refer to all 64 bit CPU's as being AMD64. Had me tricked when I started.

It depends on your hardware but there are two tools to create a working config. For parallel port breakout boards there is stepconf and it also has the ability to import a Mach3 XML file. I've never used a parallel port or Mach so can't help much.

Then for most Mesa hardware, you use pncconf instead. I did use it once when the author asked me to check if his new version worked.

I just copied someone elses config in the beginning and did my edits by hand so I've never really used the config tools.

The best way to work is to get a working config regardless of the tool used is to just run it once and then edit the hal file and in i files by hand in a text editor. the INI file contains the physical info about axis length, step scaling, how many axes etc, what gui to run.

The Hal file is the logical side. A large amount of this is boiler plate stuff connecting step and direction etc, but also your custom configuration. Think of this as wiring up a circuit and connecting pins with wires. For example LInuxcnc has an internal software pin that goes true when motion starts with a M3 in gcode. So it is Hal that connects this software pin to a physical pin on your controller to enable the torch on or spindle on relay.

[Tautog13]

Rod,
Linux seems to refer to all 64 bit CPU's as being AMD64
Got it!

Will read up on pncconf & get more familiar w/Mesa (not using parallel port either) & Hal.

See you in a year.......just kidding......I will report back as I progress/or trip up........thanks again.

Charlie

[asuratman]

Hi Rod,
Whem will linux 2.9 be released ?

[robertspark]

2.9 will be the next development release.

The current stable release is 2.7.14
http://linuxcnc.org/downloads/

2.8 will be the next stable release and according to this post was imminent (around 8 june)
https://forum.linuxcnc.org/29-forum-ann ... ase#136315

making 2.9 the next development release which will probably be a few (5??) years off ..... given 2.7 (the current stable) is on version 14 at present

previous releases were (to give you an idea of timelines)
DD/MM/YY
2.7.14 - 18/6/18
2.7.13 - 9/5/18
2.7.12 - 25/1/18
2.7.10 - 19/7/17
2.7.9 - 3/6/17
2.7.8 - 4/11/16
2.7.6 - 1/8/16
2.7.5 - 27/6/16
2.7.4 - 8/2/16
2.7.3 - 27/1/16
2.7.1 - 23/10/15

[Rodw]

There have been some developments here. Version 2.8 was quarantined off a month or so ago and will soon become the release branch. As Robert says, 2.9 is on the never never plan.

However, the good news is that Plasmac has been pushed to the 2.8 branch. It will lack reverse run which is used for error recovery which is probably a not a major impediment. Plasmac will auto sense if reverse run exists and configure itself accordingly.

Unfortunately, the release manager for LinuxCNC did not want to release the reverse run feature until there had been further testing so it will be in V 2.9.

None of this is an impediment as I've only ever run the master branch of Linuxcnc and its easy now to swap between versions in about 5 minutes using the Synaptic package manager without dropping to a terminal window. As per the (cryptic) instructions here http://buildbot.linuxcnc.org/

Normally, you would install this one for master branch:

Stretch (uspace: realtime with RT-Preempt, and simulation)
architectures: amd64, i386

The last option in the first table

[Rodw]

2.9 will be the next development release.

The current stable release is 2.7.14
http://linuxcnc.org/downloads/

previous releases were (to give you an idea of timelines)
DD/MM/YY
2.7.14 - 18/6/18
2.7.13 - 9/5/18
2.7.12 - 25/1/18
2.7.10 - 19/7/17
2.7.9 - 3/6/17
2.7.8 - 4/11/16
2.7.6 - 1/8/16
2.7.5 - 27/6/16
2.7.4 - 8/2/16
2.7.3 - 27/1/16
2.7.1 - 23/10/15

Thats why they call it a stable release. Only bug fixes get pushed to the release version. There has not been many has there?