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tommylight wrote:

Leme try to explain:

Thank you for the explanation, I will try it that way.

Now I first have to get my Proma THC working to get the ArcOk and then I hopefully can start dialling in the machine.

Hello,for quite some time I am trying to get a CNC plasmacutter that was given to me to run and cut.By now I got it to move correctly and fire the torch, but one thing I seemingly can not warp my head around is homing. I do not have limit nor home switches, as I am limited to one LPT connection and am trying to use the inputs for a Proma THC.I am running PlasmaC in an Axis Window on 2.8.4 on a Thinkpad T43, if that matters.What I would like to achieve: Jog the axes manually to a zero position (left, front) by eye, then zero them out and start cutting. Whatever I try, I can not get it to work, and it seems like I have spent too much time fiddling around in settings a probably shouldn't have.I attached my .ini and .hal, and would be really happy if someone could tell me what I'd have to change to achieve what I described above, and what user inputs in LinuxCNC I would need to give the machine.Thanks.

thanks
I am using the THCAD-10 so I will switch to the mode 1.  I had manually changed in Hal from mode 2 to 0 now will change to 1.
For clarification when running Pnccof should I select mode 1 at that point.
Not having much experience with LinuxCNC but trying to learn.
I am working with another guy starting to build a Plasma table and may use LinuxCNC. Mesa seems to be out of stock on the THCAD-10. Your answer to me hints a Proma THC could be used.

If you have an arc-ok input then you require either Mode1 or Mode2. Mode2 would be if you have an external THC like a Proma or similar otherwise it should be Mode1.
Try a Halshow watch on pins db_arc-ok.in and plasmac.arc-ok-in, they both should be on when arc-ok is valid.

Auto THC should be fine if your plasma power supply is not noisy. This has no effect on arc-ok.
 

Parallel port and Mesa 6i25/7i77 on the same machine and same PC, running without a hitch for nearly 6 years:
forum.linuxcnc.org/show-your-stuff/34986...nuxcnc-and-proma-thc
So yes it is possible and it does work reliably.
-
Built in parallel ports can do:
-Mode OUT = 12 outputs and 5 inputs
-Mode IN = 13 inputs and 4 outputs
-Mode X = 8 outputs and 9 inputs
Very easy to set in LinuxCNC by editing the hal file.
M.F.G.

The configuration wizards don't really work for this application. If I remember right I ran one config just to look at the files it produced it think I told it a 7i96 mesa. You'll end up with a bunch of stuff that is clearly mesa specific. I'm thinking I copied the qtplasmac stuff out of that file though. But the files I posted I just started with the basic config that comes with the remora files from github. Hence why they are still named ec-500, I left the remora related stuff in there pretty much untouched, and just started adding to it. From there I started working through it adding one pin at a time. Using halshow in qtplasmac is going to be one of your best friends through that process.  Did you build.your own divider?  The plasma cutter were using has one built into it.  We currently have a standalone thc (proma sd, it came with the machine, wouldn't have been my choice) on our machine but it doesn't want to play nice with the divider that is in the cutter.  Plus having the thc on the main control screen would be much better that a standalone thc unit.  What I'm currently thinking is to put the arduino in the box that our current thc is occupying and where using modbus comes into play is I should be able to send the data back to the computer over ethernet.  I'm trying to avoid using usb to avoid as much potential for interference as possible.  

Hello again,First off I want to say thank you for the work that has been done here, and for help that has been given in the past.  One of these days I want to put together a post explaining and documenting the whole process of getting this machine running.   I'm working on a cnc plasma table and at this point it's around 95 percent operational running on a ec500.  One of the last hiccups I'm having is getting the THC running.  I think I'm correct in thinking that the ec500 doesn't have any analog inputs.  We have a standalone proma sd thc, but it doesn't want to work with our everlast plasma cutter.  I've checked the divided voltage coming from the machine while running and it was around 2v /-.  I know there are some really smart and helpful people here, I'm trying to figure out what my best options may be for sending the 50:1 divided voltage into linuxcnc so I can use the THC functions there.  I'm mainly just looking for some direction of where to go here.  If i need to add a arduino or such into the controls to make this work, i may have a couple of those on hand.   Thanks again, Bryson

Hello Everyone!

I thank you for your kind replies. I have been away from the PC for a while fixing the machine!

Nothing has happened, and my THCAD is working perfectly actually, cutting on a daily basis with height correction.
the thcad is thcad-10, so im only feeding divided voltage. even if it has 10.000V peak, which would more easily kill the proma (?), on the thcad side it might reach a 200v peak, which i believe it will handle.

I have put the terminals connected to my proma divider, and the proma is grounded. the terminals are not in the place of the picture, they were placed where the manual tells you to place it! ahah

 


thank you all for your kind help!

www.forum.linuxcnc.org/show-your-stuff/3...nd-proma-thc?start=0
forum.linuxcnc.org/38-general-linuxcnc-q...rade-project?start=0

Lukasch (i think he is the owner of Proma) knows his stuff, i have seen several THC150 wired to output clamps on plasma sources with HF/HV start working without issues.
Still, i never do that, i wire any THC to the output of the rectifier.

Thanks Rob. Proma specifically calls out in the voltage divider documentation that it can be connected after the HF coil (ie. directly to the external torch electrode). So far it works perfectly.

I realize that this breaks one of the plasma cutter wiring commandments, but I couldn't resist giving it a try. If it fails to fry something I think it will make adding a THC more accessible to folks that have cheapo plasma cutters and that are averse to digging around in the cutters internals. Time will tell...

Great work Alan. It's always good to see another plasma table come to life. And amazing that a Pi is doing the job for you.
Good idea to use the proma in a HF environment. Is that read by the THCAD?
a 48 V power supply might give better motor performance if your driver's can handle it. See how the cut quality is on corners and keep it in mind.

Unfortunately, the N2+ is on the back burner as it's in Leonid's hands. He says:
The state of my repository on github is not complete for building additional packages. After my last email, I decided to check my current work and push it to my repository, but I found an error in the algorithm. And now I'm making changes. I'll let you know when it's ready.

Last night I made my first cuts on my "home handyman" level plasma CNC table. It's still a messy experiment, but it's getting there. Thanks to everyone that helped me get to this point!

Here's a high level look at the build for the curious:

• Raspberry Pi 4 with PREEMPT_RT kernel
• LinuxCNC 2.9 + QtPlasmaC
• Mesa 7i96S
• THCAD-10 
• Proma voltage divider
• Reed switch for ARC_OK signal
• 24V Meanwell motor power supply
• 5V Meanwell logic power supply
• Ohmic initial height sensing circuit
• Shielded P-80 machine torch
• 40 amp plasma cutter with HF Pilot Arc
• Rails from OpenBuilds V-slot
• 3D printed plates
• Magnetic torch breakaway
• Belt-and-pinion X and Y axis drive
• Acme screw Z axis
  
  Once I can cut reliably I'll use it to make it's own aluminum plates. I also plan to swap the Raspberry Pi for an Odroid N2+ once rodw releases support for the PREEMPT_RT kernel.

RRicardo wrote:

Thank you Rod

Also try to upgrade to a non hf plasma to take advantage of omic probes like in your video since HF Plasma and omic probes are not friends i guess.

Ohmic sensing should not care about HF plasma. But  it would need an external shield so the part on the torch contacting the plate is not connected to the work clamp while not cutting

Hi Tom
I think we are using HYS=4 but is good to know, thank you.