My PlasmaC Journey

[Wise john]

Greetings to everyone......i started reading the story of your machine and it similar to mine .....i bought a chinese cnc plasma from a chinese distributor here in my country....when they installed and tested it every think was ok.....but now I am unable to do complete jobs.... because the touch goes off during cut .....the chinese guys don't reply my mail....it really frustrating after spending huge some of money to purchase their machine

[asuratman]

Do you plan to convert to linux ?

[thefabricator]

I can sympathize with you Wise John, I understand the position you are in and its not a great place to be. Having a machine that wont work due to the controller being crap, and the lack of support just compounds the problem.

If I were you I would try to learn a bit about electronics and build your own controller. It really is not that hard, just a bit of a learning curve. If you move to PlasmaC the finished result will be worth the effort!

[Wise john]

It will be my pleasure to learn it.... please just recommend me links where i can download materials on it

[thefabricator]

Start reading through these links,

https://forum.linuxcnc.org/plasma-laser ... -one-place

https://forum.linuxcnc.org/plasma-laser ... lding-them

https://forum.linuxcnc.org/plasmac

http://linuxcnc.org/docs/devel/html/pla ... guide.html

Lots of good info especially the Plasma primer and the PlasmaC user guide.

[Wise john]

Wow thank you very much

[beefy]

Rodw and thefabricator,

I'm very annoyed with you two. After all the the effort I've put into Windows based systems, learning programming, and even developing my own working THC, it seems like you guys are tempting me to the dark side. You are just a bad influence

Already got experience with the THCAD, it's what I used for my THC to read the arc volts. And the 7i96 looks like an ethernet controller and "breakout board" in one, seeing as it's got isolated I/O. My THC works but it's only a basic THC up/down signal type, and I like the sound of the much faster and precise (I'm assuming it is both of those) PID controlled THC integrated into PlasmaC.

How much control do you lose of the Z with PlasmaC. Example, could I create a custom pierce for thick sheet where the torch starts a pierce, then raises slightly higher, then slowly comes down. I would implement all that gcode in the post processor but just checking if PlasmaC allows that sort of control or is it more of a pre-programmed black box in that regard. Don't focus on that one specific example, the main point is what control of Z do I have.

In UCCNC we have the ability to write macros and plugins, which are little (or big) custom programs running within UCCNC while the gcode is running (or a single macro can run outside of gcode from a button press, an input activation, etc). A macro can also be placed within the gcode as an M command. Is that sort of thing also possible in LinuxCNC.

And this reverse run. I heard I need the development version 2.9 of LinuxCNC as version 2.8 does not have reverse run. Is that true. Mid cut restarts are a very important feature for me so would I be able to reverse run to some point before flameout, then do a dry run with torch off, then manually fire the torch just before the flameout point.

Personally I miss the technical side of plasma and I'm finding more and more people are just buying a turnkey plasma table. A very common question now is which plasma table do I buy. I'm guessing there won't be too much of that with LinuxCNC and plasma.

Hmmm, just had a look at some of your videos Rod. That THC control looks smooth.

[Rodw]

Beefy, us Aussies need to stick together so you should join us.

Really you need to be running V 2.9 of Linuxcnc. This will give you the latest QTplasmac GUI which has just been certified for production. The other versions won't be supported moving forward.

Short answer is you have no control over the Z axis. Plasmac actually by default filters out any z axis code when you open the file. But don't despair, becasue it supports puddle jump piercing which sounds like what you describe. (I've never used it). There is a magic comment you can add to your gcode that retains the Z axis code. This is designed for routing heads etc.

Piercing just happens on an M3, and Plasmac issues a spindle at speed command once its all done and motion commences.

Custom Mcodes are support by Linuxcnc. Plasmac uses some. Any executable file (usually a bash script) with the same name as your m code will be executed. But Linuxcnc also supports digital and analog pins and also wait on inputs so a lot of cool stuff can be done with these default features (eg turn relays on and off, set a PWM signal etc from gcode.

Plasmac supports user defined buttons that can execute gcode or interact with the system.

Mid cut restarts are handled in spades and you can even jog off the cut path so it can pierce before restarting.

Because you know a bit about C programming, you may like to experiment with writing your own components. These are snippets of C code wich are compiled and installed with a one line command. Once installed, they are treated as if they are part of the Linuxcnc core code. In fact, Plasmac is one huge component coupled with a sophisticated GUI.

The 7i96 is a good choice for plasma becasue of the isolate relays on outputs. It has enough I/O if used with a second THCAD for ohmic sensing. If you want to use MPG's or experiment a bit, then the 7i76e has a lot more IO and more features.

I think Linuxcnc has its place to retrofit to Chinese tables which run the Z axis with a simple DC motor so there is no control over pierce heights.
You could buy a Tormach table. It has a different GUI and motion boards but it works the same way.

One day my prebuilt controller with wiring and engineered matched motor kits will be available. But I don't really have the time...

[beefy]

Thanks very much Rod,

well, I closed my eyes, bared the pain and spent over A$400 on a 7i96 and a THCAD-10.

Now it's time to start reading and learning (all over again), not like I haven't got enough on my plate already LOL.

I certainly know what you mean about not having enough time.

No doubt we'll be chatting more on the Linux forum in the future.

[Rodw]

Thanks very much Rod,
No doubt we'll be chatting more on the Linux forum in the future.

Yes, be sure to do that as there are a lot more guys willing to help there 24/7

I'll send you an email with some useful stuff to get you going.

I did record a video on how to set up a 7i76e the other day.



The 7i96 is similar but it needs an extra 5 v Logic supply.

[beefy]

Thanks Rod,

that should help a bunch.

I had a quick look at the start of the video and was cringing when I seen the mounting brackets and the multi-pole connectors I could have bought together with my cards. You always find these things out afterwards LOL.

Keith.

[Rodw]

Thanks Rod,

that should help a bunch.

I had a quick look at the start of the video and was cringing when I seen the mounting brackets and the multi-pole connectors I could have bought together with my cards. You always find these things out afterwards LOL.

Keith.

Yes, I know it is annoying, nobody ever mentions them but they make the job easy. I did not know when I bought mine.

I may actually have some of both I could send you. I'll check it out tomorrow.

[beefy]

Thanks Rod,

if you still have my email, give me somewhere I can transfer money to and I'll buy them off you. Include the postage and an extra 10 for your efforts of course.

I was reading some of the HAL tutorial and I'm actually getting a bit excited. I've always wondered what the hell is that Hardware Abstraction Layer thingy, but once it's explained clearly in a manner that's talking to someone who's never had anything to do with it, it starts making sense. I've got a feeling the deeper I get into Linuxcnc, the more I'm going to love it, especially now that most of the hardcore technical lads have vanished from other forums. If I've got it right I think the HAL is where I can do the equivalent of plugins in UCCNC, as I see it mentions threads and functions you create to run in those threads. That sounds very plugin like. Another bonus is Linuxcnc already has lathe functionality if I ever get into that.

Crikey I don't believe it, the Mesa boards from Eusurplus have already arrived in Melbourne. It will probably take longer to get through customs than it will to come from Portugal to Australia

Keith

[acourtjester]

Funny my shipment was stuck in Chicago's International Airport for 8 day no tracking info change at that time. Customs time out I guess

[robertspark]

Funny my shipment was stuck in Chicago's International Airport for 8 day no tracking info change at that time. Customs time out I guess

Chicago airport.... Mesa hardware....why?
MESA are in the US (california)
http://www.mesanet.com/
http://store.mesanet.com/
or
https://mesaus.com/

[djreiswig]

USPS is kinda funny. If you send a letter to your neighbor down the street it goes all over the country before it gets there. Something about efficiency.

[acourtjester]

Who Knows I was going by the tracking number, It was sent as Priority Mail 2 day. There are better routes from California to Florida, Dallas Tx is better.

[robertspark]

Well, that one has got me stumped!

So much for air miles.... I guess A>B is not the shortest / quickest route if you can go by A> X>Y >Z >B...... (cnc moment there...