Plasma Table Build - Plasma Bot 4.0

[SeanMurphy265]

I'm using the relay only to turn the plasma cutter on and off. The yellow and black wires (top circle) on the breakout board are for my THC. Your diagram makes perfect sense. I was thinking backwards.

Where do I wire the torch output on my pp60c? I was thinking that pins 1 and 2 being the start and stop took care of firing the torch.

[Rambozo]

Pins 1 and 2 on the CNC plug should fire the torch, so they are the two that connect to the relay board. The relay board is for outputs only. The breakout board has both outputs and inputs.
Where do the two black wires go to that are on the top right of the relay board? (the outputs of relay 3) What do you have wired to the inputs of your relay board?
Which breakout board do you have? Nevermind, I just figured out from your picture that it must be the PBX-RF.

Since your THC will provide the arc signal, you won't need those pins in the CNC plug. So the only other thing you need is the torch output from pins 5 and 7 to go to your THC. I'm not sure if you have sorted out the voltage because of the internal resistors. I've been reading too many plasma build logs, so I lost track of where you are with that. Your THC needs full arc voltage, but the PP60 has only divided voltage and full with two dropping resisters in series. You might have to do some internal work to make that work. I guess you could pull full arc voltage right from the front panel connectors, but it would be nice to have that all bundled in the CNC cable.
I tend to work one piece at a time, so I would get the torch working under software control, then start in on setting up the THC after that.

[SeanMurphy265]

The top two black wires came pre-wired from probotix.
Pins 5+ and 7- according to the thread on voltage dividers are for full arc voltage.

I have ran some g-code with the THC on and the plasma cutter off, could this cause some problems?

I'm still under the weather and going to the doctor today, I'm hoping to get this figured out Friday morning. It seems to be something small.

[acourtjester]

Hope the DR fixes you up it’s a bummer not feeling good.
Rambozo is right work on one thing at a time start without the THC just the trigger of the torch first. Then add the THC after you have the torch triggering.
Since the THC need the plasma on for its signals, running G-code may not tell you anything of value with the problem at this point.
Rambozo has more experience then I with THC, I will stay on the bench and watch from there and learn more. It’s better to have only one person directing help when everybody is remote.

Get well soon
Tom

[Rambozo]

Rambozo has more experience then I with THC...

Not likely! Considering I have zero experience with any THC or plasma, but I understand the principles behind it, and have been working with CNC off and on for around 30 years.

[SeanMurphy265]

I sent Mark a PM and asked if he could move this thread to the automated systems CNC category. I appreciate all the help that everyone has given me, but I don't want to take away from the other projects that are being posted. I felt that I would be finished with my table after 2 or 3 months tops. I was close to that goal I made my first post a couple of weeks before I received my gantry kit and tubing for the table. There were periods of 2-3 weeks when I could not work on my table. Either paying welding jobs came up or work, and then in July when my son was born that prolonged things (but that's a good thing!).

I do appreciate all the help, and I have learned a lot from everyone's advice. I've been taking notes especially with trouble shooting and have saved and printed all the diagrams that everyone has posted. Everyone has been a tremendous help and I really appreciate it.

I don't want to take away from some of the other projects so it's time to move the thread to a more appropriate category.

Thanks
Sean

[SeanMurphy265]

OK, got some good news! I called Probotix and Jeremy helped me get going (in theory!). The doctor says I have bronchitus or maybe pneumonia (waiting on the xrays) so I can't do anything outside in the heat. I spent about 15 minutes on the phone and he should have me going. I've learned to ask people for help over the years, and in doing so I learned I made a simple but funny mistake!

The front of my control box there is a 110v plug and I plugged the walwart from the relay into the plug. It turns out that is why the first two relays came pre-wired. The plug is for a spindle so the relay can turn it on. I plugged the walwart into my power strip and the green LED's lit up! I did have a couple of things wrong in MACH3. After I plugged up the relay the right way he took me to the diagnostic screen and had me click the spindle control tabs and only the mist relay would turn on and off.

We went back to ports and pins I had the enable 1,2,3 boxes enabled (green checks). I should have had the outputs 1,2,3 boxes enabled (green checked). We cleared that up and now all three relays are clicking and in theory the plasma cutter should turn off and on.

I had to get out of this Mississippi heat. If I feel better tomorrow I may try to cut some hinges for my smoker that I desperately need to finish.

On a side note I asked about the LED's because of the advice from the earlier post, and that help get things going in the right direction. I felt that it was something small. I had to laugh at myself for using the spindle plug for the relay power!

[Rambozo]

Yeah the LEDs are really put there for troubleshooting, and are very handy. Much more so for things that don't click like relays. I was thinking about what you could be using the 3rd relay for. That's the problem with stuff that is pre-wired, you don't really learn what is going on. By using 4 axis drivers, you lost the ability to have the ribbon cable from the 4th axis to the relay board. That was a clean setup. I wasn't sure about how you had your inputs and outputs configured on your breakout board. I'm glad to hear you have it all sorted out. Will you have enough inputs left for limit switches? Are you using the Arc Good signal from your THC to an input?
Because of the inline resisters inside the PP50, you may have an issue with your THC not seeing full arc voltage. As long as it's in the range it can control, it will function fine, but what is displayed might not be the actual voltage.

I started a sketch of your wiring If you have Visio I can send it to you to finish out.

[acourtjester]

Sean
Be sure we laugh with you as we all have made mistakes too. Posting these things other can see that problems happen and with a little help they can fix them too.
Be careful if you have Pneumonia as I have heard once you get it is very easy to get it again. Some time its better to take an extra day of rest to be sure you are ok. Sparks will fly maybe a day latter.
Best to you
Tom

[SeanMurphy265]

The good thing about my THC is that can work with any plasma cutter and it's designed to read full arc voltage. I have it wired to pins 5 and 7 on the pp60c cnc port plug. If that will not work I can change those wires to the ground clamp and the +on the torch plug. The guy at Eagle Plasma told me to check the voltage with the plasma cutter running. The good thing about my THC is that you can find youtube video's with import plasma cutters running THC.

I am not using the Arc OK or OK to move pins 9 & 10 on the plasma cutter. From what I have read the OK to move has been an area of trouble for people who are using import cutters or any other non thermal arc or hypertherm plasma cutter. I'm using pins 1 & 2 for on/off and pins 5 & 7 that should read full voltage. I really hope it works well because it's a simple THC. I also like that I can change the torch height while cutting. It will require some note taking to learn the correct cut height and voltage settings.

Here is the youtube link for Proma Elektronica It's really a novel idea to build something that will work with any brand plasma cutter!

[sportbike]

. I also like that I can change the torch height while cutting. It will require some note taking to learn the correct cut height and voltage settings.

The THC from canccnc has control built into a MACH3 screen that can dynamically tweak the settings.

It is a bit pricey at $575, but might be worth it in better cut quality, pre-stored settings, etc.

The one you bought has been around for awhile I think. I looked into building a plasma table quite a few years ago and I believe that one was around, perhaps in a different version, back then.

Hopefully you get everything working.

[Rambozo]

It does look like a nice unit. The one thing I noticed is that you will have to set it for the delay for piercing as well as your gcode since there doesn't seem to be any way for your computer to talk to the THC directly. Not a big deal, but something to remember. I'm anxious to see what EmptyNester comes up with for an Arduino based solution. Having all the parameters stored in the gcode would be nice. One less thing for me to forget to program when I change materials. I'm looking forward to seeing you make some sparks real soon. Just be sure to take care of yourself, too. Being sick is no fun at all, so don't do anything to prolong that.

[EmptyNester]

I am not using the Arc OK or OK to move pins 9 & 10 on the plasma cutter. From what I have read the OK to move has been an area of trouble for people who are using import cutters or any other non thermal arc or hypertherm plasma cutter.

Sean,

Any idea what the problem with the Arc OK is? I haven't played around with that yet because I haven't wanted to start cutting and measuring voltages and signals until I had more solid hardware and a software framework in place. (I do know that it doesn't trip with the pilot arc. You have to get a cutting arc.)

[SeanMurphy265]

Sean,

Any idea what the problem with the Arc OK is? I haven't played around with that yet because I haven't wanted to start cutting and measuring voltages and signals until I had more solid hardware and a software framework in place. (I do know that it doesn't trip with the pilot arc. You have to get a cutting arc.)

My setup does not have the arc ok option, but there were some threads on cnczone (johndjmix build thread) with people having some problems with it. The easy fix was to jump the two wires together. From what it has something to do with how a specific brand of THC (geared towards hypertherm and thermal arc) reads divided voltage. This could be fixed by purchasing a product from the same company, and then the divided voltage could be read correctly. The end results that I have read usually ends up with a person forking out $2,000.00 for a hypertherm. You have to give hypertherm props they only make plasma cutters and they make them well. Hypertherm was also smart enough to get in the CNC market and made a niche market for themselves. If you think about it Miller does not have a plasma cutter with a cnc port (you can purchase a machine torch for the spectrum 875). Lincoln has only one plasma cutter with a cnc port. I'm at the point now where outside of spending money on paint, primer, and metal slats I'm done spending money on my cnc! If it can make money I may invest in a better THC, but for right now it will have to do. I will say that after running some g code last week I think you can get a good cut without THC. It may take a little time learning your pierce and cut heights, but it can be done and its all over youtube. There are several youtube videos with Everlast and other import cutters cutting just fine. For some reason there seems to be a problem with import cutters and a certain brand of THC.

I think if you can get your audrino working then you probably make a little money.

[Rambozo]

If the arc ok signal is working correctly, can anyone tell me if it goes high when the cutting arc starts, or after the pierce is complete?

[SeanMurphy265]

If the arc ok signal is working correctly, can anyone tell me if it goes high when the cutting arc starts, or after the pierce is complete?

You set that up in sheet cam. You have a pierce height and cut height.

[Rambozo]

You set that up in sheet cam. You have a pierce height and cut height.

I know the heights are setup in the gcode. What I meant by the signal going high is that it goes to a logic level of 1, which in this case is +5v. I just don't know when this actually happens. If it happens after the pierce is complete you can use it to instruct the CNC to start the next motion command. That would be really nice as it would account for any difference in material and how long it takes to pierce. However, if it is triggered by just the start of the cutting arc, it is of much less use, as you will still have to program in the pierce delay in the gcode, and it will always be the same. (with your THC you will also have to match that delay in the THC settings) It can't compensate automatically for colder or hotter material, or anything else that effects pierce time. In CNC it's what's know as an open loop. You pre-program what it should be, but there is no way to be sure it has properly happened. Closed loop gets a signal back that says something happened, now proceed.

I also don't know if the signal happens differently from the ok to move pins on the plasma cutter, or the arc ok pin on the THC. From the graph in the Eagle manual, it appears they just trigger the arc signal after the delay time. But from the voltage graph it looks like it might be possible to measure just when the pierce takes place. I can see how having a more precise pierce dwell would give you a much cleaner start. This would help for places where you have to have a short lead-in or no lead-in. It also means you would not have to pad your dwell time to account for inconsistencies.

Maybe this is another feature EmptyNester can incorporate into his THC. I bet if you take a few traces of the voltage during a CNC cut, there might be something you can trigger off of. Just a thought.

[SeanMurphy265]

That's way over my head!!!!

I ran outside and attempted to make my first cuts. It did not go so well, but it's my own fault. I should have set the THC to the correct voltage. I had the voltage set way too high and so the torch was moving up to compensate. I also need finish my slats so I can safely lay material on the table. I still have some adjusting left, but I know everything works. I also had the IPM's too high as well. Just a matter of setting my thc properly and getting the right cut speed.

[Rambozo]

You made sparks and got holes in metal. That's got to be rewarding to see. Maybe a different choice in shoes, though?

[SeanMurphy265]

You made sparks and got holes in metal. That's got to be rewarding to see. Maybe a different choice in shoes, though?

Yeah, I've been resisting the urge to make some cuts since I got off the phone with Probotix on Friday. I gave myself 15 minutes since I've been sick all week. It will probably sit for 2-3 days before I get another chance to make some cuts. I'm getting close!