Advanced Search

Do you have ohmic sensing installed and working?
Does the machine use 2 separate stpper motors, 2 drives and 2 home switches/sensors on Y axis?
Does the machine have a floating head/torch holder with it's own switch/sensor?
Also, never copy stuff at random, usually does not work properly, leave the step/dir timings at default for all drives, test properly, then decide if anything needs changing. Especially not from Gecko drives, some use 500ns, some 4000ns, some older ones 15000ns.
-22V is OK but also might not be, it is ok as when no THCAD is connected it does show negative values, but what exact value depends on scaling and offset and divider set on the board.

I finally believe I have linuxcnc setup, just a few questions regarding driver and motor settings, Is there a way to determine they are running optimally based on all the timing settings. I'm currently testing with some cheapo drivers and motors. I grabbed settings for the Gecko 203v drivers from MESA Config and brought them into PNCconf since the MESA config doesnt have the option for QTplasmac afaik and used those to get the motors spinning.

Also I'm not getting the option to manually joy Y axis as its not lit up or highlighted when machine is enabled in Qtplasmac. also appears I don't have a few other items highlighted as usable.

I chose ohmic probe and Float for torch I noticed there is also an option for Enable for both in the config. are those required?
As well THCad2 is not plugged in but is setup and qtplasmac is showing a -22 volts, is that normal or should it read 0?

Im sure ill have a few more questions as I fish this build out. Im using the 7i96s and running linuxcnc 2.9

Man you're precious. Thank you a lot for all these usefull informations. Just bought the Mesa 7I96S and the THCAD-10. Was a bit of a pain to find in europe but finally found it on eusurplus (funny how my google search always end up on one of your answer on another subject). I'm glad I can buy cheap drivers because the Mesa cost more than what I was expecting with taxes and shipping. I've read the plasmaC documentation. I'll take a picture of the inside of the plasma cutter when I have time. I'm still hesitating if I buy the Stamos or try to fiddle with the Stahlwerk I already have. I would learn more thing using the stahlwerk, but i'm afraid to break something, or worse, injure myself with these high voltages.

Thank you again, I'm a bit lost in this project and it's reassuring having someone to help a bit ! Yet, I'm exited. This plasma table will be really usefull in my work (and will save me countless hours with the grinder), and understanding how to do CNC stuff by myself is very rewarding.

I have used both of those plasma sources, both are quite good, and both can be used with CNC, granted Stahlwerk will requiire opening it and wiring in the THC and torch on and if you want the ARC OK modification as described in the PlasmaC documentation.
Stamos has connectors so much easier to wire in.
Get the THCAD 10 or 5 or 2, not the 300, and also get 2 resistors of 1MOhm value at 2W, this can be used with every plasma source.

Hi everyone,

I'm a blacksmith/metalworker with my own shop, and I'm in the process of building a CNC plasma table and I thought I would create a subject on this board to help me go through the electornic part which scares me a little.

I'd like to use LinuxCNC to run it with a Mesa7i96s and Mesa THCAD, and an old computer I have. I've found this subject which seems to be really helpfull (with a complete wiring diagram) : forum.v1e.com/t/lowrider2-plasma-build/13939/4

I'm a bit lost though because electronic is a bit complicated to me and would like some precision about how this thing works.

First I understand the needs for a floating head. I also understand that it can be build with a limit switch. I'm not sure though how it goes in the grand scheme of things. Do linuxCNC already knows how to use a floating head ? Is it as simple as telling LinuxCNC which pin of the Mesa 7I96s is connected to the limit switch of the floating head and teeling it the distance it has to go up after the switch is triggered, and then use Gcode to tell the plasma to probe the distance before each cut ?

Also I currently own a Stalhwerk cut 70 which I believe is HF. From my lecture on the subject a HF CNC plasma is really not a good idea. I'm ready to sell it and to buy another plasma CNC compatible (I'd like to have already pins on the plasma because I dont trust myself opening it and playing with voltage dividers etc, as I said I'm not confortable with electronics, even though I try to learn). Hypertherm is not really an option as of right now because of the price. I believe Stamos make a CNC compatible plasma cutter for a bit less than 700 euros.

Could someone confirm that I should wait to know which plasma I'll use before I buy the THCAD as I believe it depends on the arc voltage coming from the plasma (some already have a voltage divider, other not) ?

I'm really sorry if my questions sounds messy, I'm not a nativ english speaker and I'm a bit lost with the huge sum of inormations (sometimes which contradict themselves) I find on the internet. I would greatly appreciate any ressources you have which could help me in my project. Thank you very much for reading me. I plan on updating this subject as the building goes.

Some pictures of my 3D model and the start of the build (I'll replace the 3D printed part with aluminium one's once I've validated the build):



 

I have a Mesa 7i76e and a couple of thcads available in Brisbane.
Contact me here www.vmn.com.au/contact
and advise you have on this thread.

Hello.
Is there a simple guide for at novice? or someone who can point me in a direction?
Do we still make a working "machine" and then convert to plasmac or ?

 I tried the mesaCT tool - help- check for updates: a newer version is avaiable for download ? OK..... and how do I then do that. ( it always seems to me that you need 5 years experiance in linux/debian, in order to get started with enything) I NEED VENTING!!!!!

I have Debian 12 - BOOKWORM - MESA 7i96 - THCAD300 - A full mechanical build.

What is my next step ?  simple axis machine and then convert to plasmac or ?
 

The HF transformer secondary  is the long flat wire coil in series with the torch connection.
The plasma voltage must be taken from the non-torch end of that coil. That point should
connect to a 2 or 3 MOhm  1W resistor insulated with heat shrink (inside the CUT50 box)
and kept as far as possible from the torch end of the HF transformer and then to the negative
THCAD input. The positive THCAD input should connect to the Table or work connection inside the
CUT50 BOX.

The two wires going to the THCAD inputs should be a twisted pair or coax
(if coax, the positive lead should be the shield)


NOTE: there are voltages present in a plasma source source that can electrocute you even
after power is turned off/disconnected. Beware that both the output and primary side capacitors
may retain a a lethal charge for a long time.

Also note that this is a HF start plasma source and will require very careful shielding/grounding
of the motion/control components to avoid erratic behavior or even damage to the control
electronics from torch starts.

 

Have you configured the arc voltage input on the 7i76e tb2/th3 page? With that setup then you should come to a mesa thcad page where you can enter the scaling values from the back of your thcad10. It's all done in pncconf.

I did not set a setup page for the THCAD-10 in Pnnconf, and nothing in the manual except the description of how it works. My plasma is setup for 20:1
Is this now handled by the auto voltage setting in the software?

Not sure, the machine is the one in the attachments. 
I can connect without thcad because io will only cut a few 2mm material. 

Hello,
I have a small metalworking shop and I've built a small table for plasma cutting.
I bought a Chinese single-phase Cut50 generator that I intend to connect with THCAD.
The plasma is compatible with CNC.
How can I connect the plasma generator signal to THCAD for communication?
Can anyone provide a diagram or a datasheet?

Thank you.

I used THCAD-2 and hyper-sensing from plasmac wired the 24V+ to a touch plate and the 24V- to table frame and after some and / or logic and modifying the touch-off sub routines with m64 m65 commands around the g38 commands. I have as far as I can tell one the most accurate tool height setters available that is safe for even the smallest tooling

Spammer booted.

Been working on building my 2' x 4' table for a couple years but have a young family.  I want to finally get it done and I may of known my plan at times but with breaks in the build I have forgotten all the details.  Table is built I literally have a small list of items to do but need help.  I plan to have both Torch Height Control and Ohmic Sensing, I have the Hypertherm 45XP with the port on the back that I will be using on this table.  Have a small Hypertherm machine torch that I purchased because I didn't want the long version of the Hypertherm Machine Torch with the added weight.  This table will be using rack and pinion for movement on the X and Y axis and a ball screw for the Z axis that I designed and built.  Have a water pan that I made to cut down on the dust.

Rundown of parts that I have for this
Mesa 7I96 card and Mesa THCAD-10 for the Torch Height Control and THCAD-5 for the Ohmic Sensing
4 of TB6600 drivers from Amazon
3 of Nema 23 Bipolar 1.8deg 2.4Nm(339.87oz.in) 1.8A 57x57x104mm 4 Wires 
1 of Nema 23 CNC Stepper Motor 2.8A 178.4oz.in/1.26Nm CNC Stepping Motor
1 of Meanwell MDR-40-24 to power stepper motors
1 of Meanwell MDR-20-5  to power the 5V on the board and other small power needs

Sensors I have homing on the X and Y's and also have max on those axis's as well
Z axis I have the spring loaded for homing and then I have a max travel as well

Questions I have

1. Will the 2 power supplies be sufficient?
2. THCAD-5 wiring I'm assuming this is wired like the THCAD-*10 for Torch Height except the + is from the tip of the torch and the - is from the water table?
3. Stepper motors will they be strong enough?  I purchased them several years ago and was trying to watch my spend at the time.
4. I have seen others gearing down their stepper motors I think 3:1, I currently wasn't planning on it will this cause me issues?
5. I was planning to run water in the water table but I live in Minnesota so it get's cold and can freeze even in the garage, is there something else that people recommend in the cold climates?

I had started configuring Linux CNC, don't remember where I made it to but I'll probably have questions on that when I get back to that in the next couple of weeks.

I've been using the below diagram that I had found on a different post for my wiring. 
Thanks in advance

Mike