Chinese 5 Axis Board does work for Plasmac?

Hi guys,

my name is Giuseppe and i am trying to build plasmacutter. Why? Because i have fun building things
By the way, sorry for my bad english, it is not the best.

As i said i am building a plasmacnc machine and finally i finalised the base machine with 2 axis gantry.
It work fine, All axis move and the home switches made there job.

But now to my question, i am using a, it called mach3 breakoutboard with 5 axis, interface card.
To go on with the plasmac configuration, i need furter PINs for THC and Ohmic probe.
4 in pins for arc ok, up and down, also for ohmic probe. Also i need 2 out pins for ohmic enable and torch on.
This card don't have much in pins. I know, i can use a second lpt port card and a second breakoutboart,
but i want to try with one.
I think i can realise a plasmacnc cutter with this card but i have to use some pins for multiple usage.
For example same pin for ohmic probe and for one home switch.
This should work?

It will be nice if someone can tell me if this plan is realizable.

Bevor i despair.

Thank you

Giuseppe

LinuxCNC can use a single input pin for home/limits of all axis, just needs some tweaking to prevent any of the axis to stop on a switch, easily done using home_offset in the ini configuration file.
The BOB should work OK.
Use a floating switch mounted on the Z axis, using ohmic requires another separate power supply, more relays, and on water tables requires a Mesa THCAD5 to work reliably.
Either way you choose, having a float switch is a safety measure in case the ohmic fails to detect the material.
Here are some links to useful stuff regarding Plasma:
linuxcnc.org/docs/2.8/html/plasma/plasma-cnc-primer.html
linuxcnc.org/docs/2.8/html/plasma/plasmac-user-guide.html
forum.linuxcnc.org/plasma-laser/38974-di...rything-in-one-place
forum.linuxcnc.org/plasma-laser/35349-cn...uilding-them?start=0
forum.linuxcnc.org/show-your-stuff/38547...plasma-build?start=0
MFG.

Thank you for the reply. As i wrote my machine works fine with 4 stepper motors. Two in the gantry. I am using autosquaring. This work fine to.
I use two in pins for four home switches.
At the moment i can't realize a flowting switch. So i prefer to use a ohmic.
Someone have a wiring diagram for example for an ohmic switch?

thanks

linuxcnc.org/docs/devel/html/plasma/plasma-cnc-primer.html
Section 7.2

Thanks for the link.
This is no problem to realize. But stupid question, what will happen if i use the torch and material as a kind of switch.
GND of my BOB to material and torch to IN pin.
Surely with blocking diodes.
Finally this will do the same job?

Fire.

OK, i will make it like in the document.
I think this relay card should work
www.amazon.de/-/en/relay-module-4-channe...id=1611502182&sr=8-5

With optocoupler i think i can use the same power supply for the card as for the machine?

Otherwise a 12V power supply should work too?

Giuseppe

Thanks so far. I order now the 24V relay board and a 24V power supply.