plasma torch triggering

[anthony]

greets all, excuse what might be a dumb question.. i'm working with sheetcam and mach2 (demo versions) until my machine is actually built. going through the ropes, as it were.

for a cut sequence, which Gcode line actually turns the torch on/off?

less important (for now): if i had a way to check that the plasma torch was actually on, how do i work that into the g-code, before sheetcam starts the cut sequence?

don't know if i'm reading too much into things, and sheetcam already handles the above. trying to find potential problems.

thanks,
-anthony

[coherent]

Hi.. mine uses an M3 (or spindle on) will be used to turn a torch on, and a M5 (spindle off) to turn it off. It need to be wired via a breakout board and relay to the torch trigger wires on your plasma machine.

As far as knowing if the torch is on, many setups use a "good arc" signal before starting torch cut movement. This is because although the torch may fire, until it pierces the metal and has a good arc you obviously don't want to start cutting. You can normally set any desired "pierce delay" in the software. So the torch will move to the cut start point, fire the torch, pierce delay, note a good arc signal then start the cut.

Hope this helps a little
-Marc

[anthony]

marc, thanks, i'll look for the M-code.

re: "good arc" .. where does that signal come from?

-anthony

[Al_The_Man]

Some plasma power supplies have a contact-closure output that indicates the main arc has started (usually if it has pilot-arc start).
Al.