Plasma Torch On During Computer Shutdown

I usually let me plasma cutter run for awhile without load thinking I am letting it cool down after cutting parts for the day. I almost always turn off the plasma cutter before the computer, but a few times I have been caught off guard by shutting down the computer (using parallel ports) before the plasma cutter and just before the computer is off, the plasma torch is triggered on.

Is there a way to automatically keep the computer from activating the torch relay via the breakout board? I could add a switch to break the relay power, but then I am sure I will forget to flip this switch at some point.

Any guidance or ideas would be appreciated.

Paul

Thanks Andy,

I did wonder that they were working as designed.Although I have seen the term charge-pump, not really sure what that is. I will also look into adding some type of shutdown g-code. Thanks for the ideas!

I think the problem is once Linuxcnc shuts down and no longer controls the parallel port you really do not know what state the pins are in or if they will float.

Best practice is to shut down everything before you shut down Linuxcnc and as Andy said...

The best solution might be some sort of charge-pump or watchdog circuit.

Rick G

Thanks for the replies. My plan has been to turn off the torch before the linuxcnc computer, but just forgot this time. I do like Andy's watchdog setup. That would help make sure my absent mind doesn't do it again someday.

Oh, how shocking.