Recent PlasmaC Update and No Motion

Yep, I can see the confusion there. And I cant quite figure it out myself. It's made it a challenge to communicate what I'm seeing. I ran a 50 pierce cut program and it was fine when I posted that, but havent done it since (havent tried). Ran a few parts after that in dry cycle and then posted that because I was so stoked to have it running. But then I needed some parts for a bench I'm making and couldnt get it to go past the second pierce again. So more dry cycle testing using conversational programming. A single part can be run multiple times by itself (torch off so no noise). But if I array it, it fails second pierce (still dry cycle). Couldnt find anything in the gcode to cause this and havent tested any drawn files in the last day. All the parts I've needed are tube caps, concrete anchor feet, and supports.

Phillc54, I am spending time today writing out exactly what it does. So I will document it more clearly.

- Purged linuxcnc 2.9 and any ohmic.comp file last night and loaded in 2.8. No change to what has happened in the past and is detailed below more clearly.
- Added z homing switches just in case the z axis offset issue was still part of the problem. No change to what has happened in the past.
- Started the machine for the first time from a zero power state. Jogged machine around to make sure full motion and checked homing of switches. Shut linuxcnc interface off and restarted only the interface. Ran a program for 6 bench supports in dry cycle 3 times with no issues. 6 pierce points. Ran it with no issues with torch on to completion. Loaded a new cut program for tube caps and ran in dry cycle. Stopped on second pierce.
- Restarted only Linuxcnc interface, not the computer. Went to cut 4 thicker tube caps, only a total of 4 pierce points. Stopped after the second pierce in the program. No jog function after killing the program and in manual job.
- Restarted the entire computer. Loaded the same program. Ran with torch disabled for the path of the first part (since it had already cut). When it get to the probe point of the second part I renabled the torch, and it attempted the next cycle. However it could not establish arc. So I paused the program, let it retract and then killed the program. Found a piece of 16 ga steel to set on top of the 3/8" plate at the pierce point, used start from line, selected the m5 command of the first part and started the cycle again. It ran the whole program to completion. I then restarted the program with the torch off and it ran to the 2nd part just fine, so I killed it in the middle of the fake cut. Restarted and let it run to completion and it ran just fine with the torch off. Loaded the first program in a folder full of old previously run programs and it stopped on the second pierce. No jog function after killing the program

I have done a poor job of explaining but this is exactly what I have been experiencing since the beginning AFTER you made the new update to the offsets. Before v.166(?) it didn't go past the second pierce when I updated from v.142(? close at minimum). That is probably because it took some time to figure out just how to make it do something different. So initially when it seemed fixed I ran a cut file that I'd been trying to run and it ran past the 2nd pierce, oh happy days, but then the next file didn't cut. Very confusing road for me to figure out the entire computer needed to be shut down.

So how are you doing probing? Still with Ohmic3 or the float switch?
If Ohmic, Is it a water table? is the plate wet on the second probe?
Is the torch lifting to pierce height after probing?

If something goes wrong on a probe event and the Ohmic probe output does not turn on, it won't ever proceed to a cut. This is more likely with ohmic3 as you may need to change the settings based on different water quality etc.

I guess what I am trying to understand if the issue is my ohmic3 component, an ArcOK failure or something in Plasmac.

Regarding the Z axis settings, I found a lot of problems went away if I jogged to the top of travel and touched off at that height. eg. if I had 4" of z axis travel, touch off and enter 4.0" when touching off.

process used to update orignally that started this rollercoaster.


sudo apt update
sudo apt get-update
sudo apt-get dist-upgrade

downloaded ohmic3.comp

sudo apt-get install linuxcnc-uspace-dev

compiled ohmic3.

noted that plasmac version still read 0.142?( i could look this number up if vital)

ran configurator in upgrade mode.

at this stage, it was doing the fail to move after pierce.


made a 100/ new config fron scratch, which got homing working correctly.

applied confurator to it.
did not add any ohmic to it.

still.issue. came to the board, applied your plasmac.comp each time you loaded it.


yesterday we tried a full linuxcnc purge.

sudo rm modules (to ensure no extra reminants were left hanging)

re installed 2.9 tried again.

purged 2.9

rolled back to 2.8 tried again.


here we are now at today

ohmic is disabled enitrely until we get standard float switch cutting operational.

ohmic3.comp / .so has been purged

Ok, so not my software
So does the torch probe with float switch and rise to pierce height? If yes all probing is OK.

Next step, does the torch fire at all?
If no, sounds like a plasmac issue or faulty wiring.
Use halshow to check that the output pin is being triggered. Confirm with a multimeter.

If the output is not being enabled it is a plasmac issue..