Recent PlasmaC Update and No Motion

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..

moves to probe location
probes down,
uses float switch
finds material,
moves to pierce height
pierces.(torch works fine)
moves to cut height (torch still on)
ceases movement.
arc_okay is lost,
retracts to "pause position"
and controls are dead.

no resume. no jog. no start. no reloading.

stop button works. but jog machine will not move until restarted

(hopefully my thcad from stuart arrives this week and i can play with hypersensing ((excited)) )

reckon we can roll back to pre 0.148 and try?

tommylight wrote:

Then again i have to go do a photo shooting session there in a few days, so if i have the time i can give it a run.

What movie star now Tommy? An hour ago you were starting battles! (on another thread)

So anyway back on topic.

Normally, the only buttons enabled when the cut pauses is the resume or cancel button. You cannot jog while paused!
So possibly, the machine lost ArcOK (or did not establish an arc) and perhaps Plasmac does not recover cleanly. Lets focus on the loss of AcOK now.

Did it really happen? (Lose ArcOK) or did Plasmac imagine it?.
1. Does your machine have an ArcOK output?
2. Are you using it?
3. What material and thickness?
4. What is your pierce delay? (if too long, the material will burn away and maybe loos a valid arc.)