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Another plasma component...
- Mike_Eitel
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P. S.
Tried to find a better distance measuring for my 3D printer in Marlin for bed leveling and gave up after some crazy ideas that did not work.
For plasma distance I'd try some triangulating lasers on first thought but expect uv light problems after ignition.
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is that the environment near the torch is so nasty in terms of electrical noise and particulate matter that optical systems would tend to have a short lifetime.
That might be soluble with clean air purging of the optical path however
I do wonder if initial height sensing could be done with a sensitive back pressure sensor (inches of water) with a low (sensing) air flow rate
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I am going to have to completely rethink how to achieve this so I will need to strip all this related code out of the repo.
I will post again when I have finished this.
Cheers, Phill.
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This component to enable and disable THC operation is part of it
forum.linuxcnc.org/plasma-laser/32700-co...hc-from-within-gcode
This gmoccappy python file has a decode from file option that John came up with at around line 366
It is possible to fold a number of functions into this sinfgle analog pin if the most significant digit (or a numeric range) is used to denote the function and the rest of the number the relevant setting value.
Attachment not found
Remember that the python code is in user space hence the component to enable and disable the THC is in real time.
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rodw wrote:
This component to enable and disable THC operation is part of it/quote]
Thanks Rod, I will have a good look at this tomorrow.
Cheers, Phill.
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phillc54 wrote: It appears that hal pins cannot be read or set from python while a program is running and this causes problems with the way I have done gcode overrides.
How are you reading HAL pins?
If your python code creates its own HAL pins, and those are linked in HAL, then they will update in hard real time.
(Though the Python code itself will not be running in real-time)
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- Axis starts up in mode=0 even though I set MODE=2 in the plasmac.ini. I got around this my manually setting the pin in the plasmac.hal with:
Code:setp plasmac.mode 2
- I have problems saving values entered into the configuration tab (probe speed, pierce height, etc). If i manually edit the .cfg file and restart linuxcnc I can see that the values update however the save button doesn't seem to work. (This may be me not understanding how to configure everything)
- If the table is setup to have homing switches and software limits on the z axis. If you use a work offset (g54 in his case) and touchoff a little way above the material the torch will not be able to probe down and will instead give an error because of:
I'm not sure of the expected behavior here so i simply:Code:net p_comp:axis-min-limit ini.z.min_limit => plasmac.axis-z-min-limitand assume that the software limits will stop the torch from traveling past the table's z.min_limit.Code:sets p_comp:axis-min-limit -50
Thank you for all your hard work, the code you created is very well organised and well written. I found working with it very easy and intuitive.
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- islander261
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I have changed the way the way I decode the M67, M68 commands from Gcode. I now use a hal component to get the changes and use the python handler to update the screen state. I will post the code when I get out to the shop. The usual warnings, it works well enough for me but may contain logic errors that cause bad things with corner cases.
John
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- islander261
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Here is what I do right now. The only parameters I actually change from Gcode are the global THC enable and the THC servo enable. The global THC enable isn't needed unless you want to switch on an external THC controller. So the connection from Gcode is:
And the connections to the real time decode bit:
Sorry the code is such a mess, I get pretty random at times. The real time decoder is needed to make it work when a Gcode file is running for some reason the python to hal connection misses most of the changes then. At least I couldn't get to work reliably without the real time component.
John
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I am trying to detect a change in a HAL pin from python using hal.get_value().andypugh wrote:
How are you reading HAL pins?
I will try later today using halcmd from popen.
That seems similar to what I am seeing.islander261 wrote:
The real time decoder is needed to make it work when a Gcode file is running for some reason the python to hal connection misses most of the changes then. At least I couldn't get to work reliably without the real time component.
Zultan,
Thanks for the feedback. I will have a look at these issues after I sort out this issue I am working on.
Cheers, Phill.
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