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Hello!

im currently running a laser setup with qtplasmac where I impose the % power with a potentiometer and voltage display.

but I would like to impose power with the “Cut Amps” parameter from Qtplasmac. This seems to be the most common approach with qtplasmac.

the problem is that on “pierce” and slowdown, the laser leaves the material burned.

I’ve seen Chinese controllers connected to Lightburn or Rdworks to allow for “min-power” and “max-power”, dependant on the % of max velocity, so if the axis is really slow it will decrease the laser power.

How can this be achieved within linuxcnc? Is there a way to enable this function with qtplasmac while still having the max power to be imposed by “Cut-Amps”? Even if laser power is given somewhere else, is there a way to scale it in lower speeds?

in the picture, the problem is visible, but it is much worse in other materials.


any help will be greatly appreciated.
thanks in advance

@reboot  sudo pinirq eth0 

assuming pinirq is in /usr/bin/

How about @reboot (full path location) pinirq (renamed just ) pinirq
next line ./pinirq eth0

Can you post you current hal/ini files?
 

You don't need to chmod +x more than once so
chmod +x pinirq,txt in unnecessary (and will fail
because crontab has no idea where pinirq.txt is located)

Not sure about crontab and sudo
(will it ask you for a password during startup?)
So the systemd method of launching scripts at startup
may be better

Note that sudo ./pinirq.txt eth0 will fail because again crontab
does not know where pinirq.txt is located (you need a full path
or copy pinirq.txt to a standard executable directory like /user/bin/
Also pinirq.txt should probably be renamed just pinirq or pinirq.sh
(it only has the .txt suffix because that's required to be able to post it to the forum)

@reboot is what tells crontab to do the operation only at boot time

Hello,

This is my first time using Linux cnc as well as a mesa board. I have a plasma table I built that i'm upgrading from an arduino. I'm using open loop stepper motors. When i set up my mesa 7I96s using pncconf i get my y and z axis to run great, my x does not. If i call my x axis Y, it will run just like it should. When I tell the config it is controlling the x axis, the motor does not run smooth and when coming to a stop it goes back the other way and then shudders. I'm lost as to whats happening. Does anyone have experience with this issue?

Ok after I make the change to the grub as above I then use crontab to create an operation to run the pinirq script a boot time. With a ctrl x to write it.
@reboot chmod +x pinirq,txt
sudo ./pinirq.txt eth0    should there be a @ at the beginning of this line too???

the script is already on the hard drive from the last time I used it

"Isn't using s-curves for jogging kind of pointless? You're not cutting anything while jogging, and if you are, you're cutting straight lines, so there is no benefit, just added complications."

No... that is the ENTIRE point. Straight lines are where jerk is a problem.

Do not confuse or conflate constant velocity motion with jerk control. Constant velocity in some ways already HAS it's own form of jerk control and while not perfect, is not a pressing "problem" in linuxcnc.

Jerk control for "exact stop" start and end moves are what is critically needed here. 99.99% of the problem with jerk is in exact stop moves like rapids, lines, arcs, and yes, jogging.

Attempting to encompass moves under G64 early will be the death of this project like it has been every other attempt. It is a vastly more complex task and should be left as stage 3. Stage 1 should be reliable jerk control on moves in exact stop. Stage 2 would be the parts of g64 that "fail" smoothing (sharp transitions). Stage 3 would be g64 motion and anything else complicated.

Well I have it running, don't know what I did. Now what doesn't work is the spindle (Bosch router).??

The output indicators for OUT4 and OUT5 are close to TB2
(To not compromise the higher isolation voltage of those outputs)

greetings, im working on getting my servo spindle working and im having some issues with the outputs on my mesa 7i96s.  i have the spindle enable physically wired to output #5 and i have the brake physically wired to output #4. when i go into linuxcnc and turn my spindle on, the light on tb2 comes on (you know the one for the spindle and brake on tb2?) and does the same for the brake, the output on tb 2 for the brake comes on.  in pncconf i have the outputs on tb3 configured to output #4 and #5. brake and spindle respectively. should the lights on tb2 on the mesa board come on when i activate the spindle and brake and not the lights on the outputs on tb3? i don't understand why the outputs on tb2 are coming on and not the outputs on tb3. am i missing something? why would the lights on tb 2 illuminate when nothing is connected to them and nothing is configured for them to come on but yet when i try to turn on my spindle, or operate the brake, those are the lights that light up and those are the outputs that are enabled. NOT THE OUTPUTS ON TB3.  you would think that if you configure an output on tb3, that light on tb3 should come on when the output is activated. NOT the output where there is nothing connected? what am i missing? i don't know if im not phrasing this question correctly or not but i asked the same question in another post but never received an answer. any help would be greatly appreciated. just so i am as clear as i can be with this; when i turn on the spindle or brake that is configured on the outputs of tb3 the outputs on tb2 activate instead of the outputs on tb3.

After a bit more troubleshooting I think I've figured it out. Thanks Corn and Tommy for setting me on the right path, it looks like it was in fact due to the 4k display. Appreciate your patience and sorry for not reporting/conveying the errors I got clearly, as mentioned before I'm very new to linux after 15 years of exclusively using windows, still learning the way of things.

I tried reverting back to a clean debian 12 install and this time noticed that  6.1.0-18 would launch fine but 6.1.0-21 would crash with the same ramdisk error. Launched into 6.1.0-18, edited the grub config with "GRUB_GFXMODE=640x480", ran update-grub, and it booted into 6.1.0-21 just fine. After that ran "sudo apt install linuxcnc-uspace".

6.1.0-21-RT now launches with no issues, jitter values are about the same as I saw from the live USB: ~250k-300k max jitter as long as I don't adjust brightness/unplug the power supply. Enough for me to play around and get my machine setup but I will definitely be looking use a more stable computer in the future. Really appreciate the support from you guys even though this wasn't really a LinuxCNC issue

Yes

Those should work, I use something similar on most of my machines. They only work with steel, not aluminum.

If memory serves
Brown is +
Black goes to mesa (signal wire)
Blue is -
The sensor usually has a wiring diagram on the sticker

The easy way to test this
Hook up power leave the signal wire unplugged.

Put a piece of steel by it, light should light up on the back of it.

Now plug the signal into the next open digital input on the mesa

Move piece of steel and make sure mesa led lights up (or turns off if it's on by default)

You will need to configure your hal file so it's looking at the right input. Chances are if you used pnf config you did this without knowing it.

Now when you try to home z will go first. Shake a piece of steel in front so it turns the sensor on and off about once a second until the y axis starts going.


If it doesn't let us know what's going on and we will help more.

Thank you so much for your fast reply PCW.

Does that mean that I can run the board in mode 3 and use inputs 16 and 17 as MPG-inputs and use inputs 18 and 19 as normal digital inputs with full field voltage (24V) compatibility?