SKR PRO V1.2, NEJE 40640 and Lightburn

OK, obviously nothing works the first try, but dang…I have research to no avail…

Have the MPCNC Primo running SKR Pro V1.2 with Marlin. Just added the NEJE 40640. I have been able to get the board talking to the laser and get a pulse to fire from the LCD screen, but I cannot get Lightburn to fire the laser. It connects and it will move the laser as if it is running the test file, but it doesn’t fire. It also doesn’t fire the laser when I hit the button test fire.

After reading the forums for wiring, I have a dedicated power supply for the laser, have the PWM board hooked up to the laser with the 4 wire cable and the two pin cable from that board hooked up to PC9 and ground

Any thoughts?

There are a couple of things to be aware of. First, there is a laser timeout to prevents the laser from continuing to fire if the laser is not moving. I believe in the latest V1 maintained version of Marlin, there is a bug in Marlin where the timeout does not play well with the laser menu. Marlin has fixed this bug, but V1 has not made a release version with the fix.

Second, starting with the latest V1 maintained version of Marlin, if you want to use inline commands (highly recommended), you need the following at the top of your laser file:

M3 I

If you have Lightburn setup for inline commands and the top of file does not have this command, the laser will not fire. This line can automatically be added to all Lightburn files by using the Start GCode section. If you haven’t already found it, inline commands are enabled in the following section:

image

This is on the Basic Settings page. Due to a bug in Lightburn, on some displays, you must resize the Basic Settings dialog to see this setting. Note that M03/M05 will work without the M3 I above, but the cut and engraving quality will not be as good as using inline commands.

Finally, if you just want to verify that your laser is working, you can use M42 to manipulate PC9 directly. This bypasses all laser-specific code. You can try with different S values in the range of 0 to 255 to make sure the laser varies in intensity.

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Worked!!! Thank you so much.

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why do you write m3 I and not m03 I? or is it the same thing?

It is the same thing. I’ve always thought that having two formats is a bit weird. It means a bit more work for the parser. There is probably some historical reason why both work.

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Okey Dokey to add to this…

I am trying to find the perfect focus. The Fire button is there, I have the laser firing when framing, but when I press it, the laser only stays on for a few seconds. It is suppose to stay on until I press the fire button again so I can change the focus. Any thoughts on why the software is turning it off after such a short time?

I’m sorry if this is a stupid question, when you say use M42 do you mean from the Console tab of Lightburn?

Also, the laser timeout issue that you mentioned, would that be why I can fire the laser for 1/2 a second from the Marlin menu and then have to toggle it off and back on to get it to flash for another half second?

I’ve got Lightburn controlling my axes very nicely, but something is still amiss with laser control.

As always thank you Robert!!!

BTW Ken I saw the pictures of your Primo when I was reading a topic on Z Touchplates.

Very nice and tidy build!

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when you say use M42 do you mean from the Console tab of Lightburn?

Anywhere you can set or run g-code will work with an M42. That includes the console line in Lightburn. I have the command in a couple of places for my machine, including a file on my SD card.

I must have something wrong or this janky laser isn’t working or I’m a nincompoop…

Tried sending the M42 command to light up the laser like so:

Laser doesn’t fire though. I get this…
image

Another strange thing is when I try to manually setup my device in Lightburn as a Marlin device it will say ready but the Move tab buttons won’t work. But if I do Find my device it comes up as a GRBL machine, but the Move tab buttons will move my axes.

Any insights would be great.

I can “blink” the laser from the Marlin menu by setting an intensity and toggling it on, but it’s only on for a second.

The M42 g-code allows you to manipulate pins. I believe the command format for the SKR PRO.

M42 PC9 S1   ; Laser on at lowest power
M42 PC9 S128 ; Laser on at half power
M42 PC9 S255 ; Laser on at full power
M42 PC9 S0   ; Laser off

The S commands go from 0 to 255.

I have no idea about your other issue. If it were me, I would just delete the profile(s) and then add them back.

Thank you very much!

I have been working the laser before I do cnc wood, not sure why…; )

I have been doing wood pens for work, business cards, etc…tried to get the laser to do acrylic, the interweb solutions for a diode laser haven’t worked as of yet…

The only way I have found to fire the laser, for framing when I have to change out the job, is to change the percentage of power from 2 to 3, and then back every time I frame. But that is just setup, once I run the job it will keep framing until I don’t use the program or I switch jobs out

My latest try is to do aluminum, I added a little oil/alcohol misting system and will give that a shot soon.

Yeah that’s that my goal too. I also figured that I’d try try a laser first before milling.