Can't see the G-Code edit box

txturbo · July 11, 2025, 2:33pm

I am trying to add a bit of G-Code to the beginning and end of my run to manage a digital output on my lmcv4-fiber-m board to turn on/off my filter fan. According to the docs there should be a tab in Lightburn that allows this but I am unable to access it. Any ideas?

Rick · July 11, 2025, 9:25pm

You should be able to click into either of those ‘Start GCode’ or ‘End GCode’ edit boxes and type your GCode there. As noted on that tab,

“No validation is performed and it is up to the user to ensure the commands will not damage their
machine.”

ednisley · July 11, 2025, 10:12pm

If it’s this board:

Then it does not use G-Code and, thus, none of the G-Code-specific options are valid.

@JohnJohn: This should be more obvious in the doc, as “allows for modification of the GCode output for GCode devices” doesn’t specifically exclude DSP / fiber laser controllers.

Rick · July 11, 2025, 10:33pm

Oh my, all apologies - I totally missed this is a galvo. I might need a nap.

txturbo · July 12, 2025, 12:04am

Maybe I can accomplish the task in a different way. Is it possible to get one of the two digital outputs (output 4 or 5) on the mcv4-fiber-m board to change states when the laser is turned on?