I have created a BL Touch threadI wonder if posting it here destroyed any formatting or did they look like that in the file, all bundled into one line. If the latter perhaps its using linux format, but I think if you use wordpad to open it, it'll be correctly formatted regardless , but not in notepad.
I'm just mentioning this specifically because if the formatting is good, its a lot easier to follow whats going on for you as anything to the right of the ; is a comment in marlin gcode. But those long lines look like multiple lines of command/comment munged into one. With the right formatting, its a list of Gcodes then a semicolon and a comment about what that does to make it more human readable.
Back to your posted code these are the important bits.
G28 ; home all axes <- this will home the axes, on ender with bltouch, there's a microswitch on the x and y but on the z there's no axis microswitch switch (you remove this when you fit bltouch if its retrofitted), so its homed using the contact point of the bltouch and it'll do this itself automatically.
G29 ; auto level <- this sets off the bed auto level proceedure built into marlin firmware. https://marlinfw.org/docs/gcode/G029-ubl.html If you read that page, it looks like the bed mesh levelling points are already stored in the printers firmware, so its not specifying G29 P0 verb to specify the levelling mode, so its just recalling the probe points from firmware (maybe it'll take one point automatically, idk). I cant remember how to dump out the bed mesh levelling point values, but you probably can find that in google, but its not important if its already set up and adhering well.
This is how my ender5 behaves with the crtouch too. Under klipper those mesh probe points are stored in a file, and it draws a heat map of the bed level so you can see how warped your bed is from a pretty graphic (mines quite bad, creality shipped it to me with the bed levelling screws overtightened distorting it into a crown shape during shipping, though as its meshed, it doesnt affect anything).
If you need more clarity, I think you should start a new thread in this subforum to get this thread back on track
Just trying to separate the thread.
Hopefully the mods could transfer the relevant sections if one gets a few minutes spare?
