OK, well after i uploaded marlin 1.0.2 FW and setup the Auto Bed Leveling

OK, well after i uploaded marlin 1.0.2 FW and setup the Auto Bed Leveling as per tom sanladerers vid, it works great when manually inputting the Gcode thru pronterface… however, even tho i added the G29 to the start code, it doesnt function properly… X and Y home then Z homes to the center of the bed… however it dosnt lower to the bed to probe it, it stays wherever the X carrage is in height and probes the air…then i get a Z endstop hit indication and everything freezes…ex… the X and Y home to 0, but the Z is at say 100mm above the bed…when it is told to home it moves to the center as it should, then moves up and down 10mm probing for the bed that is in fact 90mm below it… iv gone thru everything that i can think of to include removing the Z MAX endstop, and it didnt make any bit of difference…BUT if i manually enter the G28 and then G29 into pronterface it all works perfectly… thoughts? i also tried Cura and it did the same thing…so its not a software issue, i think its gcode or FW related…im wondering if it has something to do with the safe homing function?

on a side note, during heat up, the LCD says heating bed, but not heating nozzle, where do i go to find the text and customize it the way i want? i found the text to display in the config.h file to say mendel ready…but cant find the others>…

I think you have to add G28 X0 Y0 before the G29 in the gcode header. I would even put G28 X0 Y0, then G28 Z0, then G29. As for the heat up message, doesn’t it normally heat up the bed first and wait for it to get up to temp before heating the extruder?

i have the gcode written exactly like that… the X Y home perfectly… Z goes to the center, but wont go to the bed… then it probes the air…

as for the text, i was just wondering where to find it… its working just fine…

G21 ;metric values
G90 ;absolute positioning
M82 ;set extruder to absolute mode
M107 ;start with the fan off
G28 X0 Y0 ;home XY axis
G28 Z0 ;home Z axis
G29 ;bed level check
G92 E0 ;zero the extruded length
G1 F200 E3 ;extrude 3mm of feed stock
G92 E0 ;zero the extruded length again
G1 F{travel_speed}
M117 Printing Part ! ;Put printing message on LCD screen

Remove the home z

G28 X0 Y0
G29

That should do it
Brook

But then how does it know where z is befor probing

G29 is a complicated z probe- it finds the exact angle of the bed so it can print perpendicular to the bed. It even works when the bed isn’t level at all. I’ve printed at 25 degree slant !
Bd

Right which is y i wanted to do it…but doesnt the z axis have to home b4 being able to measure the bed in the correct locations?

No, the sensor senses z during g29 although I do
g28 Z0
G28 x0 y0
G29

But only just in case the z is up in the air after a previous print. There is s limit in g29 that times out and don’t send the z down far enough of it’s too high

Brook

Ok…so if my z axis is say 50mm above the bed…i g28 xyz…then g29 to bed probe it…which makes sense…cuz z axis home is at the bed surface…and the probe can do its thing…but when its supposed to do all that it doesnt…manually it will in pronterface… but in gcode startup it wont…the x y will home…then x centers…but z wont come down to home in the bed center…it just stays put…then the g29 starts but goes up and down 10mm without reaching the bed…

Ill post a vid of it so it is obvious…i may be to confused to explain properly…its 318am…ill post vid later today…

I just got auto leveling working on my printer and I may know what’s up. Your startup is basically the same as mine except my G28 Z0 command doesn’t move my printer to the center of the bed, I have to manually move with G1 X100 Y100 or using rep host. After that, I then home the Z. To automate the process, I put the following in my startup gcode:

G28 X0 Y0
G1 X100 Y100
G28 Z0
G29

Pretty straightforward but noticed when it gets to “G1 X100 Y100” command, it moves at snail pace. I don’t know why yet, probably has to do with the steps/mm but it takes a minute to travel to the center. After that, it performs normally.

For your situation, I’m thinking it’s just moving at a snail pace during the Z homing after your printer homes to X0 Y0 making it it look like its frozen in place.

As for removing Z0, you should only do it if your probe is located above the build plate when you home X0 Y0. My probe is mounted in a position where it goes off the bed at the X0 Y0 position. Homing the Z will make my hotend crash into the build plate.

I tried it ur way…it works…but yea i get the same snail pace with the g28x100y100

@Chris_Lau If you want to use G1, you need to include a feed rate (F3000 for example). Alternately you could use G0.

@Johnathan_Oey ​ G28 ignores all coordinates after the axis variable. G28 X Y will give you the same results as G28 X100 Y100 for example.

yea my G28x100… was a typo… should have been G0 X100 Y100… but ill also add the feedrate to the code and see what happens… thanks JD

@Johnathan_Oey G0 will ignore feedrate, so try G1 X100 Y100 F6000.

ok…so then G1 reads feedrate but not G0 ?

Yes.

isnt the feedrate of 6000 a bit high and cause missed steps?

Feedrate is in mm/min, so F6000 is 100 mm/s.