Bed levleing has no effect

Hello, I made a custom 3D printer and got everything to work except bed leveling. I currently am doing PROBE_MANUALLY with MESH_BED_LEVELING and LCD_BED_LEVELING. I am using a Ramps 1.4 with Marlin and the LCD screen.

I can follow the on-screen instructions and the printer moves throughout the bed leveling points. I adjust the Z-axis, use a piece of paper, all of that. After bed leveling, I use Pronterface to send the code M420 S1 to enable bed leveling. I then use Cura to create the Gcode which I again send with Pronterface.

The problem is that the bed leveling does not seem to have any effect. To test it, I "leveled" the bed by setting the nozzle 5mm above the bed at all calibration points. Yet when I run the print, the nozzle is almost touching the buildplate as that is the zero point on the Z-axis.

What am I missing that would enable the bed leveling to work? I have attached my Configuration.h and Configuration_adv.h

I'd really appreciate any help, I've tried all sorts of combinations of settings but keep getting the same result. Thanks in advance!

Have you sent a M500 to Save the Bed Leveling Data points, send with Pronterface. .

No, I will try that, thank you!

Nope, that didn't do it. These were the steps I did.

1. I enabled EEPROM_SETTINGS in the Marlin Firmware and uploaded to board.
2. Ran bed leveling and set the nozzle to maximum vertical clearance for all points just so I would know if it worked. I understand this will not make a good print.
3. Sent M500 to store bed leveling settings
4. Sent M420 S1 to enable bed leveling
5. Started a print but the nozzle was not at the clearances I had leveled it at.

Is there perhaps a way to print the bed leveling values so I know if they are getting saved? M503 does not seem to have this information. Thanks again.

Alright, something is turning off M420 in between when I send M420 S1 and the print actually starts. After I do my bed leveling and send M420 S1, I send M503 S1 to view settings and get the following:

...
echo: M420 S1 Z5.01
echo: G29 S3 X1 Y1 Z5.00000
echo: G29 S3 X2 Y1 Z5.00000
echo: G29 S3 X1 Y2 Z5.00000
echo: G29 S3 X2 Y2 Z5.00000
...

I then start the print which ignores these settings. I then type M503 S1 again after canceling the print and get the following:

...
echo: M420 S0 Z5.01
echo: G29 S3 X1 Y1 Z5.00000
echo: G29 S3 X2 Y1 Z5.00000
echo: G29 S3 X1 Y2 Z5.00000
echo: G29 S3 X2 Y2 Z5.00000
...

This is the GCode from my part in Cura:

;FLAVOR:Marlin
;TIME:491
;Filament used: 0.422372m
;Layer height: 0.2
;Generated with Cura_SteamEngine 3.3.1
M104 S200 ; Heat extruder
M109 S200 ; Wait to heat extruder
M82 ;absolute extrusion mode
G28 ;Home
;Prime the extruder
G92 E0
G1 F200 E20
G92 E0
G1 Z15.0 F1800 ;Move the platform down 15mm

G92 E0
G1 F1500 E-7
;LAYER_COUNT:64
;LAYER:0
M107
G0 F900 X38.135 Y38.252 Z0.3
;TYPEKIRT
G1 F1500 E0
G1 X38.252 Y38.135 E0.00825
G1 X38.838 Y37.605 E0.04767
G1 X39.474 Y37.138 E0.08704
.. etc. ........




I looked up these codes and it doesn't appear that any of these would invalidate my bed leveling command. Anything I'm missing? Thanks for looking.

I can see why programmers use the rubber duck approach to work through problems. I've made more progress replying to my own forum post this morning than I have in the previous week of working through this problem. Apparently G28 (home) turns off bed leveling. Not sure why but I'm sure that people smarter than me have a reason for it. So by putting M420 S1 after the G28 in my GCode, bed leveling is now working. Hopefully this will be of use to someone. High fives all around.

Quote
Jeffsg605
Apparently G28 (home) turns off bed leveling. Not sure why but...

The reason is, if the machine is being homed, it very likely is because the machine just powered up and doesn't know its position on each axis.
Without knowing where the nozzle is on the bed (with certainty), it is difficult to 'correct' for the bed imperfections.

The other half of the answer is, the original 3-point bed leveling turned off bed leveling at the start of G28. That helped the developer simplify things and have the machine in a known state.
Just because it has been that way for so long, there are people that feel it should not be changed without careful thought.

But... There is a migration (configuration.h file option) where users are allowed to re-enable bed leveling after a G28 now.

I was told that you need to use the "M420 S1" After the last G92

My Cura startup G-Code
;Filament used: {filament_amount}m {filament_weight}g
;Filament cost: {filament_cost}
;M190 S{print_bed_temperature} ;Uncomment to add your own bed temperature line
;M109 S{print_temperature} ;Uncomment to add your own temperature line
G21 ;metric values
G90 ;absolute positioning
M82 ;set extruder to absolute mode
;M106 S127 ;set Fan half speed
M107 ;start with the fan off
G28 X0 Y0 ;move X/Y to min endstops
G28 Z0 ;move Z to min endstops
G1 Z15.0 F{travel_speed} ;move the platform down 15mm
;Put printing message on LCD screen
M117 My Print...
G28 X0 Y0
G1 E4.0 ;prime extruder
G92 E0 ;reset extruder length
M420 S1 ; Bed Leveling On ; I have it after the last G28 or G92
M220 S32.000000
;M420 V1 ; Print the leveling grid

Edited 1 time(s). Last edit at 05/27/2018 02:30PM by Roberts_Clif.

Thanks for the explanation guys! M420 V1 was what I was looking for as well.

M420: Enable/Disable Bed Leveling and/or set the Z fade height.
S[bool] Turns leveling on or off
Z[height] Sets the Z fade height (0 or none to disable)
V[bool] Verbose - Print the leveling grid
Send M501 ; Load data
Send a M420 V ; Print the leveling grid
Z-Offset
Z-Offset " M851 Z-0.44 " Sets the Z-offset the input -00.44

Edited 1 time(s). Last edit at 05/27/2018 08:13PM by Roberts_Clif.