Warning: the height map has a substantial Z offset

[fcwilt]

@downshift64 said in Warning: the height map has a substantial Z offset:

i heat the bed up then probe it and save the height map i have something that uses that each time i start a new print

The problem is the height map is referenced to the Z=0 datum when the height map is created.

When the height map is loaded it expects that Z=0 datum to be the same value.

Without a Z probe I'm not sure how to handle it other than assuming Z=0 is a fixed value and never changes.

Frederick

[downshift64]

ya once i get height map it is a fixed value and should never change really

[fcwilt]

@downshift64 said in Warning: the height map has a substantial Z offset:

ya once i get height map it is a fixed value and should never change really

That has not been my experience with my printers but if yours is unchanging that is great.

Frederick

[downshift64]

its an Ulitmate XL from Elite Machine Works its a solid bed

[Phaedrux]

Post your home all.

The warning is a warning, it may not apply to you, but without seeing your homing files I can't say. Your slicer start gcode does a G28 to home the printer and then G29 S1 to load the heightmap. What we don't know is what homeall.g is doing to home the printer. Is it using an endstop, or a zprobe? That's where the potential for an offset lies. You probably updated the firmware from a version that didn't have the warning to one that does. If your first layer is still good, then you have no problem and you can ignore it. Or if you want to get rid of it, post your homeall so we can see what's going on with the gcode.

[downshift64]

thank you i would like to get rid of it
G91 ; relative mode
G1 S1 Z310 F3500 ; move Z towards the switch until it triggers
G1 Z-4 F900 ; move Z back 10mm
G1 S1 Z6 F600 ; move Z slowly towards the switch until it triggers
G1 Z-4 F900 ; move Z back 10mm
G1 S1 Z6 F400 ; move Z slowly towards the switch until it triggers

G1 X-340 F7000 S1 ;
G1 X4 F600 ; move slowly 4mm in the +X direction
G1 X-5 S1 ; move slowly 10mm in the -X direction, stopping at the homing switch

G1 Y-340 F7000 S1 ; move up to 240mm in the -Y direction, stopping if the homing switch is triggered
G1 Y5 F600 ; move slowly 4mm in the +X direction
G1 Y-6 S1 ; move slowly 10mm in the -X direction, stopping at the homing switch

G4 P0 ; CLEAR BUFFER IN ORDER TO PROPERLY LOAD SAVED GRID
G90
;G29 S1 ; LOAD SAVED BED GRID

G4 P0 ; CLEAR BUFFER AFTER LOADING GRID

G1 X0 Y0 F8000

[fcwilt]

@downshift64 said in Warning: the height map has a substantial Z offset:

G4 P0 ; CLEAR BUFFER IN ORDER TO PROPERLY LOAD SAVED GRID

Hi,

I see the comment but I don't understand the purpose.

What buffer do you think needs clearing to load the height map?

I have never used G4 P0 and everything works just fine.

Thanks.

Frederick

[downshift64]

sorry i cant answer your question this is what i got when i purchased the printer

[downshift64]

maybe something to do with not having to probe the bed every time before i print

[Phaedrux]

@downshift64 said in Warning: the height map has a substantial Z offset:

G1 S1 Z310 F3500 ; move Z towards the switch until it triggers
G1 Z-4 F900 ; move Z back 10mm
G1 S1 Z6 F600 ; move Z slowly towards the switch until it triggers
G1 Z-4 F900 ; move Z back 10mm
G1 S1 Z6 F400 ; move Z slowly towards the switch until it triggers

It's saying you may have an offset because it's using an endstop to home the Z axis before loading the heightmap. If the endstop position is perfectly set then you don't have an issue, but it will still warn you.

[fcwilt]

@Phaedrux said in Warning: the height map has a substantial Z offset:

It's saying you may have an offset because it's using an endstop to home the Z axis before loading the heightmap. If the endstop position is perfectly set then you don't have an issue, but it will still warn you.

You sure?

I thought the offset warning was based on the contents of the height map file alone.

I tried to verify that but I couldn't figure an easy way to add a significant offset to each value in the file and then load it.

Frederick

[downshift64]

@Phaedrux so there is nothing i can do to get rid of the warning,, if not is it still using my heightmap as intended

[Phaedrux]

You can get rid of the warning and any potential offset by using the z probe to home the z axis. (Provided your z probe z offset in g31 is correct).

If your first layers are good, then yes your height map is being applied and all is good.

[downshift64]

@Phaedrux i only use the z probe only when i change something with my printer like a new bed or i switch out the nozzle to make sure everything is still good

[downshift64]

@downshift64 could i go back to the board software that didnt have this warning

[Phaedrux]

Is the warning that obtrusive?

[downshift64]

@Phaedrux no just everything worked great before i upgraded the board just wanted to go back to that, that way i know everything works as it should

[downshift64]

right now i dont know if its following the height map or the z min i set it to

[Phaedrux]

bedlevel_nozzle_0.4_200x200-0.3-0.8.stl

Do two test prints. Once with G29 S1 active, and again with G29 S1 commented out. You should be able to tell if it's working as intended.

I don't think going back a firmware version to avoid a warning message is such a great idea. You also give up any bug fixes and improvements. But to each their own.

All the warning is saying is that the Z0 point wasn't established by a probe before the heightmap is loaded. As long as the Z0 point of the endstop is the same now as it way when the heightmap was created, you should have no issues. The reason the probe is preferred is that it's getting a current reading from the actual bed surface each time. No if your endstop is accurate and the build quality good (as it would appear yours is) then the endstop method is fine.