Warning: the height map has a substantial Z offset

fcwilt

I also have a macro for loading the height map. The macro I have for starting a print invokes this file.

Notice here that I am showing the invoking of the macros for configuring the probe and setting the Z=0 datum.

The code that performs these function, that I included the previous post, is essentially what is in these two macros.


M98 P"configprobe.g"		; configure Z probe

M98 P"probeZ.g"			; set Z=0 Datum

G29 S1                          ; load height map

M376 H10		        ; set bed compensation taper

downshift64

thank you i will give them a try does it matter where i put these commands in the config.g

downshift64

i dont use a BLTouch i attach a probe then when i am done take it off and usually dont use it again unless something changes

fcwilt

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

thank you i will give them a try does it matter where i put these commands in the config.g

They should NOT be part of config.g.

If you do like I do and create the height map manually by invoking the macro you would create a macro to do that.

If you wish to create the height map on every print you should invoke the code when starting a print.

As to loading the height map it should be part of the code you invoke when starting a print.

I have my slicer invoke a macro called "print_begin.g". All of the code needed to prepare for printing is in that macro.

Also In this macro I invoke the macro to load the height map.

Frederick

downshift64

damn i wish this was easier

fcwilt

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

i dont use a BLTouch i attach a probe then when i am done take it off and usually dont use it again unless something changes

Hmm...

Then I don't know how you are going to set the Z=0 datum without a Z probe.

I have found that I needed to install a BLTouch as the Z=0 setting changed as the bed assembly heated up. So each print potentially needed to have Z=0 set again - which is what I do now.

Frederick

downshift64

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

fcwilt

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

damn i wish this was easier

If you have a Z probe AND make use of macros called via M98 it can be fairly straightforward and easy to maintain.

Frederick

downshift64

my slicer start g code
G90 ; use absolute coordinates
M83 ; extruder relative mode
M104 S[first_layer_temperature] T0 ; set extruder temp
M140 S[first_layer_bed_temperature] ; set bed temp
M190 S[first_layer_bed_temperature] ; wait for bed temp
M109 S[first_layer_temperature] T0; wait for extruder temp
G28 ; home all without mesh bed level
G29 S1 ; mesh bed leveling
G1 Z0.25 F2500
G1 Y0 F1000.0 ; go outside print area
G92 E0.0
G1 X60.0 E9.0 F1000.0 ; intro line
G1 X100.0 E12.5 F1000.0 ; intro line
G92 E0.0
M221 S{if layer_height<0.075}100{else}95{endif}

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