How is the “Height Map” Used?
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@tmeryhew said in How is the “Height Map” Used?:
; Z-Probe
M950 S0 C"exp.heater3" ; create servo pin 0 for BLTouch
M558 P9 C"^zprobe.in" H5 F240 T12000 ; set Z probe type to bltouch and the dive height + speeds
G31 P500 X-45 Y-7 Z2.345 ; set Z probe trigger value, offset and trigger height
M557 X15:215 Y15:195 S20 ; define mesh gridOk looks like you have a bltouch. If it's working, you should be able to change the homeall as I indicated above, and it should start using the probe to home Z, and with your slicer start gcode it should home XYZ and then generate a new heightmap and it should be active during the print.
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; homeall.g
; called to home all axes
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; generated by RepRapFirmware Configuration Tool v3.2.3 on Fri Mar 19 2021 21:41:05 GMT-0700 (MST)
G91 ; relative positioning
G1 H2 Z5 F12000 ; lift Z relative to current position
G1 H1 X-305 Y-225 F3600 ; move quickly to X and Y axis endstops and stop there (first pass)
G1 H2 X5 Y5 F12000 ; go back a few mm
G1 H1 X-305 Y-225 F360 ; move slowly to X and Y axis endstops once more (second pass)
G90 ; absolute positioning
G1 X150 Y110 F6000 ; move probe to bed center
G30 ; probe the bed; Uncomment the following lines to lift Z after probing
;G91 ; relative positioning
;G1 Z5 F200 ; lift Z relative to current position
;G90 ; absolute positioning -
And to clarify, yes it appears to be working. I can definitely generate a height map. Are there other things I should be looking for to confirm its working?
Other than obviously not crashing into the bed.
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The best way to test is to print a first layer test print twice. Once with G29 in the start gcode, and again with G29 S0 in the start gcode to disable it.
Something like this file works well.
bedlevel_nozzle_0.4_200x200-0.3-0.8.stl
I think the missing piece of the puzzle in your case was not using the probe to home z.
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@Phaedrux thank you so much. You guys really know your stuff. I'll go ahead and work on this right now.
How can I save/export all of my settings as a JSON once I have it dialed in?
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@tmeryhew said in How is the “Height Map” Used?:
How can I save/export all of my settings as a JSON once I have it dialed in?
You can back up the .g files in the /sys folder of your SD card.
From DWC, go to the system tab, there is a check box above the list of files, click it to select all the files, then right click on the file list area and select "Download as zip" to save all the files there as a zip file on your computer.
Then if you ever needed to restore the configuration to that point you could upload that zip file again to the system tab. Or extract it and upload a particular file you want.
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I've gone in and made the changes you describe. I am running the file you sent as we speak. I sent M122 and this was the result.
Should my "comp offset" be 0.000? Does this mean anything?
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No the important thing is that it indicates the mesh is loaded.
It should be moving the Z axis to compensate for the surface of the bed now.
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@Phaedrux so when I run the test print the second time with G29 S0, should it still probe the bed? Because that is what it's doing right now.
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@tmeryhew said in How is the “Height Map” Used?:
@Phaedrux so when I run the test print the second time with G29 S0, should it still probe the bed? Because that is what it's doing right now.
Yes G29 S0 probes the bed.
G29 by itself first looks for a file mesh.g - if found the file is executed.
If the file is not found then G29 behaves just like G29 S0 and probes the bed creating the height map.
Some folks create a height map with every print.
Others, like me, have a separate macro for creating the height map when desired.
That height map is then simply loaded using G29 S1 at the start of every print.
Your printer - your choice.
Frederick
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Sorry I should have said G29 S2 to clear the heightmap.
https://duet3d.dozuki.com/Wiki/Gcode?revisionid=HEAD#Section_G29_Mesh_bed_probe
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This first one is with the start code set to G29 S2.
This second picture is when I had it set to G29.
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And when it had G29 did it actually probe the bed surface?
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@Phaedrux Yes it did. It just seems like it performed worse with the mesh compensation on...
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Ok, let's work on improving your BLtouch performance.
M558 P9 C"^zprobe.in" H5 F240 T12000Let's try changing that to this
M558 P9 C"^zprobe.in" H4 F120 T6000 R0.5 A10It may take slightly longer to perform the G29 but the results should be more accurate.
You should also go through this again and remeasure your trigger height and XY offsets for G31.
https://duet3d.dozuki.com/Wiki/Test_and_calibrate_the_Z_probe
