I recently installed a BL touch V3.1 on my Taz Pro with a Lulzbot H1.75 Hemera print head. The retracted probe height is set within parameters according to the BL Touch documentation.
I’m trying to measure/set my Z probe offset. When using the Z-offset Wizard in DO version 49, the machine zeros all axes correctly, but instead of the print head stopping after the Z axis is zeroed, it stops only briefly, then countinues to drift downward until the nozzle crashes into the bed. I’ve tried changing the initial/default offset to more positive and negative values, however, the end result is the same. I power down the machine immediatly upon impact, so I’m not sure what would happen next (continued downward travel, or eventual stop/rise)
Has anybody experienced a similar issue?
Is there something I should be doing differently? I have no previous experience with a BL Touch or Zero Offset Wizardry. Any suggestions are appreciated.
The problem I was having was due to my misunderstanding of how the Z offset Wizard worked, not a mechanical or wiring issue. My Probe Z offset is configured properly now and all is good.
I am using the original Archim2 board that came with my TAZ Pro and Lulzbot’s new H1.75 Hemera. I added the BL touch to the print head assembly by modifying the cooling fan shroud to accept an adjustable bracket to which the BLT is mounted. I am currently using the settings for Lulzbot’s M1.75 head that Marcio included in version 49, and plan to help him configure settings for the H1.75.
I still have a few questions about the BL touch that you could help with:
When you replaced the Rambo on your TAZ 6 with the Archim2, did you also add the color LCD? Some of my questions have to do with the touch screen GUI and Drunken Octopus.
When I initiate a ‘Probe Mesh’ sequence in the ‘Leveling’ menu, are the results stored in the EEPROM automatically by the firmware, or do I have to ‘save’ them manually with a M500 command in my start up sequence? My hope is to probe a mesh only occasionally, not before every print.
If they are stored, do you know in which location (S 0)?
Do I have to retrieve the mesh data from that location before each print, and activate the UBL (G29 A?)
I have more questions, but suspect you will answer most of them by sharing your configs/startup up file modifications…
I do not use a color LCD and I do all of my mesh maintenance through the terminal.
Here is the gcode I use to create and store a mesh:
G28 ; home all axes
M420 S0 ; Turning off bed leveling while probing
M155 S30 ; reduce temperature reporting rate to reduce output pollution
M190 S85 ; wait for the bed to get up to temperature
G29 P1 ; automatically populate mesh with all reachable points
G29 P3 ; infer the rest of the mesh values
G29 P3 ; infer the rest of the mesh values again @BEDLEVELVISUALIZER ; tell the plugin to watch for reported mesh
M420 S1 V ; enabled leveling and report the new mesh
G29 S1 ; Save UBL mesh points to slot 1 (EEPROM).
G29 F 10.0 ; Set Fade Height for correction at 10.0 mm.
G29 A ; Activate the UBL System.
M500 ; save the current setup to EEPROM
M155 S3 ; reset temperature reporting
M140 S0 ; cooling down the bed
Note that the slots are arbitrary. If I used filaments that required significantly different bed temps I would create a different mesh per temp.
I then recall that slot (S1 in my case) via start gcode and also perform a 3x3 tilting correction with the code below:
; This gcode has been hacked together by Jason to incorporate ABL
M73 P0 ; clear GLCD progress bar
M75 ; start GLCD timer
G90 ; absolute positioning
M82 ; set extruder to absolute mode
G92 E0 ; set extruder position to 0
M140 S{bed_temperature[0]} ; start bed heating up
M190 R{bed_temperature[0]} ; wait for bed to get to temp
M104 S160; start warming extruder to 160
G28 ; Home all axis
G29 A ; enable ABL
G29 L1 ; Load saved mesh from bank 1
G29 J3 ; 3x3 point tilt mesh
M109 R{first_layer_temperature[0]} ; wait for extruder to reach printing temp
M117 TAZ 6 Printing… ; progress indicator message on LCD
; END_START_GCODE
Let me know if this helps stitch things together for your printer.
Thank you for sharing your code - it explains a lot about how the ABL data is stored and retrieved.
Marcio has added a menu to the touch screen GUI on the TAZ pro that allows the BL touch to be independently tested/reset and a probe mesh to be initiated, displayed, and edited. The ‘save’ button he created on the display is not yet highlighted, so I don’t think it is programmed/active yet. However, once complete, it will allow all these routines to be implemented with the touch of a button, rather than through a separate OctoPrint plugin or a specific gcode file - truly masterful (Thanks Marcio!)
Until the DO GUI subroutine programming is complete, it’s nice to know that all the UBL features can be accesses through the terminal.
BTW: the TAZ Pro’s LCD and video card are available for purchase from Lulzbot (or other vendors, I’m sure, if you just want to get the part numbers and find your own source). I think the cost was around $100. The board plugs into the Archim2 with a 10 pin cable (sold separately) and adds a whole new dimension to the DO experience.