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Probe offset help

Posted by danskinn 
Probe offset help
March 12, 2019 10:07AM
Hi there,
I had been using Marlin 1.1.5 on this printer for quite a while and then something happened and the machine wouldn’t boot up.
I have since replaced the ramps 1.4 with new parts and flashed Marlin Buggix 2.x and have printed 2 things, but noticed the G29 not
activate. I have a bltouch mounted to the left and slightly in front of the nozzle (25,6) are my offsets. My printers origin (0,0) is in the back right.
Looks like Marlin is expecting it to be in the front left.
Printable area is 250x250x250.

Having a heck of a time trying to gwt the probe points right for BiLinear probing.

Do I need to go back to 1.1x branch?
Do I need to chenge where my printers origins are?

Any and all help is greatly appreciated!
Dan
Re: Probe offset help
March 12, 2019 10:47AM
Hello Dan;

Do you have the Original Marlin 1.1.5 firmware with your configurations.

There is a program called WinMerge
This program will help move the Original Configuration.h, Configuration_adv.h and Pins_RAMPS.h from Marlin 1.1.5 to Marlin 2.0.x BF


In order for G29 to function Bed leveling need to be setup and configured for your 3D Printer.
{something like this though these are my Marlin 2.0.x BF Bi-Linear Settings}

// Enable this option for a probe connected to the Z Min endstop pin.
#define Z_MIN_PROBE_USES_Z_MIN_ENDSTOP_PIN
// A Fix-Mounted Probe either doesn't deploy or needs manual deployment.
#define FIX_MOUNTED_PROBE
// Z Probe to nozzle (X,Y) offset, relative to (0, 0).
#define X_PROBE_OFFSET_FROM_EXTRUDER 0 // X offset: -left +right [of the nozzle]
#define Y_PROBE_OFFSET_FROM_EXTRUDER 25 // Y offset: -front +behind [the nozzle]
#define Z_PROBE_OFFSET_FROM_EXTRUDER -0.5 // Z offset: -below +above [the nozzle]

#define RESTORE_LEVELING_AFTER_G28

#define AUTO_BED_LEVELING_BILINEAR
#define ENABLE_LEVELING_FADE_HEIGHT

#define GRID_MAX_POINTS_X 6
#define GRID_MAX_POINTS_Y GRID_MAX_POINTS_X

// Set the boundaries for probing (where the probe can reach).
#define LEFT_PROBE_BED_POSITION MIN_PROBE_EDGE + 10
#define RIGHT_PROBE_BED_POSITION (X_BED_SIZE - (MIN_PROBE_EDGE + 10))
#define FRONT_PROBE_BED_POSITION MIN_PROBE_EDGE + 15
#define BACK_PROBE_BED_POSITION (Y_BED_SIZE - (MIN_PROBE_EDGE))

One thing you have to remember when flashing a new marlin Firmware, as the old setting will remain in memory until this is done..
You must manually configure the Firmware settings with
M502 : Restore defaults from Firmware
M500 : Store Settings

If you have questions regarding Marlin 2.0.x BF Post.

Edited 2 time(s). Last edit at 03/12/2019 10:48AM by Roberts_Clif.


Electronics Technician / Computer Programmer
Re: Probe offset help
March 12, 2019 03:08PM
Hi Roberts_Clif,
Thank you for replying.

I searched my pc for the old firmware before leaving for work this morning, I think I found it, just had to leave before I could dig into it

I have BLTouch so I enabled that setting

#define BLTouch

"// Z Probe to nozzle (X,Y) offset, relative to (0, 0)."
"#define X_PROBE_OFFSET_FROM_EXTRUDER 0 // X offset: -left +right [of the nozzle]" <---- My machine = +left -right
"#define Y_PROBE_OFFSET_FROM_EXTRUDER 25 // Y offset: -front +behind [the nozzle]" <---- My machine = +front -behind
"#define Z_PROBE_OFFSET_FROM_EXTRUDER -0.5 // Z offset: -below +above [the nozzle]"

"#define AUTO_BED_LEVELING_BILINEAR" is enabled

"#define GRID_MAX_POINTS_X 6" I have 3 for now

These parameters are the confusing bit in this iteration of Marlin
"// Set the boundaries for probing (where the probe can reach)."
"#define LEFT_PROBE_BED_POSITION MIN_PROBE_EDGE + 10"
"#define RIGHT_PROBE_BED_POSITION (X_BED_SIZE - (MIN_PROBE_EDGE + 10))"
"#define FRONT_PROBE_BED_POSITION MIN_PROBE_EDGE + 15"
"#define BACK_PROBE_BED_POSITION (Y_BED_SIZE - (MIN_PROBE_EDGE))"

My probe is +25mm to the left and +6mm of the nozzle, but my machine goes LEFT for positive movement and Bed moves Back (away from you) for positive movement.This motion is mirrored on practically every other printer.

"One thing you have to remember when flashing a new marlin Firmware, as the old setting will remain in memory until this is done.."
"You must manually configure the Firmware settings with"
"M502 : Restore defaults from Firmware"
"M500 : Store Settings"

Yes, this was forgotten initially. I will do this after every upload.

Thank you,
Dan
Re: Probe offset help
March 12, 2019 05:18PM
If you find your Marlin 1.1.5 Configurations I can help you get them into the new marlin.


My proximity sensor is 25mm directly behind the Nozzle.
#define MIN_PROBE_EDGE 10

I decided on a border of 20mm so + 10
"#define LEFT_PROBE_BED_POSITION MIN_PROBE_EDGE + 10"
"#define RIGHT_PROBE_BED_POSITION (X_BED_SIZE - (MIN_PROBE_EDGE + 10))"

Edited 1 time(s). Last edit at 03/12/2019 05:28PM by Roberts_Clif.


Electronics Technician / Computer Programmer
Re: Probe offset help
March 12, 2019 07:18PM
I believe I have sorted it now. I found my old config.h and my probe points were a bit greater than I was specifying so I bumped them up from 10 to 30 and 230. So 30,230,30,230.
I also did the M502 followed with M500 and is verkingg!!
Also added 6 probe points fro each axis. Takes for ever, but maye it will be even out to the edge? The prusa is running 7x7 and it helps.

Thank you for your help,
Dan
Re: Probe offset help
March 12, 2019 09:05PM
Now that you have this done you can learn the next Step.

Auto Bed Bi-Linear Bed leveling Data can bed Saved.

Using M500 or LCD Menu Store Settings.

Then adding M420 S1 to one of the Last lines of your Startup G-Code you can restore the Bed leveling data
or
You can restore the data with LCD Menu Bed Leveling "On/Off"
or
you can enable
#define RESTORE_LEVELING_AFTER_G28


Electronics Technician / Computer Programmer
Re: Probe offset help
March 12, 2019 09:59PM
What?? Get outa town. I thought that the mesh was only saved in UBL.
I did notice the that selecting Level Bed from lcd initiated homing first.
I did what you recommended in an erlier post and enabled

#define RESTORE_LEVELING_AFTER_G28 This might be required for saving G29.
I will have to add the gcode to save or load the mesh.
How do I save the mesh? If there is a restore command, there must be a store command?

Dan
Re: Probe offset help
March 13, 2019 08:33AM
I power the 3D Printer on then do a
M503 - Report Settings
M502 - Factory Reset
G28 - Auto Home
G29 - Bed Leveling (Manual)
M500 - Save Settings
to save the Mesh.

Some are not needed only M502 and M500 or LCD menu Bed level and Store Settings.

Then to restore Bed leveling data Use M420 S1 is startup G-Code after the Last G28

M420 - Bed Leveling State

Then only bed level if I see a problem in the 1st layer of a print - But I still have Baby Steps enabled.
Plus I always have a 1-2 lap skirt to allow for adjusting the baby steps before the print begins.
I can quickly adjust baby steps to correct the 1st layer and continue this Print before Print failure.

Edited 2 time(s). Last edit at 03/13/2019 08:38AM by Roberts_Clif.


Electronics Technician / Computer Programmer
Re: Probe offset help
March 13, 2019 09:59AM
That is berry helpfull, thank you.
I took a screen shot for reference. I always wondered what babystepping was. Never looked into it.

Seems similar to Prusas Live Z adjust. It would be nice if the final height was saved to Z probe offset
after adjusting with babystepping.

This makes me think you could potentially fix a layer shift if you caught it in time and babystepped X and or Y.
Prusa is using trinamic 2130 so they can have a software closed loop system to help avoid skipps and therefore
Layer shifts and crashes.
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