[RRF 3.2.2] Can't figure out the offset between Z0 and mesh

[fcwilt]

@pkos said in [RRF 3.2.2] Can't figure out the offset between Z0 and mesh:

We're basically both doing the same, but you're doing it all via gcode, I do it via turning the printer on and off, just to be sure. So your gcode is equivalent to my steps 7-10.

Well the warning message about the loading of the height map and the Z=0 datum not being set suggests that perhaps homing with the probe is not quite the same as setting Z=0 with a second G30.

You can easily create a macro to try the code I posted to see if it makes a difference.

Frederick

[pkos]

@jay_s_uk I can't use H2 on the Switchwire. It's a CoreXZ device - individual motor motion creates havoc

[pkos]

@fcwilt Sure, I'll give it a try once the print here is done.

[fcwilt]

@pkos said in [RRF 3.2.2] Can't figure out the offset between Z0 and mesh:

@jay_s_uk I can't use H2 on the Switchwire. It's a CoreXZ device - individual motor motion creates havoc

CoreXZ?

I've heard of CoreXY but not CoreXZ.

Is yours laid out like this?

Thanks.

Frederick

[fcwilt]

@pkos said in [RRF 3.2.2] Can't figure out the offset between Z0 and mesh:

@fcwilt Sure, I'll give it a try once the print here is done.

If the problem is occurring when loading the height map just change the G29 to G29 S-1

I have two macros that in essence do what I posted - one to create the height map and one to load it.

Frederick

[pkos]

@jay_s_uk I double checked the other printer. It has H2 (that one is CoreXY) and the problem is exactly the same on that one. I wouldn't say this particular line is the problem.

[pkos]

@fcwilt Pretty much yeah.

https://vorondesign.com/voron_switchwire

[pkos]

@fcwilt No, that's not the issue and besides - this would not be a solution either I want to use a mesh

Let's reset.

The problem appears the moment I run bed mesh probing for the very first time.
I could of course skip it and not have an issue, but that's not the point.

So again.

I am able to configure both printers perfectly and manually find my Z0.

However, the moment I start to run G29 to get the printer to build a mesh map - the problem appears in that already the first probing produces a result 0.2-0.3mm above Z0.

And since the mesh is built incorrectly - each time I try to load it later with G29 S1 - it's loads that value incorrectly. The intermediary G30s were to check if that is the issue or not. They were definitely not a solution.

[fcwilt]

@pkos said in [RRF 3.2.2] Can't figure out the offset between Z0 and mesh:

@fcwilt No, that's not the issue and besides - this would not be a solution either I want to use a mesh

The code snippets I suggested to try are intended to create/load the height map for mesh compensation.

And they address the very issue the warning message talks about - the Z=0 datum not being set.

The Z=0 datum must be set before creating and before loading a height map.

If you create the two macros and try them you have nothing to lose but a bit of time and they might solve the problem.

Frederick

[pkos]

@fcwilt - don't me wrong. I am not ignoring your suggestion I am just saying - I'm already doing it and that does not help and doesn't immediately touch on my problem.

Let's completely ignore the loading of the map before printing for now. That totally doesn't matter for what I feel is the core of this problem.

Let's focus on the very first mapping of the mesh for now. As if the printer had a brand new SD card, brand new setup.

If you take a look at my homez.g - you will see I am actually doing what you are doing (except the babysteps being removed with code by you and me by turning the printer on and off - your way is WAY more convenient ; and I use M561 while you use G29 S2, but those do exactly the same).

Then, I move my carriage on top of a particular point - in my case it's X145 Y130 - and run a G30 there.

Then, I immediately hit G29 and upon that - I am already getting a map raised by 0.2-0.3. I specifically highlighted that point on the resulting mesh map.

So while you have it as a single snippet to be called at will, I have the same just spread across a couple files.

[fcwilt]

@pkos said in [RRF 3.2.2] Can't figure out the offset between Z0 and mesh:

Then, I move my carriage on top of a particular point - in my case it's X145 Y130 - and run a G30 there.

Then, I immediately hit G29 and upon that - I am already getting a map raised by 0.2-0.3. I specifically highlighted that point on the resulting mesh map.

I don't know if the issue still exists in 3.2.2 but sometimes in the past the height map displayed was not the most recent.

Rename the existing .CSV file something like heightmap_saved.csv and create a new one.

Then in the height map viewer you should see both of them and can force a refresh by loading the old one then the new one.

This may not be needed in 3.2.2 but it will insure you are seeing the most recent.

---

Also she warning referenced the Z=0 datum not being set so somehow the height map is being loaded without it being set.

Frederick

[pkos]

@fcwilt Yep, I remember that problem, and I tried reloading the whole webUI to be sure AND (I forgot to write about it) - I even deleted the previous csv before the probing.

And yes, I do have the warning about Z datum when I load the height map, but that's a second problem. First I want to understand why the very first bed mesh is already raised.

[fcwilt]

@pkos said in [RRF 3.2.2] Can't figure out the offset between Z0 and mesh:

And yes, I do have the warning about Z datum when I load the height map, but that's a second problem. First I want to understand why the very first bed mesh is already raised.

If the Z=0 datum is not set when creating the height map you can get that error since creating the height map also loads it.

Frederick

[pkos]

OK. Again.
Tell me how my code differs from yours.

First your code:

G29 S2                 ; cancel mesh bed compensation
M290 R0 S0             ; cancel baby stepping
G90 G1 Xaaa Ybbb       ; move probe to center of bed
G30                    ; set Z=0 datum
G29                    ; create height map

Now my code - combined from the files and process I posted:
Turn on the printer (so no need to run G29 S2 or M290, since nothing is set).
Then this:

G91              	; relative positioning
G1 H1 Z15 F6000	    ; lift Z relative to current position
G90              	; absolute positioning
G1 X145 Y130 F6000 	; go to first probe point that covers one of the mesh points
G30              	; home Z by probing the bed

G91             	; relative positioning
G1 Z5 F6000      	; lift Z relative to current position
G90             	; absolute positioning

Then immediately trigger mesh:

G29

Where are we different (I am skipping the extra moves like raising the hotend as that cannot have any impact on the core issue here)?

Please note I wrote in my original post - before starting a print (M561 before G29 S1) - I get the error. But that only appears when I start printing something and run G29 S1. Not after I create the mesh - that wouldn't make sense, since I am running G30 immediately before creating the mesh.

[fcwilt]

@pkos said in [RRF 3.2.2] Can't figure out the offset between Z0 and mesh:

Where are we different (I am skipping the extra moves like raising the hotend as that cannot have any impact on the core issue here)?

I cannot imagine that those extra steps are related to the problem.

Please note I wrote in my original post - before starting a print (M561 before G29 S1) - I get the error. But that only appears when I start printing something and run G29 S1.

My bad - you mentioned step 11 and looked at line 11 in your homeZ.g file not the steps above that.

So before loading the height map at the start of printing are you doing a G30 in the same XY location?

Frederick

[pkos]

Yep. Exactly the same spot.
And of course, the nozzle is raised by that distance. I have to babystep down to the plate by roughly the 0.2-0.3mm.

And I would expect this behavior since the actual mesh has that offset.

[fcwilt]

@pkos said in [RRF 3.2.2] Can't figure out the offset between Z0 and mesh:

Yep. Exactly the same spot.
And of course, the nozzle is raised by that distance. I have to babystep down to the plate by roughly the 0.2-0.3mm.

And I would expect this behavior since the actual mesh has that offset.

This is most curious.

All I can think of at this point is to create two macros with my code snippets then run the one that create creates the height map and then immediately run the one that loads it.

I'm trying to eliminate anything that is somehow happening behind the scenes causing the problem.

Do you have any code somewhere that might be changing the probe Z trigger height setting with one value being used when creating the height map and another when loading?

Grasping at straws there.

I'm running out of ideas.

Frederick

[pkos]

Tried your macros - no change. As in - the offset is still there. Even the error appears - which is weird, because I know at some point in my tinkering yesterday I managed to set a series of commands that made the error disappear, but of course - not the offset itself.

I do not have any gcode that could in any way impact the probe Z trigger. That I double checked

I am pretty much stuck as well It totally baffles me.

[fcwilt]

@pkos said in [RRF 3.2.2] Can't figure out the offset between Z0 and mesh:

I am pretty much stuck as well It totally baffles me.

Here is something to try.

When doing the G30 you are positioning the probe at one of the probe points for the grid? Yes? No?

IF that is the case try a position that is in the middle of 4 grid points.

I will be racking my brain trying to recall anything else that might be causing the problem.

Frederick

[pkos]

@fcwilt Correct. I am probing exactly one of those spots. I'll try between the 4 tomorrow assuming the printer will even start. Currently, the board refuses to launch (different, known issue with the minis, waiting for a board replacement). If it were only on this printer, I'd think it's the board at fault and leave it at that But the other printer has the same problem, so yeah.