Another Delta Homing Issue

too.stroke

First post and brand new to working with duet/delta so apologies if I'm missing forum etiquette .

I have a Duet2 Wifi with a smart effector.

To begin with, this issue was nonexistent this morning and I can't think of anything meaningful I may have changed that could cause this, but then my ignorance is why I'm here.

The issue I'm having is one of my axis is refusing to home at first on home command.
Let me give an example:

1: axis 1, 2, and 3, are 200mm below their (optical)endstops.
2: I click "home all" in the web interface.
3: axis 1, and 2 both home normally but axis 3 doesn't move at all.
4: axis 1 and 2 have both finished homing, I click "home all" in the web interface again.
5: axis 3 homes (seemingly) normally.
6: I click "home all" in the web interface again.

7: axis 1, and 2, both do their home sequence as follows:

   move up to endstop fast
   stop at endstop
   move down (5?)mm
   move up to endstop slowly together
   move down (5?)mm and stop home sequence

8: axis 3 however does THIS:

     do nothing
     move down (5?)mm
     do nothing
     move down (5?)mm and stop home sequence

I do wish to note that this behavior is not consistent either. Sometimes axis 3 won't home normally on the second or third command, but will instead do its weird home sequence (refusing to go up) and sometimes axis 3 will go up normally on the first ascent but not the second.

My best guess as to the root of all this is axis 3 doesn't want to go up SOMETIMES ?
but only during home sequence (goes up normally when I tell it to change z level and during printing)

Its a complete mystery to someone with as little delta experience as me.
please let me know what documentation I can attach to provide useful information!

Cheers

cosmowave

@too-stroke can you please share your homedelta.g file from the sys folder?

too.stroke

@cosmowave
Absolutely, my homedelta.g is as follows:

; homedelta.g
; called to home all towers on a delta printer
;
; generated by RepRapFirmware Configuration Tool v3.2.3 on Fri Jul 30 2021 12:02:42 GMT-0700 (Pacific Daylight Time)
G91                        ; relative positioning
G1 H1 X649 Y649 Z649 F1800 ; move all towers to the high end stopping at the endstops (first pass)
G1 H2 X-5 Y-5 Z-5 F1800    ; go down a few mm
G1 H1 X10 Y10 Z10 F360     ; move all towers up once more (second pass)
G1 Z-5 F6000               ; move down a few mm so that the nozzle can be centred
G90                        ; absolute positioning
G1 X0 Y0 F6000             ; move X+Y to the centre

cosmowave

@too-stroke Eventually it helps, when you insert a "M400" command between line 6 and 7.

too.stroke

@cosmowave
I can see how the M400 can be useful however it hasn't improved my issue.
I was thinking it might be a endstop triggering prematurely, however, I watched the endstop trigger LED's on the mainboard while homing and none of the endstops triggered (visibly) prematurely when my Y axis refused to home.

A Former User

This post is deleted!

dc42

@too-stroke I think you have a bad connection between the homing switch for tower 3 and the Duet. Use the Object Model Browser in DWC, or M119, to check the reported status of the homing switch as you operate it. You will probably find that it reports as triggered when it isn't.

too.stroke

@Herve_Smith @cosmowave @dc42

The M400 may have actually solved the issue after all...
I'm not sure why, and need to do some more testing in the morning but I've been able to successfully home multiple times now.

I realized it didn't work initially cause I wrote m400 not M400
for now I'm just glad its working again, however I do wish I knew what caused this in the first place...

Thanks for all the help though!

dc42

@too-stroke said in Another Delta Homing Issue:

@Herve_Smith @cosmowave @dc42

The M400 may have actually solved the issue after all...
I'm not sure why, and need to do some more testing in the morning but I've been able to successfully home multiple times now.

I realized it didn't work initially cause I wrote m400 not M400
for now I'm just glad its working again, however I do wish I knew what caused this in the first place...

Thanks for all the help though!

M400 is not required because it is implicitly executed after any homing move. Also m400 is treated exactly the same as M400. I think you have an intermittent connection between the endstop and the Duet. With the endstop not triggered, try waggling the cable while watching the endstop states in the object model browser.

A Former User

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dc42

@Herve_Smith by a "homing move" I mean any G0 or G1 command that stops when the corresponding endstop is triggered.

A Former User

This post is deleted!