Initial Homing issues - Sequence of Errors

[B0M0A0K]

I am wondering if the issue with the Z axis hitting the bed is because I am using a glass plate as the bed surface. The end stop switch was adjusted to allow for this, but I am wondering if there is a need to allow for that in the homez.g file?

; homez.g
; called to home the Z axis
;
; generated by RepRapFirmware Configuration Tool v2 on Wed May 29 2019 19:19:18 GMT+0100 (British Summer Time)
G91 ; relative positioning
G1 Z5 F6000 S2 ; lift Z relative to current position
G1 S1 Z-400 F1800 ; move Z down until the endstop is triggered
G92 Z0 ; set Z position to axis minimum (you may want to adjust this)

; Uncomment the following lines to lift Z after probing
;G91 ; relative positioning
;G1 S2 Z5 F100 ; lift Z relative to current position
;G90 ; absolute positioning

[A Former User]

@b0m0a0k said in Initial Homing issues - Sequence of Errors:

The one that worries me here is the Z axis. When it triggers the stop switch it is pressed hard against the bed, so I need to back that off a little. I have tried lowering the bed as much as it will go and its still pressed hard.

Not quite sure how this is built, but sounds like you need to move your z-switch. but strange if it worked before you replaced the board.

[B0M0A0K]

@bearer said in Initial Homing issues - Sequence of Errors:

.. but strange if it worked before you replaced the board.

Yes, that's what bothers me as well.

[A Former User]

Not familiar with the printer, maybe you could add a picture showing the bed, the switch and the axis raised, and showing the bed, switch and axis lowered?

or maybe first double check that the switch triggers correctly again, it really shouldn't need any force at all.

[B0M0A0K]

I think I have fixed the Z-Axis issue. By moving the Z-Axis up by hand prior to each homing test I had inadvertently unbalanced the Z-Axis (the left hand was at a different level to the right). I have now re-balanced the Z-Axis and this time, when I tested homing I was still able to get the paper under with enough room to adjust the bed height.

I'm going to run that test a couple more times just to be sure.

[Phaedrux]

It's there commands that are raising the z axis before each homing move.

G1 Z5 F6000 S2 ; lift Z relative to current position

This is to give the nozzle some clearance before moving things around.

In the Z homing files you can have it automatically raise the z axis again to give some clearance as well.

; Uncomment the following lines to lift Z after probing
;G91 ; relative positioning
;G1 S2 Z5 F100 ; lift Z relative to current position
;G90 ; absolute positioning

So if you remove the ; on those lines it will raise another 5mm for clearance.

@b0m0a0k said in Initial Homing issues - Sequence of Errors:

The one that worries me here is the Z axis. When it triggers the stop switch it is pressed hard against the bed, so I need to back that off a little. I have tried lowering the bed as much as it will go and its still pressed hard.

Is the endstop trigger height modifiable? Either with a set screw, or moving the switch mount position? You could also add a spacer if you need it to trigger sooner.

Does the switch stop movement if you trigger it by hand before the nozzle hits the bed?

[Phaedrux]

@b0m0a0k said in Initial Homing issues - Sequence of Errors:

I think I have fixed the Z-Axis issue. By moving the Z-Axis up by hand prior to each homing test I had inadvertently unbalanced the Z-Axis (the left hand was at a different level to the right). I have now re-balanced the Z-Axis and this time, when I tested homing I was still able to get the paper under with enough room to adjust the bed height.

I'm going to run that test a couple more times just to be sure.

Yes that could definitely explain it. The X axis must be parallel to the bed.

If you have 2 Z motors you can hook each up to a separate driver and then use a self leveling routine to get them evened before printing. You'd need a Z probe for this to be most effective.

https://duet3d.dozuki.com/Wiki/Bed_levelling_using_multiple_independent_Z_motors

[B0M0A0K]

@phaedrux OK, so I wasn't going to mention this until I was happy that basic operation was working properly, but I have a BLTouch sitting here ready to be installed as well. Am looking forward to adding that once the basic operation with the new board has been confirmed.

Next step is to "Home All" and see what happens.

[B0M0A0K]

Is it normal for the printer to return to needing Home on all axes every time you move something on the bed. Seems like each time I move something and then go to use "Head Movement" I get this sort of thing;

M120
G91
G1 Z5 F6000
M121

Error: G0/G1: insufficient axes homed

[Phaedrux]

Did you send that sequence of commands?

[B0M0A0K]

That was the sequence I uncommented in an attempt to get the extruder to raise a little off the bed after homing.

[Phaedrux]

I guess I'm confused by the M120 and M121.

So after homing all you can't move the axis with the jogging buttons on the machine control tab?

[dc42]

After you do Home All, do all of the homing buttons in DWC change colour from orange to blue (meaning that the axis has been homed)?

[B0M0A0K]

@phaedrux I'm pretty sure its not you, it's my horribly green newbie understanding of how to work GCode. I'm learning on the fly.

[B0M0A0K]

@dc42 Yes, they do.

At this stage I usually need to disable the steppers so I can move the printer head back the centre of the printer so I can run the test again for confirmation. That's the point at which I usually see the "Error: G0/G1: insufficient axes homed" message on one or more of the axes. I'm just trying to make sure that this is normal and not indicative of a problem.

[dc42]

@b0m0a0k said in Initial Homing issues - Sequence of Errors:

At this stage I usually need to disable the steppers so I can move the printer head back the centre of the printer so I can run the test again for confirmation. That's the point at which I usually see the "Error: G0/G1: insufficient axes homed" message on one or more of the axes. I'm just trying to make sure that this is normal and not indicative of a problem.

Yes, that's normal. When you disable the motors, they can't be assumed to hold position, so the firmware flags the corresponding axes as not homed. You must home the axes before you jog them.

[B0M0A0K]

@dc42 That's great. Thanks for the confirmation, much appreciated.

[Dougal1957]

also it is a good idea to have the M92 (steps/mm) line Before the M350 (Microsteps) line that way any change to the M350 will automatically adjust the steps in the firmware to be correct.