Nozzle crashes before print starts.

ajcraig99

@phaedrux
No I appreciate the response, most of the issues I have run into have been user error, this one might very well be too!

dc42

Take the H5 parameters out of all the G30 commands in bed.g. They will cause the firmware to think that Z=0 is 5mm below the bed.
I don't see an S parameter on the final G30 command in bed.g.
How are you homing Z? Please post homeall.g and homez.g.

ajcraig99

@dc42

Thankyou, H5 removed from bed.g I think this came from the auto configuration tool.

I don't understand the S parameter, have read through the wiki again but from what I can see, leaving it blank is correct?

The value of the S parameter specifies what computation to perform. If the value is -1 then the Z offsets of all the 
points probed are printed, but no calibration is done. If the value is zero or not present, then this specifies that the 
number of factors to be calibrated is the same as the number of points probed. Otherwise, the value indicates the 
number of factors to be calibrated, which must be no greater than the number of points probed.

Here is homez.g - Should this all be replaced with just a single line saying G30?

G91               ; relative positioning
G1 Z5 F6000 S2    ; lift Z relative to current position
G1 S1 Z-295 F1800 ; move Z down until the switch triggers
G92 Z-0.1         ; set Z position to trigger height
G1 Z10 F500       ; lift Z relative to current position

dc42

For bed levelling using multiple independent Z leadscrews (which is what I think you are trying to do), the S parameter on the final G30 command should be equal to the number of Z leadscrews. See the wiki page about this type of bed levelling.

I would be very surprised if configtool added nonzero H parameters to thew G30 commands. So far as i can see, it only ever adds H0. Perhaps you got confused with the H parameter in the M558 command, which is the dive height and is typically set to 5mm?

ajcraig99

@dc42 No I have a single stepper driving 2x leadscrews, they are just sharing a GT2 belt. So the S parameter should be blank?

Yes I might have confused it with M558, I was playing around quite a bit trying to get the Piezo working ( which still isn't working perfectly.

dc42

@ajcraig99 said in Nozzle crashes before print starts.:

@dc42 No I have a single stepper driving 2x leadscrews, they are just sharing a GT2 belt. So the S parameter should be blank?

In that case, I suggest you use mesh bed compensation instead (G29). See https://duet3d.dozuki.com/Wiki/Using_mesh_bed_compensation. It's more powerful than the old 3, 4 and 5-point levelling that used bed.g and G32.

If you have manual bed levelling screws then you can use G32 and bed.g to probe and tell you what adjustments to make to them, so as to get the bed as level as you can before you run mesh bed compensation. See https://duet3d.dozuki.com/Wiki/Using_the_manual_bed_levelling_assistant.

ajcraig99

Well it seems G29 is a whole other can of worms that I don't have the patience for tonight.

G29
Error: Z probe already triggered before probing move started

Will try again tomorrow.

Phaedrux

@ajcraig99 said in Nozzle crashes before print starts.:

Here is homez.g - Should this all be replaced with just a single line saying G30?

Yes, the way you have it would be correct if using an endstop. To use the probe, you would move the head into position and then use G30 to seek Z0.

Phaedrux

@ajcraig99 said in Nozzle crashes before print starts.:

G29
Error: Z probe already triggered before probing move started

Do you have a deployprobe.g and retractprobe.g in the sys folder? What is in them?

ajcraig99

No delploy or retract files in my directory from what I can see.

I fixed homez.g but found I would get the same false trigger error unless I added a 1 sec delay before G30 if I had an XY travel before G30, If the nozzle was already in the XY position and didn't have to travel, it would work without the delay.

So it seems I am getting false readings from the Piezo as a mechanical issue caused by XY movement?

the same happens with G29, if it's already in the first XY position, it will do the first probe, move to the second and then false trigger the moment it goes to probe.

I have the precision piezo orion which only has one adjustment pot which I will continue to play with but can I force a P500 delay before any probing move in G29 or is that a bit hacky?

Working homez.g

; homez.g
; called to home the Z axis
G91                        ; relative positioning
G1 Z5 F6000 S2             ; lift Z relative to current position
G1 X50 Y50                 ; Move to probe pos
G4 P1000                   ; Wait 1 second
G30                        ; Probe Z

Non working homez.g

; homez.g
; called to home the Z axis
    G91                        ; relative positioning
    G1 Z5 F6000 S2             ; lift Z relative to current position
    G1 X50 Y50                 ; Move to probe pos
    G30                        ; Probe Z

Phaedrux

You can try adding an R value to your M558 command to add a pause before probing starts. Try M558 R1 to add one second delay.

https://duet3d.dozuki.com/Wiki/GCode#Section_M558_Set_Z_probe_type

ajcraig99

Awesome, making progress! Thanks to @dc42 the 5mm plunge should be fixed and thanks to @Phaedrux the Piezo seems to be working properly now. I will try another test print and report back.

I am hoping it can compensate for the sag in my bed.

ajcraig99

Success! Thankyou so much for everyones help!

Now I move onto print settings.

Phaedrux

Awesome!