G92 ERROR in Mach3: "Speed is too high"

[Riccds 0]

Hi all, I'm having problems with occasional G92 A0 (and similar) calls. Cura introduces this code line sometimes to "reset" the extruder coordinates. Howerver Mach3 stops operation and gives error "Speed is too high" in the status bar.

 

Do you know a way to

1- make Mach3 accept it

OR

2- prevent Cura from using this statement

 

??? Thank you

 

Edited December 8, 2022 by Riccds

[Riccds 0]

Ok I think I finally found at least a remedy, disabling g92 in Cura. In the printer settings -> machine settings ->deselect "Apply Extruder offsets to GCode". I still get two lines
G92 E0
G92 E0

at the start of the file but I can delete those easily if necessary. I don't know if disabling extruder offsets can give problems on big prints. Hope not.

[Riccds 0]

Talked too soon. When selecting Mach3 flavour the option has no effect. It doesn't work. I think this is a bug. Will search where to report it.

[GregValiant 1,346]

I was typing.  I'll post this anyway.

That is an odd one.

G92 is defined in Marlin firmware as "Set Position" and there is no mention of speed at all.  The RepRap Wiki gives the same description in regards to MakerBot firmware.  G92 E0 sets the extruder location to zero.  The "Extruder Offsets" is the distance between nozzles on a Dual Extruder printer.  It shouldn't be making a difference here.

G92 E0 is important in Cura as rounding errors can creep into the calculation of the E values and so Cura resets the E (G92 E0) about every 10,000mm³ (about every 4158mm of 1.75 filament).  In a large print there will be several G92 E0 lines within the gcode.

You may want to switch to "Relative Extrusion" in the Special Modes section.  The extruder always starts from 0 and so doesn't need resets.  Then you could use the Search and Replace post processor...

Search: G92 E0

Replace: ;G92E0

By replacing the line with itself but with a semi-colon in front it becomes a comment and the printer should ignore it.

 

The question comes to mind...How do you reset the extruder in Mach3 if G92 doesn't work?  G92 is also used to set temporary locations of the other axis.

 

[Riccds 0]

44 minutes ago, GregValiant said:

I was typing.  I'll post this anyway.

That is an odd one.

...

 

Yes, I can confirm that G92 seems to be used also in Mach3. However many users seem to have issues with it. But I think I am the only one having this "speed too high" error and I have been struggling all day to find why. Perhaps my Mach3 is corrupt. However I am very reluctant to reinstall as setting it up is a real pain.

I specify that I am using a custom printer(makerbot was selected only for testing), actually it's not even a printer, it's an engraving machine to which I patched an extruder very very recently 😆. So G92 is not useful in engraving/milling and I never had to use it directly: I always set an offset with Mach3 button/features.

I will make some further test with G92 on my machine in case this proves useful to the community. But the solution you proposed seems very fine. I took a look at the resulting GCode and it seems neat. I will report back if there is any issue.

Thank you very much, your solution is super to me. I actually didn't even have to delete those two lines. As you say however it will probably be better for me to find a real solution to this rather than a work around if the rounding errors give rise to important artifacts.

Edited December 8, 2022 by Riccds

[Riccds 0]

1 hour ago, GregValiant said:

I was typing.  I'll post this anyway.

That is an odd one.

 

Nope, again I was happy too fast. This unfortunately was not a solution or not a complete solution. 😅
The point is now the gcode has lines like "G00 X Y Z A" with X, Y, Z being in absolute coords and A in relative coords. But both are interpreted as relative or both absolute depending if I set G91 or G90. Mach3 does not understand M82 and M83.

[GregValiant 1,346]

Time for different firmware.  Trying to piecemeal that one together to work with Cura (or PrusaSlicer or IdeaMaker) is going to continue to generate problems.

Do you have any idea where the "G00 X Y Z A" came from?  I've never seen a Cura gcode with a reference to an "A" axis.

[Riccds 0]

11 hours ago, GregValiant said:

Time for different firmware.  Trying to piecemeal that one together to work with Cura (or PrusaSlicer or IdeaMaker) is going to continue to generate problems.

Do you have any idea where the "G00 X Y Z A" came from?  I've never seen a Cura gcode with a reference to an "A" axis.

This piece of GCode was generated by Cura.

Cura's Mach3 flavor uses an A instead of E because Mach3, I guess, is pretty old but still very widespread among the router/engraving/milling community as it is quite a good piece of software but it wasn't conceived with 3d printers in mind, so E is not contemplated but only general purpose X Y Z A B C axes are.

 

I think I can easily make a script to adjust a Cura generated GCode to avoid G92. But It clearly is strange that G92 gives problems to my Mach3. The point is, I don't know if my breakout board/stepper drivers/mandrel will accept a different control software/firmware. I made the same 3d printing job with Prusa Slicer and it did work without problems, however I found Prusa Slicer's supports to be terrible. Anyway, I'll work on it and report back.