ZLift with Firware Retraction bug

jbainesy

Hi guys,

I'm think I've found a bug in 0.94 firmware relating to Z Lift on firware retracts.

Retract actually works as I imagine it should, but on undo (G11) the Z move back toward the bed is actually performed during the first X/Y move (so it ramps down toward the table DURING the first X/Y movement instead of dropping down BEFORE the movement begins).

Anyone else using firmware retracts able to confirm?

Repetier

At least in the code it looks correct as it does not move x or y and only adds a pure z move:

else if(!isRetract && isRetracted())

{

distance += (isLong ? EEPROM_FLOAT(RETRACTION_UNDO_EXTRA_LONG_LENGTH) : EEPROM_FLOAT(RETRACTION_UNDO_EXTRA_LENGTH) );

if(zlift > 0)

PrintLine::moveRelativeDistanceInStepsReal(0,0,-zlift,0,Printer::maxFeedrate[Z_AXIS], false);

retractDistance(-distance);

setRetracted(false);

}

I assume you are talking here about 0.92.x firmware. Will test it when I get some time and think of it. It is at least not the intension of the code above.

jbainesy

yes, sorry, 0.92.4 i meant :-)

Does that chunk of code actually spit out a "G1" as well? because if not (I'm unsure how this would actually be treated) the Z move may be performed in the next G1 block?

It is much more noticable when doing simple objects (such as a cube) where the retract ramps a significant distance after a unretract.

This was running from SD card, I had just used gcode and all worked as expected with firmware retracts, all I did was change the Z jump height in EEPROM from "0" to ".2mm" using the PC and then ran the code from the SD again with the bug that is in question.

Repetier

The code adds a pure z move (x and y are 0), This is a separate move and next G1 should add one more move independently with the new Z height. Do you have autoleveling enabled? The move will apply rotations to the z move.

I will test it with a exaggerated and slow move so I can see what is really going on.

jbainesy

Thanks, I have switched it off for now as it was messing with a customers print but I will test and report any further findings. Watch the Z mootor carefully during z jumps.

Repetier

Ok, I could reproduce the bug very well. Looks like I have solved it in 0.92.6.

jbainesy

Great news!

I updated just the other day at work, to .92.5 - is .92.6 up yet / if not, when do you expect to put it up?

Thanks for looking into it, really do see benefits to firmware retraction so I appreciate the effort ;-)

jbainesy

Ah I see, it's done. Downloaded for testing ;-)