Hiccups on 3HC expansion board

[jay_s_uk]

I have M83 in my config, an M82 at the start of my gcode and then a switch straight back to M83.
Its setup the same as my other machines.

[deckingman]

OK, so I just tried a few G10/G11 cycles to exercise my extruders. To be clear, the reason why I did that is that I can't run a print right now so have no other way of exercising the extruders. Also firmware retraction happens at a much faster speed than "normal" extruder moves and exercises all 6 extruders simultaneously.

After about 20 cycles, I ran M122 B1 and the result shows zero hiccups. My steps per mm are around 410, micro-stepping is 16X. Firmware retraction is set to use a feedrate of 3600.

So I don't think this is a firmware issue. Also, I did manage to get a print out of my machine yesterday using 3 extruders in mixing mode which wasn't half bad.

[jay_s_uk]

@dc42 any update on a beta build to sort the hiccups out? I'm happy to carry out testing etc

[dc42]

It's built, but I've not had a chance to test it yet.

[deckingman]

@jay_s_uk Have you managed to sort out why the filament gets fully retracted at the end of the print? Are you absolutely sure that there are no problems with your configuration or the gcode file that you are trying to print?

[jay_s_uk]

@deckingman
It's not at the end of the print, its mid print.
And I use the same sliced files on all my other machines which run duets

[deckingman]

@jay_s_uk Perhaps you have a blocked, or partially blocked nozzle, causing the extruder to skip steps on extrusion moves but not on retraction moves? I've only done limited printing with my experimental hot end, but I can't replicate your problem.

Edit. Try disconnecting the filament from the hot end and run that print again to see if you still get hiccups.

[jay_s_uk]

@deckingman
I'm running a print now without filament and I'm still getting hiccups

[deckingman]

@jay_s_uk What does extruder movement look like? Normal or erratic? Can you upload the gcode file somewhere and post a link to it. I should have my machine back together soon so I can try running your file and see if it gives me the hiccups too

[jay_s_uk]

Hmm, I've swapped from driver 1 to driver 2 and the problem has gone away.

[deckingman]

For info, I've just finished a print of about half an hour, ran an M122 part way through and another at the end - no sign of any hiccups

[jay_s_uk]

Ok, the issue is still there after swapping drivers so ignore that

[dc42]

I'm sorry for the delay. The new firmware was affected by a chip feature that didn't cause a problem in a debug build but did in a release build. It's taken me more than half a day to track it down and fix it, and now I need to review and remove most of my earlier attempted fixes. I should have a beta tomorrow.

[jay_s_uk]

@dc42 no rush

[dc42]

I've put a binary of the new EXP3HC firmware at https://www.dropbox.com/s/7rqp6pul9ip3yam/Duet3Firmware_EXP3HC.bin?dl=0. Please monitor it carefully when using it, it's had only a little testing.