Multiple Print Failures

Dr_Ju_Ju

Hi Chris,

Yes everything is fully earth bonded, and I've also replaced the interconnections....

chrishamm

@Dr_Ju_Ju Please note that earth (PE) is not ground (GND). Also try to avoid running motor/heater cables over the SPI ribbon cable if possible.

Dr_Ju_Ju

@chrishamm

no motor cables come anywhere near the SPI connection, or any other cables, apart from the case fans, which come on/off at the start and end, of a print.

All 0v lines are bonded to earth, I don't believe the problem is environmentally connected, as I have multiples printers running concurrently, with no problems

gloomyandy

@Dr_Ju_Ju Did this printer work OK at some point? If it did, what has changed since then?

Dr_Ju_Ju

@gloomyandy
yes it used to work fine, and even now it can still produce some great prints !! but it also wastes filament & time when it just stops at some point during a print

gloomyandy

@Dr_Ju_Ju So what if anything has changed since it was working well? Have you updated anything? Changed any of the printer hardware?

Dr_Ju_Ju

@gloomyandy
no hardware changes, & just the normal software updates pre & post the problems ...

Phaedrux

If you have spare hardware can you try swapping the Pi and then the Duet with one that is working?

jay_s_uk

@Dr_Ju_Ju do you really need to run in SBC mode? If you're not using something like pythonDSF I would just ditch the pi and run in standalone mode

Dr_Ju_Ju

@Phaedrux

I don't have a spare Pi @ the mo, but I do have a Rock64 / Rock64Pro spare both running Mate, so will the Duet SBC software run on them ??

@jay_s_uk

I suppose it comes down to what the Voron recommendations were, also I originally tried a Duet2 ethernet (not on this 'Voron' but a previous iteration), in non SBC mode, which was an abject failure, so I was hoping that a Duet3-SBC, would be better....

jay_s_uk

@Dr_Ju_Ju IMO, standalone mode is better. Majority of my machines run as standalone

timschneider

@Dr_Ju_Ju
@chrishamm

Hi I've a similar problem sometimes in SBC mode - https://forum.duet3d.com/topic/34315/rff-3-5-0-rc1-spi-reset-mid-print

since chris gave me the hint about the interference I was working on that topic to get down to the problem. So I hooked everthing up to a spectrum analyzer and saw that the 8MHz SPI bus is generating a lot of noice and harmonics.

green line is the 6xd in standalone mode, and the pink color is the 6xd in sbc (rock 4c+) with 130mm ribbon cable without ferrit or shielding.

set_1_green_6xd_standalone_set_2_pink_sbc_130mm_ribbon_cable.png

the green line is the 6xd in sbc mode with 30mm ribbon cable.

the following shows in pink the 6xd connected to the rockpi c4+ with 130mm ribbon cable with one ferrit 139 Ohm @ 100MHz on the sbc side.

the following shows the 130mm ribbon cable without a ferrit but aluminium foil as shield.
set_1_green_sbc_130mm_ribbon_cable_shielded_with_alu_foil.png

for reference the rock 4c+ without the duet

so it can be seen from the above, that shielding and ferrit will help to reduce emi and emc - I'm working on that topic, as it is not satisfying for me.

Maybe, you can put a ferrit core around the ribbon cable and make it shorter as a quick measure.

But anyhow, the print should not stop, even if the spi need to do a restart - that should be handled by the software to do a resume - as I can do a manual resume in such case.

chrishamm

@timschneider The SPI protocol between Duet and SBC is designed to retry three times in a row on failed transfers. If that count is exceeded, both endpoints reset the connection.