Duet mini 5+ freezes and shuts off heaters

Michael Hathaway

My original case had a 92mm fan on the front side and it was designed to blow air on the front and force the air around to the back side to cool the steppers. Still its hot air circulating and I need to do this a little differently this time. I didn't really have problems until we had a few really hot days and I was printing high temperature plastics, which made the chamber even hotter, surpassing the limits of the system.

droftarts

@michael-hathaway when you initially asked about this problem, there were a number of useful pieces of information that you weren’t forthcoming with: that the Duet (and PSU, I think) are mounted inside the heated chamber, the high ambient temperature at the time, printing high temperature materials. This lead to a focus on other factors that might cause the reset, rather than the obvious one; the board temperature.

What sort of temperature does the chamber get to? You are stressing the electronics on the board running it inside the enclosure. The MCU itself may be rated to 85C (operating temperature, not ambient temperature), but other components on the board may not be, and could be causing voltage fluctuations and the ‘phantom’ resets. I don’t think we publish a temperature range of operation for Duet boards (I’ll ask @dc42), but subjecting it to heat intentionally seems less than ideal. I think you have got away with it in past, but a combination of factors has pushed the board beyond its temperature limits. Is it possible to mount it outside the enclosure?

Ian

Michael Hathaway

@droftarts I agree with you completely.

The boards are not faulty, I am just pushing them to their limits. It's not really intentional though, I have just gotten away with it until now.

I don't think it is the MCU causing the shutdown, but something else on the board. I have printed no less than 20,000 prints on my original Duet mini 5. IMO it's way better than the American or any other boards on the market.

It's just a Prusa aluminum clad enclosure, many people use these. I have never pushed the chamber over 60°C and I know it was over 50 when I was having problems with the MCU in the 67-70C range. It was 48°C here in the shade and my workshop was close to that temperature. Both the combined high ambient temperature and the increase current through the board to bring the hotend up to 330C is what I think caused the resets/emergency shutdown.

Michael Hathaway

Will the Duet 6HC handle higher temperatures better than the mini 5+? Are the components on the board higher grade?

TLAS

@michael-hathaway said in Duet mini 5+ freezes and shuts off heaters:

The printer went 5 layers and stopped. I have no idea why it is freezing.

We’ll maybe you shouldn’t (should) leave it out in the cold? Sorry, couldn’t resist…

I’m fully certified to use dad jokes…
https://youtu.be/4CeWYM08s7A

Michael Hathaway

@tlas I don't wish to wire for external board. I am not the first person to print inside an enclosure. I just didn't know the thermal limits of this board until now. I will end up switching over to the 6HC as it seems to be more robust.

TLAS

@michael-hathaway
Mostly a joke there (board freezing… leaving it out in the cold…).

I can understand why folks would want to keep the boards in heated chambers.

FYI, bringing in a line of compressed air at ~10 psi is helpful to provide local cooling without impacting the overall chamber too much.

Michael Hathaway

@tlas I joked with a friend this morning when I told him I was going to water cool my MCU.

droftarts

@michael-hathaway Unfortunately, I don't think it's just the MCU, and this issue isn't just limited to the Mini 5+. Other components aren't rated higher than 85C, and running at high temperatures will shorten the life of all the components. We don't give recommended operating temperature limits (though we are talking about it), because the board heating itself up due to FETs/stepper drivers/power supplies on the board is very application specific.

With the 6HC, the higher rating on the stepper drivers mean they run cooler, so don't add as much self-heating to the board, so perhaps that's what you mean when you say they are more robust.

We really don't advise running Duets in heated chambers; it will shorten their life.

Ian

Michael Hathaway

@droftarts Yes, this is what I said in my previous statement to you. It is all the components on the board.

The chamber is heated by the bed and hotend. The reason why it prints petg and not the high temp nylon is because the chamber temp rises much higher with the higher temp plastics. Especially on very hot days. I realize now that I cannot print my higher temp plastics until I bring cold air in to cool the electronics.

Michael Hathaway

A small update: The issue has nothing to do with heat of the chamber or the Duet 3 mini. After a ton of testing, I have narrowed the issue down around the extruder.

Exhausting all other tests, I decided to run a print cycle with no filament running through the extruder and it finished the print. I am able to print at high temperature with flexible Nylon, but the stiff carbon fiber nylon throws a reset.

I installed a new stepper and Bontech extruder. I will post results later.

Michael Hathaway

10/25/2022, 1:15:28 AM 	m122
=== Diagnostics ===
RepRapFirmware for Duet 3 Mini 5+ version 3.4.1 (2022-06-01 21:06:56) running on Duet 3 Mini5plus Ethernet (standalone mode)
Board ID: 6MFQS-V096U-D65J0-40KMJ-JS03Z-R72JU
Used output buffers: 1 of 40 (22 max)
=== RTOS ===
Static ram: 103684
Dynamic ram: 105204 of which 0 recycled
Never used RAM 32752, free system stack 168 words
Tasks: NETWORK(ready,25.9%,260) ETHERNET(notifyWait,0.3%,568) HEAT(notifyWait,0.0%,358) Move(notifyWait,0.0%,290) CanReceiv(notifyWait,0.0%,942) CanSender(notifyWait,0.0%,372) CanClock(delaying,0.0%,339) TMC(notifyWait,0.7%,81) MAIN(running,72.1%,422) IDLE(ready,0.2%,29) AIN(delaying,0.8%,264), total 100.0%
Owned mutexes:
=== Platform ===
Last software reset at 2022-10-25 00:59, reason: User, GCodes spinning, available RAM 32752, slot 0
Software reset code 0x0003 HFSR 0x00000000 CFSR 0x00000000 ICSR 0x00489000 BFAR 0xe000ed38 SP 0x00000000 Task MAIN Freestk 0 n/a
Error status: 0x00
MCU revision 3, ADC conversions started 101415, completed 101415, timed out 0, errs 0
Step timer max interval 1486
MCU temperature: min 41.6, current 42.2, max 43.3
Supply voltage: min 23.8, current 23.9, max 24.1, under voltage events: 0, over voltage events: 0, power good: yes
Heap OK, handles allocated/used 0/0, heap memory allocated/used/recyclable 0/0/0, gc cycles 0
Events: 0 queued, 0 completed
Driver 0: standstill, SG min 0, read errors 0, write errors 0, ifcnt 9, reads 5301, writes 9, timeouts 0, DMA errors 0, CC errors 0
Driver 1: standstill, SG min 0, read errors 0, write errors 0, ifcnt 9, reads 5301, writes 9, timeouts 0, DMA errors 0, CC errors 0
Driver 2: standstill, SG min 0, read errors 0, write errors 0, ifcnt 12, reads 5298, writes 12, timeouts 0, DMA errors 0, CC errors 0
Driver 3: standstill, SG min 0, read errors 0, write errors 0, ifcnt 9, reads 5301, writes 9, timeouts 0, DMA errors 0, CC errors 0
Driver 4: standstill, SG min 0, read errors 0, write errors 0, ifcnt 9, reads 5301, writes 9, timeouts 0, DMA errors 0, CC errors 0
Driver 5: not present
Driver 6: not present
Date/time: 2022-10-25 01:15:24
Cache data hit count 172505060
Slowest loop: 12.16ms; fastest: 0.13ms
=== Storage ===
Free file entries: 9
SD card 0 detected, interface speed: 22.5MBytes/sec
SD card longest read time 1.0ms, write time 9.1ms, max retries 0
=== Move ===
DMs created 83, segments created 3, maxWait 42811ms, bed compensation in use: mesh, comp offset 0.000
=== MainDDARing ===
Scheduled moves 2, completed 2, hiccups 0, stepErrors 0, LaErrors 0, Underruns [0, 0, 2], CDDA state -1
=== AuxDDARing ===
Scheduled moves 0, completed 0, hiccups 0, stepErrors 0, LaErrors 0, Underruns [0, 0, 0], CDDA state -1
=== Heat ===
Bed heaters 0 -1 -1 -1, chamber heaters -1 -1 -1 -1, ordering errs 0
Heater 0 is on, I-accum = 0.6
Heater 1 is on, I-accum = 0.5
=== GCodes ===
Segments left: 0
Movement lock held by null
HTTP is idle in state(s) 0
Telnet is idle in state(s) 0
File is idle in state(s) 0
USB is idle in state(s) 0
Aux is idle in state(s) 0
Trigger is idle in state(s) 0
Queue is idle in state(s) 0
LCD is idle in state(s) 0
SBC is idle in state(s) 0
Daemon is idle in state(s) 0
Aux2 is idle in state(s) 0
Autopause is idle in state(s) 0
Code queue is empty
=== Filament sensors ===
Extruder 0 sensor: ok
=== CAN ===
Messages queued 909, received 0, lost 0, boc 0
Longest wait 0ms for reply type 0, peak Tx sync delay 0, free buffers 18 (min 18), ts 506/0/0
Tx timeouts 0,0,505,0,0,402 last cancelled message type 30 dest 127
=== Network ===
Slowest loop: 9.29ms; fastest: 0.03ms
Responder states: HTTP(0) HTTP(0) HTTP(0) HTTP(0) FTP(0) Telnet(0), 0 sessions
HTTP sessions: 1 of 8
- Ethernet -
State: active
Error counts: 0 0 0 0 0
Socket states: 2 2 2 2 2 0 0 0

Michael Hathaway

Last software reset at 2022-10-25 00:59, reason: User, GCodes spinning, available RAM 32752, slot 0
Software reset code 0x0003 HFSR 0x00000000 CFSR 0x00000000 ICSR 0x00489000 BFAR 0xe000ed38 SP 0x00000000 Task MAIN Freestk 0 n/a
Error status: 0x00

Michael Hathaway

@nikscha
24 Oct 2022, 14:30
Printer runs perfectly without errors with no filament loaded. Petg, non-composite nylon, everything works. Yes my nozzle is grounded to the frame and Earth ground.

I now have a Nema 17 x 48mm stepper on a Bontech extruder, pulling from 2.5Kg spool and pushing through 500mm of bowden tube.

Maybe there is too much friction with carbonfiber nylon?

Currently printing test cube with M92 E1.

dc42

@Michael-Hathaway said in Duet mini 5+ freezes and shuts off heaters:

Yes my nozzle is grounded to the frame and Earth ground.

If it works OK without filament, it does sound as though it is ESD. Have you checked with a multimeter that there is continuity between the hot end metalwork and Duet ground? Also check that the extruder motor body is connected to the same ground, in case it is the extruder motor building up ESD and flashing over to the phase connections.

Michael Hathaway

Hello and thank you. Where on the Duet mini would be the appropriate place to place an earth ground?

Michael Hathaway

@dc42 Is it safe use the 24v power supply ground on the board?

Michael Hathaway

"At the power supply, you can also connect the DC - terminal to the earth terminal, that way any shorts on the low voltage side to the high voltage side will be shunted to ground as well. If you do this you need to be a bit more careful about ground loops when connecting via USB."

https://forum.duet3d.com/post/122714

Michael Hathaway

I made some progress.

Everything grounded, and verified. Still failed to print.

And then I purposely added load to the extruder and reproduced the failure. I didn't know that excessive pull force on the extruder, pulling from a large 2Kg spool would trigger a reset.

Increased current to 1200 fail, 1400 fail, 1600 and it almost finished the print. However, 1600 is beyond the capability of the mini 5, so I will have to find another solution to reduce pull resistance from the spool. Other materials work well, but not carbon fiber.

I will test some more and report back.

Phaedrux

@Michael-Hathaway said in Duet mini 5+ freezes and shuts off heaters:

solution to reduce pull resistance from the spool

Larger internal diameter PTFE tube?

The surface texture of the carbon fiber materials is very rough. Lots of friction.