I need help diagnosing heater faults?

Asdasd1234

Nope, this was during an abs print so no print cooling fan whatsoever. It was mid layer too. After that initial drop, it shot over temp which it never normally does

dc42

My best guess is that the heater cartridge became disconnected. When the connection was restored, the PID overshot because once the target temperature is reached, the PID in RRF switches to a more aggressive mode to help maintain temperature in the presence of varying load.

Asdasd1234

Thanks, I'll try replacing that tonight then, cheers.

From the graph I provided then, is it safe to assume its probably not the thermistor due to it not cutting out but instead dropping temp over time?

dc42

Thermistor issues normally cause positive or negative spikes or steps in the temperature graph.

Asdasd1234

Nope, no luck unfortunately. I've replaced both the heating cartridge and thermistor but still failing.

Different symptoms now though. It's like it doesn't want to heat past 200c now without having the "heating too slowly" error pop up

Pics below of the temp graph after a failure + the temp graph from that period

https://i.imgur.com/LK8qu3F.png
https://i.imgur.com/KELf3jP.png

weirdly enough after replacing the heating element, I cant get it to heat up once. Before at least I got half way into the first layer

deckingman

@asdasd1234 Long shot but is your power supply behaving itself? No voltage drop? Running M122 will report min and max voltage (among a host of other things).

Asdasd1234

I assume it is as the bed is working fine. But I'll check the supply now after another error to see. give me 5 mins

Asdasd1234

EDIT: I'm not sure why, but it has suddenly started working and I cant make it fail again. I guess I'll have to wait until next time it kills my print half way through to check lol

The log should be below now :
I remembered my bed is run through a relay so that'll work regardless
I did notice the voltage dropped a bit (down to 11.1v) as it tried heating the hotend to higher temps.
I'm going to hook up a multimeter and measure the current in a second to see what its actually delivering

M122
=== Diagnostics ===
Used output buffers: 3 of 32 (9 max)
=== Platform ===
RepRapFirmware for Duet WiFi version 1.20 running on Duet WiFi 1.0
Board ID: 08DGM-95BLL-N6PSS-6JTD2-3SN6J-1JUBJ
Static ram used: 15448
Dynamic ram used: 99064
Recycled dynamic ram: 176
Stack ram used: 1392 current, 8608 maximum
Never used ram: 7776
Last reset 00:03:25 ago, cause: power up
Last software reset time unknown, reason: User, spinning module GCodes, available RAM 7768 bytes (slot 3)
Software reset code 0x0003 HFSR 0x00000000, CFSR 0x00000000, ICSR 0x0041f000, BFAR 0xe000ed38, SP 0xffffffff
Error status: 0
Free file entries: 9
SD card 0 detected, interface speed: 20.0MBytes/sec
SD card longest block write time: 69.6ms
MCU temperature: min 43.4, current 45.1, max 45.5
Supply voltage: min 11.1, current 11.8, max 12.0, under voltage events: 0, over voltage events: 0
Driver 0: standstill, SG min/max not available
Driver 1: standstill, SG min/max not available
Driver 2: standstill, SG min/max not available
Driver 3: standstill, SG min/max not available
Driver 4: standstill, SG min/max not available
Date/time: 2018-09-06 19:52:11
Cache data hit count 792879229
Slowest main loop (seconds): 0.263302; fastest: 0.000041
=== Move ===
MaxReps: 0, StepErrors: 0, FreeDm: 240, MinFreeDm 240, MaxWait: 0ms, Underruns: 0, 0
Scheduled moves: 0, completed moves: 0
Bed compensation in use: none
Bed probe heights: 0.000 0.000 0.000 0.000 0.000
=== Heat ===
Bed heaters = 0 -1 -1 -1, chamberHeaters = -1 -1
Heater 0 is on, I-accum = 0.3
Heater 1 is on, I-accum = 0.5
=== GCodes ===
Segments left: 0
Stack records: 1 allocated, 0 in use
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
serial is idle in state(s) 0
aux is idle in state(s) 0
daemon is idle in state(s) 0
queue is idle in state(s) 0
autopause is idle in state(s) 0
Code queue is empty.
Network state is running
WiFi module is connected to access point
Failed messages: pending 0, notready 0, noresp 0
WiFi firmware version 1.20
WiFi MAC address 5c:cf:7f:44:ed:66
WiFi Vcc 3.38, reset reason Turned on by main processor
WiFi flash size 4194304, free heap 17096
WiFi IP address 192.168.1.35
WiFi signal strength -51dBm, reconnections 0, sleep mode modem
HTTP sessions: 1 of 8
Socket states: 2 0 0 0 0 0 0 0
Responder states: HTTP(1) HTTP(0) HTTP(0) HTTP(0) FTP(0) Telnet(0)

Asdasd1234

Hi, Just a follow up on my previous post. I still can't make this work
I've eliminated the issue of the temp dropping suddenly that I had above (replaced the thermistor). But I've started to get the following error on 80% of attempts to heat my extruder before a print.

"Heating fault on heater 1, temperature rising much more slowly than the expected 1.5°C/sec"

If it makes it to temperature, then the print goes ok, but it's taking me 5 attempts to start each print

I've replaced the thermistor, the heating catridge, and I'm now trying my third power supply. I've also run the auto-PID on the hotend. I don't know what to try next The heater is heating up, its just the firmware expects it to heat up faster than it does.

Is there any way to reduce it down a bit or make it take an average over a few seconds before just going "nah, start again"?

dc42

Have you run heater tuning? https://duet3d.dozuki.com/Wiki/Tuning_the_heater_temperature_control
Check that the screws in the E0 or E1 heater terminal block of the Duet are still tight. if you used the ferrules, also check that the wires are still gripped firmly by the ferrules.

Asdasd1234

I've read through all that before but it goes a bit over my head to be honest. I did the autotune "M303 H1 S240" then the command it prompted me to use to save it when it finished. I did this after I started getting the issue, but it's done nothing to solve it. From best I can tell, my heater is heating up just fine and at the expected rate so I'm sure it has something to do with the PID settings, but they're all greek to me and I'd be worried to tweak one incase I cause it to overheat or something.
The case I have it in holds the wires in place so they shouldn't be able to be pulled out. But I'll definitely check that when I'm back from work

Thanks for your help so far!

dc42

@asdasd1234 said in I need help diagnosing heater faults?:

I did the autotune "M303 H1 S240" then the command it prompted me to use to save it when it finished.

If you sent M500 to save the new heater model parameters, that saves them to config-override.g. That only has an effect if your config.g file has command M501 at or near the end, so that config.g executes config-override.g. Alternatively, you can add a suitable M307 command to config.g as described in that link.

To check whether the firmware is using the values found by auto tuning, send M307 H1. If it reports the following:

Heater 1 model: gain 340.0, time constant 140.0, dead time 5.5, max PWM 1.00, calibration voltage 0.0

then those are the default values, and it is not using the results of auto tuning.

Asdasd1234

Thanks, I'll check that today and let you know how it goes.

Asdasd1234

That seems to have worked! Thanks!