Heater fault on heated bed because it's rising to slow.

Gixxerfast

@exerqtor said in Heater fault on heated bed because it's rising to slow.:

Well in that case it looks like the heater tuning needs more work

Actually, I have more heater problems as well with the b7 than I had with the b6. Instead of one error while heating up that just could be restarted I now have to restart it three times. And I have done the heater tuning (pid calibration).

Thing is a have a active carbon filter under the bed where the fans kicks in at 65C. Although it's a very low airflow it seems to disturb the heating process.

I would like an option to just turn all this control off. Max temp supervision is enough for me as far as I can understand it now.

Sorry to hog in in this thread.

SIam

Short feedback from my side, the problem is not solved

The Result from the pid tuning with RFF 3.4.b6:
M307 H0 R0.460 C286.278:286.278 D0.90 S1.00 V24.3 B0 I0

and the result from PID tuning with RRF 3.4.b7:
M307 H0 R0.484 K0.438:0.000 D0.85 E1.35 S1.00 B0

and the error:
Error: Heater 0 fault: temperature rising too slowly: expected 0.43°C/sec measured 0.19°C/sec

hestiahuang

@siam @joeko pls refer to the workaround to make your printers work first. Change the code and build at your local, then flash it. The workaround I posted above.

hestiahuang

@hestiahuang said in Heater fault on heated bed because it's rising to slow.:

@dc42
yes, I did. Ran Auto PID and saved, also restarted. But still failed, even I used bangbang mode, full speed, I mean.

After above, I got this too

Then I changed the code and built Beta7 version, everything looks good now.
I adjusted the factor 0.5 to small value simplely => RepRapFirmware\src\Heating\LocalHeater.cpp => Line#317 => if (actualTemperatureRise < expectedTemperatureRise * 0.5)

Quoted here.
However I don't have dropbox, and can't share my firmware here. Good Luck!

hestiahuang

@hestiahuang said in Heater fault on heated bed because it's rising to slow.:

@hestiahuang said in Heater fault on heated bed because it's rising to slow.:

@dc42
yes, I did. Ran Auto PID and saved, also restarted. But still failed, even I used bangbang mode, full speed, I mean.

After above, I got this too

Then I changed the code and built Beta7 version, everything looks good now.
I adjusted the factor 0.5 to small value simplely => RepRapFirmware\src\Heating\LocalHeater.cpp => Line#317 => if (actualTemperatureRise < expectedTemperatureRise * 0.5)

Quoted here.
However I don't have dropbox, and can't share my firmware here. Good Luck!

Highlight the code for you all again.

I adjusted the factor 0.5 to small value simplely => [RepRapFirmware\src\Heating\LocalHeater.cpp] => Line#317 => if (actualTemperatureRise < expectedTemperatureRise * 0.5)

SIam

@hestiahuang your workaround is not for everybody to make, so the easier way is to half the R value and the bed is heating without error

hestiahuang

@siam I want to say even I use bangbang mode the issue is still, bangbang is using the full power(24V) already. So code change is the only way to me.

dc42

@siam said in Heater fault on heated bed because it's rising to slow.:

Short feedback from my side, the problem is not solved

The Result from the pid tuning with RFF 3.4.b6:
M307 H0 R0.460 C286.278:286.278 D0.90 S1.00 V24.3 B0 I0

and the result from PID tuning with RRF 3.4.b7:
M307 H0 R0.484 K0.438:0.000 D0.85 E1.35 S1.00 B0

and the error:
Error: Heater 0 fault: temperature rising too slowly: expected 0.43°C/sec measured 0.19°C/sec

Please post the temperature plot while heating up the bed, to help me diagnose this.

SIam

@dc42 here you can download a short video:

https://kleinersonnenschein.eu/video/heaterfault.mp4

hestiahuang

@dc42 said in Heater fault on heated bed because it's rising to slow.:

@siam said in Heater fault on heated bed because it's rising to slow.:

Short feedback from my side, the problem is not solved

The Result from the pid tuning with RFF 3.4.b6:
M307 H0 R0.460 C286.278:286.278 D0.90 S1.00 V24.3 B0 I0

and the result from PID tuning with RRF 3.4.b7:
M307 H0 R0.484 K0.438:0.000 D0.85 E1.35 S1.00 B0

and the error:
Error: Heater 0 fault: temperature rising too slowly: expected 0.43°C/sec measured 0.19°C/sec

Please post the temperature plot while heating up the bed, to help me diagnose this.

yes, the same issue, I mean too.

hestiahuang

@dc42 said in Heater fault on heated bed because it's rising to slow.:

@siam said in Heater fault on heated bed because it's rising to slow.:

Short feedback from my side, the problem is not solved

The Result from the pid tuning with RFF 3.4.b6:
M307 H0 R0.460 C286.278:286.278 D0.90 S1.00 V24.3 B0 I0

and the result from PID tuning with RRF 3.4.b7:
M307 H0 R0.484 K0.438:0.000 D0.85 E1.35 S1.00 B0

and the error:
Error: Heater 0 fault: temperature rising too slowly: expected 0.43°C/sec measured 0.19°C/sec

Please post the temperature plot while heating up the bed, to help me diagnose this.

Want to confirm that, the same printer with different firmware, such as rrf and klipper, no issue on klipper

hestiahuang

@dc42 said in Heater fault on heated bed because it's rising to slow.:

@siam said in Heater fault on heated bed because it's rising to slow.:

Short feedback from my side, the problem is not solved

The Result from the pid tuning with RFF 3.4.b6:
M307 H0 R0.460 C286.278:286.278 D0.90 S1.00 V24.3 B0 I0

and the result from PID tuning with RRF 3.4.b7:
M307 H0 R0.484 K0.438:0.000 D0.85 E1.35 S1.00 B0

and the error:
Error: Heater 0 fault: temperature rising too slowly: expected 0.43°C/sec measured 0.19°C/sec

Please post the temperature plot while heating up the bed, to help me diagnose this.

For the bed heater case above, it is very normal that take 5~10mins to heat the bed from around 20°C to around 80°C, (80°C-20°C) / 0.19°C/sec /60sec/min=5.26min. So I think 'the quick factor' is good to apply to tools heater but not for bed heater.

dc42

@siam thanks for the video, that's really helpful.

What I suspect is happening is that your bed heater has a high thermal mass (e.g. aluminium plate) and the thermistor is embedded in the heater, not in good contact with the plate. Does that describe your bed heater? This makes the long-term heating behaviour very different from the short-term behaviour. The current tuning algorithm measures the short term behaviour, because that is what is required for computing suitable PID parameters.

Please can you do a video of the heater being tuned, so that I can see the complete temperature graph during the tuning process.

As a workaround until I have a solution, if you reduce the R parameter in the M307 command by 30%, that should be sufficient to avoid getting heater faults.

dc42

@siam @hestiahuang please try the firmware build at https://www.dropbox.com/sh/5ubjszy9fmlvzwu/AAAeOMGP-Yi-Gn9LZwQoPfita?dl=0.

Gixxerfast

@dc42 I wasn't addressed but I tried it anyway since I was having problems but with this version it heated up without any errors. Absolutely perfect. Before, with b7 I would have had three errors before reaching target temp. Thanks!

NikA

I also have this problem and noticed that the difference is double (or half) of what is expected.
tuning again and again did not change much, but it looks like you're already fixing the problem

I have a suggestion: could you add a feature that makes it possible to zoom in on the temperature chart (as in temporarily increase the window size or open in a new window)?
The way it currently is makes it impossible to see small changes, but I would be interested in seeing them.
I think it would make it possible to see changes when feeding too fast or having air flow etc

SIam

@dc42 I have tested the new firmware, thanks for this! Now the PID-Tuning takes a long time (over a half hour) and after this I get now a warning;

If I use this PID settings to heat up my bed, I still get the heater fault
Error: Heater 0 fault: temperature rising too slowly: expected 0.34°C/sec measured 0.11°C/sec

I have recorded the PID Tuning and you can view this long video under:

https://kleinersonnenschein.eu/video/pidtuning_3.4.b7+1.mp4

I hope this will help you when you need more tests then let me know

But first I wish you and the whole great duet team a merry Christmas, thanks for your hard work!

Phaedrux

@siam Perhaps I've asked this before in another thread, but can you show/describe what your bed assembly is like?

SIam

I forget to answer your question

What I suspect is happening is that your bed heater has a high thermal mass (e.g. aluminium plate)

My Alu plate is 420 x 420 x 8 mm

and the thermistor is embedded in the heater,not in good contact with the plate.

yes it is

Does that describe your bed heater?

yes

As a workaround until I have a solution, if you reduce the R parameter in the M307 command by 30%, that should be sufficient to avoid getting heater faults.

I haven't test with 30% at the moment, I reduce it to 50% and this works for now

SIam

@phaedrux The structure of the heating plate is as follows :

First the Alu plate with 420 x420 x 8 mm

Then this silicone heatbed :
https://de.aliexpress.com/item/32612060131.html?spm=a2g0o.9042311.0.0.27424c4daTA4uh
With 220V / 500W
and under this I have a cork plate for isolation.