Issues with PID Tuning (RRF 3.4.0-b7)
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I just changed my aluminium heatblock to a copper one and my 40W heater to a 50W one and now it's impossible to correctly PID tune it. I'm using RRF 3.4.0-b7
After PID tuning my heater I have the simptoms below:
- Temp overshot, more than 10C which triggers a heater fault
- Worse temp holding than with aluminium heatblock and 40W heater
- Temperature slowly climbs up to trigger a heater fault during printing. This one is possibly caused by the fan even tough the fan barely cools the heatblock. It's like the fact that the heatblock is way over target temp is disregarded to compensate a fan which doesn't really cool the heatblock.
Yes, I can delete the secound K and lower S but I swapped the heatblock and heater hoping it would be better. I sort of suspect E as well. I doubt 1.35 would be right for all the heatblock variations.
Something is wrong with PID tuning which makes it unable to tune a different heatblock and stronger heater.
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I‘m also having PID issues with my new Rapido Hotend.
Lowering PWM to 0.5 does help a bit but it still overshoots during a print. -
@argo I don't think reducing PWM is the solution.
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Have you tried one of the unofficial beta “+” releases posted here?
https://github.com/Duet3D/RepRapFirmware/commit/e0e741a76f7183dd94668218b0eb4d3e9d53d014
There was a commit regarding PID right after the release of beta 7.
I’ll test it soon and report back.Edit: Initial impression with Beta7+7: after new PID calibration hotend temperature stays stable at the target temperature. It initially overshoots a bit but then settles at stays at the temperature.
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@argo I have beta7+5.
Not really related but do you know how can I update RRF firmware through bash if all of my software up to date (so RRF firmware update doesn't get triggered).
I found no info last time when I connected an expansion board, and ended up having to update it through DWC.According to bash:
reprapfirmware is already the newest version (3.4-b7-2).
While in DWC I have b7+5 -
Sorry can't help you with that. I'm using my Duet boards in standalone board and I'm glad I don't need a Pi or something because else I could use Klipper tbh ^^
aaaand PID still does not work during a print (RRF 3.4.0-b7+7):
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@argo I think it would help if you explain what is wrong with your pid control and what the two graphs you have posted are showing.
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Well, the graph is not flat and jumping around. The extruder temp is set to 210°C and the graph on the right shows that it is jumping around. Sometimes it almost hits 220°C.
I did PID calibration for T0 and it gives me this gcode to use:
M307 H1 R5.035 K0.663:0.153 D4.06 E1.35 S1.00 B0 V24.4 -
I just retuned my hotend heater which has a copper block with a 50w heater.
2022-01-15 17:28:08 m115 FIRMWARE_NAME: RepRapFirmware for Duet 3 Mini 5+ FIRMWARE_VERSION: 3.4.0beta7+7 ELECTRONICS: Duet 3 Mini5plus WiFi FIRMWARE_DATE: 2022-01-14 08:58:342022-01-15 17:10:37 M303 H1 S250 Auto tuning heater 1 using target temperature 250.0°C and PWM 1.00 - do not leave printer unattendedThe result was this:
M307 H0 R0.620 K0.495:0.000 D0.91 E1.35 S1.00 B0and my temp regulation seems to work pretty good:
I suggest you show what commnd you use for pid calibration (heater tuning) and an M115 and M122.
Are you sure your PSU is not on the limit or you have some voltage drop somewhere? (I'm not an electrical engineer
)I'm going to start a print soon just to verify that it can respond correctly during the print.
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@argo Was it any different on other versions of RRF with the same hotend? I'm trying to help separate out any possible regression in this beta release from a possibly general problem with supporting your type of hotend with RRF.
If the same hotend worked better on a previous release, then please ignore the rest of this post. If it didn't then maybe the following will help....
What does the graph look like if you are not printing (just set the hotend to a fixed temperature), is it more stable then?
What happened at 15:55 on the first graph? Did anything (like the cooling fan level) change at that point? There seems to be a particularly large change in temperature at that point.
There seems to be a relatively large difference between the fan on and fan off values for the K parameter. Does the Rapido Hotend have any sort of "sock" on it? I wonder if the cooling fan is blowing back from the print surface and causing problems?
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@argo It climbs up temp because of the secound K value
M307 H1 R5.035 K0.663:0.153 D4.06 E1.35 S1.00 B0 V24.4
Thats for fan compensation
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I changed the hotend while running RRF 3.4b7 (official b7 from github) so can't tell yet if it works well with 3.3 stable.
The Rapido Hotend comes with a full silicone sock and only a small tip of the nozzle is visible and can be targeted by the parts cooling fan.
The fan speed changes from 85% to 100% during a print. Before that I had a Mosquito Magnum which did not have any sock and did not have issues with temperatures (also 3.4b7).I just flashed 3.3 stable to compare the results and did PID tuning:
M307 H1 B0 R4.821 C119.7:101.0 D4.26 S1.00 V24.4
And here is the graph whilst printing with 3.3 stable:
Target temp is again 210°C and it keeps jumping between 209.3 - 210.5°C.
It's not perfect but far better than with 3.4b7 but still it struggles to hold the temperature whilst printing with that kind of heater. When idling and without the parts cooling fan running the temperature stays perfectly at 210°C.Next I'll try the classic heater PID without the fan included.
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Just did a new PID (still RRF 3.3) as a H(eater) and not T(ool) so there is no calibration with the fan included.
M307 H1 B0 R4.676 C121.5 D4.48 S1.00 V24.3
And the temperature is pretty stable during a print:
Should make no difference with RRF 3.4.0-b7 but I'll also test the PID as a heater and not tool.
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try firmware 3.4 beta 7+7
https://www.dropbox.com/sh/i5vox3xmkd55gaz/AAC19mI0WEC5GmEjLOBRbKs-a?dl=0
if you still have problems I help you in another way
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3.4 beta7+7 - the results were even worse with PID
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This post is deleted! -
then for the bed try to give this code in duet web control
M303 H0 S80 Y3
Y3= 3 hysteresis cycles
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I have no PID issues with the bed.
The extruder PID calibration does not work for me when the parts cooling fan is included. Therefore I need to start the PID calibration as a heater and not as a tool.
The Rapido uses a different kind of heater which needs less power at higher temperatures. Maybe that is causing trouble for the PID calibration.
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ok try this code to calibrate as a tool M303 T0 S205 Y3
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undefined Phaedrux moved this topic from General Discussion
