PID tunning - heated chamber
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Hey guys,
I have a problem heating up with my heated chamber. My chamber is 600mm x 600mm x 800mm and is heated by a 2kW heater. The heater has its own temp sensors that protect it from overheating. The heater sits on the bottom of the chamber and the temp-sensor that I have installed to transmit the chamber temperature to the Duet2 is about 500mm away from the heater at the height of the print head.
If I start the heating now, the message comes:
"Error: Heating fault on heater 3, temperature rising much more slowly than the expected 1.8 ° C / sec"I then started PID tuning. Then the message came after 1min:
"Auto tune canceled because temperature is not increasing"The heating takes 3 minutes so that the remote chamber sensor detects a rising temperature.
I then tried to enter the PWM manual. If I understand correctly, the P value is the value that indicates how quickly something heats up. The lower the R value, the faster the element gets up to temperature.
To try this out I took the values from my heating bed and set the P value to 400 and added it to the config.g:M301 H3 P400 I5.416 D128.0
Now the software should know that the heating element takes a long time, at least that's what I thought.
But no, the same avoidance still occurs when heating up:
"Error: Heating fault on heater 3, temperature rising much more slowly than the expected 1.8 ° C / sec"I had at least hoped that the C/sec went down.
Do any of you have any idea what I'm doing wrong?
Board: Duet Ethernet 1.02 or later + DueX5 (duetethernet102)
Firmware: RepRapFirmware for Duet 2 WiFi/Ethernet 2.03 (2019-06-13b2) -
@Chris25 said in PID tunning - heated chamber:
Firmware: RepRapFirmware for Duet 2 WiFi/Ethernet 2.03 (2019-06-13b2)
I suggest you update your firmware to RRF 3.2 as it has a new tuning algorithm that should handle a slow chamber heater much better.
If you still have access to DWC. Upload these 3 zip files, one at a time. Don't extract them. Reboot after each. Use M115 to verify the firmware has been applied.
https://github.com/Duet3D/RepRapFirmware/releases/download/2.05.1/Duet2Firmware-2.05.1.zip
https://github.com/Duet3D/RepRapFirmware/releases/download/3.0/Duet2and3Firmware-3.0.zip
https://github.com/Duet3D/RepRapFirmware/releases/download/3.2/Duet2and3Firmware-3.2.zip
That will get your firmware and DWC up to date.Updating from an older firmware like 2.03 will require some changes to the config file, so it might be a good idea to run through the configurator tool and generate a fresh set for RRF3.
https://configtool.reprapfirmware.org/Start -
@Chris25 and @Phaedrux
Wouldn't it make sense to heat up the printbed, before and while you are doing PID tuning of the heated chamber? IMHO, that's the real world scenario.The 2kW heater, does it have a huge thermal capacity (like an oil-radiator) or does it heat the air up immediately? Is there a chamber fan?
Maybe you have to warm up the heaterbody before you start tuning. It sure is an AC heater. -
@o_lampe said in PID tunning - heated chamber:
Wouldn't it make sense to heat up the printbed, before and while you are doing PID tuning of the heated chamber? IMHO, that's the real world scenario.
Yes. Trying to get close to the actual use case scenario before tuning would be best.
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Thank you for your answers.
It is direct air heating.
I updated the firmware to 3.2. It was like you said, I had to upload a new config after the update, but no problem.
The PID Tunning is now much more patient, but unfortunately it was still not enough.
I then heated up the 2kw air heater together with the heating bed 750W that then worked.
And your idea of updating also solved another problem:
https://forum.duet3d.com/topic/20444/pwm-fan-noctua-nf-a14-duet2/5The M950 command was only inserted with firmware 3 and thus led to malfunctions in the fans.
Big thank you
