Question Warm bed autopid tune numbers are very high compared to examples on marlin firmware

Question Warm bed autopid tune numbers are very high compared to examples on marlin firmware

Warm bed autopid tune numbers are very high compared to examples on marlin firmware

Ive been battling with temperature runaways on warm bed.
I'm keeping 110c on be for ABS printing
it prinst ok for a while, like 20 layers(it varies) then comes runaway and it asks for reset
I have hictop aluminium 12v 200w
link here [shopping.hictop3dprinter.com]
My printer came equipped with 24v 360w power unit.

Anyways i did PID autotunes for nozzle and bed.
Nozzle gave quite normal ones but bed gave following

90c
PID Autotune finished! Put the last Kp, Ki and Kd constants from below into Configuration.h
#define DEFAULT_bedKp 274.38
#define DEFAULT_bedKi 36.73
#define DEFAULT_bedKd 512.47

110c
#define DEFAULT_bedKp 381.67
#define DEFAULT_bedKi 44.12
#define DEFAULT_bedKd 825.45

Can these be right?
here is marlin firmware default:
//120V 250W silicone heater into 4mm borosilicate (MendelMax 1.5+)
//from FOPDT model - kp=.39 Tp=405 Tdead=66, Tc set to 79.2, aggressive factor of .15 (vs .1, 1, 10)
#define DEFAULT_bedKp 10.00
#define DEFAULT_bedKi .023
#define DEFAULT_bedKd 305.4

are my numbers ok too or am I missing something. Im sorry I have read a lot but I really still dont understand this fully.
I dont want to burn my printer.

Also tips on why the thermal runaways happen and solutions are most welcome.

I have own made 4mm bed where are 3 bearing blocks, then I have a big pile of wool between bed and the 4mm Y-axis plate

I try google but I get overwhelmed with info and I cannot piece it together.
Printer is Hictop 3dp11 with 24v PSU and MPX-3 board. I have upgraded to E3D V6 nozzle and bowden extruder.

Also i have lots of other upgrades and I used CRC white lithium grease for bearings and leadscrews so its nearly quiet.
I can give some upgrade tips and Im happy to. Also im happy to tell the right firmware(if you buy hictop you get it with broken firmware and it just does not work)
Also I designed a electronics to raise voltage to autolevel sensor to 24v and my electronics drops in voltage to board for 4.4v so it doesnts broke.
Accuracy is increased with this upgrade for autolevel sensor.

Here are my numbers for 100c which are yet different again.

#define DEFAULT_bedKp 96.24
#define DEFAULT_bedKi 1.96
#define DEFAULT_bedKd 1180.22

I would take the word of your PID autotune values.

Do you know that is actually the bed that is causing the runaway? Is it specified?

Runaway is triggered when the temperature drops in relation to heat been asked for.
I would say that a more likely cause would be a wiring fault to a thermistor or thermistor not making good contact with whats being heated.
It could be to the hot end after it has raised to a certain height.(??)

Try it on bang-bang bed heating see if that affects it, though the fact that you ran an autotune up to 110 means that your bed is capable of reaching that temp ok.

Yes I know its the bed causing runaways cus on error it says "bed plaa plaa runaway" sorry dont have the right text atm. Used Repetier host

I disabled the bed PID and configured advanced config. I basically double the values likes seconds etc.
Stopped getting the bed runaway. now it works 110c fine.
configuration_adv.h added

#if ENABLED(THERMAL_PROTECTION_BED)
  #define THERMAL_PROTECTION_BED_PERIOD 40    // Seconds WAR INC TO 40 WAS 20
  #define THERMAL_PROTECTION_BED_HYSTERESIS 4 // Degrees Celsius WAR INC TO 8 WAS 4

the WAR just lets me know I have chaned it and I keep changelog on all changes to firmwared.

I just dont understand why in hell I get those ridiculous high values on PID autotune on bed.
Anyways like I said. Disabled that part on config, made changes to advanced config and now I can finally print ABS fine.

Thank you for answer anyways.
If someone can answer or explain why I get those readings Id be happy to learn more