PID tuning?  

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crawlerin
(@crawlerin)
Honorable Member

Is PID tuning necessary? If yes how to do it? Connect to PC and through direct g-code? There is no option for this in menu.

I have also noticed that when nozzle heats up, it does not reach target temperature at once, but it goes like this: 239 ->240 -> 239 -> 238 -> 237 -> 238 -> 239 -> 240 -> starts printing, then it's stable. Just curious, why printers do this?

Posted : 14/05/2020 5:43 pm
bobstro
(@bobstro)
Illustrious Member

Look for PID tune in the calibration menu. It takes a few minutes and you just start it, select a temperature and leave it alone. Yes, you should do it to ensure consistent temperatures.

My notes and disclaimers on 3D printing and miscellaneous other tech projects
He is intelligent, but not experienced. His pattern indicates two dimensional thinking. -- Spock in Star Trek: The Wrath of Khan...
Posted : 14/05/2020 6:39 pm
crawlerin
(@crawlerin)
Honorable Member

@bobstro

I don't seem to find it 😐 Do you know where it should be? I am printing right now but I don't recall MINI having separate calibration menu.

Posted : 14/05/2020 6:53 pm
bobstro
(@bobstro)
Illustrious Member
Posted by: @crawlerin

I don't seem to find it 😐 Do you know where it should be? I am printing right now but I don't recall MINI having separate calibration menu.

Ah man, sorry. Was posting while on a call and didn't catch that this was the Mini forum. Wish they'd let us filter what to see in recent posts more. Sorry about that.

 

My notes and disclaimers on 3D printing and miscellaneous other tech projects
He is intelligent, but not experienced. His pattern indicates two dimensional thinking. -- Spock in Star Trek: The Wrath of Khan...
Posted : 14/05/2020 6:56 pm
Karl Herbert
(@karl-herbert)
Famed Member

@crawlerin

here you can find interesting information about pid tuning:

https://oxi.ch/2017/03/28/prusa-i3-and-all-marlin-based-3d-printers-pid-tuning-with-octoprint-slic3r-and-simplify3d/

Statt zu klagen, dass wir nicht alles haben, was wir wollen, sollten wir lieber dankbar sein, dass wir nicht alles bekommen, was wir verdienen....
Posted : 14/05/2020 10:18 pm
zoltan
(@zoltan)
Member Moderator
Posted by: @crawlerin

Is PID tuning necessary? If yes how to do it? Connect to PC and through direct g-code? There is no option for this in men  u.

I have also noticed that when nozzle heats up, it does not reach target temperature at once, but it goes like this: 239 ->240 -> 239 -> 238 -> 237 -> 238 -> 239 -> 240 -> starts printing, then it's stable. Just curious, why printers do this?

When the heater  heats the nozzle at the starting point it can overrun the target temperature, oscilates arround the target temperature for a while and then comes to the stable phase. The number, amplitude of the oscilations  and the stability along the target temperature depends on the P,I,D constants set for the nozzle heater. There is almost a science concerning PID control. PID tuning focuses on PID control optimization for particular 'stabilized temperature'. So when you want to have the best stabilisation for eg. PETG which is heated by 240°C, you run PID tunning setting the temperature argument to 240. 

You can run on MINI a PID autotunning ,connecting the MINI to PC via Pronterface. Sending a command M303 E0 SXXX C8 asks for PID autotunning for nozzle =E0 (extruder 0=nozzle) at temperature XXX. C8 menas 8 cycles of measurement.

After getting the P,I and D constants you can put them to MINI via command M301 (see link below) into the Prusaslicers before print g-codes. By this you will impact only the concreate print.  

Link https://reprap.org/wiki/PID_Tuning

MINI has internally in EEPROM a set of  default P,I,D constants , you can list them by M501 sent to printer.

This post was modified 3 months ago 4 times by zoltan
even an old man can learn new things 🙂
Standard I3 mk3s, FW 3.9.0, no closed box, sketchup , fusion 360, PrusaSlicer, Windows 10
PRUSA MINI FW 4.1.0, technical background...
Posted : 16/05/2020 5:47 pm
crawlerin
(@crawlerin)
Honorable Member

@karl-herbert @zoltan

Thanks, those are useful information.

Posted : 17/05/2020 2:58 am
gordon.w
(@gordon-w)
Estimable Member

A pull request for new PID defaults has been merged ( https://github.com/prusa3d/Prusa-Firmware-Buddy/pull/469 ) so whilst it doesn't help with tuning, hopefully it should mean that the defaults are better.

Posted : 19/05/2020 8:48 am
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