PID tuning?  

RE: PID tuning?

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.

RE: PID tuning?

@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.

RE: PID tuning?

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.

RE: PID tuning?

@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/

RE: PID tuning?

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.

RE: PID tuning?

@karl-herbert @zoltan

Thanks, those are useful information.

RE: PID tuning?

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.