2023-11-03 - heater PID tuning in 3D printer

whenever hotend is changed, or heatbed covered / rebuild, PID needs to be tuned, to make sure it performs well (i.e.: fast heating, stable temperature, etc.).

the process is simple – just connect USB cable to your printer and run serial terminal. eg. for anycubic chiron, using picpcom that'd be:

picocom --imap lfcrlf --echo --baud 250000 /dev/ttyACM0

first check existing settings with M503. on my firmware it was (stock):

M301 P20.00 I0.50 D106.55
M304 P97.10 I1.41 D1675.16

first is heatend, while second is heatbed.

note that stock values differ a lot from values on my customized setup. this is to be expected. make sure to tune these every time you change sth around heating or cooling.

now run 10x tuning procedure for heatend, for 230 deg.C, and then save it to RAM (i.e. as current values – that's the U1 part at the end):

M303 E0 S230 C10 U1

my output was:

#define  DEFAULT_Kp 25.67
#define  DEFAULT_Ki 1.80
#define  DEFAULT_Kd 91.43

now write these values to EEPROM:

M500

next run 10x tuning procedure for heatbed, for 80 deg.C, and then save it to RAM:

M303 E-1 S80 C10 U1

my output was:

#define  DEFAULT_bedKp 213.50
#define  DEFAULT_bedKi 42.59
#define  DEFAULT_bedKd 267.60

now write these values to EEPROM:

M500