"Marlin is an open source firmware for the RepRap family of replicating rapid prototypers — popularly known as “3D printers.” It was derived from Sprinter and grbl, and became a standalone open source project on August 12, 2011 with its Github release. Marlin is licensed under the GPLv3 and is free for all applications." - https://marlinfw.org/docs/basics/introduction.html
Marlin is used on the Ender line of printers, as well as many others.
Show firmware info
In a serial terminal, type
M115. You will see something like:
Send: M115 Recv: FIRMWARE_NAME:220.127.116.11 (Jul 6 2022 19:18:56) SOURCE_CODE_URL:www.creality.com PROTOCOL_VERSION:1.0 MACHINE_TYPE:Ender-3 Pro EXTRUDER_COUNT:1 UUID:cede2a2f-41a2-4748-9b12-c55c62f367ff Recv: Cap:SERIAL_XON_XOFF:0 Recv: Cap:BINARY_FILE_TRANSFER:0 Recv: Cap:EEPROM:1 ...lots of similar lines lines... Recv: Cap:CHAMBER_TEMPERATURE:0 Recv: Cap:COOLER_TEMPERATURE:0 Recv: Cap:MEATPACK:0 Recv: ok Send: M155 S2 Recv: ok
Perform a PID Autotune
In octoprint or some other terminal interface:
M303 S215 C10to perform a 215ºC tuning test 10 times. You will get Kp, Ki, and Kd values back at the end of the test.
- Enter those values in the terminal as
301 Pxx.xx Ixx.xx Dxx.xx
M500to save the values to the EEPROM.