I'm using an Anet A8 with Marlin 1.1.6.

I've read countless guides on PID auto-tuning and never saw that the fan needed to be on, but when I look at the Marlin source code's ANet A8 configuration (here: example_configurations\ANet\A8\Configuration.h) it states:


  // ANET A8 Standard Extruder at 210 Degree Celsius and 100% Fan
  //(measured after M106 S255 with M303 E0 S210 C8)
  #define  DEFAULT_Kp 21.0
  #define  DEFAULT_Ki 1.25
  #define  DEFAULT_Kd 86.0

#endif // PIDTEMP

So, should activate the fan before running the auto-test if I wish to update the PID values in Marlin for my Anet A8?


You should run the fan at what you expect it to be at the majority of the time it is printing. If you tune at 100% fan and never use a fan then it will be too aggressive, if you tune at 0% fan and use the fan then you will struggle to maintain/reach temperature.

  • 1
    $\begingroup$ Thank you, that completely makes sense and I think is an important tidbit that all bazillion of these guides should mention. $\endgroup$ – Adam Plocher Nov 27 '17 at 17:06
  • $\begingroup$ One last (possibly stupid) question: does it matter if there is filament in the printer when Auto-Tuning? $\endgroup$ – Adam Plocher Nov 30 '17 at 6:48
  • $\begingroup$ Ideally I'd think you should extrude when you tune but I'm not sure if that is possible. Having filament in might help but most of it is going to ooze out as it heats up anyway. $\endgroup$ – tjb1 Nov 30 '17 at 12:12

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