M303 "F" parameter highlight
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I just wanted to highlight something here. When PID tuning a tool (as opposed to a heater) I happened to notice that during phase 4, the fan slider indicated a speed of 70% which rather surprised me as I was expecting it to be 100%. Checking the documentation for M303, I see that this is a newish feature added in firmware 3.3 and the default fan speed is 0.7. I've read the release notes for 3.3 again (twice) but I don't see any mention of it. So I'm highlighting it here. When PID tuning a tool, use the F parameter to set an appropriate part cooling fan speed (in my case, I want 1.0 instead of the default 0.7).
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@deckingman yup...I notice that too...I was to ask this but menatime my attention was on other things and forget...now that you pointed out the PID tunning command should look something like this
M303 T0 S240 F1.0 for a 100% fan speed ? -
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@weed2all That M303 looks right to me. I'll try it later and report back if anything strange happens.
I'm curious as to why the default is 0.7. If I had a part cooling fan that was over powered, I'd use the X parameter in M106 to limit the speed. The logic of having a different, (temporary) value for fan speed when tuning the heater escapes me, but I assume there must be a good reason for it.
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The default speed is 0.7 in an attempt to get reasonable accuracy over the range 0.4 to 1.0 using extrapolation and interpolation, rather than good accuracy at 1.0 and poor accuracy at low speeds.
If you configure your slicer to use full fan PWM whenever the fan is on (which might be appropriate when printing PLA) then 1.0 would be better.
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@dc42 said in M303 "F" parameter highlight:
The default speed is 0.7 in an attempt to get reasonable accuracy over the range 0.4 to 1.0 using extrapolation and interpolation, rather than good accuracy at 1.0 and poor accuracy at low speeds.
If you configure your slicer to use full fan PWM whenever the fan is on (which might be appropriate when printing PLA) then 1.0 would be better.
Thanks for the explanation. Personally, I usually only use the fan for bridges and/or very short layer times, so I'll stick to using 100% when PID tuning.
