Fan controle with board temp?
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Hi,
I connected the case fan to my Duet3 and I can pwm control it. I have now the idea to control the speed of the fan with the temperature of the Duet. Is that somehow possible?
Cheers, Chriss
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automatic adjusting. no
what you can do is turn it on to a certain speed when for example the hotend reached 50C.
(technically you could create a macro based on conditional code that you would execute each layer during printing)
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Assuming RepRapFirmware 3
M308 S9 P"mcu-temp" Y"mcu-temp" A"mcu" ; define sensor 9 to be mcu temperature M950 F2 C"!out4" Q25000 ; configure fan 2 M106 P2 S1 L0.25 B0.5 H9 T35:50 C"mainb" ; cooling electronics space thermostatic on sensor 9 35 to 50C
The first line defines a sensor 9 ('S9') to be the internal temperature sensor of the processor on a Duet 3 MB6HC.
The second line defines fan number 2 ('F2') on OUT4 with settings suitable for a standard 4-wire PWM case fan.
The third line controls fan 2 ('P2') according to sensor 9 ('S9'), with it starting at 35C and running at full speed above 50C, and varying (roughly) linearly in between. The L and B values are just what my fan needs to start reliably.
Is that what you are trying to do?
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Is that what you are trying to do?
Yes, that is exactly what I'm trying. I was not aware that the "S9" is available and the internal temperature.
@Veti Your approach was my first idea. The second idea was to start the fan in the startcode and stop it in the stop code. I will go with achrn's approach.
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It can also make sense to tie it to the temp of the hotend and bed since if those are running, chances are a print is running, or is at least being preheated/idle.
MCU temp is a good proxy for the board temp. Just be sure to calibrate your CPU temp reading and adjust the temp set point to run the fan fast enough to matter.
https://duet3d.dozuki.com/Wiki/Calibrating_the_CPU_temperature
https://duet3d.dozuki.com/Wiki/Mounting_and_cooling_the_board
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@Chriss said in Fan controle with board temp?:
Yes, that is exactly what I'm trying. I was not aware that the "S9" is available and the internal temperature.
S9 is just what I use (because it's away from the other temperature sensors). It could (I assume) be any S number not being used for something else.
I realise my gcode is correct, but explanation of it is wrong - I should have said "according to sensor 9 ('H9')", the S parameter in that line is fan speed.