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Only turn on extruder cooling fan when temperature is above xx degrees

danededane

Only turn on extruder cooling fan when temperature is above xx degrees
May 07, 2022 02:52AM

Registered: 2 years ago
Posts: 8

Hello ,

I've been looking at the following in marlin configuration_adv.h:

#define E0_AUTO_FAN_PIN -1
#define EXTRUDER_AUTO_FAN_TEMPERATURE 50
#define EXTRUDER_AUTO_FAN_SPEED 255 // 255 == full speed

My board is "lgt kit v1.0"

LGT_KIT_V1.0-schematics.jpg

But as far as I understand I cannot control fan 2 and 3 because they are directly 24V and ground connected. Right?

So my question is, do I have other options? can I use other pins on the board to act like D7 (FAN1 Parts cooling fan)?

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Dust

Re: Only turn on extruder cooling fan when temperature is above xx degrees
May 07, 2022 04:55AM

Admin
Registered: 14 years ago
Posts: 7,171

Correct you cannot used those always on fans.

Yes you could use D7, to turn on an external mosfet to drive the fan.

Edited 1 time(s). Last edit at 05/07/2022 04:56AM by Dust.

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danededane

Re: Only turn on extruder cooling fan when temperature is above xx degrees
May 07, 2022 04:59AM

Registered: 2 years ago
Posts: 8

Hi Dust ,

But D7 is used for parts cooling . Other options ? .

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Dust

Re: Only turn on extruder cooling fan when temperature is above xx degrees
May 07, 2022 05:19AM

Admin
Registered: 14 years ago
Posts: 7,171

Not according to that diagram, D7 is up top, D9 is the cooling fan.

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danededane

Re: Only turn on extruder cooling fan when temperature is above xx degrees
May 07, 2022 05:31AM

Registered: 2 years ago
Posts: 8

Oh sorry , my bad !

But I'm using D7 for my newly installed 3DTouch confused smiley

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Dust

Re: Only turn on extruder cooling fan when temperature is above xx degrees
May 07, 2022 05:47AM

Admin
Registered: 14 years ago
Posts: 7,171

So use another pin that isnt in use.

D4, D5, D6 or D11

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danededane

Re: Only turn on extruder cooling fan when temperature is above xx degrees
May 07, 2022 05:51AM

Registered: 2 years ago
Posts: 8

Lets say I would use D11

Should I then just write:
#define E0_AUTO_FAN_PIN D11

or

#define E0_AUTO_FAN_PIN 11

??

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Dust

Re: Only turn on extruder cooling fan when temperature is above xx degrees
May 07, 2022 06:12AM

Admin
Registered: 14 years ago
Posts: 7,171

#define E0_AUTO_FAN_PIN 11

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danededane

Re: Only turn on extruder cooling fan when temperature is above xx degrees
May 07, 2022 06:44AM

Registered: 2 years ago
Posts: 8

That seems to be working .

But I'm only getting around 5V between the D11 and the ground pin next to. Can that be true?

Right now my parts cooling are running like on this drawing:
[imgur.com]

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Dust

Re: Only turn on extruder cooling fan when temperature is above xx degrees
May 07, 2022 07:45AM

Admin
Registered: 14 years ago
Posts: 7,171

D11 is a io pin. it is 5v It is also low current, so you don't use it to control a 5v fan either.

This is why you need the external mosfet

The IO pin turns on the mosfet The mofet provide the 12v or 24 to the fan

Edited 1 time(s). Last edit at 05/07/2022 07:56AM by Dust.

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danededane

Re: Only turn on extruder cooling fan when temperature is above xx degrees
May 07, 2022 11:27AM