All Metal Hot End Fan

Hi Guys,

I have now had my all metal hot end fan in for about a week now, and printing is great, but I have my hot end fan plugged into the ramps board where it says "fan" which seems to be on permanently. I also have a fan cooling down the actual ramps board too, as it was getting really hot, and that is plugged into the spare extruder heating wires (which is controlled via geode)

Now what I want to know is (and i have searched all over for the question), can the extruder fan be controlled via gcode?

I ask this, as I would like to have the fan turned off while the hot end isn't running, and when the hot end does heat up, then the fan should turn on. As the fan is on before the hot end, it seems to cool down my heated bed, which means it takes so much longer to heat the bed up.

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Regards,

James Simpson

All the RAMPS boards I've seen pictures of don't have a "FAN" labeled terminal since it can be configured any way you want. Typically the fan is configured for D9 which is the middle of the three terminals on the side of the board. Is that where it's plugged in at? If not, please provide a picture.

It's actually wired into the 12v aux, I already have my ramps fan wired into D9, but then I suppose, I could change the connectors around, and have the extruder fan into D9 and then the Ramps fan into the 12v aux port. But I only ever have my that fan on when there is a print running.




Edited 1 time(s). Last edit at 06/02/2014 02:24PM by JamesSimpson.

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Regards,

James Simpson

Ideally you'd leave D9 for cooling the workpiece and get a 2nd MOSFET fan driver (example circuit). You can use an unused servo connection or pin 45 which is a PWM output pin. Either can be controlled with the M42 P## S### command. The P parameter is the pin number. The S number is a number from 0 to 255 with 255 full on. 75% on for instance would be 255 * .75 = approximately 191, so the command would be M42 P45 S191 to turn a fan on 75%.