Ramps 1.4 d2 pins for12v extruder fan, polarity?

Hello

I am almost finished with my prusa i3 build (graber) lasercut edition, with ramps 1.4 electronics and I have a quick question:

Does the 12v extruder fan that is supposed to connect onto d2 12v aux pins have polarity? If so which way?

The prusa i3 rework instructions in reprap wiki suggest to plug it into d2 but no indication of polarity

Thanks in advance.
Rui

I would wire up the fan up to 12v that is always ON when printer is ON.
Use the D9 pin to drive a cooler fan to squirt air for cooling of all ready
laid down PLA, and it is software controlable.

I would keep any power around D2 clean --- inducing any ripple (back emf from fan) may mess with CPU power supply.
D2 pin 2 is gnd pin 1 +

Ok thanks.

If I wire the extruder fan onto d2, would that keep it on when I plug the power on? I am yet to install firmware onto ramps, would this mean until I do so, no power would be allocated to the d2 pins, hence if i even plug the extruder in correctly, it would not turn on?

I have attached an image, from this view is the top one positive and bottom one negative?

Thanks again

Rui.in.Roskill Wrote:
-------------------------------------------------------
> Ok thanks.
>
> If I wire the extruder fan onto d2, would that
> keep it on when I plug the power on? I am yet to
> install firmware onto ramps, would this mean until
> I do so, no power would be allocated to the d2
> pins, hence if i even plug the extruder in
> correctly, it would not turn on?

D2 is the label for the diode that is right there. The pins above D2 are the 12V auxiliary pins, and will always have power as long as RAMPS has power. The top pin should be positive.

You are correct that without firmware, the extruder (heater and motor) will not turn on.

---

Help improve the RepRap wiki! Just click "Edit" in the top-right corner of the page and start typing. Anyone can edit the wiki!

Thanks for your help.

I would NOT wire to D2.
Wire to 12V supply right at 12V PS terminals, when you switch ON the power supply
the fan will start spinning always cooling extruder.
I don't like using plug as a switch.
Your arduino will power up when you plug in USB.

You can also wire up a RAMPS cooling fan to 12V to keep mosFETs and drivers cool
place fan above or on the side of the RAMPS board to blow over the board.

cozmicray Wrote:
-------------------------------------------------------
> I would NOT wire to D2.
> Wire to 12V supply right at 12V PS terminals,
> when you switch ON the power supply
> the fan will start spinning always cooling
> extruder.
> I don't like using plug as a switch.
> Your arduino will power up when you plug in USB.

Um, as I explained, that pin header is not D2. It is directly connected to 12V, so will be powered any time the power supply is connected and turned on.

---

Help improve the RepRap wiki! Just click "Edit" in the top-right corner of the page and start typing. Anyone can edit the wiki!

Right so to reiterate what has been said:

The pins to the right (or above d2) are 12v auxilary pins, not d2 pins (as labeled on ramps), which from the image (earlier post), top pin positive and bottom pin negative. Cameron, you are suggesting that with or without firmware, when extruder fan is plugged onto the pins (red on top, black on bottom) fan should turn on as long as power is plugged in? I plugged it in the first time and no response when power is plugged in (though I see a flashing green ramps led)

And perfection, you are suggesting that I plug the 12v extruder fan onto one of the right hand side 12v pins, such as d10, d9 or d8? Which can Also be used for extra fan additions, correct?

My preference is to plug the extruder fans onto the pins NEXT to D2, and save d9 for extra fan addons, while reserving d8 for my heatbed. D10 is already used for heater cartridge.


Appreciate your inputs thus far.

And ps, this image is the type of wiring I am referring to found on the reprap wiki.

Looks like the D2 holes we are talking about are fed by D10 source.

So soldering in pins to D2 holes is better than putting the wires for the fan
in the power supply screw terminals.?

FWIW --- I made up a set of 12V pins on a small perf board spaced as standard molex
4 sets of +/- pins all wired directly up to 12v
I can plug fans, LED lights, etc to this bus.

I hope we all agree there is NOT a D2 connect point!!!

cozmicray Wrote:
-------------------------------------------------------
> Looks like the D2 holes we are talking about are
> fed by D10 source.

According to the RAMPS schematic, those pins are connected directly to 12V.

---

Help improve the RepRap wiki! Just click "Edit" in the top-right corner of the page and start typing. Anyone can edit the wiki!

Look at the printer circuit board -- the layout shows it goes to D10 a 12V source.

My point -- solder in pins/wires to D2 holes or BETTER just tie wires into 12v supply screw terminals.

Ok great. Will plug fans as planned. Thanks for be feedbacks.

Quote
Rui.in.Roskill
Ok great. Will plug fans as planned. Thanks for be feedbacks.

I'm building a prusa i3 with custom hot end which requires a dedicated fan. I'd like to save D9 for print fan and therefore I'd like to use "D2 holes" for extruder fan.

Rui.in.Roskill, can you tell if "D2 holes" proved to be the right choice?

is there any way to control the hotend cooling fan? i just need on/off because its annoying to have the printer run so noisy after it stops printing.

i imagine a relay controlled by some of the aux pins, but before I do that is there maybe a simpler solution?

Quote
sungod3k
is there any way to control the hotend cooling fan? i just need on/off because its annoying to have the printer run so noisy after it stops printing.

i imagine a relay controlled by some of the aux pins, but before I do that is there maybe a simpler solution?

There are several different fan controllers. Some plug in the servo connections, others just need an available pin. I use a modified version of this to control my hot end fan and some LED lights under my xcarriage. If you only will need on/off, any of the aux pins will work. If you need PWM, one of the servo pins or D45 along the edge provide PWM pins will get you what you need

Edited 1 time(s). Last edit at 02/11/2015 10:05AM by cdru.