RAMPS 1.4 and fan control.

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RAMPS 1.4 and fan control.

Postby geoffs » Fri Mar 08, 2013 10:10 am

With a dual extruder setup, how does one control the extruder fans?
There are 3 FET outputs on the RAMPS board but these are used for the extruders and the heat bed.
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Re: RAMPS 1.4 and fan control.

Postby SystemsGuy » Fri Mar 08, 2013 11:34 am

Pick an unused pin, define that in pins.h as your fan, and add a MOSFET to control it.


geoffs wrote:With a dual extruder setup, how does one control the extruder fans?
There are 3 FET outputs on the RAMPS board but these are used for the extruders and the heat bed.
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Re: RAMPS 1.4 and fan control.

Postby cvoinescu » Fri Mar 08, 2013 11:40 am

What SystemsGuy said. FAN_PIN (and FAN1_PIN, if you want) are what you need to define. Some boards already have more than three MOSFETs, and it would be a good idea to look at which pins they use. For instance, the RUMBA (pin assignment) has MOSFETs on pins 2, 3, 6, 7, 8, 9 (the latter for the heated bed). If you need help choosing a MOSFET or connecting it, just ask.
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Re: RAMPS 1.4 and fan control.

Postby geoffs » Fri Mar 08, 2013 11:41 am

SystemsGuy wrote:Pick an unused pin, define that in pins.h as your fan, and add a MOSFET to control it.



I thought there may have been an obvious (simple) answer that I hadn't thought of.
Should be easy given I can plagiarise both the circuit and the software to drive it :D
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Re: RAMPS 1.4 and fan control.

Postby SystemsGuy » Fri Mar 08, 2013 12:18 pm

Exactly! :-) Only thing to keep in mind is you want a logic level fet - other than that, it's very straightforward. I'd personally toss a diode into the mix since motors are dirty, but....

geoffs wrote:
SystemsGuy wrote:Pick an unused pin, define that in pins.h as your fan, and add a MOSFET to control it.



I thought there may have been an obvious (simple) answer that I hadn't thought of.
Should be easy given I can plagiarise both the circuit and the software to drive it :D
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Re: RAMPS 1.4 and fan control.

Postby geoffs » Fri Mar 08, 2013 12:54 pm

This might be just what I'm looking for. Not sure if the board/circuit diagram is open source

https://www.dropbox.com/s/7shvnc8niiu8j ... .01.06.jpg
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Re: RAMPS 1.4 and fan control.

Postby bdring » Fri Mar 08, 2013 1:23 pm

RRD seems to sell something that might work.

http://www.ebay.com/itm/NEW-Reprap-Ramp ... 0905708869

$T2eC16Z,!)EE9s2uiQRyBQgYHPucN!~~60_57.JPG
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Re: RAMPS 1.4 and fan control.

Postby SystemsGuy » Fri Mar 08, 2013 1:39 pm

I think it is, but this is the one I use - it's quick & easy. He also sells a SMD kit on ebay for a couple of bucks - I've intended on ordering a couple just cause they are handy and never seem to get around to it! :P


http://www.thingiverse.com/thing:22202

geoffs wrote:This might be just what I'm looking for. Not sure if the board/circuit diagram is open source

https://www.dropbox.com/s/7shvnc8niiu8j ... .01.06.jpg
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Re: RAMPS 1.4 and fan control.

Postby geoffs » Fri Mar 22, 2013 9:31 am

No motor movement :?

I spent a frustrating couple of hours today trying to move the XYZ motors. I had no luck with Repetier via the reprapdiscount LCD. Arduino loads OK but no response from the motors.
Found and loaded the RAMPS test program, still nothing.
Double checked everything and even dragged out the oscilloscope for a look.
Found the problem was a misunderstanding on my part of the function of the two power inputs on the ramps board. I had power plugged into the 11A connection only and not into 5A :oops:
Test program now runs OK.
Reloaded repetier and tried again, all motors move! Exciting stuff.

Time for some more reading about tuning then on to the extruder. Still need to fit some endstops

Regards
Gepff
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