One idea for extra cooling fans August 03, 2014 05:03PM |
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Re: One idea for extra cooling fans August 03, 2014 05:33PM |
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Re: One idea for extra cooling fans August 03, 2014 05:33PM |
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Re: One idea for extra cooling fans April 14, 2015 02:26PM |
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Re: One idea for extra cooling fans April 14, 2015 04:36PM |
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Re: One idea for extra cooling fans April 14, 2015 04:53PM |
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Re: One idea for extra cooling fans April 15, 2015 10:40AM |
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Re: One idea for extra cooling fans April 15, 2015 11:38AM |
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Re: One idea for extra cooling fans April 15, 2015 03:44PM |
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orictosh
I can confirm the bug; I'm currently printing an item but it's hard to tell if the fan is responding from the gcode produced by slic3r as there is not many overhangs or quick layers.
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orictosh
before the upgrade the G32 command in pronterface would should show the results of G32 in the serial window but with 1.04 it dosen't show the results.
Re: One idea for extra cooling fans April 20, 2015 03:53PM |
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Re: One idea for extra cooling fans April 20, 2015 04:56PM |
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Re: One idea for extra cooling fans April 20, 2015 05:36PM |
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Re: One idea for extra cooling fans April 20, 2015 06:14PM |
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Re: One idea for extra cooling fans April 20, 2015 06:31PM |
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Re: One idea for extra cooling fans April 20, 2015 07:22PM |
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Re: One idea for extra cooling fans April 21, 2015 08:20AM |
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Re: One idea for extra cooling fans April 21, 2015 08:31AM |
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Re: One idea for extra cooling fans April 21, 2015 08:40AM |
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Re: One idea for extra cooling fans April 21, 2015 10:37AM |
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dmould
Probably explained a while ago, but why is the FET needed for 3-wire control? It seems to act as a invertor, but If the fan's PWM control input is fed direct from the fan output of the duet (possibly with a pullup to 12V), surely a simple firmware change could supply the correct polarity pulses?
Dave
Re: One idea for extra cooling fans April 21, 2015 11:03AM |
Registered: 9 years ago Posts: 177 |
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orictosh
Yes, using a 4 wire fan and a 2N7000 mosfet is good way to power a cooling fan so it gives variable speed and cooling when needed and requested by slic3r. The yellow wire is not used in this case.
Looking at my diagram, I would say the the PWM signal is on the negetive fan0 connection as it connected to gate pin
[attachment 53250 4_wire01.JPG]
The +12v pin is connected to red (Postive) of the fan
The Brown wire is the PWM control wire which is connected to the Drain on the mosfet
The Black is the gnd wire for the fan and is connected to the Source pin on the mosfet
Current flows from the source to drain and the gate controls the flow with the PWM signal coming from the negetive fan0 connection.
The source pin and fan's ground is connected to a gnd pin on the J6 connecter on duet board, the pin on the left above the hot end fan connection.
Sending M106 S255 should turn the fan full on and I found that ran from S145 to S255 in a previous post.
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dc42
One reason is that the fan PWM input has a voltage rating of 5.25V maximum, see [www.formfactors.org]. The fan output from the Duet has a LED and 4.7K series resistor pulling it up to +12V. So you should at least use a diode between the fan output and the PWM input.
Re: One idea for extra cooling fans April 21, 2015 01:18PM |
Registered: 10 years ago Posts: 2,472 |
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dc42
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dmould
Probably explained a while ago, but why is the FET needed for 3-wire control? It seems to act as a invertor, but If the fan's PWM control input is fed direct from the fan output of the duet (possibly with a pullup to 12V), surely a simple firmware change could supply the correct polarity pulses?
Dave
One reason is that the fan PWM input has a voltage rating of 5.25V maximum, see [www.formfactors.org]. The fan output from the Duet has a LED and 4.7K series resistor pulling it up to +12V. So you should at least use a diode between the fan output and the PWM input. My fork and zpl's already include an option for inverting the PWM.
Re: One idea for extra cooling fans April 21, 2015 02:41PM |
Registered: 10 years ago Posts: 665 |
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dmould
Alternatively, if you want to get it working without waiting to get a diode, then removing the 4k7 LED series resistor on the Duet board would, if I understand correctly, make the Duet's fan output completely open-drain and so able to drive the fan directly with no additional components needed (although it would disable the LED indicator). I assume that the fan input has an internal pullup to 5V (otherwise your FET mod would not work as shown).
Re: One idea for extra cooling fans April 22, 2015 08:02AM |
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zombiepantslol
I've been running my 4-pin PWM fan (SunOn 40x40x20mm) without any diodes connected for about a year now and it's working perfectly fine, though it's possible the results may look different if another fan is used (so I wouldn't recommend it, do what dc42 and dmould say and you're on the safe side). Btw this additional M106 'I' parameter was basically the first mod I did to the Duet firmware, at that time I really wouldn't have thought I'd stay in this business for so long
Re: One idea for extra cooling fans April 22, 2015 08:07AM |
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dmould
I note that the specifications that DC42 referenced do not state that the fan's input must have an internal pullup or be capable of being driven from an open drain source.
Re: One idea for extra cooling fans April 22, 2015 09:14AM |
Registered: 10 years ago Posts: 2,472 |
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dc42
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dmould
I note that the specifications that DC42 referenced do not state that the fan's input must have an internal pullup or be capable of being driven from an open drain source.
True, but IMO it is strongly implied by the "Absolute maximum current sourced: Imax = 5 mA (short circuit current)", "Absolute maximum voltage level: VMax = 5.25 V (open circuit voltage)" and "If no control signal is present the fan shall operate at maximum RPM" bits.
Re: One idea for extra cooling fans April 22, 2015 10:12AM |
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Re: One idea for extra cooling fans April 22, 2015 10:47AM |
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dc42
I found a later version of that document here [www.formfactors.org] which specifically mentions a pullup, and driving the PWM input from an open drain or open collector device.
Re: One idea for extra cooling fans April 22, 2015 05:18PM |
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Re: One idea for extra cooling fans August 24, 2015 09:12PM |
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