How would you do it ?

acme15 said:
I just thought you would like to know that I did a bit of digging, and the bottom (SYS_FAN2) header on the GA-EX58-UD5 has the pinout:

GND
Speed Control
Sense
+5V

And there are two regular 3 pin fan headers elsewhere on the board.

Source: http://download.gigabyte.eu/FileList/Manual/motherboard_manual_ga-ex58-ud5(p)_e.pdf

Can we move on now? :p
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Thanks Acme for proving it's not PWM. I couldn't find it when I searched.
I assume speed control would be variable voltage. The +5 pin is where the PWM signal would be if it was PWM

So just like I've stated in first post here. Don't know what would use the +5 volt pin.
 
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doyll said:
Thanks Acme for proving it's not PWM. I couldn't find it when I searched.

So just like I've stated in first post here. Don't know what would use the +5 volt pin.
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I don't even...

The second pin is labelled 'Speed Control' rather than '12v' as on most PWM headers, and the 'Speed Control' pin is labelled as '5v' rather than 'Speed Control' - again, as on most PWM headers.

All this tells me is that the Speed Control pin on a regular PWM fan header carries 5 volts which are manipulated by a variable resistor which is responsible for controlling the fan speed, and on the SYS_FAN header on that Gigabyte board, the variable resistor which is responsible for controlling the fan speed happens to be in-line with the 12v pin rather than the 5v pin. Meaning that while it may not be of the standard pin-out, the speed should still be adjustable in the BIOS.

You dwell on that, i'm off to make a sandwich because i'm hungry. After which I'll get on with my life. :)
 
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acme15 said:
How do you know that the speed control pin on a regular PWM fan header is not in actual fact carrying 5 volts and the actual speed control is done by manipulating those 5 volts with a variable resistor?

The speed control pin doesn't carry a signal, it carries a voltage, a fan is just a fan, it can't interpret a digital signal telling it how fast to spin, but the speed will change in direct proportion to the voltage it receives.

Why is it such an impossibility that the Gigabyte motherboard might control the fan speed using the same principle but on the 12v pin rather than on the 5v pin?
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1/Because PWM is a signal to circuit board in fan.
2/I think the speed control pin is 12v but can be voltage controlled by mobo. I have ran 3 pin fans on it but never tried to change their speed.
3/Don't understand the third about "12v pin rathar than on the 5v pin?"

PWM fans have a circuit board in them that the PWM signal goes to. This board than pulses the 12v lead to power the fan.

A copy / paste straight from this site: http://en.wikipedia.org/wiki/Fan_control
"Pulse-width modulation
Pulse-width modulation (PWM) is a common method of controlling computer fans. A PWM capable fan is usually connected to a 4-pin connector (pinout: Ground, +12V, sense, control). The sense pin is used to measure the rotation speed of the fan and the control pin is a open-drain or open-collector output, which requires a pull-up to 5V or 3.3V in the fan. Unlike linear voltage regulation, where the fan voltage is proportional to the speed, the fan is driven with a constant supply voltage; the speed control is performed by the fan based on the control signal.
The control signal is a square wave operating at 25kHz, with the duty cycle determining the fan speed. Typically a fan can be driven between about 30% and 100% of the rated fan speed, using a signal with up to 100% duty cycle. The exact speed behaviour (linear, off until a threshold value, or a minimum speed until a threshold) at low control levels is manufacturer-dependent."
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4 pin PWM pinout and what each pin does:
*Ground
*Power - +12 V
*Sense - a tachometer that measures the actual speed of the fan as a pulse train, frequency being proportional to speed. With each fan rotation, there are two pulses sent through this pin.
*Control - PWM signal (Pulse-width modulation), gives the ability to adjust the rotation speed on the fly without changing the input voltage delivered to the cooling fan

Pulse-width modulation (PWM) is a common method of controlling computer fans. A PWM-capable fan is usually connected to a 4-pin connector (pinout: Ground, +12V, sense, control). The sense pin is used to relay the rotation speed of the fan and the control pin is an open-drain or open-collector output, which requires a pull-up to 5V or 3.3V in the fan. Unlike linear voltage regulation, where the fan voltage is proportional to the speed, the fan is driven with a constant supply voltage; the speed control is performed by the fan based on the control signal.

The control signal is a square wave operating at 25 kHz, with the duty cycle determining the fan speed. Typically a fan can be driven between about 30% and 100% of the rated fan speed, using a signal with up to 100% duty cycle. The exact speed behaviour (linear, off until a threshold value, or a minimum speed until a threshold) at low control levels is manufacturer dependent.
http://en.wikipedia.org/wiki/Fan_control
 
I know now about pulse width modulation, I read up on it after I came up with a different theory which proved to be incorrect and then remembered it's existance :D.

I am unsure as to what the 5v pin is for in this instance, but it does look to me as though the 12v pin supports the older version of fan speed control, meaning that you can adjust the value in the BIOS, but it will not automatically adjust or anything fancy.

It remains a mystery... Never mind. :p

What did you have in your sandwich? ;)

OP you could control the fans in the same way Doyll does by connecting multiple to the CPU_FAN header, but it would rely on your existing fans being PWM. Otherwise we'll have to think of something else :)
 
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to use PWM control on your case fans you will need to use the PWM control in the CPU_fan socket.

Are you controlling the Noctua fans speed with the CPU_fan socket?
 
i'll have to double check tomorrow.

i know one of them is plugged into the CPU fan header.

in all honesty i didnt put this rig together, just know it needs a good clean out etc.

i believe the fans are NF p12's on the CPU cooler. i dont think they are pwm

EDIT: ive just checked, fans are NF p12's and only 3pin.

so i guess i could put PWM case fans into the CPU header, and use 3 pin fan headers for CPU fans ?
 
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That's a good guess. If they are just running at fixed speed you can plug them into other headers and use the CPU_fan header for the PWM fans and they will change speed with CPU heat.

Might need to go into Bios and change settings for PWM control to work. I use ET6 (Gigabyte EasyTune6) to control mine.

If you had 2 more PWM fans and another PWM splitter you could daisy chain the spitters together and control all fans with PWM.


Edit: need all fans to be similar rpm range
 
acme15 said:
I know now about pulse width modulation, I read up on it after I came up with a different theory which proved to be incorrect and then remembered it's existance .

What did you have in your sandwich? ;)

OP you could control the fans in the same way Doyll does by connecting multiple to the CPU_FAN header, but it would rely on your existing fans being PWM. Otherwise we'll have to think of something else :)
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Nice thick slice of honey smoked ham with fried egg and cheese with brown sauce on one side. :D

PWM is very interesting bit of technology. Has been used extensively on power tools for years as it doesn't burn up motors like lowering the voltage can and also makes it much easier to control the speed when load is applied.. like routers and drills, mills, etc.
 
I've ordered pwm fans specifically. As the Noctua fans for the cpu are only 3 pin ill put then on 3 pin fan headers. Run my pwm case fans off the cpu header.
 
doyll said:
Nice thick slice of honey smoked ham with fried egg and cheese with brown sauce on one side. :D

PWM is very interesting bit of technology. Has been used extensively on power tools for years as it doesn't burn up motors like lowering the voltage can and also makes it much easier to control the speed when load is applied.. like routers and drills, mills, etc.
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What a sandwich :D

Indeed it is, I honestly forgot ever learning/reading about PWM... I thought it was still done with variable resistors and other clunky methods :rolleyes:
 
bbbearrr said:
I've ordered pwm fans specifically. As the Noctua fans for the cpu are only 3 pin ill put then on 3 pin fan headers. Run my pwm case fans off the cpu header.
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Should work fine. If there's anything else I can help with just ask. Maybe I'll know.;)

acme15 said:
What a sandwich :D

Indeed it is, I honestly forgot ever learning/reading about PWM... I thought it was still done with variable resistors and other clunky methods :rolleyes:
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I'm a bespoke joiner by profession so have many power tools using similar PWM speed controls in them. Almost never have a problem with them. Cordless batteries go out and occasionally a switch or trigger on a drill.
 
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