PWM Fans Won't Turn Off

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iBeta2

Junior Member

Beiträge: 43

PWM Fans Won't Turn Off

Montag, 26. Dezember 2011, 20:00

Ok, I know this isn't the original thread (Asus Matrix GTX580 - PWM Fans Won't Turn Off) , but I was not allowed to post further there?!
[*]
'Sie sind nicht angemeldet' is the message.... well thankyou.
[*]
Anyway, thanks 'hrmes' , I had not heard of that, but it fits with what is happening. I can only think that PWM has problems controlling the fans at low rpm, ie they have to have 20%+ duty cycle to work properly.
[*]It would certainly explain what is happening.
[*]In light of all that, hrmes request in the original post ...' If fan channel 4 is in PWM mode and is given a fan speed value of 0 then turn off the 12V line. Could this be done Shoggy ? '
[*]is the only possible solution.
[*]2 other things:
[*]Shoggys reply indicated that he, unfortunately, hadn't understod the question.
[*]Hrmes idea ('Aquaero sets the +12V line to 0V when the lower limit reached') MUST be implemented by AC, at least if they want the PWM channel to be anything else than a marketing ploy.

hrmes

Junior Member

Beiträge: 26

Mittwoch, 28. Dezember 2011, 22:12

There is another thing you can do to stop PWM fans. You can modify the cable of the PWM fan to get the 12V power from another (analog) Aquaero fan channel and configure that fan channel to give 12V constantly except for the temperature range that you want the fan to stop. I must say though that I haven't tried that method before, it's just theory.

This also has the disadvantage that you "waste" a fan channel that could control one or more fans on it's own. The best solution must be the firmware update that I described earlier.

Can I ask if PWM fan control is otherwise accurate in your case ? For example does 50% speed in the fan channel translate to 50% fan RPM ?

iBeta2

Junior Member

Beiträge: 43

Freitag, 27. Januar 2012, 00:56

Well it's a hack alright, but don't see why it wouldn't work - not for me tho' 'cos I'm using all 4.

The PWM 50% rotation works fine for me, but only if the 'Minimum Fan Power' is set to zero in the Fans Tab Settings. For some reason a positive MFP here will cause a 2/3 percentage when it should be 1/2.

I agree, what is the point of a fan, specifically designed to save power at low rotations, that will not turn off?!? I thought it was an Asus 'safety feature' or something for their graphic card fan, but if it's universal then maybe there's a technical reason that makes PWM unreliable between 0-20%. But it cannot be unreliable at 0%, so it is really up to AC to cough up a firmware alteration that solves this - it could be made as an option at least.

Sorry about the late reply - never noticed.

kroks

Newbie

Beiträge: 3

Donnerstag, 18. Oktober 2012, 08:56

up

please update aquaero so we can turn off pwm fans at 0%

Shoggy

Sven - Admin