Monitoring Fan RPM

I plugged 2 of my case fans into the motherboard fan headers to monitor
their RPM. I'm thinking of installing a fan controller, namely the
Coolermaster Aerogate II. If I do that, software based fan monitoring
program will stop working (because the fans won't plug to the motherboard).

One way to solve the problem is to "redirect" the RPM feedback wires to the
motherboard (the 12V and ground wires still go to the fan controller), but
it won't work in this case because the Aerogate also needs the feedback
wires to display the RPM.

Can I split the feedback (yellow) wires into two? One goes to the Aerogate
(together with the 12V and GND), and the other one goes to the motherboard,
will it affect the accuracy of reported RPM? I know RPM detection is based
on the pulses per second, but I'm not sure if splitting the wire will weaken
the signal thus casuing a lower reported RPM?

"Peter" <> wrote in message
news:TwGqb.365$...
> I plugged 2 of my case fans into the motherboard fan headers to monitor
> their RPM. I'm thinking of installing a fan controller, namely the
> Coolermaster Aerogate II. If I do that, software based fan monitoring
> program will stop working (because the fans won't plug to the
motherboard).
>
> One way to solve the problem is to "redirect" the RPM feedback wires to
the
> motherboard (the 12V and ground wires still go to the fan controller), but
> it won't work in this case because the Aerogate also needs the feedback
> wires to display the RPM.
>
> Can I split the feedback (yellow) wires into two? One goes to the
Aerogate
> (together with the 12V and GND), and the other one goes to the
motherboard,
> will it affect the accuracy of reported RPM? I know RPM detection is
based
> on the pulses per second, but I'm not sure if splitting the wire will
weaken
> the signal thus casuing a lower reported RPM?



It should be fine, in fact 3 pin-to-4 pin adaptor leads which feature a
seperate RPM-monitoring cable are readily available:

http://tinyurl.com/u1au

"nightic" <> wrote in message
news:bofdbs$1c31k7$...
>
> "Peter" <> wrote in message
> news:TwGqb.365$...
> > I plugged 2 of my case fans into the motherboard fan headers to monitor
> > their RPM. I'm thinking of installing a fan controller, namely the
> > Coolermaster Aerogate II. If I do that, software based fan monitoring
> > program will stop working (because the fans won't plug to the
> motherboard).
> >
> > One way to solve the problem is to "redirect" the RPM feedback wires to
> the
> > motherboard (the 12V and ground wires still go to the fan controller),
but
> > it won't work in this case because the Aerogate also needs the feedback
> > wires to display the RPM.
> >
> > Can I split the feedback (yellow) wires into two? One goes to the
> Aerogate
> > (together with the 12V and GND), and the other one goes to the
> motherboard,
> > will it affect the accuracy of reported RPM? I know RPM detection is
> based
> > on the pulses per second, but I'm not sure if splitting the wire will
> weaken
> > the signal thus casuing a lower reported RPM?
>
>
>
> It should be fine, in fact 3 pin-to-4 pin adaptor leads which feature a
> seperate RPM-monitoring cable are readily available:
>
> http://tinyurl.com/u1au



Zalman themselves include the 3 pin-to-3 pin version of the above described
cable with their ZM-FC1 fan controller but I am unsure as to where you can
buy these leads seperately:

http://tinyurl.com/u1b9

"nightic" <> wrote in message
news:bofdrs$1drddj$...
>
> "nightic" <> wrote in message
> news:bofdbs$1c31k7$...
> >
> > "Peter" <> wrote in message
> > news:TwGqb.365$...
> > > I plugged 2 of my case fans into the motherboard fan headers to
monitor
> > > their RPM. I'm thinking of installing a fan controller, namely the
> > > Coolermaster Aerogate II. If I do that, software based fan monitoring
> > > program will stop working (because the fans won't plug to the
> > motherboard).
> > >
> > > One way to solve the problem is to "redirect" the RPM feedback wires
to
> > the
> > > motherboard (the 12V and ground wires still go to the fan controller),
> but
> > > it won't work in this case because the Aerogate also needs the
feedback
> > > wires to display the RPM.
> > >
> > > Can I split the feedback (yellow) wires into two? One goes to the
> > Aerogate
> > > (together with the 12V and GND), and the other one goes to the
> > motherboard,
> > > will it affect the accuracy of reported RPM? I know RPM detection is
> > based
> > > on the pulses per second, but I'm not sure if splitting the wire will
> > weaken
> > > the signal thus casuing a lower reported RPM?
> >
> >
> >
> > It should be fine, in fact 3 pin-to-4 pin adaptor leads which feature a
> > seperate RPM-monitoring cable are readily available:
> >
> > http://tinyurl.com/u1au
>
>
>
> Zalman themselves include the 3 pin-to-3 pin version of the above
described
> cable with their ZM-FC1 fan controller but I am unsure as to where you can
> buy these leads seperately:
>
> http://tinyurl.com/u1b9


Typo:
I mean "ZM-MFC1 fan controller...".

Thanks. I know where to get fan headers and pins, so I can solder my own
wires, that's not a problem.

However, the Zalman scenario is different than mine. The ZM-MFC1 only
controls the voltage to adjust the fan speed, it doesn't monitor the RPM, so
there's nothing behind the "feedback" pin on the faceplate, it simply
re-route the feedback wire to the motherboard.

The Coolermaster Aerogate II that I'm interested in has both functions - fan
speed adjustment and RPM display - therefore, it actually reads the pulses
coming from the feedback wire. My concern is that if I "intercept" the
feedback and wire it to the motherboard, now there're two places reading the
pulses: 1) Areogate, and 2) motherboard, would that weaken the signals and
causing incorrect RPM readings?

For each turn (revolution) that the fan makes, the magnetic field changes
twice and produces two pulses, RPM sensing devices are basically pulse
sensors that detect number of pulses per second (Hz). If the fan produces
100 pulses per second, it means it has turn 50 times (100 divided by 2),
which is equivalent to 3000 RPM (50 times 60).

I don't know what will happen if I connect the fan's feedback wire to two
RPM sensors (Aerogate and motherboard) and that's why I'm posting this.


"nightic" <> wrote in message
news:bofdvh$1donp9$...
>
> "nightic" <> wrote in message
> news:bofdrs$1drddj$...
> >
> > "nightic" <> wrote in message
> > news:bofdbs$1c31k7$...
> > >
> > > "Peter" <> wrote in message
> > > news:TwGqb.365$...
> > > > I plugged 2 of my case fans into the motherboard fan headers to
> monitor
> > > > their RPM. I'm thinking of installing a fan controller, namely the
> > > > Coolermaster Aerogate II. If I do that, software based fan
monitoring
> > > > program will stop working (because the fans won't plug to the
> > > motherboard).
> > > >
> > > > One way to solve the problem is to "redirect" the RPM feedback wires
> to
> > > the
> > > > motherboard (the 12V and ground wires still go to the fan
controller),
> > but
> > > > it won't work in this case because the Aerogate also needs the
> feedback
> > > > wires to display the RPM.
> > > >
> > > > Can I split the feedback (yellow) wires into two? One goes to the
> > > Aerogate
> > > > (together with the 12V and GND), and the other one goes to the
> > > motherboard,
> > > > will it affect the accuracy of reported RPM? I know RPM detection
is
> > > based
> > > > on the pulses per second, but I'm not sure if splitting the wire
will
> > > weaken
> > > > the signal thus casuing a lower reported RPM?
> > >
> > >
> > >
> > > It should be fine, in fact 3 pin-to-4 pin adaptor leads which feature
a
> > > seperate RPM-monitoring cable are readily available:
> > >
> > > http://tinyurl.com/u1au
> >
> >
> >
> > Zalman themselves include the 3 pin-to-3 pin version of the above
> described
> > cable with their ZM-FC1 fan controller but I am unsure as to where you
can
> > buy these leads seperately:
> >
> > http://tinyurl.com/u1b9
>
>
> Typo:
> I mean "ZM-MFC1 fan controller...".
>
>

"Peter" <> wrote in message
news:gUIqb.549$...
> Thanks. I know where to get fan headers and pins, so I can solder my own
> wires, that's not a problem.
>
> However, the Zalman scenario is different than mine. The ZM-MFC1 only
> controls the voltage to adjust the fan speed, it doesn't monitor the RPM,
so
> there's nothing behind the "feedback" pin on the faceplate, it simply
> re-route the feedback wire to the motherboard.
>
> The Coolermaster Aerogate II that I'm interested in has both functions -
fan
> speed adjustment and RPM display - therefore, it actually reads the pulses
> coming from the feedback wire. My concern is that if I "intercept" the
> feedback and wire it to the motherboard, now there're two places reading
the
> pulses: 1) Areogate, and 2) motherboard, would that weaken the signals and
> causing incorrect RPM readings?
>
> For each turn (revolution) that the fan makes, the magnetic field changes
> twice and produces two pulses, RPM sensing devices are basically pulse
> sensors that detect number of pulses per second (Hz). If the fan produces
> 100 pulses per second, it means it has turn 50 times (100 divided by 2),
> which is equivalent to 3000 RPM (50 times 60).
>
> I don't know what will happen if I connect the fan's feedback wire to two
> RPM sensors (Aerogate and motherboard) and that's why I'm posting this.


That'll teach me to only skim posts before replying - d'oh!

Peter wrote:
> Thanks. I know where to get fan headers and pins, so I can solder my
> own wires, that's not a problem.
>
> However, the Zalman scenario is different than mine. The ZM-MFC1 only
> controls the voltage to adjust the fan speed, it doesn't monitor the
> RPM, so there's nothing behind the "feedback" pin on the faceplate,
> it simply re-route the feedback wire to the motherboard.
>
> The Coolermaster Aerogate II that I'm interested in has both
> functions - fan speed adjustment and RPM display - therefore, it
> actually reads the pulses coming from the feedback wire. My concern
> is that if I "intercept" the feedback and wire it to the motherboard,
> now there're two places reading the pulses: 1) Areogate, and 2)
> motherboard, would that weaken the signals and causing incorrect RPM
> readings?
>
> For each turn (revolution) that the fan makes, the magnetic field
> changes twice and produces two pulses, RPM sensing devices are
> basically pulse sensors that detect number of pulses per second (Hz).
> If the fan produces 100 pulses per second, it means it has turn 50
> times (100 divided by 2), which is equivalent to 3000 RPM (50 times
> 60).
>
> I don't know what will happen if I connect the fan's feedback wire to
> two RPM sensors (Aerogate and motherboard) and that's why I'm posting
> this.

Umm, can't tell you categorically but I'm sure it will be fine.
--
~misfit~

Peter wrote:
[...]
> I'm thinking of installing a fan controller,
> namely the Coolermaster Aerogate II. If I do that, software based
> fan monitoring program will stop working (because the fans won't plug
> to the motherboard).
[...]
> Can I split the feedback (yellow) wires into two? One goes to the
> Aerogate (together with the 12V and GND), and the other one goes to
> the motherboard, will it affect the accuracy of reported RPM? I know
> RPM detection is based on the pulses per second, but I'm not sure if
> splitting the wire will weaken the signal thus casuing a lower
> reported RPM?

Unless your measurement circuit draws enough current to smoke the wires in
the fan, you should be fine.

--
Michael Brown
www.emboss.co.nz : OOS/RSI software and more
Add michael@ to emboss.co.nz - My inbox is always open

It didn't work. Splitting the RPM feedback (yellow) wire into two (one goes
to the motherboard, the other goes to the Aerogate II), the motherboard
reports the RPM correctly, however, Aerogate failed to detect the RPM.
Aerogate starts to report the correct RPM once the other wire is unplugged
from the motherboard.

I don't understand why, but that's how it turned out to be.


"Peter" <> wrote in message
news:TwGqb.365$...
> I plugged 2 of my case fans into the motherboard fan headers to monitor
> their RPM. I'm thinking of installing a fan controller, namely the
> Coolermaster Aerogate II. If I do that, software based fan monitoring
> program will stop working (because the fans won't plug to the
motherboard).
>
> One way to solve the problem is to "redirect" the RPM feedback wires to
the
> motherboard (the 12V and ground wires still go to the fan controller), but
> it won't work in this case because the Aerogate also needs the feedback
> wires to display the RPM.
>
> Can I split the feedback (yellow) wires into two? One goes to the
Aerogate
> (together with the 12V and GND), and the other one goes to the
motherboard,
> will it affect the accuracy of reported RPM? I know RPM detection is
based
> on the pulses per second, but I'm not sure if splitting the wire will
weaken
> the signal thus casuing a lower reported RPM?
>
>

On Wed, 12 Nov 2003 23:04:21 GMT, "Peter" <> wrote:

>It didn't work. Splitting the RPM feedback (yellow) wire into two (one goes
>to the motherboard, the other goes to the Aerogate II), the motherboard
>reports the RPM correctly, however, Aerogate failed to detect the RPM.
>Aerogate starts to report the correct RPM once the other wire is unplugged
>from the motherboard.
>
>I don't understand why, but that's how it turned out to be.

try this: RPM sensing:

FAN ---i--->I------ MoBo
rpm I
I---->I ----- Aerogate

(separate the tacho wire with 2 diodes
>I (anode-cathode/marked!)

-- Regards, SPAJKY
& visit site - http://www.spajky.vze.com
Celly-III OC-ed,"Tualatin on BX-Slot1-MoBo!"
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