Fan Controllers and 3 pin fans - question about RPM display

[meggiedude]

Hiya,

Newbie to the game of extra cooling and OC.

I am added 2 extra sickleflow 120mm fans to my Cooler Master case. (which has MSI MB and i5 4670K).
Will be adding H80 Water Cooler later and fan controller before I look at OC.

Using google as my friend I have seen that some fan controllers can control the speed of three pin fans like my Sickleflows, but they can't report the rpm of the fans ?? - so you just get 0000 on the display??

Is this going to be the case if I get a fan controller for my unit, and also will it be able to report temp and RPM of the H80 cooler??

Ta.

MD

[flearider]

with a fan controller you go off temps and sound .. cupid hwmonitor is your friend ..

[meggiedude]

Excuse my ignorance here, but you've lost me a tad.
hwmonitor cupid is a s/w utility?? I don't want to to this in s/w.
I'd like to see the rpm's on the fan controller if that is possible, rather than 0000rpm

[flearider]

then buy some pwn 4 pin fans .. that will give you rpm .. you can do 3pin on some controllers or motherboards but his uses voltage up and down .. to adjust the speed
what I don't understand is why you need the rpm of the fan ? depending on the fan 1 could be 1000 rpm and the other could be 1500 rpm giving the same cooling .. ?
with a fan it's all to do with air flow (cmf)and air pressure and what noise you want to hear or not .. ?

[Pob255]

Ok lets start from scratch.

1 - rpm display on a fan controller will depend on the controller used, so can display rpm some don't
How well they display rpm depends partly on the fans.
A normal 3pin fan has 3 wires, one for ground one for +12v and one for TAC (which is the rpm signal, so it tells what ever it's plugged into what the rpm is)
A fan controller with RPM monitoring with a 3pin fan plugged into it should be able to read and display what the rpm is, if it just reads 0000rpm then there is an incompatibility with the fan or the controller or a fault in one or both.
A fan controller works by reducing the voltage to the fan, thus slowing it.

4pin PWM fans are the same and different, they can sill work in the same way as a 3pin fan, they still have ground, +12v and TAC, however they add in a 4th PWM signal wire.
What this means is that if they are plugged into something that can send a PWM signal (such as the 4pin cpu cooler header on the motherboard) They can control the fan's speed via this.
The way it works to to pulse an on/off signal to the fan to slow it down rather than reduce the voltage, the advantage of PWM over voltage reduction is in advanced software control and avoid issues from reduced voltage.
Depending on the fan most have a minimum voltage limit to start turning, around 5v, and a separate minimum running voltage, ie a fan might not start turning at 5v but once it is spinning 5v might well be enough to keep it spinning.
Other common problems is that some fan motors start to develop noises, ticking or buzzing, as you reduce the voltage.
The upshot of all this is that most PWM fans have a lower minimum speed than trying to reduce speed by voltage.

[meggiedude]

then buy some pwn 4 pin fans .. that will give you rpm .. you can do 3pin on some controllers or motherboards but his uses voltage up and down .. to adjust the speed
what I don't understand is why you need the rpm of the fan ? depending on the fan 1 could be 1000 rpm and the other could be 1500 rpm giving the same cooling .. ?
with a fan it's all to do with air flow (cmf)and air pressure and what noise you want to hear or not .. ?

I do understand what you are getting at, and am not necessarily disagreeing with you.
My point may be a superfluous one to some, but its a bit of a waste of a Fan controllers LCD display showing RPM, if all it displays is a row of 0000rpm where it should be displaying RPM. i.e it looks a bit naff.
If some 3 pin fans display the RPM on the controller but some don't then there should at least be some indication of this risk at point of sale.

I can't order a new set of 4pin fans dude - as I've just ordered the 3pin ones already (OK, out of ignorance). I haven't got the fan controller yet - hence the question.

[meggiedude]

Ok lets start from scratch.

1 - rpm display on a fan controller will depend on the controller used, so can display rpm some don't
How well they display rpm depends partly on the fans.
A normal 3pin fan has 3 wires, one for ground one for +12v and one for TAC (which is the rpm signal, so it tells what ever it's plugged into what the rpm is)
A fan controller with RPM monitoring with a 3pin fan plugged into it should be able to read and display what the rpm is, if it just reads 0000rpm then there is an incompatibility with the fan or the controller or a fault in one or both.
A fan controller works by reducing the voltage to the fan, thus slowing it.

4pin PWM fans are the same and different, they can sill work in the same way as a 3pin fan, they still have ground, +12v and TAC, however they add in a 4th PWM signal wire.
What this means is that if they are plugged into something that can send a PWM signal (such as the 4pin cpu cooler header on the motherboard) They can control the fan's speed via this.
The way it works to to pulse an on/off signal to the fan to slow it down rather than reduce the voltage, the advantage of PWM over voltage reduction is in advanced software control and avoid issues from reduced voltage.
Depending on the fan most have a minimum voltage limit to start turning, around 5v, and a separate minimum running voltage, ie a fan might not start turning at 5v but once it is spinning 5v might well be enough to keep it spinning.
Other common problems is that some fan motors start to develop noises, ticking or buzzing, as you reduce the voltage.
The upshot of all this is that most PWM fans have a lower minimum speed than trying to reduce speed by voltage.

Thanks for the explanation mate.

Checking out my MSI motherboard I have 2 x 4 pin headers for CPU fans (only using one at the moment). Pins are listed as 1) Ground, 2)12v, 3)Sense, 4) Speed Control
Also one 4 pin headers for Sys fan1 (unused until new fans arrive). Pins are listed as 1) Ground, 2)12v, 3)Sense, 4) NC
And two 3 pin headers for Sys fan 2&3 (both unused until new fans arrive). Pins are listed as 1) Ground, 2)12v, 3)No use

My current case fan currently takes power from the PSU - not from a header.

The two Fans I have on order are 3 pin Sickleflows.

[kalniel]

I'm not sure that flearider is quite understanding, hence the series of posts that don't seem to make sense. He would do well to read the post by Pob above and your original post again more carefully.

Pobs post is spot on - ignore the 4pin/3pin and software red herrings. If a fan controller can't read the signal line then it's at best not compatible with the fan signal, or at worst, either the controller or fan is broken. One way to test would be to use the motherboard fan headers first, and see if the RPM is correctly reported in the BIOS or a software monitor - that way you know your fans are OK. Then you can hook them up to the fan controller and see if the controller can pick up the RPM - if not, return it as faulty.

[meggiedude]

I'm not sure that flearider is quite understanding, hence the series of posts that don't seem to make sense. He would do well to read the post by Pob above and your original post again more carefully.

Pobs post is spot on - ignore the 4pin/3pin and software red herrings. If a fan controller can't read the signal line then it's at best not compatible with the fan signal, or at worst, either the controller or fan is broken. One way to test would be to use the motherboard fan headers first, and see if the RPM is correctly reported in the BIOS or a software monitor - that way you know your fans are OK. Then you can hook them up to the fan controller and see if the controller can pick up the RPM - if not, return it as faulty.

Thanks - appreciate the advice. Will try that.

[Pob255]

Well one bit from Flearider I would agree with is

what I don't understand is why you need the rpm of the fan ?

or more to the point a fan controller that reads the rpm.
Yes it's a nice additional feature, to be able to see what speed the fan is doing, but it's not really needed.
Really you only need to worry about two factors, speed setting high enough to cope with heat and speed setting low enough to make the fan "quiet"

In many way an RPM display is about as much use as strapping an Air flow meter and Sound level meter to your case.
They give you the actual numbers but unless you're doing actual testing/comparison of fans the numbers are not that important compared to the results.

What fan controller are you looking at getting?
If you're looking at up to 3 fans then my favourite is still the low cost Akasa AK-FC-06BKV2 about £12 http://www.scan.co.uk/products/35-ak...x-usb-20-ports (please note it says PWM compatible but it's just a voltage control not a PWM control) or AK-FC-06U3BK about £15 http://www.scan.co.uk/products/35-ak...2-usb-30-ports (again simple voltage control not actually PWM)
Both of these go in a 3.5" external slot (the floppy drive bay) and have additional USB front ports via a motherboard header (the AK-FC-06BKV2 is USB2, the AK-FC-06U3BK is USB3)

If you want more fans then you can use the Akasa AK-FC-08BKV2 http://www.scan.co.uk/products/akasa...shed-ali-panel or Zalman ZM-MFC1 Plus http://www.overclockers.co.uk/showpr...odid=BB-010-ZA basically the same thing but harder to find now as AFAIK they are no longer made.
Another alternative is the NZXT Sentry Mesh http://www.scan.co.uk/products/nzxt-...ller-525-black or Mix2 http://www.scan.co.uk/products/nzxt-...-525-bay-black basically the same but uses sliders rather than knobs

[kalniel]

It's bling.

Which looks silly if it's just displaying 000

[Ttaskmaster]

Is there any way to tell if a 3-pin fan will be compatible with a fan controller's RPM display?

[Pob255]

All fans should be as long as they are 3pin and same goes for fan controllers with readouts

The most probable reason it's not reporting the speed is that ether the fan or the controller is faulty.
Another reason that a controller could be reading 0 rpm, that is if the fan is stopped.
Again depends on the controller and the fan, but a fan has a minimum start voltage which is higher than it's minimum running voltage, so if you set a fan very low the voltage might be enough to keep it spinning, but the next time you turn your pc on the low voltage isn't enough to start up the fan.

What fan controller are you looking at?
I see your getting some coolermaster Sickleflow fans? if so one thing to be aware of on them, AFAIK, they actually report incorrect rpm.
It's some marketing, because it's a 9 bladed fan it must be the equivalent of a 7 bladed fan at a higher speed, right?, so they adjusted the tac signal to match.
That doesn't make it a bad fan, just not a 2000rpm fan, which would sound like you had put a vacuum cleaner inside your case, I think they are actually around 1700rpm.
However there's minimum start voltage is very low, around 3v which is lower than most fan controllers go.

Most fan controllers go between 5v minimum and 12v maximum, some also go to Off aka 0v but that's generally a hard cut off, so if the controller has settings 0 to 10, then 0 would be 0v, 1 would be 5v, 2 would be 5.7v, 3 would be 6.4v, etc to 10 being 12v

[meggiedude]

It's bling.

Which looks silly if it's just displaying 000

Unfortunately there is some truth in what you say
Well according to my 14 yr old anyway.
It will bling up an otherwise boring looking case.
Nothing wrong with a bit of strategic bling now and then.

[meggiedude]

All fans should be as long as they are 3pin and same goes for fan controllers with readouts

The most probable reason it's not reporting the speed is that ether the fan or the controller is faulty.
Another reason that a controller could be reading 0 rpm, that is if the fan is stopped.
Again depends on the controller and the fan, but a fan has a minimum start voltage which is higher than it's minimum running voltage, so if you set a fan very low the voltage might be enough to keep it spinning, but the next time you turn your pc on the low voltage isn't enough to start up the fan.

What fan controller are you looking at?
I see your getting some coolermaster Sickleflow fans? if so one thing to be aware of on them, AFAIK, they actually report incorrect rpm.
It's some marketing, because it's a 9 bladed fan it must be the equivalent of a 7 bladed fan at a higher speed, right?, so they adjusted the tac signal to match.
That doesn't make it a bad fan, just not a 2000rpm fan, which would sound like you had put a vacuum cleaner inside your case, I think they are actually around 1700rpm.
However there's minimum start voltage is very low, around 3v which is lower than most fan controllers go.

Most fan controllers go between 5v minimum and 12v maximum, some also go to Off aka 0v but that's generally a hard cut off, so if the controller has settings 0 to 10, then 0 would be 0v, 1 would be 5v, 2 would be 5.7v, 3 would be 6.4v, etc to 10 being 12v

OK - Thanks.

So, as you have seen I am looking at 2 new sickleflows to go with current Cooler Master case fan and (if its possible to at least report back on temp, if not rpm) a H80 Water cooler, ready for a bit of OC.
If purchasing at Scan then was originally looking at the NZXT Sentry 2 FC, but I understand they are not so good with LED's like the sickleflows.
Really looking at something mainly running in auto mode, with maybe the odd tweak. Don't really want to be tweaking manually all day or night.
PC will be used for heavy load overnight Handbrake batch conversion/encoding along with standard day-to-day stuff.
So the load will vary - hence the need for an auto mode.

[Pob255]

Ok most fan controllers will have some issues with LED fans, in that they work by reducing voltage, which will not just slow the fan but also dim the LEDs
How much the LED's dim will depend on how much the voltage is reduced, but all told I'd not worry too much about it.
The only way around that is to get fans with a separate feed for the LEDs, off hand the Bitfenix fans are the only fans that do that, although I think the NZXT fans also have it.

The way the auto mode works on most fan controllers is that they also have a temperature probe, basically a wire with a small flat sensor on the end, the controller will then adjust the fan speed based of the temperature sensor readings, so where you place it will effect the results.

The NZXT Sentry 2 uses 5 sensors, one for each fan and comes with thermal tape to stick them down with, the main down side of this system is that wires and cable management can get a bit messy with all the extra wires.

All told for what you want it's fine.