Control 2 fans as if they are 1?

I'm currently planning out my first PC build and have come to an unusual problem.

As part of my build I decided to include an LCD screen-type fan controller, [this one] (http://www.newegg.com/Product/Product.aspx?Item=N82E16811999218) to be precise.

My problem is that I'll also be getting a twin-fan liquid cooling system as my CPU cooler. I'll want to change the RPM of the fans via the controller so what's the best way to connect both fans to the controller, given that as far as the controller is concerned this is only one fan?

All help is appreciated, thanks.

Robert English

Posted 2013-10-13T22:54:22.827

Reputation: 222

I'm not sure that I get it. The controller panel you pointed out has 4 fan connectors, and each one can be controlled separately. OR I don't understand the issue you have with it – Nikola Dimitrijevic – 2013-10-13T23:01:52.837

2If you are trying to control both fans using the single controller channel, than you have to tweak your fan cables. Assuming that you have 3-pin connectors on your fans, each connector have the Red, Black and Yellow wire. Connect Red to Red and Black to Black wire between the fans, but not Yellow to Yellow. Now, connect one fan connector in controller, and you can control both fans using a single controller channel. Don't connect Yellow wires to each other as you may cause fan speed reading issues, since controller will have the problem if he get unsynchronized RPM signal over the single wire. – Nikola Dimitrijevic – 2013-10-13T23:26:57.810

1I am not sure, but if my head still serves me, you should be able to find 3-pin fan Y-type adapter cable for connecting two fans into single connector. But you have to cut the second Yellow wire on such cable in your case. – Nikola Dimitrijevic – 2013-10-13T23:28:43.603

Thank you. Your second comment is exactly what I was looking for. Please make it an answer to allow me to up-vote it. Sorry if the question was a little hard to read. Not sure how better to describe it. Feel free to edit for others to understand better. – Robert English – 2013-10-14T06:30:40.730

Answers

If you are trying to control both fans using the single controller channel, than you will have to tweak your fan cables. Assuming that you have 3-pin connectors on your fans, each connector has the Red, Black and Yellow wire. Connect Red to Red and Black to Black wire between the fans, but not Yellow to Yellow. Now, connect one fan connector in controller, and you can control both fans using a single controller channel. Don't connect Yellow wires to each other as you may cause fan speed reading issues, since the controller will have the problem to display correct fan RPM numbers if it gets an unsynchronyzed RPM signal over the single wire

However, you should be able to find the 3-pin Y-type adapter cable (fan cable adapter) for connecting two fans into a single connector. But you will have to cut the second Yellow wire (if exists) on such cable in your case.

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Nikola Dimitrijevic

Posted 2013-10-13T22:54:22.827

Reputation: 3 363

What should happen with the two yellow cables? – Robert English – 2013-10-14T19:49:21.387

1When you have both connected, RPM reading goes crazy. The rotor in each revolution causes an electrical pulse, which is sent on the sense pin. According to standard (or convention... i'm not sure), there are two pulses per revolution, generated using the Hall effect by taking advantage of the magnetic field involved with the rotor revolution. So If you get four pulses in irregular random time frames instead of two in regular time frames, your RPM sensor will read... well, who knows what... :) – Nikola Dimitrijevic – 2013-10-14T21:21:37.367

Thanks again. I've noticed there are quite a few with 4 pins. Though I'm trying to find fans with 3 pins. How would one go about doing this using 2 4-pin fans? – Robert English – 2013-10-15T19:51:03.333

This purely to prevent an unnecessary question for those looking for the same thing. – Robert English – 2013-10-16T07:48:44.250

Disregard the last blue wire on 4-pin connector in your case, since your controller have only 3-pin connectors. This wire won't have any influence in your case as it won't be connected anyway – Nikola Dimitrijevic – 2013-10-16T08:46:32.063