Help - Setting up a Fanbus to use w/ MX2 or MX5??

[anitract]

I am wondering if this is possible, as it is something I really want to do! If it is I will be getting LCDs for 3-5 computers. I tried posting on another forum with little results...so I decided to consult the real experts.

Situation:
I want to use a Sunbeam Rheobus to controll the speed of 4 case fans. I then want to use an MX2 or MX5 to just display the RPMs (i.e. not controll the speeds as that would be done by the fanbus). Is this possible?

My Solution(?):
Here is what I thought might work...connect my fans to the fanbus controller, then use RPM pass-throughs to send just the RPM lines of the fans to the MX2/MX5. Here is a description of what the RPM pass-through does if you don't know.

Does this sound like it would work? If not, how can I accomplish what I want to do? Thanks!

Edit: Looking closer at the fanbus, it uses 3-pin fan headers. The link I gave for the RPM pass-through uses molex, so I'd either have to use a molex-to-3pin adapter, or find a diff. cable....nevertheless, my questions still stand.

[Paradigm]

The MX series will do this no problem, with one catch. Your RPM pass-through cable only passes the RPM wire. It should work, but there is a chance that you could get some noise on that line without a good ground connection. If you can, get a cable that does both RPM and ground to a 3 pin connector. Other than that, our RPM sensing doesn't care if you use the speed control.

[anitract]

Excellent. That is exactly what I wanted to know. I am getting excited to do this already! One other quick question I'll throw out there: anyone know where one could purchase a custom cable like paradigm just suggested? I'm not so great with wiring and such...

*Off to buy LCD displays *

[anitract]

Would this work? Take a regular 3-pin extension cable and disconnect the RPM wire from the end, then put a 3-pin head on that wire...thus making a cable w/ 2 ends..one with just the RMP passthrough, and the other w/ the other 2 wires.

It sounds easy enough in theory...even for someone who knows next to nothing about electronics wiring.

Making one with the ground passing through to two ends as was suggested by paradigm sounds harder. Can this be done?

If either of these methods are easy enough I'll just do the mod myself.

[Paradigm]

Sorry for the tall order. If you have any soldering skills it would be easy to construct a cable yourself. Grab one of those extension cables, along with whatever plug you need to fit into your rheobus. Then chop the extension cable in half EXCEPT for the yellow wire. You have three plugs with bare wires on the other end now. Now make the following connections

1) Wire ALL the grounds together. It's usually the black wire. On the 3 pin connectors if you look at the end with the key at the top, it is the leftmost wire. On 4 pin connectors, it is the middle two.

2) Now wire the 12V line from the plug where the fan will plug into, to the plug that will go to your baybus. The 12V line in 3 pin plugs is dead center, for 4 pins it is the yellow wire.

3) Trim down what would have been the 12V line that is now going to the display as you don't need it any more.

If you're having a difficult figuring out what I'm talking about, let me know and I'll see if I can get the time to make/post a pretty picture.

One more note: While I suggested that you pass the ground to the display too, it's only a suggestion. If you keep your wires fairly short, it might not make a difference. If you can, I reccommend it, otherwise, give it a shot without and see if it works. You won't physically damage anything if you don't. All that will happen is that your RPM measurements will be very irratic.

[anitract]

Wow, thanks for the walkthrough. The support around this place is nothin short of amazing! I THINK I understand what you are talking about...but if you have spare time to make a pretty picture please feel free to do so!

Once the extension cables come that I ordered, I'll try w/out the ground and see if that works.