PLC PWM Fan Hub??? HELP!

[Jorogumo4]

Hello everyone,

I'm in need of some big boy help. I have built a dual system inside of the Phanteks Enthoo Mini XL DS. I've been building this for a while now. Though I have a downfall that I'm trying to resolve. It started when I found out the fan hub in the back of this case is a 3 pin. So I get no PWM controls. Which is making my fans run at like 60-70% pretty much all the time. It's loud and annoying. However here's my hick up. I cannot just go out and buy a fan controller, because I need to hook up BOTH systems to this. Your standard fan controller won't be able to read both PWM signals. So I think I've come up with a solution but I'm not sure how to execute.

I pretty much need to program a PLC to read both systems temperatures, select the highest temperature, send that signal to a PWM fan header and tell the fans what speed to run at. Basically I want to have my cake and eat it too. I need to find a way to have my case fans run on a temperature curve regardless of which OR both systems are on.

Any ideas? Any tips?

 

 

(Second system isn't hooked up yet, GPU is in the mail, once it's here the bottom system will be plugged up and running as well.)
(I can run each system independently)

[dj_ripcord]

I'd say a full-blown PLC with PWM control is a little overkill, but definitely the right track.

 

You say you don't want a hub, but the Corsair Fan Commander actually does exactly what you need. Has 3 temperature inputs. I would place a thermistor in the center, between the two systems so you have an average reading. Then I would place one near system A and one near system B. Then you can control fan curves via corsair's software (assuming the controller is actually PROGRAMMED and doesn't rely on the software to be running.) Maybe research that. See if that's an issue.

 

OR you can grab one of these and it should do the trick! As long as it has power from the PSU! Which, most PSU's have at least one 12v rail thats active at all times. Might have to do some soldering for that. Or buy a 12v power brick with at least 2A of current handling depending on how many fans you have.

[Jorogumo4]

3 minutes ago, dj_ripcord said:

Corsair Fan Commander actually does exactly what you need. Has 3 temperature inputs.

So my concern is the temp probes. I really want to avoid the temp probes and get direct temp reads from the motherboard. 

The 3 "Temp" headers on the Commander, can I just plug my CPU FAN header to that?
System 1 goes CPU FAN to TEMP 1
System 2 goes CPU FAN to TEMP 2.
Then I plug my fans up accordingly to the controller?

[dj_ripcord]

Just now, Jorogumo4 said:

So my concern is the temp probes. I really want to avoid the temp probes and get direct temp reads from the motherboard. 

The 3 "Temp" headers on the Commander, can I just plug my CPU FAN header to that?
System 1 goes CPU FAN to TEMP 1
System 2 goes CPU FAN to TEMP 2.
Then I plug my fans up accordingly to the controller?

That's a negative. Those temp ports are not gonna like to take any voltage input. The thermistors are literally a Thermal-Resistor. The temp ports are looking for a change in resistance, not voltage like the fan header will give you.

 

Either way, with your original PLC idea, you'd definitely need thermistors.

 

I wouldn't be so worried about them. Your PC is black, they're very easy to hide.

[Jorogumo4]

Just now, dj_ripcord said:

That's a negative. Those temp ports are not gonna like to take any voltage input. The thermistors are literally a Thermal-Resistor. The temp ports are looking for a change in resistance, not voltage like the fan header will give you.

 

Either way, with your original PLC idea, you'd definitely need thermistors.

 

I wouldn't be so worried about them. Your PC is black, they're very easy to hide.

Yeah I was just in the middle of typing this before your response.

"Looking at it closer it's not actual fan headers on that TEMP header huh? Wouldn't I lose PWM control then? I supposed this is where my struggle is. I want temp readings from BOTH systems, and I want PWM control on all fans regardless of which system is on."

Lol. But yeah. Looks like I may need to do a PLC. Of which I have NO idea how to do this. I've looked at a few online but I have no idea what to get or how to program it or how to wire this stuff. Hahaha.

[dj_ripcord]

1 minute ago, Jorogumo4 said:

Yeah I was just in the middle of typing this before your response.

"Looking at it closer it's not actual fan headers on that TEMP header huh? Wouldn't I lose PWM control then? I supposed this is where my struggle is. I want temp readings from BOTH systems, and I want PWM control on all fans regardless of which system is on."

Lol. But yeah. Looks like I may need to do a PLC. Of which I have NO idea how to do this. I've looked at a few online but I have no idea what to get or how to program it or how to wire this stuff. Hahaha.

Well that second thing I sent you is essentially a PLC. Albeit a really basic one.

 

PLC's just take input, do some math based on what you programmed, and spits out an output. In the case of that fan controller I linked, it's essentially a PLC that was designed to do one thing and one thing only. control fan speed based on temp.

[Jorogumo4]

8 minutes ago, dj_ripcord said:

Well that second thing I sent you is essentially a PLC. Albeit a really basic one.

So... Would I hook these two ports to CPU FAN on the motherboard? Sorry if my questions seem a bit dumb. I'm really not knowledgeable when it comes to this stuff. Haha. Though I am reading up and trying to understand this little tiny device. And run a power and ground to the 12v?

[dj_ripcord]

mmmm, that phrasing is a little confusing. The white plugs at the top are for the actual fans. DO NOT connect these to the motherboard headers. port on bottom center is for the temp probe. Other than that, feed it 12v and ground and it will work..... But I just thought of something. Since it needs power at all times, whether one system is on or the other, that means the fans COULD run 100% of the time, even when both systems are off. I don't know enough about this controller to confirm that, but id hope that they have a function to completely turn them off when the temp is low enough. Can't be sure without reading the manual.

 

ALSO, keep in mind that your case is metal..... and this device has metal pins exposed on the bottom. So, DON'T LET IT TOUCH THE CASE!! Put some duct tape on the bottom or something...

[Jorogumo4]

@dj_ripcord Hmm.. Yeah that little guy is still going against what I want then.

I don't want to use temp probes because I want to get accurate CPU temps from the motherboards. I need to plug up both systems into a controller that can then take both readings and choose the higher temp reading. Once the higher temp reading is established, it acts like a normal fan controller. Giving more voltage to the fans the hotter the system gets. 

I want this to work when either system is on. Can be one or the other.
But I also want the fans to turn off when the system does.

I don't want 24/7 fans.
I don't want to manually control the fan speed.
I want PWM functionality over a temp fan curve.

I want both systems to be able to utilize this without frying anything.

Like I said, I want to have my cake and eat it too. Hahaha.

[dj_ripcord]

Just now, Jorogumo4 said:

@dj_ripcord Hmm.. Yeah that little guy is still going against what I want then.

I don't want to use temp probes because I want to get accurate CPU temps from the motherboards. I need to plug up both systems into a controller that can then take both readings and choose the higher temp reading. Once the higher temp reading is established, it acts like a normal fan controller. Giving more voltage to the fans the hotter the system gets. 

I want this to work when either system is on. Can be one or the other.
But I also want the fans to turn off when the system does.

I don't want 24/7 fans.
I don't want to manually control the fan speed.
I want PWM functionality over a temp fan curve.

I want both systems to be able to utilize this without frying anything.

Like I said, I want to have my cake and eat it too. Hahaha.

Then I don't think you have any feasible options in front of you....

 

Consumer-use motherboards do not have any kind of output of the onboard temp sensors besides the ones that are readable within the software.

 

The only kind of data you can get from the motherboards is the voltage seen at the PWM headers. You could have a microcontroller, such as an Arduino programmed to sense these voltages (or the actual PWM) signal and then pass that information onto the fans. But you still won't have direct temperature control without some kind of software running like SpeedFan to allow you to set the PWM curve. The Arduino would need to be programmed in such a way that the highest PWM value takes precedence, and if there is no value detected, to also shut the fans off. That's kinda easy from my perspective but probably difficult for you considering how you said earlier you are new to electronics...

 

If that's still too much, maybe buy a lot of fans, connect half to one board and half to the other?

 

Thats the best I got...

[Jorogumo4]

15 hours ago, James Evens said:

Do you have programming knowledge?

I can tell you using a atmel 328p (arduino uno) is a bad idea (used them since i wanted to get rid of my arduino nano collection). Better use a STM32 or STM8 which has enough hardware PWM pins.

Programming is very simple: the STM already support detecting PWM signals and generating the PWM signal. You only need to add some hysteresis which can be simple as two if statements.

 

Yeah I was looking into this
https://www.st.com/en/evaluation-tools/stm32f0discovery.html

But I have NO programming knowledge and have no idea how I'd get this to work with what I want.

[Jorogumo4]

@dj_ripcord - The only fesiable option for me at this point really is a PLC. Which requires me to learn how to do programming XD 

[Jorogumo4]

So I kinda got it figured out here.

It clicked in my head that I don't need the PLC to handle temp readings at all. The motherboard can do this. The motherboard reads the temp and tells the PWM header a signal, and how fast it wants the fans to speed (by a certain voltage)

Basically.
System 1 tells the PLC what voltage it wants the fans to spin at.
System 2 tells the PLC what voltage it wants the fans to spin at.
It's going to be the PLC's job to take both these values, figure out which value is higher.
Pass the higher value to a Fan Hub. And then all 3 fans will be plugged into this fan hub.

[Jorogumo4]

@James Evens
So this is a terrible diagram but I imagine this is kind of what I want right? 

Which STM would you recommend for this purpose?
What's the best way to hook the STM up to my motherboard fan headers so that it gets the readings?
What's the best way to hook the STM up to a fan header so that I can run multiple fans?

[Jorogumo4]

1 hour ago, James Evens said:

STM32F030F4P6 board is also enough for this task.

That's ironic. Haha. I was just looking at that one.
SMAKN Utility Arduino STM32F030F4P6

 

How exactly would I run all 3 of my system fans on this though? I have no problem with them all spinning at the same speed. As long as it's appropriate to what the motherboard is telling them to do so that it's not stupid loud at idle. 

Here are the fans I plan on buying as well for my case.
https://www.bequiet.com/en/casefans/718

[Jorogumo4]

@James Evens
Also, will this work with either 3 pin or 4 pin fans? Or does it have to be a 4 pin fan?

[Jorogumo4]

@James Evens
So. I buy the STM32L100C-DISCO.
And I buy my three x 4pin pwm fans.
What else do I need to make this work? Obviously I'm gonna have to do my homework on wiring it up and programming it, but having trouble figuring out what exactly I'm going to need. So that I can sit down, do my homework, and hook it all up.