Please help me with the wiring(Mosfet, resistors) to control a systemair K 200 EC fan with a esp32. FanInput: 0-10VDC,pwm

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1

I am new to electronics, and just read 5 hours about that topic, and everybody is giving confusing and different solutions. Resistors, fly-back diode etc.
Just wanna not risk my Systemair K 200 EC fan.
So I hope to get some final help here.

Is the systemair controlled via 0-10V, or a pwm signal, or can it do both?
It is labelled:

ControlInput: 0-10 VDC/PWM

The docs are pretty good, with interactive charts and stuff, but very little info regarding the pwm.

Only these two pictures: Ausgang = exit

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Here is the link to the fan, if it is needed:
K Rohrventilatoren · Systemair
K 200 EC sileo.

Also regarding the resistors and flyback diode.
Everybody has different info. Even AIs can't seem to agree.

The esp32 gets power via usb, or a little thingy for breadboards, that can give me 3.3V or 5V.
The systemair is obviously 230V.
It is stated to remove the little potentiometer- plate(also in the picture), when controlling externally.

I have bought several MOSFET IRLB8721 for that also I have:

  • SN2222 Transistor.
  • IC4N35
  • IC74HC595
  • capacitators
  • resistors
  • 1N4007 Diode

From what I understand so far, we need at least two resistors. 1 x10k and a 1x 1k-2k. Some even said 333ohm instead of 1k-2k. And probably a diode. And my 4N35 (Optocoupler) COULD be added for extra safety.

But lets focus on a basic minimum setup first, so I can built from there on.
I hope someone with good knowledge could be so kind. I saw many videos, that did it wrong, and so difficult as newbie to navigate. :face_with_peeking_eye: :crazy_face:

2

I get it that you think you are not a complete novice, but generally, studying electricity and electronics is measured in years. Your confusion comes from lack of knowledge. If you see something confusing, further research the subject until the confusion about resistors, fly-back diode etc. is gone.

"AI" has zero knowledge, is know to be misleading, or completely incorrect.

You should start with something more in line with "5 hours" of study, not 230VAC.

1 Like
3

Well you clearly are not here to help. And you "I get that you think..."...what? ok.
The breakout board of the fan has NO 230V. 10mA Max. But you clearly saw that with your years of experience. And your rant about AI is emotional and not based on logic. "AI" has no knowledge,...not sure if you meant "reason", but obviously it makes no sense to argue with you.

4

I agree. After five hours, keep studying, call an electrician for HV, and "AI" has no knowledge.

2 Likes
5

Why you want to make such a circuits if you are not comfortable doing it?
There are pwm to 0-10V converters around.
Cheap AE example:
aliexpress.com/item/1005003768480689.html

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Why start a new thread?

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And for others, I never said my electronics knowledge is 5 hours, just how to wire the whole thing. Yesterday I spent 12 hours alone, on deciding on the right mosfet.
But the main thing is, what kind of signal the systemair really takes.
I tried to find all posts with the systemair, and I THINK it is 0-10VDC, or a pwm with 10V.
Nowhere is mentioned, what the pwm signals voltage is, but since the breakout board of the control module has a 10v output, the pwm signal is probably 10V pwm.
again the only info is: (The two pictures)
InputControlsignal: 0-10 VDC /PWM

So I understand, if you don't wanna give a full scematic, but maybe someone can point me the direction?

Many sources say a mosfet only with 2 resistors is fine. Mine is not the best, could get a bit warm, but I will test it.(I have active cooling in my electronic box)

But one post talking about the systemair in specific, mentioned a optocoupler approach and a 420ohm resistor. I think this confirms the 10V pwm signal right?
The optocoupler approach then seems valid right?
I am on the right track?

8

I found them in my research as well. But isn't PURE pwm control, not 0-10VDC the better choice? At least that rule is said with pc case fans.

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Hi ledsyn.
Well this thread was more about "Which mosfet for the job", and this one, how to make the control. Basically a new problem.

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Pc-fans regulate speed with PWM, not 0-10V.

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I think the thread was about the whole project, but ye ye.

I also think I gave you enough info in the last post in that thread how to wire a mosfet to the fans terminal block, no?

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I am talking about pwm here the whole time. The systemair can have 0-10VDC OR PWM(suspected 10V)!

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Then give it PWM. I expect that the circuit reads logic level PWM or analog 0-10V.
10V PWM just doesn't make any sense to me...
But I can't say it's impossible it wants that.

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Yes you did say it.
But I was not "ready" to test it, or at least research a bit more, before trying anything. And since finding many contradicting solutions, and also WRONG Videos on YT(A blessing I realized with my 0 knowledge at all), I am cautious.
Was ready to test it with a 3pin pc fan, but realized it's different then the systemair.
So I try to get that one right.

Their was a german post, that mentioned systemair.
And he said optocoupler works best, because of a 100% problem.
Too bad I can't see the pictures. Need to register.

Until now, this seems the best source to try out, if nothing else arises here.
I dont have PC817, but IC4N35, should also work as I heard?
Here is all the stuff I have:

  • IRLB8721
  • SN2222 Transistor.
  • IC4N35
  • IC74HC595
  • capacitators
  • resistors
  • 1N4007 Diode

Also one problem for me: He said:
"This also works with EC fans!"
WITHOUT CHANGING OR ADDING ANYTHING?(maybe a little resistor not mentioned or something)

I have translated it to english:

Here's a translation of the German forum post about dimming with PWM, Arduino/Raspberry Pi, PCA9685, and optocouplers:

Dimming via PWM (Raspberry Pi, Arduino, PCA9685, etc.) and Optocoupler

In the following, I assume that you have already generated a PWM signal (3.3V or 5V) with a frequency of 1kHz using your microcontroller (MC) and now want to pass this on to your Mean Well constant current source.

This also works with EC fans!
You only need an optocoupler (PC817) and a resistor*.

Connection (see Fig. 1 and Fig. 2):

  1. The corresponding PWM pin of the MC is connected to the anode of the PC817 (pin 1) through the resistor*.

  2. The cathode of the PC817 (pin 2) is connected to the GND of the Raspberry Pi/Arduino.

  3. The collector (pin 4) is connected to DIM+ of the Mean Well constant current source / for Systemair EC fans 10V (connection 4 / red).

  4. The emitter (pin 3) is connected to DIM- of the Mean Well constant current source / for Systemair EC fans control channel (connection 3 / yellow).

pc817.PNG
Fig. 1: Connections and internal structure of the PC817

Untitled Diagram.png
Fig. 2: Connected PC817 (left MC, right constant current source)

*IMPORTANT: Instead of the 1kOhm resistor shown in Fig. 2, a 420± Ohm (Raspberry Pi/3.3V) or a 760± Ohm (Arduino/5.0V) resistor must be used so that approximately 5mA reaches the PC817 and it switches cleanly. The limited control range I previously observed could be attributed to the incorrect choice of resistor. Now, both an HLG constant current source and an EC fan can be dimmed over the entire control range.

Finished!

Notes:
When using a 2N2222 transistor, I noticed that the maximum light intensity was not reached despite a 0% duty cycle. This manifested as a slight increase in intensity when manually disconnecting DIM+ and the transistor. This phenomenon no longer occurs with the above-mentioned variant using an optocoupler. The cost of both variants is about one euro (excluding shipping).

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see my last post, I think it IS 10V pwm, according to the german post.

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Feel free to think what you want.
In that case pin4 on your image needs to give 10V PWM output.
But if you use potentiometer and set it to middle way, it would give 5V PWM to pin 3...
So?

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It depends on what receiving electronic there is inside also. And that pot is to be removed when external control is connected.

@quantummagic You have the last post in your previous thread, I'm not going to repeat that here. As for how to wire the MOSFET to your MCU, I'll leave you to fetch that info elsewhere.

18

Not also. It depends on receiving electronics.
I expect circuit that is for analog 0-10V, but might accept "pseudo analog" produced with PWM. That's not PWM sensing circuit that reads duty cycle.
Of course there could be some super sophisticated circuit that can read PWM duty cycle and in case of static voltage level, read it as analog voltage.
But I'm quite confident that here's not a circuit that accepts only 10V PWM.

19

ok Kim, I just tested what you said before and measured the poti.

  1. White/Tachometer
  2. Blue/Ground
    3.Yellow/control Signal 0-10V
    4.Red/10V

Of course it is as you said:
Left/right is ground/power, middle is Control 0-10V rising linearly, with poti setting.

I heard with pc-pwm fans, true PWM is more efficient, but since most industrial fans use 0-10V as I heard, it's probably better to use 0-10V directly, and NO pwm signal at all?

So the octocoupler method is not the optimal approach? Since the fan internally uses the 0-10V method probably.
But the german post said, it's the best method.

Ledsyn, did not use any resistor, so I was sceptical, or maybe he assumed I know that.
But this is basically the PWM method, with constant 10V?
So not optimal?
Also later in the german thread, someone said his big climate fan(similar to mine) is DIRECTLY driven by the 3.3V logic. He said you dont need 10V.

So what approach is generally the best now?
Sorry for not just trying blindly the first solution.
I wanna be extra safe. esp32 can get damaged, or the mosfets, but the systemair not. :see_no_evil: :face_with_peeking_eye:

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yes you are correct, see my last post please.