PWM fan control not working
Hello how I've been trying to figure out how to add PWM control to a fan.
Currently the fan never turns off and only seems to accelerate to a max setpoint of 40% anything higher doesn't seem to make a difference.
I've tried every step on the os.ratrig.com/docs/guides/4028 but nothing seems to make a difference.
Octopus 1.1 board
I've currently got my fan wired as such:
12v+ plugged into J56 fan 7
Ground plugged into J64 PA3
PWM plugged into J50 PA8
Fan is a AVC model DBTB0428B2G 12v 1A
Attached is the only change I've made to printer.cfg
And the ratos general pins from my config
If anyone has any idea I'd appreciate the input
Solution:Jump to solution
The thing is:
The 4028 needs PWM signal to turn off, not turn on. Of there is no signal, the fan will be on.
Combining with enable_pin, whenever you enable the fan it gets power. Without PWN signal will always be on...
51 Replies
post your printer.cfg and a pic of the wiring to the octopus please
As a note for the future, this would have been better under #fix-my-printer , but not a big deal 🙂
Sorry, I wasn't sure if this was an OS issue or a printer issue. FMP would be a better place indeed
Hello.
To make thing easy to you, you can connect both 12V and GND to J64. 12V is always there since the switching is always done by GND.
Then, on the configurator, did you select INPUT VOLTAGE PWM or Digital PWM on 2-pin port for this fan?
Can you chare RatOS.cfg? almost all configs are there, including the fans, not on RatOS.cfg.
I ask this about the configurator because seem like the fan is not getting the PWM signal...
Interesting. I have power and ground coming from the same J56, not using the heater outputs at all
You can use the heater output as the enable pin so it doesn't go to 100% when starting klipper
It's how the documentation said to put it, and it's in another room so I don't mind the noise when it restarts. Which is very seldom 🙂
What configurator are you referring to?
What version of RatOS are you using?
2.1
Update everything (always starting with RatOS and then all the others).
Then, on the left side, click on configurator.
This will help you get everything running.
Alright, I'll have to take a look on Sunday. Thanks
Documentation also says to do it this way
https://os.ratrig.com/docs/guides/4028#my-fan-runs-at-100-until-klipper-boots
Connecting a 4028 fan | RatOS
4028 server fans are becoming a popular option for part cooling because of their light weight and great pressure and flow rates. In this guide we'll go over how to connect one and use it for part cooling. 4-pin fans usually aren't used in 3d printers, and many boards only provide 2-pin ports, but fear not! There's always a way.
Interesting. I'll take a look at the 3.1 dozuki docs later
I have tried wiring it every way with all the relevant config changes on this documentation
I think there is also a mistake on this documentation. In one of the pictures it shows a 12v and 24v jumper for the fan 7 header and the pwm signal
Pull requests are welcome
The jumper is not the important part. It was already in the image used to make this instructions. The green box is what matters…
And this instructions are for RatOS 2.0, not 2.1.
New documentations is being made.
Aww that would probably explain why it didn't work
also, the documentation on "supported boards" showing the wiring diagram have this quite visible
Aww, I missed that note
you can do what I told you before.
Connect black and red wire to any of the open fan ports (from fan 3 to fan5).
Connect the blue wire to fan0 (GND pin)
on printer.cfg you just need to include this:
[fan]
enable_pin: whatever_pin_you_used (if fan3, it will be PD13 in an octopus board)
everything else is already configured on RatOS.cfg
Let me try that quick
this is what I use on V-Minion, VC3.1 and VC4 IDEX. I know it works 😉
fan still runs when printer is turned on
using fan 5
it does run faster if I change the setpoint but never stops
@MDFPereira That setup works!
Also turns out I had it setup in the configurator to use a 2 pin digital pwm.
The next thing to figure out is the fan curve. Seems like anything 1-100% is just 100%
I also spoke about the digital pwm signal above 😉
About the fan curve, what fan are you using? The one within the kit?
Where did you connect the fan plugs?
Sadly not, the one that came with the kit died with a motherboard because of our bed probe
Fan is a AVC model DBTB0428B2G 12v 1A
Fan header 5 has the 12v and ground, blue wire is in fan 0 gnd
Ok. Let’s check pinout first
Did you configure it as digita pwm on the octopus or the toolboard?
Wait....
I changed it from digitial. Digital wasnt working
I am only using the octopus
No.
It has to be digital. Mandatory for 4028
Input voltage is only for 2 wire fans
If digital is not working is for other reasons
Okay. I've reverted it and now the fan never turns off. it still accelerates but never goes to 0
Because it is missing the PWM signal from fan0
Try testing both cycle times
cycle_time: 0.00004
Or
cycle_time: 0.01
Under your [fan] config
Current setup:
Try cycle_time: 0.00004
No differnce with either cycle ti,e
On printer.cfg
Change the blue wire to fan4 and on pin: set it to PD14
I said fan header 5 but I meant fan header 4 but I have the right pin listed for the port im using
Go fan5 on blue wire and set pin to PD15
Okay, progress
it now stops but still feels like it goes to 100%
going to try the other cycle
Still running at either 0 or 100% no curve
Solution
The thing is:
The 4028 needs PWM signal to turn off, not turn on. Of there is no signal, the fan will be on.
Combining with enable_pin, whenever you enable the fan it gets power. Without PWN signal will always be on
Do you have any other fan? If so, connect it to where the blue wire is. Be careful about the pinout
I NEVER had success with this AVC fans
have some laying around, toasted some just for testing
I dont have any other fans at the moment. Correct me if im wrong but I thought PWM signals are 5v?
I figured it out
I just commented out the enable_pin and it started working perfectly
Though I never would have got there without your help ❤️
you can leave the enable_pin uncomented. that only means you fan will only get power when requested
you welcome
I will check again my AVC fans without an inverted pin 😛
Because I love the rampup time on them... They are quite fast
The ramp up on this fan is pretty crazy too
I know, AVC, the same I have in the drawer
Same model