Voron 2.4 exhaust fan 3 pin config

[SamppaD]

I want to use a Sunon MF60252VX-1000U-G99 3 pin fan for a exhaust on a voron 2.4R2 and use a chamber temperature to control the fan
I have connected  + and - to HE2 PB10 and  tachometer yellow wire to end stop pin PG11 . I found a basic 2 pin fan config on Voron site for temperature sensor controlled fan but
Klipper needs Pulse-per-revolution  and tachometer_poll_interval values for 3 pin fan MF60252VX-1000U-G99.   Where can I find this information? Any easy way to get this to work,config examples? Thanks.

 

 

 

Edited January 13 by SamppaD

[VDZ]

Look for the full fan config at Klipper3d, copy past and edit as required. I am currently using a two wire fan with PID control, this is working well for me.

[Penatr8tor]

Hey @SamppaD

I think this is where you want to look.

Configuration reference - Klipper documentation

The "Fan" section has examples for temperature controlled fans. As for 3 wire fans... you generally need power and then use one of the neg pins of a fan port for your tach wire.

[Tom3D]

 

Hello -

you are facing several problems.
The simple 2-pole Chinese fans also work with a pulsed signal to control the speed.
Most of the better fans, which all have a small electronic, do not work anymore - they need a smooth voltage and the pulsed signal is always a on - off Signal for them - but you cannot control the speed with it. Connecting capacitors as described in the forums doesn't work either - I've wasted days ... horrible much time on it.
The 3rd Tacho cable is just a feedback Signal that you don't really need and can't use for anything.

my solution was a module from a project called SilentFan - ee is like a driver module for a stepper motor and can be easily adjusted and then provides the fan with a clean DC voltage and you can regulate the fans from 5 to 100% speed cleanly.. Just some simple Lines in the printer.cfg

i ordered the Boards in China and soldered serveral of that Modules.

The upper is a sample of the Pinouts of my Spider Board

 

 

[multi_pin Fan_enable_pin]
pins: PE0, PE1

[fan_generic Electronic_Bay_Fan]
##    Electronic Bay FAN - In M8 E4-Mot Position
pin: multi_pin:Fan_enable_pin
max_power: 1.0
shutdown_speed: 0.0
cycle_time: 0.00005
kick_start_time: 0.5
hardware_pwm: false # False/true can be enabled if the pin supports hardware PWM feature
 

 

 

 

SilentFan.pdf

Edited January 14 by Tom3D

[WhiteKnight]

Also be careful with connection of tachometer pin. Depending on the circuit of the board/fan this may result in fried pin or controller. If you decide to get RPM for some reason then put a diode like 1N4148 (or similar) between the tachometer wire and the board - inline, line on the diode towards fan.

 

Edited January 14 by WhiteKnight

[SamppaD]

Okei. Thanks everyone for a fast reply on this issue. I noticed that it doesn't work correctly with 3 pin connection,rpm is reported as 6 rpm when fan is running at 100% rpm should be  about 5700. Also for testing purposes noticed that when printer.cfg fan target value setting is changed from 35C to 20C fan starts at 100% (chamber temp 22C) this is what i expected, but when setting is changed from 20C to 35C fan slows down to about 30% and stay on? I  don't know is this as it supposed to work or abnormal behave  of fan. I dont have diode at hand so i have to purchase some from local elect.shop. At this time i have to disable this future.
 

My config for this is
[temperature_fan chamber]
pin: PB10
max_power: 0.5
shutdown_speed: 0.0
kick_start_time: 5.0
cycle_time:0.01
off_below:0.1
#tachometer_pin: PG11
#tachometer_ppr: 1 
#tachometer_poll_interval: 10
sensor_type: Generic 3950
sensor_pin: PF5
min_temp: 0
max_temp: 70
target_temp:45.0
control: watermark
gcode_id: C

 

To update this post,I have removed fan yellow wire from PG11 endstop port and strange issues disappeared. I would suspect that as Whiteknight advised a diode is necessary for this to work

Edited January 14 by SamppaD
Update

[WhiteKnight]

As noted by Tom3D, some fans do not have a possibility to work with a PWM modulated power. Yours is of this kind. The PWM signal supplied by the board is too slow frequency, so that it looses power and powers back each cycle. That's why it's working on high duty cycle (power interruptions inside cycle are small and are compensated by fan's internal circuit) and shuts down at low. 

Ideally you need to supply a constant voltage or very high frequency. If the board outputs a software PWM, which may overload the board's processor if you go to required high frequency (specified as 21-28kHz for Noctua fans in particular, yours would be similar). You can try to setup hardware PWM output, if that's supported by the board. Look here for more details - https://www.nicksherlock.com/2022/01/driving-a-4-pin-computer-pwm-fan-on-the-btt-octopus-using-klipper/

Diode for RPM monitoring is a must, otherwise you'll damage the processor's input pin sooner or later. You can cut the wire,  solder the diode in the gap (it's tiny enough) and cover by a heat-shrink. There is some info why the current flows via PWM output instead of ground, but I don't remember the exact link to these explanations.

[SamppaD]

Hi. Thank you for the link included. Yea just my luck,i asked specifically for a PWM Sunon fans and this is what I got. Well I can use this fan as a basic 2 pin config,leaving yellow wire disconnected.