part fan always on

JTM

Hello everyone, New to the world of Duet2 Wifi boards and have been tinkering with my own design printers using the Duet2 Wifi board. my issue is i cant get the part fan to work as a variable speed fan controlled by the web interface. i have tried the PWM fan pins Fan0 Fan1 and Fan2 with no success, although when plugged into Fan1 the fan runs continuous and at full speed regardless of when print is started or running. My config file for fans looks like this:
; Fans
M950 F0 C"fan0" Q500 ; create fan 0 on pin fan0 and set its frequency
M106 P0 S0 H-1 ; set fan 0 value. Thermostatic control is turned off
M950 F1 C"fan1" Q500 ; create fan 1 on pin fan1 and set its frequency
M106 P1 S1 H1 T45 ; set fan 1 value. Thermostatic control is turned on

Is there something ive done wrong here? I kinda really need to get my part fan running as i'm printing with LDPE in a pellet extruder and need the part cooled as i print. Any help would be greatly appreciated.

jay_s_uk

@jtm What's you M563 command in your config?

JTM

@jay_s_uk

Thats the M563 command

M563 P0 D0 H1 F0 ; define tool 0
G10 P0 X0 Y0 Z0 ; set tool 0 axis offsets
G10 P0 R0 S0 ; set initial tool 0 active and standby temperatures to 0C

jay_s_uk

@jtm I can't see anything wrong with your config.
It may be that the fan you have doesn't like PWM control.
Are you able to turn it on and off, just not control its speed?

JTM

@jay_s_uk thats the issue i have on pin Fan1 its always on, never goes off, i cant switch it off and its at 100% speed. On pin Fan0 and Fan2 it wont turn on at all. I've put in fan speed into my slicer and even switched on fan whilst printing to no avail. i'm using a blower type fan which i used before on a Rumba board, but since changing to Duet i cant get it running correctly.
Ill double check once these current prints stop that the fan is always on regardless of print activity.

jay_s_uk

@jtm If Fan 1 is always on regardless it sounds like the mosfet has blown.
You can confirm this by removing the SD card and powering the board and seeing if the fan runs

JTM

@jay_s_uk i tested the fan this morning while everything was cold at around 15c. plugged the fan into Fan1 pin and it was off, and then heated the nozzle, the fan came on at 45c and stopped when i stopped heating and temp dropped below 45c.
M106 P1 S1 H1 T45 ; set fan 1 value. Thermostatic control is turned on

I gather that T45 starts the fan at 45c and one of the other parameters P1 S1 or H1 controls the speed of the fan?

jay_s_uk

@jtm so thats good then, fan1 behaves as its been programmed.
P1 is the fan number
S1 tells it to be on
H1 ties it to the heater in your tool.
We just need to work on Fan0 now.
Maybe try dropping the Q value from 500 to 250 in the M950 for fan 0

JTM

@jay_s_uk is fan 0 the part fan? i thought that was fan 1?

dc42

@jtm said in part fan always on:

@jay_s_uk is fan 0 the part fan? i thought that was fan 1?

We strongly recommend that you choose fan 0 to be the part cooling fan and fan 1 to be the hot end cooling fan.

jay_s_uk

@jtm fan0 is typically the part cooling fan, fan1 is the heatbreak cooling fan (the one blowing on the hotend).
That's how your config is setup.
Any fan that is thermostatically controlled can't be controlled using DWC.

JTM

@jay_s_uk ok so ive got the fan plugged into the wrong pin, its in Fan 1 , so i need to change to pin fan0?

jay_s_uk

@jtm you can either swap it physically on the board, so the part cooling fan is plugged into fan0 and the heatbreak fan is plugged into fan1 or you can swap the pin assignments in your config.g. i.e.

M950 F0 C"fan1" Q500 ; create fan 0 on pin fan0 and set its frequency
M106 P0 S0 H-1 ; set fan 0 value. Thermostatic control is turned off
M950 F1 C"fan0" Q500 ; create fan 1 on pin fan1 and set its frequency
M106 P1 S1 H1 T45 ; set fan 1 value. Thermostatic control is turned on

JTM

@jay_s_uk i can change the plug easy, ill swith to fan0 and i have to change S0 to S1?

jay_s_uk

@jtm nope, your config is setup perfectly.
Just swap the fan over

JTM

@jay_s_uk i have a print running right now, if i swap to pin Fan0 will that create any problems whilst its printing?

jay_s_uk

@jtm golden rule is don't unplug anything while powered up

JTM

@jay_s_uk ok lol ill wait till its finished, but that will be tommrow. Ive tried it before but never has it run whilst printing

JTM

@jay_s_uk I powered down as you suggested, changed the plug to pin Fan0 and now it all works ! i have a controllable part fan thanks so much for your help, it was driving me crazy ! turns out i was changing things with power on.