Issuing m106 command changes speed of both fans

imonsei

I have a duet3 6hc on a v-core printer.

My fans are configured like this:

M950 F0 C"out7" Q500                   ; create fan 0 on pin out3 and set its frequency
M106 P0 C"Hotend Fan" S0 H1 T45 L255   ; set fan 0 name and value. Thermostatic control turned on for Hotend
M950 F1 C"out4" Q500                   ; create fan 1 on pin out4 and set its frequency
M106 P1 C"Layer Fan" S0 H-1		       ; set fan 1 name and value. Thermostatic control is turned off

I have noticed that my slicer's gcode doesn't specify which fan to change speeds on, so both the fans are changing speeds. Is this working as intended?
I would have thought that when you ask the slicer to do more or less cooling on bridges, for instance, it is the layer fan you would like to have fan speed change on?
Is there a way to achieve this?
Also I thought the L255 parameter made the fan for the hotend run at max speed when turned on, so I'm clearly misunderstanding something.

Thanks for your time.

deckingman

@imonsei You are probably getting confused with the DWC interface showing your layer fan as well as a tool fan. Is the name you see under fan control "Tool Fan", or is it "Hotend Fan" as you have named it? If you've set the hot end fan as thermostatic, then it shouldn't show up on the UI so you should not see "Hotend Fan". But you see "Tool Fan" as well as "Layer Fan".

The reason DWC has a "Tool fan" as well as whatever other non-thermostatic fas you have configured, is that some people, especially those with multiple tools, have multiple fans. So DWC shows the one that is currently in use as the "Tool Fan". It can be confusing if you have only one part cooling fan because the "Tool Fan" and your part cooling fan will always be one and the same.

Edit. Your hot end fan is thermostatic so you can't control the speed and it won't show on DWC. Therefore the "L" parameter is being respected but you can't see that on the DWC. To check, you'd have to change the "L" parameter and physically observe the fan to see if it is turning slower.

imonsei

@deckingman That's a bit odd, because in the web interface it shows controls for both, and if i change the one fan slider, it changes the other slider a second later.
Same thing when the gcode changes the fan speed, the web interface's 2 sliders both change.
It also "sounds like" it's changing both, but I could be mishearing it, and I cannot verify visually.
On the web interface on PC is two buttons that switches between the fan you want to change speeds for. Clicking back and forth shows no difference in value. On mobile web interface you can see two sliders, and they both change. Just to make sure I'm describing it properly.
You are correct that it says "tool fan" and "Layer fan".

(I have the newest stable firmware and web control)

deckingman

@imonsei I agree that it can seem odd - but trust me "Tool Fan" and the non-thermostatic fan that you've given the name "Layer Fan" are one and the same. The fan cooling your hot end (fan 0) is thermostatic so cannot be controlled via any slider. If it could, then you'd see it with the name you've given it - i.e. "Hotend Fan".

imonsei

@deckingman thank you for your explanation much appreciated.