Thermostatic fan for drivers

fma

Hi!

I plan to use 2 fans to cool down the drivers, as my Duetwifi/x5 will be in a box.

Is it possible to create a thermostatic fan, routed to a specific thermistor, without any heater? If not, how should I create a dummy heater for that?

Thanks,

dc42

Yes it's possible using firmware 1.19. See the description of virtual heaters at https://duet3d.com/wiki/G-code#M305:_Set_temperature_sensor_parameters.

You can also implement thermostatic cooling without an extra thermistor, by configuring a fan to turn on according to the readings from virtual heaters 100 and 101.

fma

Excellent! So, something like this should work:

M106 P1 S0.5 H101 T0:100
M106 P2 S0.5 H102 T0:100

If I'm correct, the fans should run at half speed when there is not problem, and at full speed when over-temperature warning occurs. Is it a good setting?

I'm wondering if FETs (especially bed FET) need to be cooled when Duets are in a box?

dc42

No, those M106 settings mean the fans will be off when the temperature is below threshold, and on at half speed when it is hot.

You should cool the PCB as a whole when the CPU or drivers are hot, not just the drivers.

I have my electronics cooling fan configured like this:

M106 P2 H100:101 T45:55 L0.3 ; electronics cooling fan

meaning turn on at 30% if the CPU temperature reaches 45C, and increase to full speed gradually as the temperature rises to 55C. Also turn it on a full speed if any of the main board drivers reports over temperature warning.

fma

Ok, thanks!

deckingman

Frederic,

What David has suggested will work fine but for info, if you want to see and display the driver temperature, then you need to stick a thermistor on it with a small dab of epoxy adhesive. The you can create a virtual heater using M305 and channel number from 102 upwards https://duet3d.com/wiki/G-code#M305:_Set_temperature_sensor_parameters. You can then use the "S" parameter to give it a meaningful name and view it on DWC under "+Extra". Of course you could also use this virtual heater to control a fan as per David's instructions.

HTH

fma

Yes, I think I will add some thermistors, in the future. For now, David's solution is fine.

Thanks for the tip.

Dougal1957

@deckingman:

Frederic,

What David has suggested will work fine but for info, if you want to see and display the driver temperature, then you need to stick a thermistor on it with a small dab of epoxy adhesive. The you can create a virtual heater using M305 and channel number from 102 upwards https://duet3d.com/wiki/G-code#M305:_Set_temperature_sensor_parameters. You can then use the "S" parameter to give it a meaningful name and view it on DWC under "+Extra". Of course you could also use this virtual heater to control a fan as per David's instructions.

HTH

And when you have selected it with the Extra button you can select to have it shown on the Temp graph.

Doug

RGN01

Doug, can it also be displayed on the PanelDue?

Thanks.

Richard

dc42

@RGN01:

Doug, can it also be displayed on the PanelDue?

Thanks.

Richard

Not yet.

RGN01

Thanks, David.