Mounting and cooling the Duet
This information has been moved to the individual hardware pages.
Duet 3 Mini 5+ WiFi and Ethernet: Duet 3 Mini 5+ Hardware overview
Duet 3 Mainboard 6HC: Duet 3 Mainboard 6HC Hardware Overview
Duet 2 WiFi and Ethernet: Duet 2 WiFi/Ethernet Hardware Overview
Duet 2 Maestro: Duet 2 Maestro Hardware Overview
Using MCU temp as proxy temp reading for driver temp
The MCU (AKA CPU) can generally be used as a good indicator of the driver temps. This has the benefit of giving a real time temperature reading to use for thermostatic control of a chassis fan.
M106 P2 T45:65 H100:101:102
Sets up an electronics cooling fan that starts to turn on when the MCU temperature (virtual heater 100) reaches 45C and reaches full speed when the MCU temperature reaches 65C or if any TMC2660 drivers (virtual heaters 101 and 102) report that they are over-temperature.
M308 S2 Y"drivers" A"DRIVERS" ; configure sensor 2 as temperature warning and overheat flags on the TMC2660 on Duet M308 S3 Y"mcu-temp" A"MCU" ; configure sensor 3 as thermistor on pin e1temp for left stepper M950 F2 C"fan2" Q100 ; create fan 2 on pin fan2 and set its frequency M106 P2 H2:3 L0.15 X1 B0.3 T40:70 ; set fan 2 value
Creates sensors for the driver overtemp flag and the MCU temp reading using M308 as S2 and S3. Creates a fan port for Fan2 with M950. Then creates a fan command to link those sensors to fan2 with a temp range of 40-70 using M106.
Note that the MCU temperature must be calibrated to get an accurate temperature reading. See here: Calibrating the MCU temperature
mcu-temp in Duet3 Mini5+
Unfortunately the SAME54P20A chip used in the Duet 3 Mini does not have a functioning temperature sensor. In theory it does have an on-chip temperature sensor, but the errata document for the chip says it doesn't work.
Due to this you would be unable to monitor the MCU temp in order to control fans. The driver sensors do work for fan control, but only return flags of warning and overtemp, so fine grained control of fan speed would not be possible with a separate thermistor.