The Duet 3 Expansion Mini 2+ is specifically designed for the expansion header of the Duet 3 Mini 5+. It may be possible to use it with other mainboards but this is not supported. It provides 2 x TMC 2209 stepper motors drivers with the same configurability as the 5 mounted on the Duet 3 Mini 5+ (i.e. UART control of all supported TMC2209 features, and stall detection signals).

The main hardware features of the Duet 3 Expansion Mini 2+ are listed below.

Compatible RepRapFirmware versions: RRF 3.2 and later on the Duet 2 mini 5+ mainboard. There is no firmware loaded directly onto the Mini 2+ itself

The drivers are number "5" and "6" to reference them, for example to assign them as the third and fourth extruder:

M584 X0 Y1 Z2 E3:4:5:6

The Duet 3 Expansion Mini 2+ has mounting standoff holes that align with matching holes on the Duet 3 Mini 5+

Nylon standoffs are provided to mount the Duet 3 Expansion Mini 2+ securely.

• 11mm tall for 1.6mm PCB with 2.5mm holes -e.g. FIX-MADA-11 or TRDLCBST-7-01

Standoffs are supplied with the mini 2+

The stepper drivers' heatsinks are connected to the PCB and the majority of the heat is dissipated via the PCB. In many applications passive cooling will be sufficient, especially if the mini 5+ with mini2+ combination is mounted vertically in a well ventilated position. If active cooling is needed then a fan blowing from the side along the line of the stepper drivers is recommended this should cause airflow across the back of the mini5+ and the back of the mini 2+/

• STEP file