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Description of Connections
Duet 3 Expansion 3HC provides the following connectors:
2-way barrier strip: two pins for main VIN and GND; The positive side is protected by a 10A fuse.
4-pin JST VH DRIVER_0 thru DRIVER_2: Stepper motor connections. (see note below)
2-pin JST VH OUT_0 thru OUT_2: these are intended for extruder heaters or fans. Maximum recommended current 6A each. If you connect inductive loads to these outputs, you must use external flyback diodes.
4-pin KK connectors with offset spigot OUT_3 thru OUT_5: these are intended for PWM-controllable fans. The connector fits a standard PC-type 4-pin PWM fan. Alternatively, a 2-pin fan may be connected between the V_OULCn pin (+ve) and the OUT_n_NEG pin (-ve). The positive supply to these connectors is the centre pin of the 3-pin jumper block labeled OUT3-OUT5_Select. This selects between V_FUSED and 12V. Alternatively you can connect a 3-terminal buck regulator to the 3-pin jumper block to supply the required voltage to the centre pin.
2-pin KK connectors labelled OUT6 thru OUT8: these are intended for fans. Maximum recommended current 2.5A each. Flyback diodes are built-in to these outputs.
5-pin KK connectors labelled IO_0 thru IO_5: these are for endstop switches, Z probes, filament monitors and other low-voltage I/O functions. Each connector provides both 3.3V and 5V power. The inputs will tolerate up to 30V. The outputs are 3.3V signals levels with 470R series resistors.
2-pin KK labelled GND and VIN: This is for powering an always-on fan or similar.
2-pin KK labelled TEMP_0 thru TEMP_2: connections for thermistor or PT1000 sensors.
6-pin SWD connector: This is for initial boot-loader programming an firmware debugging.
Diagnostic LED: When the expansion board starts up this LED will blank rapidly. If the expansion board is connected to a main board running compatible firmware, the LED on the expansion board will switch to blinking synchronously with the main board LED once time sync has been established across the CAN bus.
- The 4 wire motor and OUT0, OUT1 and OUT2 are JST VH series connectors. They require a minimum of 22AWG wire (20AWG or 0.5mm2 recommended. Most NEMA17 size stepper motor wire will will not be thick enough. You will need a suitable crimping tool for the crimp pins, for example Engineer PA21 (use the 2.2mm jaw opening to crimp the bare wire and the 2.5mm on to crimp the insulation). Alternatively you can solder the wire to the crimp pin
- The two banks of Low Current outputs (OUT3-5, OUT6-8) can be separately selected to be powered by either VIN or internal 12V. Total 12V fan current draw must not exceed 800mA.
Prototype wiring is the same as version 1.0 wiring.