@Tryptamine said in Common lines for compact wiring - PCB design:
Things I am still unsure about:
the BLT has GND twice. Is it sufficient to wire only one ground to some ground of the Duet, or does the ground have to be connected twice?
One ground wire should suffice.
How to dimension the smoothing capacitor between 5v and GND?
I suggest 100uF.
Is the 50 mils connection for the heater PWM large enough?
Use e.g. https://www.4pcb.com/trace-width-calculator.html to check.
Should I fuse the 24V on the board?
Not necessary if the VIN fuse on the Duet provides sufficient protection and you take the 24V wire from the fused supply on the Duet, e.g. from the heater output connector (assuming that connector has a high enough rating for the total 24V current). If you take it directly from the 24V PSU then you should fuse it.