This is a question borne of sheer ignorance, but I'm not sure if it's a good or bad thing.
I'm designing a PCB (1) that will connect to another PCB (2). The latter has all of the power, ground, IO connections, etc. The one I'm designing is sort of a daughterboard that will offload some of the connections. Currently, I'm running 34 wires to the daughterboard, two of which are GND. Because I have a ground plane, if both of these GND wires are connected to ground pins on PCB(2), assuming a common ground plane there, are there any benefits? Are there downsides?
I did this for two reasons:
- Redundancy
- Ensure tolerance of all grounded devices
But thinking it through, I'm concerned about:
- Creating a ground loop
- Possibly different potentials due to trace length (minimal, the whole PCB(1) is roughly 4cm x 4cm)
So - should I change my design to not contain two ground wires back to PCB(2)? I won't be mad about freeing up another wire, for sure.
Update with additional information:
This is for a 3D printer, moving connections from the main boards to a daughterboard in the tool side.
The main electronics are a Duet Wifi board and a Duex 5 board. These boards are both wired to separate +24v connections from the PSU, but the ground is daisy chained (PSU -> Duex5 -> DuetWifi) to ensure a common ground and no variance in potential. Both boards have a variety of connectors (fans, sensors, etc) that include a ground pin. I don't want to carry a ground wire for each of them to the daughter board as it adds unnecessary weight and eats wires that could be used for other signals.
The plan is/was to use to ground wires (one from each of the two main boards) to wire a common ground plane on the daughterboard that anything which needs grounding wires into.
My thought was that there's both redundancy and that connecting to the ground plane on each of the two main boards, whose ground planes are directly connected as well, would help to ensure potential across all devices connected to any of the three boards.
