Since I have four different power supplies by now, I was thinking of how to handle the "GND situation" of the different devices.
I have one old ATX power supply, which I modified to be a bench power supply a few years ago. Since it delivers all the commonly used voltages for digital devices, without the need of adjustment, I kept it. Like all(?) ATX power supplies, the protective earth wire of the mains connection is tied to the GND pole of the power supply's DC output.
The next power supply is a "classic" 30 Volt, 5 Ampere linear power supply with a big transformer an power transistors. On the front there is a small piece of metal, which connects the terminals of PE/earth/case and DC GND. Since it came this way, I kept it in place.
Additionally I have two DPS power supplies from Ruideng. Both of these are "floating". Both use a grounded power supply (36 and 60 Volt respectively). The PE wire is connected to the metal case of the power supply, but not to the GND pole of the DC output.
I was asking myself, if it would make sense, to tie all GND poles to the PE/earth wire, especially if I use two of the power supplies on the same device, in which case they would need a common ground connection anyway.
Does this make sense? What would or could be the downside of "grounding" the latter two devices by connecting the DC GND pole to PE of the mains supply? I also thought of using a switch to make the connection optional.
Somehow having all devices on the same ground potential, seems favourable to me. Especially with USB devices or digital stuff connected to a PC. But I wouldn't ask, if I already knew the answer. :-)