What does this mean?
Dont parallel connected different DC input from different PSU into the same Hashing board.
It means you cant use two different power supplies for one S3
Antminer S3 is packet with 2 PCI-E slots in each PCB(blade).
You may connect one blade with a psu and the other blade with another psu. Then just link the common of both.
There is no power loaded from controller to 1 blade or viceversa so its safe to use 2 PSUs.
There will be no harm in doing it. But never ever connect the PCI-E connector of one PSU
to a blade and a PCI-E connector of another PSU to the same blade.
That's what the statement means.