68amp-9lemo.pdf

In principle there exist four different grounds at the boards that can be tied together via jumbers as required:

• AIGND(0-7): This are the internal screens of NI-cables's analog pairs arriving from PXI-6133 combined on this board.
• DGND: This is the digital ground arriving from PXI-6133.

• protective earth: the protective ground that covers silding planes on board and is connecte to the metall covver of modul and crate by the front connector.

• GND: This are the screens from BNC analog signals arriving at the back from the digtizers. They are lead seperated through over the board but are combine because the feed throughs at the back of the chassis are not isolated against each other.
  Therefore there is a forced connection of GND with protective earth about the chassis.