I have a question for the PXI-2531 and PXI-2532.
It states that it has 512 single point inputs.
Looking at the connector I can only see 256 inputs.
Why is this?
Basic topology explained here. This is basic stuff. You really need to understand this in order to use the board. Think in terms of rows and columns. The rows and columns (i.e. 4x128) are inputs/outputs. The crosspoints are the switches that connect a specific row to a specific column.