Dear DFGary:
Thanks for your great help. I am very appreicate it.
I thought about what you said in your previours mail. I would like to have sth that need you to make sure.
You said about the hard ground of NI 5112. Did you mean the hard ground is different wire of PCI 6250 AIGND?
That is why it pull the 6260 voltage of 0 volts. Is it because the voltage source will drive everything to NI 5112, not 6250 anymore.
Is that what you mean? I wish you could reply to me. Thanks!