When I measure the Voltage 0 V by the NI 4070-PCI,there is -0.01 V ;I don't know which one cause this:
the equipment ,the product or the card 4070.
Another (more likely) possibility is incorrect connection/termination/calibration, etc.
This is not a LabVIEW programming question, but a hardware question. You should ask in one of the hardware boards.