usb-6009 nicht in Ordnung?

Bist du dir sicher, dass du alles korrekt angeschlossen hast?

Laut Handbuch:

http://www.ni.com/pdf/manuals/371303h.pdf

Connecting Reference Single-Ended Voltage Signals
To connect reference single-ended voltage signals (RSE) to the
NI USB-6008/6009, connect the positive voltage signal to the desired
AI terminal, and the ground signal to a GND terminal.
When no signals are connected to the analog input terminal, the internal
resistor divider may cause the terminal to float to approximately 1.4 V
when the analog input terminal is configured as RSE. This behavior is
normal and does not affect the measurement when a signal is connected.

Leg alle unbenutzten Kanäle doch mal auf Masse.

VDB