National Instruments NI 9215 - Manual (Page 11)

© National Instruments Corp. 11 NI 9215 Operating Instructions and Specifications
Connecting Differential Voltage Signals to the NI 9215
You can connect grounded or floating differential signals to the
NI 9215. Connect the positive voltage signal to AI+ and the
negative voltage signal to AI–. To connect grounded differential
signals to the NI 9215 with screw terminal, you must also connect
the signal reference to the COM terminal, as shown in Figure 4.
Figure 4. Connecting a Grounded Differential Voltage Signal to
the NI 9215 with Screw Terminal
Voltage
Source
+
–
AI+
AI–
COM
NI 9215 with
Screw Terminal