National Instruments USB-6002 - Analog Input Signal Source Configuration; Recommended Input Modes for Signal Sources

14 | ni.com | NI USB-6001/6002/6003 User Guide
Signal Sources and Recommended Input Configuration
Table 6 summarizes the recommended analog input mode(s) for floating signal sources and
ground-referenced signal sources.
Table 6. NI USB-6001/6002/6003 Analog Input Configuration
Signal Source Type
Analog Input Mode
*
Floating Signal Source
(Not Connected to
Building Ground)
Ground-Referenced
Signal Source
†
Examples:
• Ungrounded
thermocouples
• Signal conditioning with
isolated outputs
• Battery devices
Example:
• Plug-in instruments with
non-isolated outputs
Differential (DIFF)
Referenced
Single-Ended (RSE)
*
Refer to the Taking Differential Measurements section for descriptions of the RSE and DIFF modes
and software considerations.
†
Refer to the Ground-Referenced Signal Sources section for more information.
+
–
+
–
AI+
AI–
AI GND
Signal Source DAQ Device
+
–
+
–
AI+
AI–
AI GND
Signal Source
DAQ Device
V
cm
+
–
+
–
AI
AI GND
Signal Source DAQ Device
Ground-loop potential (V
A
– V
B
) are added
to measured signal.
+
–
+
–
AI
AI GND
V
B
V
A
DAQ DeviceSignal Source