National Instruments NI 9234 - Manual (Page 9)

© National Instruments Corp. 9 NI 9234 Operating Instructions and Specifications
Figure 3. Connecting a Floating Signal Source to the NI 9234
The NI 9234 can also provide an IEPE excitation current for each
channel to measure ground-referenced or floating IEPE sensors.
Typical IEPE sensors have a case that is electrically isolated from
the IEPE electronics, so connecting the sensor to the NI 9234
results in a floating connection even though the case of the sensor
is grounded.
NI 9234
AI+
AI–
+
–
Signal
Source