Connecting signal sources to the ni 9234 – National Instruments NI 9234 User Manual
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© National Instruments Corp.
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NI 9234 Operating Instructions and Specifications
Each channel has a BNC connector to which you can connect
a signal source. You can also enable excitation current on a
per-channel basis to connect Integrated Electronics Piezoelectric
(IEPE) sensors. Refer to the
section for more
information. The center pin of the connector, AI+, provides the DC
excitation, when enabled, and the positive input signal connection.
The shell of the connector, AI–, provides the excitation return path
and the signal ground reference.
Connecting Signal Sources to the NI 9234
You can connect ground-referenced or floating signal sources to
the NI 9234. To avoid picking up ground noise, use a floating
connection. To further minimize ground noise, prevent the metal
shells of the BNC connectors from coming in contact with each
other, the modules, or the chassis.
If you make a ground-referenced connection between the signal
source and the NI 9234, make sure the voltage on the AI– shell
is in the common-mode range to ensure proper operation of the
NI 9234. The AI– shell is protected against accidental contact with
overvoltages within the overvoltage protection range. Refer to the
section for more information about operating
voltages and overvoltage protection.