BNC-2111 Installation Guide
6
ni.com
Installing the BNC-2111
To connect the BNC-2111 to your DAQ device, complete the following
steps. Consult your computer user manual or technical reference manual
for specific instructions and warnings.
Note
If you have not already installed your DAQ device, refer to the
DAQ Quick Start
Guide
for instructions.
1.
Place the BNC-2111 near the host computer or use the optional DIN
rail-mounting kit, which you can order from National Instruments. The
DIN rail-mounting kit can only be used with the BNC-2111 with metal
enclosure. For more information about the DIN rail-mounting kit, refer
to the National Instruments Web site at
ni.com
or call the branch
office nearest you.
2.
With your DAQ device powered off, connect the BNC-2111 to your
DAQ device with the selected cable.
3.
Determine if your input signals are floating source or
ground-referenced:
•
Floating Signal Sources
—A floating signal source is not
connected to the building ground system, but has an isolated
ground-reference point. Some examples of floating signal sources
are outputs of transformers, thermocouples, battery-powered
devices, optical isolators, and isolation amplifiers. An instrument
or device that has an isolated output is a floating signal source.
•
Ground-Referenced Signal Sources
—A ground-referenced
signal source is connected to the building system ground, so it is
already connected to a common ground point with respect to the
device, assuming that the computer is plugged into the same
power system as the source. Nonisolated outputs of instruments
and devices that plug into the building power system fall into this
category.
4.
Make sure the referenced single-ended (RSE)/nonreferenced
single-ended (NRSE) switch is set correctly for your application. Set
the switch to RSE to measure floating source signals, or to NRSE to
measure ground-referenced signals. The switch setting will be applied
to all 16 analog input BNC connectors. Refer to the
