Chapter 2 Configuration, Installation, and Signal Connection
BNC-2090 User Manual
2-4
National Instruments Corporation
Table 2-1.
Jumper W1 Settings
Configuration
Description
100
Ω
to Ground—Use this
setting to reduce any potential
ground loop current, thereby
improving the system noise
performance. (When the BNC-
2090 is rack-mounted, it will be
connected to a different ground.)
This is the factory-default setting.
GND—Use this setting when the
BNC-2090 metal case is neither
connected to any other ground via
a rack mount nor connected to the
MIO ground via a shielded cable
such as the SH6868. (Use this
setting when you use the R6868,
R6850, or SH6850 cable.)
You can also disconnect the
shield from the MIO ground by
removing the jumper from W1,
which prevents the ground loop
current from being carried in the
DGND return of the shielded
cable. This option is best for
rack-mount configurations
where the BNC-2090 metal case
is already grounded.
R1
100
Ω
W1
100
Ω
TO GND
SHIELD
GND
Digital
Ground
R1
100
Ω
W1
100
Ω
TO GND
SHIELD
GND
Digital
Ground
R1
100
Ω
W1
100
Ω
TO GND
SHIELD
GND
Digital
Ground