Chapter 2 Configuration and Installation
© National Instruments Corporation 2-7 SCXI-1121 User Manual
Position AB-R1 connects the analog reference to the SCXIbus guard.
Position A-R0R1 is the parking position and the factory setting.
Position AB-R2 enables the Pseudodifferential Reference mode and
connects the analog reference to the OUTREF pin on the rear signal
connector. Select this mode when the SCXI-1121 has to operate with data
acquisition boards that have a nonreferenced single-ended (NRSE) input. It
is not recommended to use differential-input data acquisition boards when
jumper W33 is in the AB-R2 position.
Table 2-2. Jumper W33 Settings
Jumper Description Configuration
W33 Factory setting in
parking position
W33 Connects the
analog reference to
AOGND (pins 1
and 2 of the rear
signal connector)
W33 Connects SCXIbus
guard to the analog
reference
W33 Enables the
Pseudodifferential
Reference mode
(pin 19 of the rear
signal connector is
connected to the
analog reference)
•
•
•
•
•
•
A
B
R2 R 1 R0
•
•
•
•
•
•
A
B
R2 R 1 R0
•
•
•
•
•
•
A
B
R2 R 1 R0
•
•
•
•
•
•
A
B
R2 R 1 R0