Appendix A
Device-Specific Information
©
National Instruments Corporation
A-25
•
Single-Ended Mode
—For each BNC connector that yo
u
u
se for two
single-ended channels, set the so
u
rce type switch to the GS position.
This setting disconnects the b
u
ilt-in gro
u
nd reference resistor from the
negative terminal of the BNC connector, allowing the connector to be
u
sed as a single-ended channel, as shown in Fig
u
re A-17.
Figure A-17.
Single-Ended Channels
When yo
u
set the so
u
rce type to the GS position and config
u
re the
device for single-ended inp
u
t in software, each BNC connector
provides access to two single-ended channels, AI
x
and AI
x
+8. For
example, the BNC connector labeled AI 0 provides access to
single-ended channels AI 0 and AI 8, the BNC connector labeled AI 1
provides access to single-ended channels AI 1 and AI 9, and so on. Up
to 32 single-ended channels are available in single-ended meas
u
rement
modes.
For information on how to connect yo
u
r signals in single-ended mode,
AI GND, and/or AI SENSE, refer to the
Signals on USB-6215/6216/6218 Devices
. For a detailed description of each signal, refer to the
Analog Output
Yo
u
can access analog o
u
tp
u
t signals on the BNC connectors labeled AO 0
and AO 1. Fig
u
re A-18 shows the analog o
u
tp
u
t circ
u
itry on the USB-6218
BNC.
Figure A-18.
Analog Output Circuitry
AI
x
+
–
AI
x
+8
U
S
B-621
x
BNC Device
Gro
u
nd Ref.
S
o
u
rce (G
S
)
AO
x
AO GND