©
National Instruments Corporation
3-1
3
Signal Connections
This chapter describes how to connect input and output signals to your
BNC-2140.
You can connect the external analog signals through six BNC connectors.
Four BNC connectors are for input signals and two connectors are for
output signals.
The SHC68-C68-A1 shielded cable connects the BNC-2140 internal
analog signal connector to the DSA plug-in device. A single 68-pin 0.8 mm
VHDCI connector connects the analog I/O signals to the shielded cable.
I/O Connectors
Table 3-1 shows the pin assignments for the six external I/O BNC
connectors.
Table 3-1.
BNC Analog I/O Connector Signal Descriptions
Signal Name
Reference
Direction
Description
+ACH<0..3>
AIGND
Input
+Analog Input Channel 0 through 3—Each channel
can have ICP enabled or disabled. This signal passes
through the BNC internal conductor.
–ACH<0..3>
AIGND
Input
–Analog Input Channel 0 through 3—In SE mode
the inverting (–) terminal is tethered to ground
through a 50
Ω
resistor. This signal passes through
the external BNC shell.
+DAC0OUT
–DAC0OUT
Output
+Analog Output Channel 0—This pin supplies the
analog non-inverting output channel 0. This signal
passes through the internal BNC conductor.
–DAC0OUT
+DAC0OUT
Output
–Analog Output Channel 0—This pin supplies the
analog inverting output channel 0. This signal
passes through the external BNC shell. In SE mode,
the inverting (–) terminal is tethered to ground
through a 50
Ω
resistor.
UM.book Page 1 Tuesday, July 14, 1998 10:37 AM
