©
National Instruments Corporation
7
BNC-9920 Operating Instructions and Specifications
You can measure resistors with values ranging from 100
Ω
to 1 M
Ω
.
4.
Measure V
CC
on AI 3 and the voltage drop across the internal 10 k
Ω
resistor on AI 11.
5.
With these measurements, calculate the resistor value using the following formula:
Connecting Analog Output Signals
Use the AO 0 and AO 1 BNC connectors on the BNC-9920 front panel to connect analog output signals
from channels AO 0 and AO 1 of the NI 9263 to external devices. Refer to the
NI 9263 Operating
Instructions and Specifications
for information about using these signals.
Using the Function Generator
The BNC-9920 has a function generator that produces sine or triangle waveforms and TTL-compatible
square waveforms. Use the switch below the Sine/Triangle BNC to select a sine wave or triangle wave
output for the connector. A TTL-compatible square wave is always present at the TTL Square Wave
BNC.
To adjust the frequency of the function generator, select your frequency range using the Frequency
Selection switch. You can select 0.1–10 kHz, 1–100 kHz, or 13–1000 kHz. The Frequency Adjust knob
adjusts the frequency within the preselected range for the sine or triangle wave and the TTL square wave
outputs.
The Amplitude Adjust knob adjusts the amplitude of the sine or triangle wave output up to 4.4 V
p-p
.
Connecting User-Defined Signals
The USER 1 and USER 2 BNC connectors enable you to make a BNC connection to the digital I/O
signal of your choice. The USER 1 and USER 2 BNC connectors are routed in the BNC-9920 to the
USER 1 and USER 2 screw terminals, as shown in Figure 5.
Figure 5.
USER 1 and USER 2 BNC Connections
Figure 5 shows an example of how to use the USER 1 and USER 2 BNC connectors. To access the
DIO 16 signal from a BNC connector, connect the USER 1 screw terminal to the DIO 16 screw terminal
with a 28–16 AWG wire.
Resistor Value
V
AI 3
V
AI 11
–
V
AI 11
10 k
Ω
(
)
⁄
---------------------------------------
=
U
S
ER 2 BNC
Intern
a
l
Connection
U
S
ER 1 BNC
D GND
U
S
ER 2
U
S
ER 1
D GND
Intern
a
l
Connection
