BNC-2120 Installation Guide
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© National Instruments
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9
Using the Function Generator
The BNC-2120 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 Timing I/O Signals
Connect the timing I/O signals of your DAQ device to the PFI 0/P1.0 (AI START TRIG) BNC
or the timing I/O screw terminals on the BNC-2120. When connecting signals to the screw
terminals, use 28–16 AWG wire with the insulation stripped to 0.28 in.
Table 2 describes the timing I/O BNC and terminal signals on the BNC-2120.
Table 2.
BNC-2120 Timing I/O BNC/Terminal Descriptions
BNC/Terminal
Description
PFI 0/P1.0
Programmable Function Interface channel 0 or Port 1 Digital
Input/Output channel 0
AI START TRIG (AI Start Trigger Signal)—As an output, this pin is the
ai/StartTrigger signal. In post-trigger DAQ sequences, a low-to-high
transition indicates the initiation of the acquisition sequence. In
applications with pre-trigger samples, a low-to-high transition indicates
the initiation of the pre-trigger samples.
PULSES
section for information
about using these terminals.
UP/DN
PFI 1/P1.1
Programmable Function Interface channel 1 or Port 1 Digital
Input/Output channel 1
AI REF TRIG (AI Reference Trigger Signal)—As an output, this pin is
the ai/ReferenceTrigger signal. In applications with pretrigger samples,
a low-to-high transition indicates the initiation of the post-trigger
samples. AI Reference Trigger
is not used in applications with posttrigger samples.
