Using The Function Generator; Connecting Timing I/O Signals - National Instruments BNC-2120 Installation Manual

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

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.
BNC/Terminal
PFI 0/P1.0 Programmable Function Input 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 Refer to the
terminals.
UP/DN
PFI 1/P1.1 Programmable Function Input 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.
PFI 2/P1.2 Programmable Function Input channel 2 or Port 1 Digital Input/Output channel 2
AI CONV CLK (AI Convert Clock Signal)—As an output, this pin is the ai/ConvertClock
signal. A high-to-low edge on AI CONV indicates that an A/D conversion is occurring.
PFI 3/P1.3 Programmable Function Input channel 3 or Port 1 Digital Input/Output channel 3
CTR 1 SOURCE (Counter 1 Source Signal)—As an output, this pin is the Ctr1Source
signal. This signal reflects the actual source connected to the general-purpose counter 1.
BNC-2120 Installation Guide
Table 2. BNC-2120 Timing I/O BNC/Terminal Descriptions
Using the Quadrature Encoder
Description
section for information about using these
8
.
p-p
ni.com