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National Instruments Corporation
7
BNC-2121 Connector Accessory for 660X Devices
To measure position using counter 0 of a 660
X
device, make the following
connections.
1.
Connect a wire from channel A to SOURCE of counter 0
(default PFI 39).
2.
Connect a wire from channel B to UP/DOWN of counter 0
(default PFI 37).
Note
If you want to simulate a Z channel, connect a wire from the
Trigger
spring terminal
to GATE of counter 0 (default PFI 38).
Creating a Square Wave
The BNC-2121 has a function generator that produces TTL-compatible
square waveforms.
To create a square wave, complete the following steps.
1.
Access the square wave output by connecting signals to the
spring
terminal.
2.
Use the
Frequency Selection
switch to select a frequency range of
10 Hz–200 Hz, 150 Hz–20 kHz, or 14 kHz–1 MHz.
3.
Adjust the frequency within the range you selected by turning the
Frequency Adjust
knob.
Viewing the State of the DIO Lines
The eight Digital I/O indicators indicate the state of PFI <0..7> on a
660
X
device. When the LED is lit, the channel is in the high state. When
the LED is off, the channel is in the low state.
Using the BNC-2121 to Perform Counter Applications
This section explains how to connect signals to the BNC-2121 to test,
demonstrate, and perform counter applications with a 660
X
device. To find
the correct application to perform, refer to the
660X User Manual
.
Counter program examples mentioned in this section are in the following
locations.
•
NI-DAQ—
Measurement Studio\CVI\Samples\DAQ\Ctr
•
LabVIEW—
Program Files\National Instruments\
LabVIEW\Examples\DAQ\Counter\NI.TIO.llb
