Chapter 4
Digital I/O
Analog Output Series User Manual
4-6
ni.com
Connecting Digital I/O Signals
The DIO signals, P0.<0..7>, are referenced to D GND. You can
individually program each line as an input or output. Figure 4-2 shows
P0.<0..3> configured for digital input and P0.<4..7> configured for digital
output. Digital input applications include receiving TTL signals and
sensing external device states, such as the state of the switch shown in the
figure. Digital output applications include sending TTL signals and driving
external devices, such as the LED shown in the figure.
Figure 4-2.
Digital I/O Signal Connections
Caution
Exceeding the maximum input voltage ratings, which are listed in the
specifications of each AO Series device, can damage the DAQ device and the computer.
NI is
not
liable for any damage resulting from such signal connections.
AO
S
erie
s
Device
+5 V
LED
TTL
S
ign
a
l
+5 V
S
witch
I/O Connector
D GND
P0.<0..
3
>
P0.<4..7>