NI 6509 User Guide and Specifications
16
ni.com
Signal Connections
Figure 6 shows an example of signal connections for three typical
digital I/O applications. Port 0 is configured for digital output, and port 7
is configured for digital input.
Figure 6.
NI 6509 Signal Connections
Digital output applications include sending TTL signals and driving
external devices such as the LED shown in the figure. Digital input
applications include receiving TTL signals and sensing external device
states such as the state of the switch in the figure.
Protecting Inductive Loads
When inductive loads are connected to output lines, a large
counter-electromotive force may occur at switching time because of the
energy stored in the inductive load. These flyback voltages can damage
the outputs and/or the power supply.
41
43
45
47
67
69
71
73
50, 100
NI 6509
+5 V
+5 V
LED
Port 7
P7<7..4>
Port 0
P0<3..0>
GND
TTL Signal
