Figure 2-10. example digital i/o connections – National Instruments NI PXI-7831R User Manual
Page 38
Chapter 2
Hardware Overview of the NI PXI-7831R
© National Instruments Corporation
2-17
Figure 2-10 shows signal connections for three typical DIO applications.
Figure 2-10. Example Digital I/O Connections
Figure 2-10 shows DIO<0..3> configured for digital input and DIO<4..7>
configured for digital output. Digital input applications include receiving
TTL, LVTTL, CMOS, or LVCMOS signals and sensing external device
states, such as the state of the switch shown in the figure. Digital output
applications include sending TTL or LVCMOS signals and driving external
devices, such as the LED shown in the figure.
The NI PXI-7831R SH68-C68-S shielded cable contains 34 twisted pairs
of conductors. To maximize the digital I/O available on the NI PXI-7831R,
some of the DIO lines are twisted with power or ground as they are run
through the cable, and some DIO lines are twisted with other DIO lines as
they are run through the cable. To obtain maximum signal integrity, place
*3.3 V CMOS
†
Use a pull-up resistor when driving 5 V CMOS devices.
LED
TTL, LVTTL, CMOS, or LVCMOS Signal
+5 V
Switch
I/O Connector
DGND
NI PXI-7831R
DIO<0..3>
DIO<4..7>
+5 V
5 V CMOS
†
TTL or
LVCMOS*
Compatible
Devices
DGND