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Figure 2-11. example digital i/o connections, 11 sho – National Instruments NI 785xR User Manual

Page 40

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Chapter 2

Hardware Overview of the NI 78xxR

© National Instruments Corporation

2-19

R Series Intelligent DAQ User Manual

Figure 2-11. Example Digital I/O Connections

Figure 2-11 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 Figure 2-11. Digital output
applications include sending TTL or LVCMOS signals and driving external
devices, such as the LED shown in Figure 2-11.

The NI 78xxR SHC68-68-RDIO cable contains individually shielded
bundles that route each digital signal on an individually shielded pair of
wires, and each signal is twisted with its own wire to digital ground.

*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 783

x

R/784

x

R/785

x

R

DIO<0..3>

DIO<4..7>

+5 V

5 V CMOS

TTL or
LVCMOS*

Compatible
Devices

DGND