Appendix B Connecting I/O Signals
NI 781xR User Manual B-4 ni.com
end of the cable into the appropriate I/O connector and connect the other
end of the cable to the appropriate signal accessory.
Caution Connections that exceed any of the maximum ratings of input or output signals
on the NI7 81xR can damage the NI 781xR and the computer. Maximum input ratings for
each signal are given in the Protection (Volts) On/Off column of Table B-2. NI is not liable
for any damage resulting from such signal connections.
You can use the CompactRIO R Series Expansion chassis and CompactRIO
I/O modules with the NI 781xR. Refer to the CompactRIO R Series
Expansion System Installation Instructions for information about
connecting the chassis to the NI 781xR.
Table B-1. I/O Connector Signal Descriptions
Signal Name Reference Direction Description
+5V DGND Output +5 VDC Source—These pins supply 5V from the computer
power supply using a self-resetting 1A fuse. No more than
250mA should be pulled from a single pin.
DGND — — Digital Ground—These pins supply the reference for the
digital signals at the I/O connector as well as the 5V supply.
DIO<0..39> DGND Input or
Output
Digital I/O signals.
Table B-2. NI781xR I/O Signal Summary
Signal Name
Signal
Type and
Direction
Impedance
Input/
Output
Protection
(Volts)
On/Off
Source
(mA at V)
Sink
(mA atV)
Rise
Time Bias
+5V DO — — — — — —
DGND DO — — — — — —
DIO<0..39>
Connector<0..3>
DIO —–0.5 to+7.0 5.0 at 2.4 5.0 at 0.4 12 ns —
DIO = Digital Input/Output DO = Digital Output