Figure 12.
Controller Serial Port
Pin 1
Pin 5
Pin 6
Pin 9
Table 2.
DB-9 Pin Descriptions
Pin
Signal
1
DCD
2
RXD
3
TXD
4
DTR
5
GND
6
DSR
7
RTS
8
CTS
9
RI
Using the Internal Real-Time Clock
The system clock of the cRIO-9072/9073/9074 is synchronized with the internal high-
precision real-time clock at startup. This synchronization provides timestamp data to the
controller. You can also use the internal real-time clock to correct drift of the system clock.
Refer to the
Internal Real-Time Clock Specifications
for the accuracy specifications of the
real-time clock.
Using the SMB Connector for Digital I/O
(cRIO-9074 only)
You can use the SMB connector of the cRIO-9072/9073/9074 to connect digital devices to the
controller. For example, if you connect the pulse-per-second output of a GPS device to the
SMB connector of the cRIO-9072/9073/9074, you can use the GPS device to correct for drift
of the system clock.
For software that supports GPS drift-correction and other digital I/O through the SMB
connector, go to
and enter the Info Code
criosmb
.
NI cRIO-9072/9073/9074 User Manual and Specifications
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© National Instruments
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