National Instruments CompactRIO cRIO-9072 - Using the Internal Real-Time Clock; Using the SMB Connector for Digital I;O (Crio-9074 Only)

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 ni.com/info and enter the Info Code criosmb.
NI cRIO-9072/9073/9074 User Manual and Specifications | © National Instruments | 13