NI cDAQ-9178 - Clock Routing

NI cDAQ-9178/9174 User Guide and Specifications 66 ni.com
Clock Routing
Figure 59 shows the clock routing circuitry of the NI cDAQ-9178/9174 chassis.
Figure 59. NI cDAQ-9178/9174 Clock Routing Circuitry
80 MHz Timebase
You can use the 80 MHz Timebase as the Source input to the 32-bit general-purpose counter/timers.
The 80 MHz Timebase can be generated from the onboard oscillator.
20 MHz Timebase
The 20 MHz Timebase normally generates many of the AI and AO timing signals. It can function as the
Source input to the 32-bit general-purpose counter/timers.
The 20 MHz Timebase is generated by dividing down the 80 MHz Timebase, as shown in Figure 59.
100 kHz Timebase
You can use the 100 kHz Timebase to generate many of the AI and AO timing signals. It can also
function as the Source input to the 32-bit general-purpose counter/timers.
The 100 kHz Timebase is generated by dividing down the 20 MHz Timebase by 200, as shown in
Figure 59.
÷ 4
÷ 200
80 MHz Timebase
100 kHz Timebase
20 MHz Timebase
Onboard
80 MHz
Oscillator