National Instruments Eight-slot USB Chassis NI cDAQ-9172 - Manual (Page 74)

NI cDAQ-9172 User Guide and Specifications 74 ni.com
Otherwise, the mode depends on the signal that drives Counter n Source.
Table 10 describes the conditions for each mode.
80 MHz Source Mode
In 80 MHz source mode, the NI cDAQ-9172 synchronizes signals on the
rising edge of the source, and counts on the following rising edge of the
source, as shown in Figure 46.
Figure 46. 80 MHz Source Mode
Other Internal Source Mode
In other internal source mode, the NI cDAQ-9172 chassis synchronizes
signals on the falling edge of the source and counts on the following rising
edge of the source, as shown in Figure 47.
Figure 47. Other Internal Source Mode
Table 10. Synchronization Mode Conditions
Duplicate Count
Prevention Enabled
Type of
Measurement
Signal Driving
Counter n Source
Synchronization
Mode
Yes Any Any 80 MHz Source
No Position Measurement Any 80 MHz Source
No Any 80 MHz Timebase 80 MHz Source
No All Except Position
Measurement 20 MHz Timebase,
100 kHz Timebase Other Internal Source
No All Except Position
Measurement Any Other Signal
(such as PFI) External Source
Source
Synchronize Count
Source
Synchronize Count