National Instruments Network Device DAQ S - Manual (Page 110)

Chapter 7 Counters
NI 6124/6154 User Manual 7-38 ni.com
In DAQmx, the device uses 80 MHz source mode if you perform the
following:
• Perform a position measurement
• Select duplicate count prevention
Otherwise, the mode depends on the signal that drives Counter n Source.
Table 7-5 describes the conditions for each mode.
80 MHz Source Mode
In 80 MHz source mode, the device synchronizes signals on the rising edge
of the source, and counts on the following rising edge of the source,
as shown in Figure 7-35.
Figure 7-35. 80 MHz Source Mode
Table 7-5. 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,
or PXI_CLK10 Other Internal Source
No All Except Position
Measurement Any Other Signal
(such as PFI or RTSI) External Source
Source
Synchronize Count