User Guide

NI cDAQ-9172 User Guide and Specifications 64 ni.com
Counter n Source Signal
The selected edge of the Counter n Source signal increments and
decrements the counter value, depending upon the application the counter
is performing. Table 7 lists how this terminal is used in various
applications. Table 8 lists Counter n Source minimum pulse width.
Routing a Signal to Counter n Source
Each counter has independent input selectors for the Counter n Source
signal. You can route the following signals to the Counter n Source input:
•80MHz Timebase
•20MHz Timebase
• 100 kHz Timebase
• Any PFI terminal
• Analog Comparison Event
In addition, you can route Counter 1 TC or Counter 1 Gate to
Counter 0 Source. You can also route Counter 0 TC or Counter 0 Gate to
Counter 1 Source.
Table 7. Counter Applications and Counter n Source
Application Purpose of Source Terminal
Pulse Generation Counter Timebase
One Counter Time Measurements Counter Timebase
Two Counter Time Measurements Input Terminal
Nonbuffered Edge Counting Input Terminal
Buffered Edge Counting Input Terminal
Two-Edge Separation Counter Timebase
Table 8. Counter n Source Timing
Description
Synchronization
Mode
Min (ns)
*
†
Max (ns)
Counter n Source
Pulse Width
80 MHz Source 6.2 —
Other Internal Source 12.5 —
External Source 16.0 —
*
The times in this table are measured at the pin of the device.
†
Actual performance depends on the module in use.