User Guide

© National Instruments Corporation 67 NI cDAQ-9172 User Guide and Specifications
waiting for the Gate signal when it is armed. Counter output operations can
use the arm signal in addition to a start trigger.
Software can arm a counter or configure counters to be armed on a
hardware signal. Software calls this hardware signal the Arm Start Trigger.
Neutrally software routes the Arm Start Trigger to the Counter n HW Arm
input of the counter.
Routing Signals to Counter n HW Arm Input
You can route the following signals to the Counter n HW Arm input:
•Any PFI terminal
• ai/ReferenceTrigger
• ai/StartTrigger
• Analog Comparison Event
You can route Counter 1 Internal Output to Counter 0 HW Arm. You can
also route Counter 0 Internal Output to Counter 1 HW Arm.
Some of these options may not be available in some driver software.
Counter n Internal Output and Counter n TC Signals
Counter n TC is an internal signal that asserts when the counter value is 0.
The Counter n Internal Output signal changes in response to Counter n TC.
The two software-selectable output options are pulse output on TC and
toggle output on TC. The output polarity is software-selectable for both
options.
Routing Counter n Internal Output to an Output Terminal
You can route Counter n Internal Output to any output PFI terminal.
Frequency Output Signal
The Frequency Output (FREQ OUT) signal is the output of the frequency
output generator.
Routing Frequency Output to a Terminal
You can route Frequency Output to any output PFI terminal. The FREQ
OUT signal can also route to DO Sample Clock and DI Sample Clock.