User Guide

Chapter 2 Hardware Overview
© National Instruments Corporation 2-9 NI 5911 User Manual
Figure 2-3.
Trigger Sources
Analog Trigger Circuit
The analog trigger on the NI 5911 operates by comparing the current
analog input to an onboard threshold voltage. This threshold voltage is the
trigger value, and can be set within the current input range in 170 steps.
This means that for a ±10 V input range, the trigger can be set in increments
of 20 V/170 = 118 mV. There may also be a hysteresis value associated
with the trigger that can be set in the same size increments. The hysteresis
value creates a trigger window the signal must pass through before the
trigger is accepted. You can generate triggers on a rising or falling edge
condition. For a more complete discussion of triggering, see Chapter 3,
Common Functions and Examples, of your NI-SCOPE Software User
Manual.
Gain
Analog
Input
High
Level
Low
Level
+
–
COMP
COMP
Analog
Trigger
Circuit
ATC_OUT
a. Analog Trigger Circuit
Trigger
Software
ATC_OUT
RTSI <0..6>
PFI1, PFI2
7
2
Arm
b. Trigger and Arm Sources