National Instruments E Series - Manual (Page 32)

Chapter 3 Hardware Overview
DAQCard E Series User Manual 3-10  National Instruments Corporation
In below-low-level analog triggering mode, the trigger is generated
when the signal value is less than
lowValue . HighValue is unused.
In above-high-level analog triggering mode, the trigger is
generated when the signal value is greater than
highValue .
LowValue is unused.
Figure 3-5. Below-Low-Level Analog Triggering Mode
Figure 3-6. Above-High-Level Analog Triggering Mode
lowValue
Trigger
highValue
Trigger