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Chapter 3
Hardware Overview
©
 National Instruments Corporation
3-9
In high-hysteresis analog triggering mode, the trigger is generated when 
the signal value is greater than highValue, with the hysteresis specified 
by lowValue, as shown in Figure 3-9.
Figure 3-9.  High-Hysteresis Analog Triggering Mode
In low-hysteresis analog triggering mode, the trigger is generated when 
the signal value is less than lowValue, with the hysteresis specified by 
highValue, as shown in Figure 3-10.
Figure 3-10.  Low-Hysteresis Analog Triggering Mode
The analog trigger circuit generates an internal digital trigger based on 
the analog input signal and the user-defined trigger levels. This digital 
trigger can be used by any of the timing sections of the DAQ-STC, 
including the analog input, analog output, and general-purpose 
counter/timer sections. For example, the analog input section can be 
configured to acquire n scans after the analog input signal crosses a 
specific threshold. As another example, the analog output section can 
be configured to update its outputs whenever the analog input signal 
crosses a specific threshold.
highValue
Trigger
lowValue
highValue
Trigger
lowValue
PCI_E.book  Page 9  Thursday, June 25, 1998  12:55 PM