National Instruments 3.21E+04 Manual De Usuario

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Chapter 4     Signal Connections
AT-MIO/AI E Series User Manual
4-32
 National Instruments Corporation
detection requirements for each timing signal are listed within the 
section that discusses that individual signal.
In edge-detection mode, the minimum pulse width required is 10 ns.  
This applies for both rising-edge and falling-edge polarity settings.  
There is no maximum pulse-width requirement in edge-detect mode.  
In level-detection mode, there are no minimum or maximum 
pulse-width requirements imposed by the PFIs themselves, but there 
may be limits imposed by the particular timing signal being controlled.  
These requirements are listed later in this chapter.
Data Acquisition Timing Connections
The data acquisition timing signals are SCANCLK, EXTSTROBE*, 
TRIG1, TRIG2, STARTSCAN, CONVERT*, AIGATE, and 
SISOURCE.
Posttriggered data acquisition allows you to view only data that is 
acquired after a trigger event is received.  A typical posttriggered data 
acquisition sequence is shown in Figure 4-13.  Pretriggered data 
acquisition allows you to view data that is acquired before the trigger of 
interest in addition to data acquired after the trigger.  Figure 4-14  
shows a typical pretriggered data acquisition sequence.  The description 
for each signal shown in these figures is included later in this chapter.
Figure 4-13.  Typical Posttriggered Acquisition
1
3
0
4
2
TRIG1
STARTSCAN
CONVERT*
Scan Counter