Chapter 4
Signal Connections
4-22
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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.
DAQ Timing Connections
The DAQ 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 DAQ sequence is shown in
Figure 4-11. 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 4-12 shows a typical pretriggered DAQ sequence. The
description for each signal shown in these figures is included later in this
chapter.
Figure 4-11.
Typical Posttriggered Acquisition
Figure 4-12.
Typical Pretriggered Acquisition
1
3
0
4
2
TRIG1
STARTSCAN
CONVERT*
Scan Counter
Don't Care
0
1
2
3
1
0
2
2
2
TRIG1
TRIG2
STARTSCAN
CONVERT*
Scan Counter
