National Instruments 6023E Switch User Manual


 
Chapter 4 Signal Connections
6023E/6024E/6025E User Manual 4-36 ni.com
Figures 4-23 and 4-24 show the input and output timing requirements for
the TRIG2 signal.
Figure 4-23. TRIG2 Input Signal Timing
Figure 4-24. TRIG2 Output Signal Timing
STARTSCAN Signal
Any PFI pin can externally input the STARTSCAN signal, which is
available asan output onthe PFI7/STARTSCANpin. Refer toFigures 4-17
and 4-18 for the relationship of STARTSCAN to the DAQ sequence.
As an input, the STARTSCAN signal is configured in the edge-detection
mode. You can select any PFI pin as the source for STARTSCAN and
configure the polarity selection for either rising or falling edge. The
selected edge of the STARTSCAN signal initiates a scan. The sample
interval counter starts if you select internally triggered CONVERT*.
As an output, the STARTSCAN signal reflects the actual start pulse that
initiates a scan. This is true even if the starts are externally triggered by
another PFI. You have two output options. The first is an active high pulse
with a pulse width of 50 to 100 ns, which indicates the start of the scan. The
second action is an active high pulse that terminates at the start of the last
conversion in the scan, which indicates a scan in progress. STARTSCAN is
Rising-Edge
Polarity
Falling-Edge
Polarity
t
w
t
w
= 10 ns minimum
t
w
t
w
= 50-100 ns