Chapter4 SignalConnections
6023E/6024E/6025EUser Manual 4-36 ni.com
Figures 4-23 and 4-24 showthe input and outp ut timing requirements for
the TRIG2 signal.
Figure4-23. TRIG2Input Signal Timing
Figure4-24. TRIG2Output Signal Timing
STARTSCANSignal
Any PFIpin can ext ernally input the STARTSCAN signal, which is
availableas an output on the PFI7/STARTSCAN pin. Refer to Figures 4-17
and 4-18 for the relationship of STARTSCAN to the DAQ sequence.
As an input, the STARTSCANsignal is configured in the edge-detection
mode.You can select any PFI pin as the source for STARTSCANand
configurethe polarity selection for either ri sing orfalling edg e. The
selected edge of the STARTSCANsignal initiates a scan. The sample
intervalcounter starts if you select internally t riggered CONVERT*.
As ano utput, the STARTSCANsignal reflects the actual start pulse that
initiatesa scan. This is true even if the starts are externally triggered by
anotherPFI. You have two output options. The first is an active high pulse
witha pulse width of 50 to 100 ns,whichindicates the start of the scan. The
second action is an activehigh pulse that terminates at the start of the last
conversionin the scan, which indicates a scan in progress. STARTSCANis
Rising-Edge
Polarity
Falling-Edge
Polarity
tw
tw=10 ns minimum
tw
tw=50-100 ns