Chapter4 ConnectingSignals
ATE Series User Manual 4-36 ni.com
STARTSCANSignal
Any PFIpin can ext ernally input the STARTSCAN signal, which is
available as an output on the PFI7/STARTSCAN pin.
Referto Figures 4-13 and 4-14 for the relationship of STARTSCANto the
DAQsequence.
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 is started if you select internally triggered CONVERT*.
As ano utput, the STARTSCANsignal reflects the actual start pulse that
initiates a scan, evenif the starts are being externally triggered by another
PFI.You have two output options. The first is an active high pulse with a
pulsewidth o f50 to 100 ns, which indicates 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
deserted toff after the last conversionin the scan is initiated. This output is
set to high-impedance at startup.
Figures 4-19 and 4-20 showthe input and outp ut timing requirements for
the STARTSCANsignal.
Figure4-19. STARTSCANInput Signal Timing
Rising-Edge
Polarity
Falling-Edge
Polarity
tw=10 ns minimum
tw