National Instruments NI 6013 User Manual

Also see for NI 6013: Note to Users

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National Instruments NI 6013 User Manual Manual pdf 51 page image

Chapter 4 Connecting Signals© National Instruments Corporation 4-25 NI 6013/6014 User ManualSTARTSCAN SignalAny PFI pin can receive as an input the STARTSCAN signal, which isavailable as an output on the PFI7/STARTSCAN pin. Refer to Figures 4-11and 4-12 for the relationship of STARTSCAN to the DAQ sequence.As an input, STARTSCAN is configured in the edge-detection mode.You can select any PFI pin as the source for STARTSCAN and configurethe polarity selection for either rising or falling edge. The selected edge ofSTARTSCAN initiates a scan. The sample interval counter starts if youselect internally triggered CONVERT*.As an output, STARTSCAN reflects the actual start pulse that initiates ascan, even if the starts are being externally triggered by another PFI. Youhave two output options. The first is an active high pulse with a pulse widthof 50 to 100 ns, which indicates the start of the scan. The second action isan active high pulse that terminates at the start of the last conversion in thescan, which indicates a scan in progress. STARTSCAN is deasserted t offafter the last conversion in the scan is initiated. This output is set tohigh-impedance at startup.Figures 4-17 and 4-18 show the input and output timing requirements forthe STARTSCAN signal.Figure 4-17. STARTSCAN Input Signal TimingRising-EdgePolarityFalling-EdgePolaritytw = 10 ns minimumtw