
Chapter 4 Connecting Signals
NI PCI-6110/6111 User Manual 4-22 ni.com
STARTSCAN SignalAny PFI pin can receive as an input the STARTSCAN signal, which is 
available as an output on the PFI7/STARTSCA N pin. Refer to Figures 4-9 
and 4-10 for the relationship of STARTSCAN to the DAQ sequence.
As an input, STARTSCAN is configured in the edge-detection mode. 
Youcan select any PFI pin as the source for STARTSCAN and configure 
the polarity selection for either rising or falling edge. The selected edge of 
STARTSCAN initiates a scan. The sample interval counter (SI2) starts if 
you select internally triggered CONVERT*.
As an output, STARTSCAN reflects the actual start pulse that initiates a 
scan even if another PFI is externally triggering the starts. Youhave two 
output options. The first is an active high pulse with a pulse width of 25 to 
50ns, 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 deasserted toff after the 
last conversion in the scan is initiated. This output is set to high-impedance 
at startup.
Figures4-15 and 4-16 show the input and output timing requirements for 
STARTSCAN.
Figure 4-15.  STARTSCAN Input Signal Timing
Rising-Edge
Polarity
Falling-Edge
Polarity
tw = 10 ns minimum
tw