Chapter2 HardwareOverview
NI5911 User Manual 2-14 ni.com
Figure2-9. MultipleBuffer Acquisition
RTSI Bus Triggerand Clock Lines
The RTSI bus allows National Instruments boards to synchronize timing
and triggeringon multiple devices.The RTSI bus has seven bidirectional
trigger lines and one bidirectional clock signal.
Youcan program any of the seven trigger lines to provide or accept a
synchronous trigger signal. Youcan also use any of the RTSI trigger lines
to providea synchronization pulse from a master board i f you are
synchronizing multiple NI 5911 boards.
Youcan use the RTSI bus clock line to provide or accept a 10 MHz
reference clock to synchronize multiple NI 5911 boards.

PFI Lines

The NI 5911 hastwo digital lines thatcan accept a trigger, accept or
generate a reference clock, or output a square wave of programmable
frequency.The functionof each PFI line is independent. However, only
one trigger source can be accepted during acquisition.

PFI Lines as Inputs

You can select PFI1 or PFI2 as inputs for a trigger or a reference clock.
Pleasesee the section, Synchronization, for more information about the use
ofreference c locks in the NI 5911.
Trigger
Acquisition
InProgress
Buffer
=Trigger Not Accepted (Pretrigger Points Not Acquired)
=Trigger Not Accepted (5 ยตs Dead Time)
=Trigger Not Accepted (Acquisition in Progress)
=Trigger Accepted
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1
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2
3