National Instruments E Series - Manual (Page 59)

Chapter 4 Signal Connections
 National Instruments Corporation 4-23 DAQCard E Series User Manual
The data acquisition signals are explained in the Data Acquisition
Timing Connections section later in this chapter. The general-purpose
timing signals are explained in the General-Purpose Timing Signal
Connections section later in this chapter.
All digital timing connections are referenced to DGND. This reference
is demonstrated in Figure 4-9, which shows how to connect an external
TRIG1 source and an external CONVERT* source to two of the
DAQCard PFI pins.
Figure 4-9. Timing I/O Connections
TRIG1
Source
DGND
PFI0/TRIG1
PFI2/CONVERT*
CONVERT*
Source
I/O Connector
E Series Card