National Instruments Data Acquisition Device E Series - Manual (Page 121)

Chapter 7 Digital Routing
E Series User Manual 7-4 ni.com
Connecting Timing Signals
Caution Exceeding the maximum input voltage ratings, which are listed in the I/O
Terminal Summary table in the specifications document for each E Series family, can
damage the DAQ device and the computer. NI is not liable for any damage resulting from
such signal connections.
The 10 PFI pins labeled PFI <0..9> route all external control over the
timing of the device. These lines serve as connections to virtually all
internal timing signals. These PFIs are bidirectional. As outputs they are
not programmable and reflect the state of many analog input, waveform
generation timing summary and counter timing signals. There are five other
dedicated outputs for the remainder of the timing signals. As inputs, the PFI
signals are programmable and can control all analog input, waveform
generation, and counter timing signals.
All digital timing connections are referenced to D GND. Figure 7-2 shows
this reference, and how to connect an external PFI 0 source and an external
PFI 2 source to two PFI pins.