Connecting pfi input signals, Figure 8-4. pfi input signals connections, Pfi filters – National Instruments Network Device DAQ S User Manual

Page 117: Connecting pfi input signals -6 pfi filters -6

Chapter 8

Programmable Function Interfaces (PFI)

8-6

ni.com

Connecting PFI Input Signals

All PFI input connections are referenced to D GND. Figure 8-4 shows this
reference, and how to connect an external PFI 0 source and an external
PFI 2 source to two PFI terminals.

Figure 8-4. PFI Input Signals Connections

PFI Filters

You can enable a programmable debouncing filter on each PFI, RTSI, or
PXI_STAR signal. When the filters are enabled, your device samples the
input on each rising edge of a filter clock. These S Series devices use an
onboard oscillator to generate the filter clock with a 40 MHz frequency.

Note

NI-DAQmx only supports filters on counter inputs.

The following is an example of low to high transitions of the input signal.
High to low transitions work similarly.

PFI 0

Source

PFI 2

Source

S Series Device

D GND

PFI 2

PFI 0

I/O Connector