Chapter 10

PFI

Isolation

Barrier

(USB-6215

and USB-6218

devices only)

Timing Signals

Digital

Isolators

 

 

 

Static DO

Buffer

Direction Control

I/O Protection

 

PFI <4..7>/P1,

 

PFI <12..15>/P1

 

 

 

 

 

47 kΩ Pull-Down

Figure 10-2.NI 621x PFI Output Circuitry

When a terminal is used as a timing input or output signal, it is called PFI x. When a terminal is used as a static digital input or output, it is called P0.x or P1.x. On the I/O connector, each terminal is labeled PFI x/P0 or

PFI x/P1.

The voltage input and output levels and the current drive levels of the PFI signals are listed in the specifications of your device.

Using PFI Terminals as Timing Input Signals

Use PFI terminals to route external timing signals to many different

M Series functions. Each input PFI terminal can be routed to any of the following signals.

•AI Convert Clock

•AI Sample Clock

•AI Start Trigger

•AI Reference Trigger

•AI Pause Trigger

•AI Sample Clock Timebase

•AO Start Trigger

•AO Sample Clock

•AO Sample Clock Timebase

•AO Pause Trigger

•Counter input signals for either counter—Source, Gate, Aux, HW_Arm, A, B, Z