Using front panel pfis as inputs, Using front panel pfis as inputs -12 – National Instruments NI PXIe-6672 User Manual
Page 25
Chapter 3
Hardware Overview
3-12
ni.com
Table 3-4 summarizes the sources and destinations of the NI PXIe-6672.
The destinations are listed in the horizontal heading row, and the sources
are listed in the column at the far left. A
✓ in a cell indicates that the source
and destination combination defined by that cell is a valid routing
combination.
Using Front Panel PFIs As Inputs
The front-panel PFIs can receive external signals from 0 to +5 V. They can
be terminated programmatically with 50
Ω resistances to match the cable
impedance and minimize reflections.
Note
Terminating the signals with a 50
Ω resistance is recommended when the source is
another NI PXIe-6672 or any other source with a 50
Ω output.
The voltage thresholds for the front-panel PFI inputs are programmable.
The input signal is generated by comparing the input voltage on the
Table 3-4. Sources and Destinations for NI PXIe-6672 Signal Routing Operations
Sour
ce
s
Destinations
Front Panel
Backplane
Onboard
Fr
o
n
t P
a
ne
l
CLKOUT
PFI <0..5>
PXI_
CLK10_IN
PXI_Star
Trigger
<0..16>
PXI TRIG
<0..7>
TCXO
Reference
PLL
CLKIN
✓
*
✓
*
✓
✓
✓
*
✓
PFI <0..5>
✓
✓
✓
Backplane
PXI_ CLK10
✓
✓
†
✓
†
✓
†
PXI_STAR
<0..16>
✓
✓
✓
PXI TRIG
<0..7>
✓
✓
✓
On
boa
rd
TCXO
✓
✓
*
✓
✓
*
✓
*
DDS
✓
✓
†
✓
†
✓
†
Global
Software
Trigger
✓
✓
✓
*
Can be accomplished in two stages by routing source to PXI_CLK10_IN, replacing PXI_CLK10 with PXI_CLK10_IN
(occurs automatically in most chassis), and then routing PXI_CLK10 to the destination. The source must be 10 MHz.
†
Routing PXI_CLK10 or DDS to PFI, PXI_Star, or PXI_Trigger is accomplished by setting PXI_CLK10 or DDS to be the
synchronization clock (NI-Sync Property Node) and then routing the synchronization clock as the source.