© National Instruments
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NI PXIe-1085 Series User Manual
(MAX). Dynamic routing of triggers (automatic line assignments) is supported through certain
National Instruments drivers like NI-DAQmx.
Note
Although any trigger line may be routed in either direction, it cannot be
routed in more than one direction at a time.
Figure 1-6.
PXI Trigger Bus Connectivity Diagram
System Reference Clock
The NI PXIe-1085 Series chassis supplies PXI_CLK10, PXIe_CLK100, and PXIe_SYNC100
independently driven to each peripheral slot.
An independent buffer (having a source impedance matched to the backplane and a skew of less
than 1 ns between slots) drives PXI_CLK10 to each slot. You can use this common reference
clock signal to synchronize multiple modules in a measurement or control system.
An independent buffer drives PXIe_CLK100 to each peripheral slot. These clocks are matched
in skew to less than 100 ps. The differential pair must be terminated on the peripheral with
LVPECL termination for the buffer to drive PXIe_CLK100 so that when there is no peripheral
or a peripheral that does not connect to PXIe_CLK100, there is no clock being driven on the pair
to that slot.
An independent buffer drives PXIe_SYNC100 to each peripheral slot. The differential pair must
be terminated on the peripheral with LVPECL termination for the buffer to drive
PXIe_SYNC100 so that when there is no peripheral or a peripheral that does not connect to
PXIe_SYNC100, there is no SYNC100 signal being driven on the pair to that slot.
PXI_CLK10, PXIe_CLK100 and PXIe_SYNC100 have the default timing relationship
described in Figure 1-7.
Figure 1-7.
System Reference Clock Default Behavior
To synchronize the system to an external clock, you can drive PXI_CLK10 from an external
source through the PXI_CLK10_IN pin on the System Timing Slot. Refer to Table B-8,
Connector Pinout for the System Timing Slot
, for the pinout. When a 10MHz clock is detected
7
H
8
H
9
H
10
11
H
12
H
PXI Trigger B
us
#2
PXI
Trigger
Bridge #2
PXI
Trigger
Bridge #1
1
2
H
3
H
4
H
5
H
6
H
PXI Trigger B
us
#1
1
3
H
14
H
15
H
16
H
17
H
1
8
H
PXI Trigger B
us
#
3
PXIe_CLK100
PXI_CLK10
PXIe_
S
YNC100
0 1 2
3
4 5 6 7
8
9 0 1 2
3
4 5 6 7
8
9 0 1 2
3
4 5 6 7
8
9
