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APPENDIX B
45
EM
X-
25
00
PX
Ie
T
im
in
g
C
on
tr
ol
le
r
EM
X-
42
50
/4
35
0/
43
80
EM
X-
42
50
/4
35
0/
43
80
EM
X-
42
50
/4
35
0/
43
80
PXI0-7 Bus Segment
PXI0-7 Bus Segment
PXI0-7 Bus Segment
EM
X-
42
50
/4
35
0/
43
80
PXI 10MHz
CLK
PXIe 100MHz
CLK
STAR/DSTAR Trigger
Figure 4-7: PXIe Chassis and Trigger Bus
M
ULTIPLE
S
EGMENT
M
EASUREMENT
In order to synchronize all cards installed on multiple trigger segments, trigger line between bus
segments must be bridged together using the
Routes
interface in Platform driver. This is because
PXI lines in each trigger segments are independent trigger buses. See the
EMX-2500 User’s Manual
or Platform driver’s online help for more detail.
When two trigger lines in different segments are bridged using the
Routes
interface, the signal only
travels in one direction. Unlike the single segment installation, this restricts the arm or trigger source
to the cards in the same segment as a trigger master card. The trigger master card is usually the card
installed at the lowest slot in a chassis. The arm or trigger events cannot be initiated from any cards
in the other segments.
M
ULTIPLE
C
HASSIS
S
YNCHRONIZATION WITH
T
RIGGER
L
INE
Multiple chassis synchronization is essentially the same as multiple segments synchronization
within a single chassis. A coordination trigger line must be bridged between two chassis instead of
two trigger bus segments. This can be achieved by physically connecting the PXI trigger lines using
an external cable through the EMX-2500 trigger connector. The PXI trigger signal can be routed
out from the master segment to the EMX-2500’s TRIG connector. The signal is then distributed to
all other chassis using external cables and routed into slave segments from the EMX-2500 trigger
connector. The signal routing between PXI trigger line and EMX-2500 TRIG connector is
configured using the Platform driver. In this configuration, only cards in the master segment in a
chassis can detect an arm or trigger event. All other cards in slave chassis synchronize to it.
For the best sample-to-sample synchronization between chassis, coordinating trigger events may
not be good enough. The sampling clock needs to be synchronized together as well. When VTI’s
