Theory of Operation
Chapter 3
SCXI-1100 User Manual
3-16
© National Instruments Corporation
SCANCLK
MCH0
Cable Assembly
Data Acquisition Board
Analog
Input
T
iming
Output
SLOT A
SLOT B
SLOT 0
SLOT X
TRIG0
SCANCON A
SCANCON B
SCANCON X
SCXI-1000 or SCXI-1001 Chassis
Analog Bus 0
SCXI Module
SCXI Module
SCXI Module
Figure 3-11. Multiple-Module Multiplexed Scanning
Multiple-Chassis Scanning
In this mode, you attach each SCXI-1001 chassis to a daisy chain of cable assemblies and
multichassis adapter boards, as shown in Figure 3-12. Program each chassis separately; each
chassis occupies a dedicated channel of the data acquisition board. Within each chassis,
scanning operations act as if the other chassis are not being used, with one exception–you must
program the Slot 0 scan list in each chassis with dummy entries of Slot 13 to fill the samples
when the data acquisition board will be sampling another chassis or data acquisition board
channel. This keeps the chassis synchronized. Notice that you can only perform multiple-
chassis scanning with the SCXI-1001 chassis and MIO boards. See Chapter 5, Programming, for
more information on multiple-chassis scanning. See Appendix E, SCXI-1100 Cabling, for more
information on the necessary cable accessories for multiple-chassis scanning.
Multichassis
Adapter
Chassis 2
Chassis 1
Data Acquisition Board
Timing Output
Input Ch. 0
Input Ch. 1
Input Ch. N
Chassis N
Multichassis
Adapter
Cable
Assemblies
Cable
Assembly
Multichassis
Adapter
Cable
Assembly
Figure 3-12. Multiple-Chassis Scanning
