Chapter 3 Theory of Operation
SCXI-1121 User Manual 3-20 www.natinst.com
Multiple-Chassis Scanning
In this mode, you attach each SCXI-1001 chassis to a daisy chain of cable
assemblies and multichassis adapter boards, as illustrated in Figure3-11.
You program each chassis separately, and 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
will keep the chassis synchronized. Notice that you can only perform
multiple-chassis scanning with the SCXI-1001 chassis and MIO-16 data
acquisition boards. See Chapter5 , Programming, for more information on
multiple-chassis scanning. See AppendixE, SCXI-1121 Cabling, for more
information on the necessary cable accessories for multichassis scanning.
Figure 3-11. Multiple-Chassis Scanning
Multichassis
Adapter
Chassis 2Chassis 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
Chassis