Theory of Operation Chapter 3SCXI-1120 User Manual 3-16 © National Instruments Corporationonto TRIG0 for the other modules and Slot 0, as shown in Figure 3-10. The scan list in Slot 0 isprogrammed with the sequence of modules and the number of samples per entry.SCANCLKMCH0Cable AssemblyData Acquisition BoardAnalogInputTimingOutputSLOT A SLOT BSLOT 0SLOT XTRIG0SCANCON ASCANCON BSCANCON XSCXI-1000 or SCXI-1001 ChassisAnalog Bus 0SCXI Module SCXI ModuleSCXI ModuleFigure 3-10. Multiple-Module Multiplexed ScanningMultiple-Chassis ScanningIn this mode, you attach each SCXI-1001 chassis to a daisy chain of cable assemblies andmultichassis adapter boards, as shown in Figure 3-11. You program each chassis separately, andeach 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 mustprogram the Slot 0 scan list in each chassis with dummy entries of Slot 13 to fill the sampleswhen the data acquisition board will be sampling another chassis or data acquisition boardchannel. This will keep the chassis synchronized. Notice that you can only performmultiple-chassis scanning with the SCXI-1001 chassis and MIO-16 data acquisition boards. SeeChapter 5, Programming, for more information on multiple-chassis scanning. See Appendix E,SCXI-1120 Cabling, for more information on the necessary cable accessories for multichassisscanning.MultichassisAdapterChassis 2Chassis 1Data Acquisition BoardTiming OutputInput Ch. 0Input Ch. 1Input Ch. NChassis NMultichassisAdapterCableAssembliesCableAssemblyMultichassisAdapterCableAssemblyChassis 2 ChassisFigure 3-11. Multiple-Chassis Scanning
