Programming instructions

Chapter 14 SCXI Hardware
© National Instruments Corporation 14-5 DAQ Hardware Overview Guide
must be sure to enter the correct device numbers in the Connected to field
of Measurement & Automation Explorer for each module you operate in
parallel mode.
By default, when a module operates in parallel mode, the module sends
its channel 0 output to analog input channel 0 of the DAQ device, the
channel 1 output to analog input channel 1 of the DAQ device, and so on.
You cannot use an SCXI-1200 to read channels from another analog input
module in parallel mode.
Parallel (Standalone) Mode for the SCXI-1200
In parallel mode, the SCXI-1200 can read only its own analog input
channels. The SCXI-1200 does not have access to the analog bus on the
SCXI backplane if you configure it for parallel mode. You should use
parallel mode if you are not using other SCXI analog input modules in the
chassis in addition to the SCXI-1200.
Parallel Mode for Digital Modules
When you operate a digital module in parallel mode, the digital lines
on your DAQ device directly drive the individual digital channels on your
SCXI module. You must cable a separate DAQ device directly
to every module that you operate in parallel mode. The SCXI-1162,
SCXI-1162HV, SCXI-1163, and SCXI-1163R modules have jumpers that
you must set correctly for the module to operate in parallel mode. Only the
DIO devices, AT-MIO-16DE-10, and the 6025E devices can use the digital
modules in parallel mode. The MIO or AI devices and the Lab and 1200
devices cannot use the digital modules in parallel mode.
You may want to use parallel mode instead of multiplexed mode for
faster updating or reading of the SCXI digital channels. For the fastest
performance in parallel mode, you can use the Digital I/O functions
described in Chapter 3, Software Overview, of the NI-DAQ User Manual
for PC Compatibles with the appropriate onboard port numbers instead of
using the SCXI functions. Refer to the SCXI Modules and Compatible DAQ
Devices section later in this chapter for information about which digital
ports on each DAQ device are actually used in parallel mode.
Note
A DAQ device that is cabled to an SCXI-1162, SCXI-1162HV, SCXI-1163, and
SCXI-1163R in parallel mode cannot be the communication path in the
Measurement & Automation Explorer.