Programming instructions

Chapter 19 Hardware and Software Setup for Your SCXI System
© National Instruments Corporation 19-5 LabVIEW Data Acquisition Basics Manual
Make sure that you change the jumper in the SCXI-1200 to the ground
position to connect the SCXI-1200 and SCXIbus grounds together. Refer to
the
SCXI-1200 User Manual
for more details.
Multiplexed Mode for Analog Output Modules
Because LabVIEW communicates with the multiplexed modules over the
SCXIbus backplane, you must only cable one multiplexed module in each
chassis to a DAQ device to communicate with any multiplexed modules in
the chassis.
Multiplexed Mode for Digital and Relay Modules
Multiplexed mode is referred to as
serial mode
in the digital and relay
module hardware manuals. When you operate your digital or relay module
in multiplexed mode, LabVIEW communicates the module channel states
serially over the SCXIbus backplane.
Parallel Mode for Analog Input Modules
When an analog input module operates in parallel mode, the module
sends each of its channels directly to a separate analog input channel of the
DAQ device cabled to the module. You
cannot
multiplex parallel outputs
of a module on the SCXIbus. You must cable a DAQ device directly to a
module in parallel mode to access its input channels. In this configuration,
the number of channels available on the DAQ device limits the total
number of analog input channels. In some cases, however, you can cable
more than one DAQ device to separate modules in an SCXI chassis. For
example, you can use two NB-MIO-16X or AT-MIO-16E-2 devices
operating in parallel mode and cable each one to a separate SCXI-1120
module in the chassis. For more information on how to configure the cabled
device, refer to the NI-DAQ Configuration Utility Online Help file in
Windows, or the
Installing and Configuring Your SCXI Chassis
section in
Chapter 2,
Installing and Configuring Your Data Acquisition Hardware
,
for the Macintosh.
By default, when a module operates in parallel mode, the module sends its
channel 0 output to differential analog input channel 0 of the DAQ device,
the channel 1 output to analog input channel 1 of the DAQ device, and
so on.