Programming instructions

Chapter 19 Hardware and Software Setup for Your SCXI System
LabVIEW Data Acquisition Basics Manual 19-4
© National Instruments Corporation
SCXI Operating Modes
The SCXI operating mode determines the way that DAQ devices
access signals. There are two basic operating modes for SCXI modules,
multiplexed and parallel. You designate the mode in the
operating mode
input in the configuration utility. Also, you may have to set up jumpers on
the module for the correct operating mode. Check your SCXI module user
manual for more information.
Note
National Instruments recommends that you use the multiplexed mode for most
purposes.
Multiplexed Mode for Analog Input Modules
When an analog input module operates in multiplexed mode, all of its
input channels are multiplexed to one module output. When you cable a
DAQ device to a multiplexed analog input module, the DAQ device has
access to that module's multiplexed output, as well as all other modules
in the chassis through the SCXIbus. The analog input VIs route the
multiplexed analog signals on the SCXIbus for you transparently. So, if
you operate all modules in the chassis in multiplexed mode, you only need
to cable one of the modules directly to the DAQ device.
Note
MIO/AI devices, and Lab-PC+ and 1200 devices support multiple-channel and
multiple-scan acquisitions in multiplexed mode. The Lab-NB and Lab-LC,
LPM devices, and DAQCard-700 support only single-channel or single-scan
acquisitions in multiplexed mode.
When you cable a DAQ device to a multiplexed module, the multiplexed
output of the module (and all other multiplexed modules in the chassis)
appears at analog input channel 0 of the DAQ device by default.
Multiplexed Mode for the SCXI-1200 (Windows)
In multiplexed mode, the SCXI-1200 can access the analog signals on the
SCXI bus. The DAQ VIs can multiplex the channels of analog input
modules and send them on the SCXI bus.This means that if you configure
the SCXI-1200 for multiplexed mode, you can read the multiplexed output
from other SCXI analog input modules in the chassis.
Note
The SCXI-1200 only reads analog input module channels configured in
multiplexed mode, not in parallel mode.