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National Instruments Corporation
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Introduction to SCXI
This chapter gives a brief overview of SCXI and helps you identify the
components of an SCXI system.
Figure 1-1 shows how you can use the flexible architecture of SCXI in three
ways—as a front-end signal conditioning system for plug-in DAQ devices,
or as an external DAQ system that attaches either directly to the computer
parallel port or an RS-232 or RS-485 serial port.
Figure 1-1a shows SCXI products as a front-end signal conditioning
system for plug-in DAQ devices. The SCXI chassis can house a variety of
signal conditioning modules. Analog input signals are conditioned and
passed to a single plug-in DAQ device for analog-to-digital conversion. The
plug-in DAQ device also controls and monitors the operation of digital I/O
and analog output modules in the SCXI system. You can monitor and
control up to 3,072 signals with a single plug-in DAQ device.
Figure 1-1b shows an SCXI-1200 DAQ module with which you can
condition and digitize your signals in the SCXI itself. The 12-bit
SCXI-1200 module in an SCXI chassis digitizes the conditioned analog
input signals and transmits the digital data to the computer parallel port.
Figure 1-1c shows an SCXI system that uses an SCXI-2000 or SCXI-2400
to transmit data digitized by an SCXI-1200 to the computer using an
RS-232 or RS-485 serial connection. If you use an RS-485, you can
connect multiple SCXI chassis within a single network. If you use an SCXI
chassis without any analog input modules, you do not need an SCXI-1200
module in that chassis.
