National Instruments SCXI-1120 - Manual (Page 13)

© National Instruments Corporation 1-1 SCXI-1120 User Manual
Chapter 1
Introduction
This chapter describes the SCXI-1120; lists the contents of your SCXI-1120 kit; describes the
optional software, optional equipment, and custom cables; and explains how to unpack the
SCXI-1120 kit.
The SCXI-1120 is a class I module consisting of eight isolated input channels. The SCXI-1120
is a module for signal conditioning of thermocouples, volt sources, millivolt sources, 4 to 20 mA
current sources, and 0 to 20 mA process-current sources. Refer to your chassis manual for a
description of the different module classes. If external excitation is provided, thermistors, RTDs,
and strain gauges can also be measured. The SCXI-1120 can operate in two output modes–in the
Parallel-Output mode with all eight input channels connected in parallel to eight data acquisition
board channels, or in the Multiplexed-Output mode with all eight channels multiplexed into a
single data acquisition board channel.
The SCXI-1120 operates with full functionality with the National Instruments MIO-16 boards.
You can use the Lab-NB, the Lab-PC, the Lab-PC+, the Lab-LC, and the PC-LPM-16 boards
with the SCXI-1120, but these boards cannot scan the module when it is configured in the
Multiplexed-Output mode. These boards can perform only single-channel reads in this mode.
You can also use the SCXI-1120 with other systems that comply with the specifications given in
Chapter 2, Configuration and Installation. You can multiplex several SCXI-1120s into a single
channel, thus greatly increasing the number of analog input signals that can be digitized.
The addition of a shielded terminal block provides screw terminals for easy signal attachment to
the SCXI-1120. In addition, a temperature sensor for cold-junction compensation of
thermocouples is included on the terminal block. This cold-junction reference (CJR) is either
multiplexed along with the eight channels or connected by jumpers to a different channel of the
data acquisition board.
With the SCXI-1120, the SCXI chassis can serve as a fast-scanning signal conditioner for
laboratory testing, production testing, and industrial process monitoring.