National Instruments SCXI-1121 User Manual
Page 40
Chapter 2
Configuration and Installation
2-24
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SCXI-1320, SCXI-1328, and SCXI-1321
Terminal Blocks
The second type of connector available to connect the transducers to the
SCXI-1121 inputs is a terminal block with an onboard temperature sensor
and screw terminals for easy connection. One terminal block, the
SCXI-1328 isothermal terminal block, has a high-accuracy onboard
temperature sensor. The terminal block kits are listed in the
section in Chapter 1,
The terminal blocks consist of a shielded board with supports for
connection to the SCXI-1121 input connector. The terminal blocks have
18 screw terminals for easy connection. Four pairs of screw terminals are
for signal connection to the four inputs of the SCXI-1121, four pairs are for
the excitation channels, and one pair of screw terminals connects to the
chassis ground.
The following warnings contain important safety information concerning
hazardous voltages and terminal blocks.
Warnings
When using the terminal block with high common-mode voltages, you must
insulate your signal wires appropriately. National Instruments is not liable for any damages
or injuries resulting from inadequate signal wire insulation.
If high voltages (
≥
42 V
rms
) are present, you must connect the safety earth ground to the
strain-relief tab. This complies with UL 1244 and protects against electric shock when the
terminal block is not connected to the chassis. To connect the safety earth ground to the
strain-relief tab, run an earth ground wire in the cable from the signal source to the terminal
block. National Instruments is not liable for any damages or injuries resulting from
inadequate safety earth ground connections.
SCXI-1320 and SCXI-1328 Terminal Blocks
When connecting your signals to the SCXI-1320 terminal block for use
with the SCXI-1121, follow the labeling on the SCXI-1320 indicated under
the module type column for the SCXI-1121 as indicated in Figure 2-11.
When connecting your signals to the SCXI-1328 high-accuracy isothermal
terminal block for use with the SCXI-1121, follow the labeling on the
SCXI-1328 indicated along the module type row for the SCXI-1121 as
indicated in Figure 2-12.