National Instruments SCXI-1121 Manuel D’Utilisation

Page de 162
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.