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© National Instruments Corporation 1-1 SCXI-1127/1128 User Manual
1
Installing and Configuring the
SCXI-1127/1128
The SCXI-1127 and SCXI-1228 modules are high-voltage
multiplexer/matrix modules. The SCXI-1127 is a high-density armature
relay module. The SCXI-1128 is a high-density solid-state relay module.
Both modules provide a 1 × 32, 2-wire multiplexer and several switch
matrix configurations on an SCXI platform. The SCXI-1127/1128 can also
operate as two 1 × 16 or four 1 × 8, 2-wire multiplexers (in independent
mode) allowing a single module to handle several multiplexing needs.
Through software-configurable switches, the module can also operate as a
1-wire 1 × 64 multiplexer, enabling you to make a large number of common
referenced measurements. It can also operate as a 1 × 64, 4-wire
multiplexer to make resistive measurements such as those needed for
thermistors and RTDs. With the use of special terminal blocks, the
SCXI-1127/1128 can become a 4 × 8 or 1 × 32, 2-wire matrix. A complete
list of possible configurations is given in Table 1-1.
To handle large channel counts, you can expand the size of the multiplexer
with additional SCXI-1127/1128 modules. These modules support the
analog bus through a special adapter, the high-voltage analog bus (HVAB)
backplane adapter in the SCXI-1357/1358 kit, at the rear of the module.
This adapter allows you to expand the HVAB without complicated wiring.
For example, you can connect two SCXI-1127/1128 modules using the
HVAB-backplane adapter to create a 1 × 64, 2-wire multiplexer.
Table 1-1.
SCXI-1127/1128 Configurations
Scanning
Configuration
Multiplexer Matrix
1-wire 1 × 64 N/A
2-wire 1 × 32 4 × 8 (also 2 × 16, 1 × 32)
4-wire 1 × 16 N/A