National Instruments 1128 用户手册

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The SCXI-1127/1128 has 64, 1-wire channels in the multiplexer mode that 
are available through the SCXI-1331 terminal block. Figure 2-4 shows the 
SCXI-1127/1128 configured as a 64-to-1, 1-wire multiplexer. A 1-wire 
configuration provides a high channel count because all input signals have 
the same reference. This common reference, called 1_WIRE_LO_REF on 
the SCXI-1127/1128, is available through the screw terminals on the 
SCXI-1331 terminal block.

Figure 2-4.  1-Wire Block Diagram

The output of the 64-to-1 multiplexer is available through the OUT0+ and 
OUT0– screw terminals on the SCXI-1331. You can also connect the output 
of the SCXI-1127/1128 to the HVAB backplane using switch AB0 to make 
the connection.

On power up, switch AB0 is open, disconnecting the SCXI-1127/1128 
from the high-voltage bus. If you are using the module with a high-voltage 
backplane, you need to close the AB0 switch to connect the multiplexer 
output to the HVAB backplane. You can do this through NI-SWITCH.

Figure 2-5 shows an example of a 1-wire configuration using the 
SCXI-1331 terminal block. The diagram shows the 1-wire terminal block 
connections for channels 4, 24, and 59. Channel 4 (R

1

) is measuring a 

resistance. The positive channel is labeled 4 while the negative terminal 
(common reference) is labeled 1_WIRE_LO_REF.

HVAB

Backplane

64-to-1

Single-ended

Multiplexer

AB0

Switch

Out0+

1_WIRE_LO_REF

Out0–

0

1

63