National Instruments SCXI-1127 用户手册

the best accuracy, while 1-wire provides the maximum channel count. Use 
the 4-wire configuration to eliminate the effects of lead resistance on the 
measurement. Since the lead resistance is typically small when compared 
with the thermistor range, the impact of the lead resistance error is smaller 
than you have in an RTD measurement. See the 

 section for more information.

A matrix is one of the most flexible switching configurations. Unlike a 
multiplexer, a matrix can connect multiple inputs to multiple outputs. 
A multiplexer is typically organized into channels and commons, while a 
matrix is organized into columns and rows. You can connect any column 
to any number of rows and any row to any number of columns. Figure 2-17 
shows an example of a 2 

× 4, 1-wire matrix configuration. At each 

intersection of a row and column, there is a switch. When the switch is 
closed, the row is connected to the column. Figure 2-17 depicts a 1-wire 
matrix; the SCXI-1127/1128 is a 2-wire matrix. The switching method for 
a 2-wire matrix remains the same. A 2-wire matrix is shown in Figure 2-21. 
Matrices are useful in applications where maximum switching flexibility is 
desired.

Figure 2-17.  2

 

× 

4, 1-Wire Matrix Configuration

×××× 1 Matrix Configuration

You can use the SCXI-1127/1128 with the SCXI-1331 to make various 
matrix configurations such as a 1 

× 32, 32 columns by one row, matrix. 

OUT0± (COM0±) provide the row signals on the SCXI-1331 terminal 
block. Screw terminals for 2-wire channel 0 provide access to column 0 of 
the 1 

× 32 matrix. Similarly, the screw terminals for channel x provides 

access to column x.

Row 0

Row 1

Col 1 Col 2 Col 3 Col 4