National Instruments SCXI -1125 用户手册

completely isolated from other channels. You can operate with 
common-mode voltage levels up to 300 V

rms

.

Figures 2-1 through 2-4 show signal connection methods that give the 
highest noise immunity.

When the negative input signal line is connected either directly or 
indirectly to earth ground (usually at the transducer end), connect this line 
to the negative input terminal, as shown in Figure 2-1. No ground 
connection is made at the SCXI-1125. This situation includes cases where 
a floating source can be riding on a high common-mode voltage that is 
ground referenced.

Figure 2-1.  Connecting a Ground-Referenced Signal

Module

+

–

+

+

+

–

–

I

High
CMV

V

out

V

s

V

cm