Chapter 4
Signal Conditioning
©
National Instruments Corporation
4-13
A three-resistor circuit for attenuating voltages at the differential inputs
of the AMUX-64T board is shown in Figure 4-7. The figure also shows the
placement of the resistors on the open component positions for differential
Channel 1. The gain G of this attenuator is given by the following equation:
(4-3)
Therefore, the input to the MIO board (V
MIO
) is
where V
SC
is the voltage applied to the screw terminals of the AMUX-64T.
The accuracy of this gain equation depends on the tolerances of the
resistors used.
Figure 4-7.
Attenuator for Use with Differential Inputs
G
R
G
R
E
R
F
R
G
+
+
(
)
--------------------------------------
=
V
MIO
V
SC
G
•
=
Channel 1
(+in)
Channel 33
(–in)
10 k
Ω
Resistor
A R5
B R6
C R7
D R8
F R68
E R67
G C4
E 10 k
Ω
+ Channel
– Channel
Input Schematic
+
–
F 10 k
Ω
V
SC
G
10 k
Ω
To
MIO board
MIO
V
