National Instruments NI SCB-68A, User Manual

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© National Instruments | 2-37
NI SCB-68A User Manual
Adding Components for Attenuating Voltage on Analog
Input Signals
You can build a two- or three-resistor circuit for attenuating voltages at the single-ended analog
inputs and differential analog inputs of the SCB-68A:
•
Differential analog input attenuators —To build a three-resistor circuit for attenuating
voltages at the differential analog inputs of the SCB-68A, refer to Figure 2-36. Refer to
Table 2-1 for component positions for all analog input channels.
The SCB-68A ships with a surface mount 0
Ω
resistor in the F and G positions. You must
remove the resistors to use these positions.
Figure 2-36. SCB-68A Circuit Diagram for Differential Analog Input Attenuation
Install resistors in positions E, F, and G of the chosen differential channel pair. Use the
following equation to determine the gain of the circuit:
• Single-ended analog input attenuators —To build a two-resistor circuit for attenuating
voltages at the single-ended analog inputs of the SCB-68A, refer to Figure 2-37. Refer to
Table 2-1 for component positions for all analog input channels.
The SCB-68A ships with a surface mount 0
Ω
resistor in the F and G positions. You must
remove the resistor to use the position.
AI i
AI i + 8
y
S C x
E
A
F
G
B
C
D
+
+
+
+ 5 V
AI GND
+ 5 V
AI GND
AI
i
AI
i
+
8
G
R
E
R
E
R
F
R
G
+ +
( )
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