©
National Instruments Corp.
5
FP-AI-102 and cFP-AI-102
Measuring Voltage with the [c]FP-AI-102
The [c]FP-AI-102 has eight single-ended input channels. All eight
channels share a common ground reference that is isolated from
other modules in the FieldPoint system. Figure 3 shows the analog
input circuitry on one channel.
Figure 3.
[c]FP-AI-102 Analog Input Circuit, One Channel
The input ranges for voltage signals are 0–20, 0–60, 0–120,
±
20,
±
60, and
±
120 V. Connect the positive lead of a voltage source to
the V
in
terminal and the negative lead to the COM terminal.
Figure 4 shows how to connect a voltage source without an
external power supply to one channel of the [c]FP-AI-102.
Figure 4.
Voltage Source without External Power Supply
V
in
V
sup
COM
Filter
V
C
12-Bit
Isolated ADC
V
sup
V
in
V
C
To Analog
Input Circuitry
To Next
Channel
1.0 M
Ω
Input
Impedance
COM
[c]FP-AI-102
Voltage
Source
+
–
