Method 2 - National Instruments PXI-6238 User Manual

Chapter 4 Analog Input
AI +
AI –
+
V
–
AI GND

Method 2

Method 2, shown in Figure 4-3, ties the AI – input to AI GND. When
measuring current up to 20 mA, this type of connection ensures that the
voltage level on both the positive and negative side are within the
common-mode input range for NI 6238/6239 devices.
AI +
AI –
AI GND
NI 6238/6239 User Manual
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+
–
AI GND
Figure 4-2. Analog Current Input Connection Method 1
+
–
Figure 4-3. Analog Current Input Connection Method 2
4-4
Isolation
Barrier
Isolation
Barrier
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