SCXI-1317 Terminal Block Installation Guide
4
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•
V
EX
is the excitation voltage.
•
R
L
is the lead resistance.
•
V
AI
is the measured voltage.
Figure 2.
Quarter-Bridge Circuit Diagram Using a 3-Wire Strain Gauge
The following symbols apply to the circuit diagram and equations:
•
R
1
and R
2
are half-bridge completion resistors.
•
R
3
is the quarter-bridge completion resistor (dummy resistor).
•
R
4
is the active measuring element.
•
R
SCAL
is the shunt-calibration resistor.
•
V
EX
is the excitation voltage.
•
R
L
is the lead resistance.
•
V
AI
is the measured voltage.
AI
QTR
SCXI-1521/B
SCXI-1317
3-Wire Transducer
Ex+
–
+
–
+
V
EX
+
–
R
SCAL
GND
R
L
R
L
R
L
R
4 (gauge)
R
3 (QTR)
R
1
R
2
V
AI
