©
National Instruments Corporation
15
SCC-SG Series Strain-Gauge Modules User Guide
Figure 10.
SCC-SG03 Half-Bridge Configuration Connection (Two Channels)
Use three lead wires to connect the strain gauges to screw terminals V
EX
+,
V
EX
–, and ACH(
X
)+. The pair of wires connected to V
EX
+ and V
EX
–
provide excitation voltage to the strain gauge. The other wire, connected to
ACH(
X
)+, senses the output voltage of the strain gauge with respect to the
internal half-bridge completion reference. Figure 10 shows two half-bridge
configurations using ACH(
X
) and ACH(
X
+8).
R
4
Strain-Gauge Active Element
R
3
Quarter-Bridge Completion Resistor, or
Temperature-Compensating Element
R
NULL
Nulling Resistor
ACH(
X
)
V
EX
+
ACH(
X
+8)
+
–
R
NULL
+
–
R
NULL
2.5 V
V
EX
–
R
4
R
3
6
5
4
3
2
1
R
4
R
3
Half-Bridge
Completion
Reference
2.5 V
Trimming
Potentiometer
2.5 V
Trimming
Potentiometer
2.5 V
Half-Bridge
Completion
Reference
2.5 V
Reserved
Reserved
No
Connect
No
Connect
Analog Ground
