VTI Instruments EX1629 - Half-Bridge Poisson; Full-Bridge Bending

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EX1629 Basic Operation 45
The half-bridge strain conversion is calculated according to:
sense-backhalfdiff
VVV
excitation
unstraineddiff
V
VV
V
r
GF
V
r
2
Setting this conversion automatically configures the input path for half-bridge mode, in which the
completion resistor is shorted and the back-half resistors are connected. This configuration is
illustrated in Figure 2-4.
Half-Bridge Poisson
This conversion applies to the following bridge configuration:
R (+ )
g
R (- )
g
V
OUT
V
EXC
R
R
+
–
+
–
FIGURE 3-4: HALF-BRIDGE POISSON CONFIGURATION
The half-bridge strain conversion is calculated according to:
sense-backhalfdiff
VVV
excitation
unstraineddiff
V
VV
V
r
121
4
r
r
VGF
V
Setting this conversion automatically configures the input path for half-bridge mode, in which the
completion resistor is shorted and the back-half resistors are connected. This configuration is
illustrated in Figure 2-4.
Full-Bridge Bending
This conversion applies to the following bridge configuration:
V
EXC
+
+
–
+
–
+
–
–
V
OUT
FIGURE 3-5: FULL-BRIDGE BENDING CONFIGURATION