©
National Instruments
23
NI WSN-3214 User Guide and Specifications
Full-Bridge Type II
This section provides information for the full-bridge type II strain-gage configuration. The full-bridge
type II only measures bending strain. Figure 21 shows how to position strain-gage resistors in a bending
configuration. Figure 22 shows the full-bridge type II circuit wiring diagram.
Figure 21.
Full-Bridge Type II Rejecting Axial and Measuring Bending Strain
A full-bridge type II configuration has the following characteristics:
•
Four active strain-gage elements. Two are mounted in the direction of bending strain with one on
one side of the strain specimen (top) and the other on the opposite side (bottom). The other two act
together as a Poisson gage and are mounted transverse (perpendicular) to the principal axis of strain
with one on one side of the strain specimen (top) and the other on the opposite side (bottom).
•
Rejects axial strain.
•
Sensitivity ~ 1.0
μ
V/V per
με
, for GF = 2.0,
ν
= 0.
Figure 22.
Full-Bridge Type II Circuit Diagram
R
4
(+ )
(– )
(– )
(+ )
R
1
R
2
R
3
R
3
R
2
R
1
R
4
Reject
s
Axi
a
l
Me
asu
re
s
Bending
V
CH
V
EX
R
1
(
–
ν
ε
)
R
2
(+
ν
ε
)
R
3
(
–
ε
)
R
4
(+
ε
)
+
–
NI W
S
N-
3
214
R
COMP
/EX–
AI+
AI–
EX+
R
S
–
R
S
+
+
–
