App-59
IM 701210-06E
Appendix
App
Calculation Example
• When Determining the Corresponding Shunt Resistance (Rs) from the Strain (
ε
)
Given a gauge factor (K) of 2,
Detailed equation
Rs = R
×
(1–
ε
)/(2
×ε
)
(6)
(equation B)
General equation
Rs = R
×
(1–2
×ε
)/(2
×ε
)
(7): Error of 1 to 2% present
(equation A)
Desired Strain
Derived by the Detailed Equation (6)
Rs value (
Ω
) Derived by the
ε
(
µ
STR)
Rs Value (
Ω
)
General Equation (7)
R=120
Ω
R=350
Ω
R=120
Ω
R=350
Ω
1,000
59,940
174,825
59,880
174,650
2,000
29,940
87,325
29,880
87,150
5,000
11,940
34,825
11,880
34,650
10,000
5,940
17,325
5,880
17,150
• When Determining the Corresponding Strain (
ε
) from the Shunt Resistance (Rs)
If we derive e from equation (6) and (7),
Detailed equation
ε
= 1/(1+2
×
Rs/R)
(8)
(equation B)
General equation
ε
= 1/{2
×
(1+Rs/R)}
(9): Error of 1 to 2% present
(equation A)
When the Bridge Resistance R is 120
Ω
RS Value (
Ω
)
Strain
ε
(
µ
STR) Derived by
Strain
ε
(
µ
STR) Derived by
the Detailed Equation (8)
the General Equation (9)
60,000
999
998
30,000
1,996
1,992
12,000
4,975
4,950
6,000
9,901
9,804
When the Bridge Resistance R is 350 W
RS Value (
Ω
)
Strain
ε
(
µ
STR) Derived by
Strain
ε
(
µ
STR) Derived by
the Detailed Equation (8)
the General Equation (9)
180,000
971
970
90,000
1,941
1,937
36,000
4,838
4,814
18,000
9,629
9,537
Appendix 11 Shunt Calibration of the Strain Module
