Table of Contents
Advertisement
6.
DATA REDUCTION
The table below shows the readout position, theoretical gauge factors, and
experimental data derived from batch calibrations for each model of strain
gauge. (Individual calibrations are available at an additional cost; contact
for more information.)
GEOKON
Model
Readout Position
Theoretical Gauge Factor Typical Batch Factor
4200
D
3.304
4200 6
D
N/A
4200 7
D
N/A
4202
E
0.391
4204
A
N/A
4210
B
N/A
4212
B
N/A
4214
B
N/A
1
The exact Gauge Factor is determined by actual calibration, there is no Batch Factor to apply.
TABLE 4: Embedment Strain Gauge Factors
6.1 READOUT BOX POSITION A
Use position A for the following models:
Model 4204
GK-404 (select digits mode)
GK-403 and GK-405 (convert the period to digits using this formula:)
2
Hz
=
------- -
Digits
1000
EQUATION 1: Period to Digits Conversion
6.2 READOUT BOX POSITION B
For gauges read in position B, gauge factors must be applied to the change in
readings. These gauge factors are either average gauge factors for that batch of
gauges, or gauge factors from individual calibrations.
6.3 READOUT BOX POSITIONS D & E
Reading for Models 4200 (position D) and 4202 (position E) are displayed on the
readout box directly in microstrain based on the theoretical equation:
2
3 –
G f
=
x10
theory
EQUATION 2: Theoretical Strain
Where:
f is the frequency in digits.
G is the theoretical gauge factor, equal to 3.304 for the 4200 gauge and 0.3910
for the 4202 gauge.
In practice, the act of clamping shortens the vibrating wire slightly, causing it to
over-register the strain. You can compensate for this by applying the batch
gauge factor supplied with each gauge. With the batch gauge factor applied, the
apparent change in strain shown on the readout box is equal to:
B
=
R
–
R
apparent
1
0
EQUATION 3: Apparent Strain
Where:
R
is the initial reading
0
R
is the current reading from the readout box, taken in position D or E.
1
MODEL 4200 SERIES STRAIN GAUGES | DATA REDUCTION | 15
1
Typical Gauge Factor
0.97 to 0.98
N/A
N/A
N/A
N/A
N/A
0.91
N/A
N/A
1.422
N/A
0.3568
N/A
0.3624
N/A
0.3665
1
Experimental Data
3.237
None
None
0.356
N/A
0.3423
N/A
N/A
Advertisement
Table of Contents
