Geokon 4425, Инструкция по эксплуатации, Страница: 15 / 27

9
4. DATA REDUCTION
4.1 Digits
The basic units utilized by Geokon for measurement and reduction of data from vibrating wire
Convergence Meters are “digits”. The units displayed by the GK-403, GK-404, and GK-405 in
position “B” are digits. Calculation of digits is based on the following equation:
Digits =
�
1
Period
�
2
x 10
-3
or Digits
=
Hz
2
1000
Equation 1 - Digits Calculation
To convert digits to deformation the following equation applies:
D = (R
1
- R
0
)
×
G
×
F
Equation 2 - Deformation Calculation
Where;
D is the calculated deformation.
R
1
is the current reading.
R
0
is the initial reading usually obtained at installation.
G is the calibration factor, usually in terms of millimeters or inches per digit taken from the
calibration report, an example of which is shown in Appendix D.
F is an engineering units conversion factor (optional), see Table 2.
From →
To ↓
Inches Feet Millimeters Centimeters Meters
Inches 1 12 0.03937 0.3937 39.37
Feet 0.0833 1 0.003281 0.03281 3.281
Millimeters 25.4 304.8 1 10 1000
Centimeters 2.54 30.48 0.10 1 100
Meters 0.0254 0.3048 0.001 0.01 1
Table 2 - Engineering Units Conversion Multipliers
For example, the initial reading, R
0
, at installation of a convergence meter with a 12 mm
transducer range is 4919 digits. The current reading, R
1
, is 6820. The Calibration Factor is
0.00258 mm/digit. The deformation change is:
Duncorrected = (6820 − 4919) × 0.002402 = +4.566 mm
Note that increasing readings (digits) indicate increasing extension.