Geokon 1300, Инструкция по эксплуатации

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9
4.2. Temperature Correction
The Model 4430 Deformation Meter used in the Model A9 Extensometer has a vibrating wire
transducer with a small coefficient of thermal expansion and the body of the transducer contracts
and expands slightly with changes in temperature. The interconnecting rods also expand and
contract so in most cases correction is advisable. Note also that in situations where temperature
changes are large (more than 10 degrees C) it may be prudent to use carbon graphite rods which
have very low coefficients of expansion. The following equation applies;
D
corrected
= (R
1
- R
0
)

G + (T
1
- T
0
)

K + L
C
+ L
R
Equation 3 - Thermally Corrected Deformation Calculation
Where; R
1
is the Current Reading.
R
0
is the Initial Reading.
G is the Calibration Factor.
T
1
is the Current Temperature.
T
0
is the Initial Temperature.
K is the calculated Thermal Coefficient,
L
C
is the correction for the change in gage length.
L
R
is the correction for the change in rod length
Tests have determined that the Thermal Coefficient, K, of the transducer changes with the
position of the transducer shaft. Hence, the first step in the temperature correction process is
determination of the proper Thermal Coefficient based on the following equation;
Thermal Coefficient = ((Reading in Digits

Multiplier)

Constant)

Calibration Factor
or
K = ((R
1

M)

B)

G
Equation 4 - Thermal Coefficient Calculation
See Table 2 for the Multiplier and Constant values used in Equation 4. The Multiplier (M) and
Constant (B) values vary for the stroke of the transducer used in the Deformation Meter.
Model: 4450-
3mm
4450-
0.125”
4450-
12mm
4450-0.5"
4450-
25mm
4450-1"
4450-
50mm
4450-2"
4450-
100mm
4450-4”
4450-
150mm
4450-6”
4450-
300mm
4450-12”
Multiplier
(M):
0.000520 0.000375 0.000369 0.000376 0.000398 0.000384 0.000424
Constant (B): 3.567 1.08 0.572 0.328 0.0864 -0.3482 -0.6778
Def, Meter
Length (L):
267mm
10.5”
267 mm
10.5"
267 mm
10.5"
292 mm
11.5"
393mm
15.49”
510.5mm
20.1”
715.2mm
28.2”
Table 2 - Thermal Coefficient Calculation Constants