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APPENDIX D - MODEL 4050 SPECIAL INSTRUCTIONS (12” GAGE LENGTH)
The Model 4050 Vibrating Wire Strain Gage is a modified version of the Model 4000 Strain
Gage designed for measuring strains over a longer base.
The Model 4000 Instruction Manual, Section 2 is applicable, however, note the following
special instructions when using the Model 4050.
The Model 4050 uses a special spacer bar 12 5/8" in length.
Before installation of the gage, remove the black protective washer trapped between the
tube and end-block with the 'V' groove.
The Model 4050 is read on
Channel B
of the GK-401 and GK-403 Readouts. To set the
gage for all-tension the reading should be approximately 2000; for all-compression,
10000; for mid-range set to 6000. Note: if a CR10 is being used the excitation range
1400 – 3500 Hz should be selected.
To set the gage pull or push on the end of the gage tube where the cable exits (not the
cable itself!).
Convert the position B reading to microstrain using the individual calibration factor
(expressed in terms of microstrain/digit) supplied with the instrument.
Microstrain (
) = (R
1
-R
0
)GF
To correct for temperature effects, for the gage only, the following equation is used.
Microstrain (
) = (R
1
-R
0
)GF + (T
1
-T
0
)K
R
1
= current reading (position B)
R
0
= initial reading (position B)
T
1
= current temperature (
C)
T
0
= initial temperature (
C)
K= +12.0 microstrain/
C
Note:
If the gage is attached to steel the net thermal effect is practically zero. If mounted on
concrete, use a K factor of +2 microstrain/
C
Other gages lengths are possible with the Model 4050. Consult the factory for
additional information
.
