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4.DATA REDUCTION FOR THE GK-403, GK-404 or GK-405 in POSITION D
4.1. Conversion of Readings to Strain Changes
Readings on channel D of all Readout Box are set up to display microstrain when used with
a 6 inch long strain gage . But the 4200X strain gage is special in that it has unusually large
range so that the displayed readout units, R, must be multiplied by the gage factor, G, on
the calibration sheet to obtain true values of microstrain,
.
= G(R
1
R
0
)
Equation 1 - Strain Calculation, channel D
Where R0 and R1 are the readout box readings in Pos D.
Note: when (R1
R0) is positive, the strain is tensile.
A typical calibration sheet is shown in Figure 6
It will be noted that the 4200Er output is not very linear varying as much a +/- 3%FS.
Therefor it is advisable to use the polynomial expression to aceive greater accuracy.
Figure 6 - Typical Calibration Sheet for the 4200ER Strain Gage
