E10169-001109 FOD
2 READING PROCEDURE
2.1 INITIAL READINGS
Gage readings should be taken as soon as the gages are received to ensure that they
have not been damaged during shipment. Please review the readout unit instruction
manual before proceeding with the reading.
Before a transducer can be used with the fiber-optic readout unit from Roctest, its gage
factor (0001000) must be first selected. The gage factor, already recorded in the memory
of the readout unit, is registered on a label installed on the cable close to the fiber-optic
connector and on the calibration sheet of the gage.
After that, readings displayed be the readout can be read and used it in the equation
supplied on the calibration data sheet to obtain the displacement in engineering units.
Steps before taking a reading
1. Select gage factor (0001000) in the readout memory
2. Associate gages to appropriate channel number and gage factor
3. Be sure that you have the displacement equation and the calibration factors
appropriate to each gage.
2.2 DISPLACEMENT EQUATION
The reading value on the readout unit must be converted in engineering unit such as
millimeter (mm) or inch (in) by the displacement equation supplied on the calibration
data sheet. The equation is:
Di = A L4+ B L3+ C L2+ D L + E (1)
where: Di = Displacement
A,B,C,D,E = Calibration factors given on the calibration data sheet
L = Current reading in unit
2.3 INTERPRETATION
The reading seen on the readout unit is the distance between the actual point and the
reference point (located at mid-range) established during factory calibration.
Therefore, it is necessary to fix your own reference point by taking an initial reading after
installation is completed. The initial displacement (D0), calculated with equation 1, gives
your reference displacement. Then you can compare the following reading (D1) to the
reference and compute the real displacement (Dreal).
