E10160-200722
FOP
Page 6
2
DATA READING AND ANALYSIS
2.1 FOP Preparation for initial reading
Gauge readings and diagnostic signal (see section 5) should be taken as soon as the
gauges are received to ensure they have not been damaged during shipment. All gauge
transducers are individually calibrated before shipment and a gauge factor (7-digit number)
and the gauge zero obtained at factory, in internal unit of Fabry-Perot cavity length, are
supplied with each gauge. Before using a transducer with the Universal fiber-optic readout
unit from Roctest and Fiso Technologies, its gauge factor must first be saved in the readout
memory and selected. The calibration factor is already recorded in the transducer's gauge
factor, which is registered on a label installed on the cable close to the fiber-optic
connector and you can also find it on the calibration sheet of the gauge. See section 4 for
relation between gauge factor and calibration factor. Please review the operating manual
of the readout unit before proceeding with readings.
First the gauge must be connected in a channel number and the appropriate gauge factor
must be assigned.
Fiber-optic pressure transducers must be nulled at least once to
adjust the zero before taken an initial reading
. For nulling your transducer follow the
instructions given in the operating manual of your readout. After nulling your transducer with
the appropriate gauge factor pre-selected, the reading will indicate 0 or a very small value.
Obviously, the transducer should not be submitted to pressure for a true zero reading and
should be stabilized in temperature (see below for more information about initial reading).
The zero adjustment of the transducer is necessary when using for the first time a
pressure transducer
.
It is also necessary to take note of the current value at
installation of the gauge zero (value between 11000 and 23000) when doing a zero
adjustment. Knowing it is possible to re-enter the initial gauge zero at installation
could be useful in the case the readout is reset or its memory content is lost.
For
more information about zero adjustment and taking note of the gauge zero see the
operating manual of your readout.
You can also select the Imperial system of unit (in this case the reading will be displayed in
psi) or the Metric system of unit (reading will be displayed in bars). See the operating manual
of your readout for more information about the system of units.
Summary steps before taking a reading
1. Save gauge factor into the readout memory
2. Connect each gauge to one of the channel input connectors
3. Associate appropriate gauge factor to the measuring channel
4. Null gauges and
record the gauge zero in internal unit of Fabry-Perot cavity length
5. Select appropriate system of units
6. Take your initial reading in engineering unit
2.2 Pre-installation initial reading
Before installing the sensor, it is necessary to take an initial reading. The procedure for
taking an initial reading is the following: