Calibrating To Known Depth Values With An Angle Beam Transducer; Figure 9-25 Setting The Reference Gain - Olympus EPOCH 650 User Manual

9.9 Calibrating to Known Depth Values with an Angle Beam
Transducer
The EPOCH 650 allows you to perform distance calibration with an angle beam
transducer based on the known depth of equal sized reflectors (usually side-drilled
holes) instead of known sound paths. The following sample angle beam calibration
details the procedure for the depth calibration.
As with any angle beam calibration, you must also verify the beam index point (BIP),
refracted angle, and perform a sensitivity calibration. It is of particular importance to
verify the refracted angle before performing a distance calibration. The acquired
depth measurement(s) used in this mode of calibration are based on calculations from
the sound path of the reflector (direct measurement) and the value of the manually
entered angle parameter. If the angle value is not correct, the distance calibration in
depth mode will not be accurate.
The following procedure describes only the depth distance calibration process for the
EPOCH 650. To verify the BIP and the refracted angle, and to calibrate for sensitivity,
see "Calibrating to Known Sound Path Values with an Angle Beam Transducer" on
page 165. The following sample angle beam calibration is performed using an

Figure 9-25 Setting the reference gain

DMTA-10055-01EN, Rev. A, February 2015
Calibration 175