DATASONICS PSA-916, Руководство пользователя, Страница: 18 / 26

3-7 DATASONICS
User’s Manual March 1997
Make sure sources of noise and turbulence such as the boat propeller and
ROV truster motors are not between the altimeter and the target surface, and
that they are well away from the transducer.
Securely fasten the PSA-916 to its platform, vehicle or instrument package,
making sure there are no obstructions between the transducer face and the
intended target. When mounting be sure the anodize is not scratched or
gouged by clamps, bolts, etc.
If the unit is mounted on an underwater vehicle, be sure that the sound beam
path is perpendicular to the horizontal flying position of the vehicle. Note that
excessive pitch or roll motion will influence the PSA-916 range measurement.
The PSA-916 radiation pattern is 14°.
Make sure the altimeter is attached to the bottom of the ROV so that it is not
affected by echos from the skids.
In applications using multiple altimeters within each others range, their
transmissions should be externally triggered to avoid crosstalk between the
units.
The sound beam pattern is an important consideration. The pattern consists
of the main beam and small side lobes stemming from it. Certain conditions
may cause range errors from sidelobe reflections.
!
A strong acoustic reflector close to the instrument reflects a side lobe sig-
nal before the main beam echo is received.
!
When using a towed vehicle to measure depth, a steep slope reflects the
side lobe before the main beam is reflected by the bottom directly below
the instrument.
!
The side lobe reflects off the bottom before a main beam aimed diago-
nally at the seabed.
3.6 Maintenance
If you exercise reasonable care, your Datasonics products should provide
you with years of reliable service.