4-23
Air Acoustic Testing
CAUTION!
Do not exceed -3 PSIG while purging the housing, as an excess vacuum
can damage the batteries.
Always perform an air acoustic test of the commands and interrogate the instrument after assembling to
assure proper working order. Every time the instrument is powered up, repeat the air acoustic test to
assure proper engagement of the On/Off plug. Place the deck box transducer within 1 meter of the
underwater unit transducer when sending commands. The position of the transducers relative to one
another may need to be adjusted to allow commands to get through in air. Ranges will not be accurate in
air; these systems are designed to operate in water. The speed of sound in air can cause errors in
command decoding and prevents accurate ranging however the systems can be tested in air. Test all
functions of the system by sending each command and verifying that the state changed according to the
command including status reply.
Setup
The specific acoustic impedance of air is quite different from that of seawater, which renders the
Transducer a far less efficient receiver when out of water. For this reason, it is necessary to place the
source (Deck Unit Transducer) within a meter or two of the 8242XS Transducer, with no obstructions to
the acoustic path. Depending on the environment, some experimentation may be necessary to find a
suitable location.
Tests
For the following tests, it will be necessary to have the proper six digit commands unique to the unit being
tested. If it appears that commands are not getting through, verify that the serial number of the unit being
tested matches that on the sheet of command codes.
Using a deck unit, ascertain whether the 8242XS is enabled or disabled by interrogating it if the unit has
just been powered up it will be enabled. Unless otherwise specified, the 8242XS will be shipped from
EdgeTech with the interrogate frequency tuned to 11 kHz and the reply frequency set to 12 kHz.
a.
Upright and Not Released:
15 pings at a 2 second rate
b.
Tilted and Not Released:
7 pings at a 2 second rate
c.
Upright and Released:
15 pings at a 1 second rate
d.
Tilted and Released:
7 pings at a 1 second rate
Summary of Contents for 8242XS
Page 18: ......
Page 22: ...SECTION 2 SPECIFICATIONS 2 4 Figure 2 2 ICD 8272 XS Short 0010816 ...
Page 23: ...2 5 Figure 2 3 ICD 8242XS Long 0011329 ...
Page 24: ......
Page 68: ...SECTION 5 MAINTENANCE 5 18 Figure 5 17 8242XS MART Main Sub Assembly 0002737 ...
Page 72: ...SECTION 5 MAINTENANCE 5 22 Figure 5 19 8242XS Acoustic Release Transducer Assembly 0003226 ...
Page 73: ...5 23 Figure 5 20 8242XS Release Mechanism Sub Assembly Page 1 of 2 002780 ...
Page 78: ...APPENDIX A REMOTE RELEASE A 2 Figure A 1 8242XS Remote Release 0018268 ...
Page 80: ...B 2 Figure B 1 8242XS Tandem Kit Drawing 0006657 ...