Edgetech 2000-TVD, Руководство пользователя по оборудованию

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6-6 6.0: TROUBLESHOOTING
2000-TVD COMBINED SONAR 0017424_REV_B
6.3.2 Transmission Verification
The 2000-CSS Towfish is different conventional side scan sonars used for many years. The early sonars
were driven with a high-powered energy burst like hitting a bell with a hammer. The transducers are
driven with a smooth rising lower power signal that matches the transducer response. Because of this,
there is no pronounced clicking noise emanating from the transducers when they are firing. Therefore,
the ‘listen for the clicking noise’ test cannot be used to verify sonar transmission during bench or on-deck
testing.
Sniffing with an oscilloscope can be used as a substitute to check transducer firing. One way is to attach
the scope probe’s ground to the towfish body and hold the open probe next to the transducer under test.
Set to about 20 to 50mV /Div.
A second method is to connect a several-turn wire loop across the scope probe and move it over the
transducer face. Electrical pickup should be noticed on the scope screen at each transmission burst.
Remember that the transducers and elements within the transducer may be firing together or in
sequence. One must make sure that the electrical pickup is not from an adjacent string.
6.3.3 Sonar Processor and Data Link
It is assumed that the sonar processor is up and working to complete system test and troubleshooting.
Refer to the sonar processor’s manual for its troubleshooting and diagnostic information.
The other thing is that the high-speed data must be up and running so that the topside and sub-sea units
are communicating with each other. If the towfish boots up correctly and passes its internal self-test,
there will be a smooth sequence of rising tones going from 2 to 3.9 kHz. A set of tones jumping from 2 to
3 kHz means that self-test has failed. These tones are generated in software in the towfish and replicated
on the surface when an EdgeTech topside computer is used to access the Towfish computer subsystem
using the Remote Desktop application. The Self-Test PASS tones repeat until data linkup has occurred
between the topside DISCOVER software, and towfish. Self-Test FAIL tones repeat indefinitely.
There will also be a video acknowledgement of successful self-test and linkup in the topside computer's
DISCOVER display window. Self-test status will also be displayed on an external video monitor if attached
directly to the towfish’s CPU board's VGA connector.
If the topside computer is unavailable and the towfish is dismantled, an external keyboard, mouse and
video monitor may be connected to the towfish’s CPU board to provide some diagnostic testing. An
external power unit will still be required.
6.3.4 Topside Power Unit
Towfish power is supplied either from an individual power/modem unit or from an integrated topside
computer. Voltage and current to the towfish are important parameters. They must be within acceptable
limits for the towfish to work properly. Check the tow cable output voltage with the system connected