Kongsberg ACS500, Инструкция по эксплуатации

Страница: 123 / 148

Technical specifications
Acoustic link
This section provides information about the acoustic link for Kongsberg ACS500.
The ACS500 communication system consists of a modem implemented on the Universal
Transponder Board (UTB) in both the ACU and the SCU. Each UTB board is directly
connected to a transducer in order to send acoustic telegrams in water depths up to
4000 m.
An acoustic telegram is sent from either the ACU computer or the ACU control on the
computer onboard the ship/rig.
The signal is received by one of the subsea transducers depending on which SCU the
operator has chosen to send the signal to. The telegram is then transferred via a serial
line connection to the SCU control module. The SCU control module will perform all
the basic control of valve solenoids and read back for sensors. A signal is sent back to
the ACU/APC as a confirmation that the operation is completed.
Two basic link principles are available in the UTB modems:
• The optimal and fast Cymbal spread spectrum coherent acoustic link
• The well-known non coherent FSK principle with a number of transmitted CW pulses
with a number of different frequencies
FSK coding has been used for the previous generations of ACS systems.
The reason why two different acoustic link principles are available is to be able to use
the most optimal solution when needed, according to the present acoustic environment
conditions.
The Cymbal Link system will operate with reduced battery consumption at severe signal
to noise ratio compared to the FSK system, though the FSK system, with narrow beam
pulse detectors is more robust regarding difficult reflection patterns in the acoustic
channel.
Specification
Cymbal
• Standard cymbal link configuration
– Spread spectrum transmission.
Typical speed 150 bits/s
• Cymbal frequency area
– 25.6 kHz centre frequency ± 2 kHz
FSK
• Standard FSK telemetry with 7 frequencies
– 12 bits/s data transmission speed
• FSK frequency area
– 24.5 kHz to 26.5 kHz
• FSK wake up
397128/C
121