Kongsberg EM 712, Maintenance Manual

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Processing Unit description
The EM 712 Processing Unit is provided to process the signals to and from the
Transmitter and Receiver Units.
The EM 712 Processing Unit is an industrial
computer using both COTS (commercial off-the-shelf)
components and custom made components. The unit is
designed and tested for rugged use.
The Processing Unit performs the receiver beamforming, bottom detection, and motion
and sound speed corrections. It contains all interfaces for time-critical external sensors
such as vessel attitude (roll, pitch, heading and heave), vessel position and external
clock. More than one sensor of each type may be connected simultaneously, with one in
use and all of them logged.
The Processing Unit controls the Transmitter and Receiver units via Ethernet
communication, and is also interfaced to the Operator station via Ethernet.
The 48 V output from the Processing Unit can be used for remote on/off control of the
Transmitter and Receiver Units.
The Processing Unit is normally located in a "sonar room" close to the transducer arrays.
The unit can also be placed in the "survey room" or on the bridge.
Processing Unit familiarization
The Processing Unit consists of an instrument case with integrated rack mounting in a
19 inch rack.
It uses both COTS (commercial off-the-shelf) components and custom made
components. Ventilation is provided through slits located on the sides. The front panel of
the Processing Unit holds a mains power switch and an information display.
The Processing Unit can be switched on/off with a remote switch.
The receive data from the Gbit link is filtered and beamformed by an FPGA unit on the
CBMF board. The result is transferred to the CPU board via the cPCI backplane.
The Transmitter Unit(s) and Receiver Unit(s) are connected to the Ethernet switch in
the Processing Unit.
Kongsberg EM 712 Maintenance Manual