Simrad FM90, Reference Manual

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System description
The Simrad FM90 is a third-wire Multibeam Trawl Sonar. It allows for accurate and
efficient monitoring of the net opening, the catch situation, and the fishing conditions. The
FM90 has a fast refresh rate that allows you to view the sonar images in real time.
The Simrad FM90 Multibeam
Trawl Sonar provides significant
improvements over the Simrad
FS70 Trawl Sonar and other
scanning sonars. The FM90 Sonar
communicates with the vessel by
means of a third-wire system using
very high bit-rate digital subscriber
line (VDSL2) communication,
transmitting real-time images of
the net opening at rapid refresh
rates. In addition, an echo sounder looking up ("up sounder") monitors fish escaping over
the net, while another echo sounder shows the foot-rope, the sea bottom, and the fish
entering the net.
By means of the submerged Trawl Unit, the FM90 communicates with a number of Simrad
PI/PX 40 kHz catch monitoring sensors by means of hydroacoustic links. Up to six
measurements can be made simultaneously. The FM90 supports pitch, roll, depth, catch,
bottom-contact, temperature, spread, height, and geometry sensors. Standard pitch, roll,
depth, and temperature sensors are also built in to the Trawl Unit.
The FM90 is a solid-state sonar system. This design eliminates moving parts, and increases
reliability and availability during fishing operations.
The FM90 Deployment Pack has a yellow top and
black bottom to assist you in visual confirmation
prior to launch and to assist in visual sighting during
recovery. It is quick filling and quick to drain. It
has improved hand holds to assist handling — even
with gloves on. The strain relief can be accessed
using standard tools without opening the entire
Deployment Pack.
Specifications and functionality
The FM90 is a unique sonar, both in design and functionality. When the FM90 sonar
pings, it sends out sound energy in a 240-degree sector. This energy is reflected from
the net, from fish, and from other targets in the water column. The reflected energy is
received by the transducer, processed, and shown on the display. Because the FM90 pings
Simrad FM90 Reference Manual