Kongsberg Simrad SN90 Reference Manual page 544

Simrad SN90 Reference Manual
Description
You must correctly set the sound
speed through the water to obtain
accurate depth readings and fish
echoes. Several parameters are
required to calculate the correct
sound speed value. If these
parameters are unknown, use the
default value of 1494 m/s. This is
a typical mean value for sound speed
in salt water.
Details
Conditions
Use these settings to set up the
SN90 system for operation in
fresh or salt water.
Sound travels at different
speeds in salt and fresh water.
For this reason, the SN90
system must know your water
profile. The default setting is
Salt.
Parameters
Use these settings to provide manual values.
Freshwater/saltwater settings, temperature, salinity, acidity, depth, and operating
frequency are all used to calculate absorption.
Temperature
Specify the water temperature. Once the salinity and temperature information
is provided, the SN90 system calculates the sound speed and absorption.
Salinity
Provide the current salinity. Once the salinity and temperature information is
provided, the SN90 system calculates the sound speed and absorption.
Sound Speed
You must correctly set the sound speed through the water to obtain accurate depth
readings and fish echoes.
Calculated
Select
Calculated
absorption based on your supplied parameters (frequency, salinity, acidity
sound speed, and water temperature).
542
to allow the SN90 to calculate the sound speed and
381294/E