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4 Functional Description
4.1 WATER TRACK U user interface
Configuration of log functions may be performed using the built-in menu system in WATER
TRACK U. The menu system is accessed using the Speed Log Master Display.
For status indication ten green and one red LED are also available on the WATER TRACK U
board. See 2.3 User interfaces for a closer description of what each LED indicates and 4.3
Menu system for details about the menu system.
4.2 Application Software
The STW-log application software has different working modes as described below.
4.2.1 Power on / software update
At power on the speed log runs a boot loader program that tests if the application software is
present and not corrupted. If the software is found and correct, the log starts to execute in
normal operation. The boot loader may also be used to download updated log software
applications when released. During update the boot loader controls erase of the old application
as well as storing of the new updated application.
4.2.2 Normal operation
Two different tasks are cyclically performed during normal operation:
x Ten consecutive speed measurements.
x One self-diagnosis cycle.
This sequence is repeated indefinitely and will only be interrupted if a menu command forcing
the log into test mode is externally requested from the NWW-82 Speed Log Master Display or
elsewhere.
4.2.3 Speed measurement
Speed measurement is the highest prioritised task and will be executed ten times in a row. The
measurement can be executed in several different modes depending on previous events and
measuring environment.
x Zero mode (4)
x Particle mode (1)
x Dirty mode (10)
x Clear mode (13)
x High speed mode (7)
Zero-mode is used if speed is below 1 knot and High speed mode is used at speeds above 40
knots. Between these two extremes Particle mode is normally used.
Should the echo signal be very strong due to high particle contents in the water, mode is
changed to Dirty mode. On the contrary if a very weak signal is returned the mode is changed
to Clear mode.
The numbers within parenthesis corresponds to the internal mode number also shown in the
mode position in the root menu window, see 4.4.1
Root Menu.
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