Home
Functions and dialog boxes
Display menu: functions and dialog boxes
The Display menu provides basic functions related to the screen behaviour and presentation of the echo data. Use the Display menu to control the visual aspects of the system, and to show or hide various elements in the presentation.
Colour Threshold function
The Colour Threshold function allows you to reduce or increase the number of colours. This will provide a filtering effect that removes the weakest echoes.

About this manual
The purpose of this publication is to provide the descriptions, procedures and detailed parameter explanations required to allow for safe and efficient use of the ST90 system. The publication also provides you with a thorough understanding of the parameters and adjustments provided by the ST90 system.
Simrad ST90
Operating procedures
Maintenance procedures
User interface
Menu system
Functions and dialog boxes
- Main menu: functions and dialog boxes
  The Main menu is located at the top of the menu structure. It offers the most common functions for efficient use of the ST90 system. Unless you hide the entire menu system, the Main menu is visible at all times, even if you close the secondary menus.
- Operation menu: functions and dialog boxes
  The Operation menu allows you to control the operating mode, the recording functionality, and how the ST90 system transmits audio pulses ("ping") into the water.
- Display menu: functions and dialog boxes
  The Display menu provides basic functions related to the screen behaviour and presentation of the echo data. Use the Display menu to control the visual aspects of the system, and to show or hide various elements in the presentation.
  - Visual Objects function
    Visual Objects is an "on/off" button used to open the Visual Objects menu.
  - Cosmetics function
    Cosmetics is an "on/off" button used to open the Cosmetics menu.
  - Motion function
    In selected views you can control how the vessel symbol shall "behave" in the presentation. The way the vessel moves in the presentation can be chosen either true or relative.
  - Transparency function
    When you open an information pane, you will see that it is transparent. This transparency allows you to see the echo data behind the pane, but it may also reduce the visibility of the information in it. The transparency can be adjusted.
  - View Range function
    Use View Range to expand the range shown in the relevant views to any percentage of the original Range setting. The expansion is made without resizing the echoes using a "zoom" effect.
  - Display Gain function
    Use Display Gain to increase or decrease the "strength" of the echo presentation.
  - Panel Backlight function
    The buttons on the Operating Panel have a built-in backlight to improve visibility on a dark bridge. Use Panel Backlight to control the intensity of the lights.
  - Colour Threshold function
    The Colour Threshold function allows you to reduce or increase the number of colours. This will provide a filtering effect that removes the weakest echoes.
  - Screen Brightness function
    The intensity of the light given off by the display presentation can be adjusted. You can use this function to increase or decrease the light from the screen to match the ambient light.
  - Display Options dialog box
    The Display Options dialog box is used to specify basic settings for the sonar presentation. The pages in the dialog box are described in a separate structure.
  - Colour Setup dialog box
    The Colour Setup dialog box controls the presentation colours used by the ST90 system.
  - Docking Views function
    Each presentation mode offered by the ST90 system provides a selection of views in a predefined pattern. These are placed at different positions with different sizes. With the Docking Views function you can move and re-size the views in the display presentation.
- Setup menu: functions and dialog boxes
  The Setup menu provides basic functions related to the installation parameters and the communication with peripheral systems.
- Active menu: functions and dialog boxes
  The Active menu offers parameters related to current views and data presentations provided by the ST90 system.
- Secondary functions and dialog boxes
- Pages in the Output dialog box
  A key function of the ST90 system is its ability to export data. The purpose of the Output dialog box is to collect all functionality related to data output in one easily accessible location.
- Pages in the Display Options dialog box
  The Display Options dialog box is used to specify basic settings for the sonar presentation.
- Pages in the Environment dialog box
  Environmental parameters such as salinity, sound speed and water temperature all play an important part to present accurate echo data. Use the Environment parameters to define these values. Depending on the current sea and weather conditions, you may need to change these values frequently.
- Pages in the Diagnostics dialog box
  The ST90 system is a computerized sonar. There are hardly any analogue circuitry, and the possibility of traditional troubleshooting is limited. In order to rectify this, a built-in software application is available to offer test and maintenance functionality. The Diagnostics dialog box controls the test and diagnose application that checks the performance of the ST90 system.
- Pages in the Installation dialog box
  Before you use the ST90 system you must set it up to communicate with the relevant peripherals. Use the Installation dialog box to set up all interfaces with external devices, and to set up basic parameters related to installation and operation. In most cases, you only need to do this once.
- Pages in the Echogram dialog box
  The Echogram dialog box allows you to control the echogram presentation in the Inspection views. Two pages control the horizontal lines and the echogram type with applied TVG (time variable gain). One page controls how fast the echogram travels horizontally across the presentation.
- Pages in the Information Pane Options dialog box
  The ST90 system offers several information panes to provide additional and detailed data from the presentations. The information panes are opened and closed from the top bar. Several of the information panes are fitted with a Setup button. Select Setup to open the Information Pane Options dialog box. Use the Information Pane Options dialog box to change the operating parameters for the data provided in the information panes.
Concept descriptions
Technical specifications
The technical specifications summarize the main functional and operational characteristics of the ST90 system. They also provide information related to power requirements, physical properties and environmental conditions.
Datagram formats
The ST90 system can send and receive information to and from several different peripherals. All transmissions take place as datagrams with data sentences. Each datagram has a defined format and length.
***

Colour Threshold function

The Colour Threshold function allows you to reduce or increase the number of colours. This will provide a filtering effect that removes the weakest echoes.

How to open

Open this function from the Display menu.

Description

The Colour Threshold function is used to control how many colours you wish to use in the echo presentation. The selected colour threshold is reflected in the bottom bar.

This setting will thus reduce or increase the number of echo colours in the presentation.

Weak echoes are shown with "cold" colours (blue).
Echoes with medium strength have warmer colours (green and yellow).
The stronger echoes are shown with the warmest colours (orange and red).

The strength of the echoes is indicated using a scale with 16 or 64 colours. When the number of colours is reduced, the ST90 system will start by removing the colours that indicate the weakest echoes. The number of colours to be deleted is defined as a percentage of the total number of colours. The higher the number, the more colours are removed (until only the strongest echoes are shown).

By reducing the number of colours you will therefore remove the weakest echoes from the presentation. This causes the filtering effect. Since most echoes are weak when the range is long, the filter effect will reduce the detection range.