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Maintenance procedures
Setting up the interfaces to peripheral devices
Setting up the input from an internal motion reference unit (MRU)
The information from a motion reference unit (MRU) (normally heave, roll and pitch information) is imported into the ST90 system to increase the accuracy of the echo data. The ST90 system is provided with a built-in motion sensor to provide electronic stabilization of the sonar beams. It is placed inside the Motor Control Unit.

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
- Lowering and hoisting the transducer from the sonar room
- Setting up the interfaces to peripheral devices
  - Installing navigation sensors and other sensors
    For the ST90 system to use and offer correct navigational information, one or more external sensors must be connected. Typical sensors are those providing navigational information (heading, speed or geographical position). To set up the communication parameters on the serial and LAN ports, use the I/O Setup page. To select which sensors to install, use the Sensor Installation page. The Sensor Configuration page allows you to define a datagram priority, so that the information from the "most reliable" sensor is used by the ST90 system. You can also define manual values in case a sensor is unserviceable, or not installed.
  - Setting up the serial and Ethernet (LAN) port parameters
    For any sensor interface to work, the communication parameters must be set up correctly. The ST90 software automatically scans the Processor Unit to locate and identify the available communication ports. Once the software has established a list of valid interfaces, you can set up and control the communication parameters.
  - Setting up the input from a navigation system (GPS)
    For the ST90 system to use and offer correct navigational information, one or more external sensors must be connected. Typical sensors are those providing navigational information (heading, speed or geographical position). To select which sensors to install, use the Sensor Installation page. Your current position is shown on the top bar if you have enabled this in the Display Options dialog box.
  - Setting up the interface for speed log input
    In order to operate correctly, the ST90 system requires input from a speed log. In most cases a suitable sensor is already installed on the vessel. A global positioning system (GPS) with a compatible output format can also be used. To select which sensors to install, use the Sensor Installation page. The vessel speed is shown on the top bar if you have enabled this in the Display Options dialog box.
  - Setting up the interface for course gyro input
    In order to operate correctly, the ST90 system requires input from a course gyro. In most cases a suitable course gyro is already installed on the vessel. A global positioning system (GPS) with a compatible output format can also be used. To select which sensors to install, use the Sensor Installation page. The current heading is shown on the top bar if you have enabled this in the Display Options dialog box.
  - Configuring the sensor priority
    With multiple sensors connected to the ST90 system, many of them will provide the same datagrams. We cannot expect that these datagrams provide the same information. The Sensor Configuration page allows you to define a datagram priority, so that the information from the "most reliable" sensor is used by the ST90 system. You can also define manual values in case a sensor is unserviceable, or not installed.
  - Setting up the input from an external motion reference unit (MRU)
    The information from a motion reference unit (MRU) (normally heave, roll and pitch information) is imported into the ST90 system to increase the accuracy of the echo data. The ST90 system is provided with a built-in motion sensor to provide electronic stabilization of the sonar beams. For improved operational accuracy, an external motion reference unit (MRU) can be used. This task is only applicable is you are using an external motion reference unit on your ST90 system.
  - Setting up the input from an internal motion reference unit (MRU)
    The information from a motion reference unit (MRU) (normally heave, roll and pitch information) is imported into the ST90 system to increase the accuracy of the echo data. The ST90 system is provided with a built-in motion sensor to provide electronic stabilization of the sonar beams. It is placed inside the Motor Control Unit.
  - Setting up the ST90 system for synchronized operation
    If you want to use the ST90 system as a master or slave in a synchronized system, you must set it up for such operation. To do this, you must select which communication port to use for the synchronization interface, and you must select the requested synchronization mode.
  - Setting up input from buoys, fish aggregating devices and other external objects
    Position information from external objects such as buoys, fish aggregating devices and other similar items can be imported into the ST90 system.
- Inserting the installation parameters
- Installing and maintaining software
- Testing the noise conditions and the sonar functionality
- Preventive maintenance
User interface
Menu system
Functions and dialog boxes
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.
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Setting up the input from an internal motion reference unit (MRU)

The information from a motion reference unit (MRU) (normally heave, roll and pitch information) is imported into the ST90 system to increase the accuracy of the echo data. The ST90 system is provided with a built-in motion sensor to provide electronic stabilization of the sonar beams. It is placed inside the Motor Control Unit.

Neither tools nor instruments are required.

The following options are available:

EM3000 LAN: This is the default setting. The Hull Unit Control board processes the sensor data.
Hull Unit Control: This is the recommended setting. The Hull Unit Control board provides unprocessed sensor data. The sensor data processing takes place in the Processor Unit.

The Hull Unit Control board is located in the lower right corner of the Motor Control Unit. Its primary purposes are:

It controls the transducer's hoisting and lowering operations and provides their status.
It reads the built-in motion sensor output and promptly transmits this crucial data to the Transceiver Unit.
It receives error reports from the hull unit sensors and sends these to the Processor Unit to generate a message.

Note:

You can only select unprocessed sensor data if the Hull Unit Control board software supports this feature. The software version must be 1.3.5 or later. Use the Hull Unit page to read the software and firmware versions from the Hull Unit Control board.

Procedure

Open the Setup menu.
On the Setup menu, select Installation.
Observe that the Installation dialog box opens. This dialog box contains a number of pages selected from the menu on the left side.
On the left side of the Installation dialog box, select Motion Reference Unit.
Set up the interface.
1. Select Internal to use the built-in motion sensor.
2. Select the sensor you want to use.
Select None to disconnect the ST90 system from both external and internal motion sensors.
At the bottom of the dialog box, select Apply to save your settings.
Make sure that the information from the sensor is visible on the top bar.
The current roll and pitch values are shown on the top bar if you have enabled this in the Display Options dialog box.
Select another input if the sensor data fails to appear on the top bar.
Continue your work in the Installation dialog box, or select OK to close it.