Synchronization page

The purpose of the Synchronization parameters is to set up the ST90 system to operate alone, or as a master or slave in a synchronized system. Synchronization is required in order to avoid interference if the ST90 system is used simultaneously with other hydroacoustic instruments within the same frequency range.

Prerequisites

The Installation dialog box is not available when your ST90 system is set to Replay mode.

How to open

This page is located in the Installation dialog box. To open the page, select Installation on the Setup menu.

Description

Whenever more than one hydroacoustic system is installed on a vessel, interference may occur. To avoid interference, you have these options:

The systems are all connected to a common synchronization system.
One of the acoustic systems is set up as "master", and controls the transmissions on the other systems.

The ST90 system offers functionality for remote transmit synchronization. It can be set up to operate in either Master or Slave mode.

In physics, interference is the phenomenon in which two waves superpose each other to form a resultant wave of greater or lower amplitude. Interference usually refers to the interaction of waves that are correlated or coherent with each other, either because they come from the same source or because they have the same or nearly the same frequency. Interference effects can be observed with all types of waves, for example, light, radio, acoustic, surface water waves or matter waves.
https://en.wikipedia.org/wiki/Wave_interference — April 2016

Note:

When you work in the Installation dialog box, you must always select Apply to save the changes made on a page. You must do this before you continue working on a different page.

Details

Synchronization Mode

Choose which synchronization mode to use.

For "slave" operation, a remote system (for example K-Sync or Simrad TU40) must be available to provide trigger pulses.

For "master" operation, a remote hydroacoustic system (sonar, echo sounder) is connected. This remote system must be set up in "slave" mode.

Stand-alone

This synchronization mode is used when the ST90 system is working by itself. Synchronization is turned off. It is the default setting. The ST90 system operates using the current settings for ping interval. The operation is independent of any trigger signals arriving at the synchronization port.

The Synchronization Delay setting is not applicable when synchronization is switched off.

Master

Master mode is used if the ST90 system shall operate as the controlling unit in a synchronized system. Any peripheral hydroacoustic system(s) are only permitted to transmit when enabled by the ST90 system. The ST90 system operates using the current settings for ping interval. It also sends trigger signals to the peripheral system(s).

This mode is unavailable if you set Synchronization Port to Transceiver Auxiliary Port.

Slave

The Slave mode is used if the ST90 system shall transmit only when permitted by a peripheral system. When the Slave mode is selected, the ST90 system will not transmit ("ping") unless an external trigger appears on the chosen synchronization port. The peripheral system may be any other hydroacoustic product (for example an echo sounder or sonar), or even a dedicated synchronization system.

The synchronization mode is not fixed. It can be changed at any time during operation.

Note:

Simultaneous transmission of more than one hydroacoustic system can only take place if the systems operate with different frequencies.

Synchronization Delay

This delay parameter is used differently depending on the chosen synchronization mode.

Stand-alone: The Synchronization Delay setting is not applicable when synchronization is switched off.
Master: In Master mode, the ST90 system waits for the delay time after the external trigger signal has been sent to the slaves before transmitting the ping. This is often referred to as a pre-trigger.
Note:
This delay will only work when the synchronization is set up using a serial port.
Slave: In Slave mode, the ST90 system waits for the delay time after the external trigger signal has arrived before transmitting the ping. This is often referred to as a post-trigger.

Synchronization Port

This is the interface port currently used to transmit or receive synchronization signals. Since the synchronization function only uses the Request To Send (RTS) and Clear To Send (CTS) signals on a serial port, you may be able to use a port that is already assigned other interface purposes. For the same reason, you do not need to define any baud rate.