Context
The motion reference unit (MRU) measures the roll and pitch movements of the vessel. Some sensor models also measure heave. The information provided by the motion sensor is used by the SN90 system to stabilize the beams.
A hull unit may be provided as an option. It allows you to lower and hoist the transducer. A motion sensor for electronic stabilization of the sonar beams is provided. It is placed inside the Motor Control Unit. For improved operational accuracy, an external motion reference unit (MRU) can be used.
With hull unit
The SN90 system uses the built-in motion sensor. The sensor uses a local area network (LAN) port on your computer. A message on the page verifies that it is connected to the SN90 system’s beamformer application.
If you wish to use an external motion sensor, connect it to a vacant serial port, and set Port to the corresponding COM port.
Without hull unit
Use an external motion sensor connected to a local area network (LAN) or serial port on your computer.
Further requirements
If you choose a serial COM port to interface the motion sensor, make sure that you do not put the same COM port to other use
on the I/O Setup page.
NoteTo align an external motion sensor to the internal sensor, you may need to adjust the stabilization
offset values.