Setting up the input from a motion reference unit (MRU)
The information from a motion reference unit (MRU) (normally heave, roll and pitch information) is imported into the MS70 to increase the accuracy of the echo data.
Prerequisites
This procedure assumes that:
•  The vessel is berthed or at sea.
•  You have a vacant interface port on your Processor Unit.
•  You are familiar with NMEA and other relevant datagram formats.
•  You know how to set up the parameters for serial and local area network (LAN) communication.
You must be equipped with a standard set of tools. This tool set must comprise the normal tools for electronic and electromechanical tasks, such as screwdrivers, pliers, spanners, a cable stripper etc. Each tool must be provided in various sizes. We recommend that all tools are demagnetized to protect your equipment.
Context
A motion reference unit (MRU) measures the vessel’s pitch and roll movements in the sea. The information provided by the motion sensor is used by the MS70 to stabilize the echo presentation.
Note
The input from the motion reference unit (MRU) is of vital importance to the MS70. An unserviceable - or inaccurate - sensor will render the scientific data useless. Due to the importance of the motion sensor data, the MS70 will stop "pinging"’ if the information from the sensor is lost.
The supported datagram formats are listed in the Technical specifications chapter.
Procedure
1 Connect the motion sensor system to serial port 1 (COM1) on your Processor Unit.
This is described in the Cable layout and interconnections chapter.
•  Make sure that the serial port is set up for RS-422 communication.
•  Observe the applicable requirements related to cabling.
•  Ensure that the total length of the serial line cable does not exceed approximately 50 meters. If a longer cable is required, you may need to use buffer amplifiers.
•  If the Processor Unit is not fitted with a suitable serial line connector, use a USB-to-serial converter. Several types are commercially available.
Image
A Local connection on the Processor Unit
B Connection on remote device
2 Observe that the interface parameters are defined in the MS70 software. No additional setup is required.