Kongsberg MRU E The extended temperature motion sensor

This 5th generation roll, pitch and heave motion sensor is specially designed

for use in marine applications that require an extended temperature range.

The MRU E is designed to operate at ambient temperatures from -25 to

+70 °C. It can be installed on open decks, inside cabinets or on bulkheads.

Typical applications

The MRU can be mounted directly under the helideck centre to measure 3-axes

linear accelerations together with roll, pitch and heave. The MRU E is typically

used in a Helideck Monitoring System where the helideck location is separate

from the accommodation and the hull. The MRU E meets HCA requirements

to measure helideck acceleration and calculate the Motion Severity Index (MSI).

Function

The MRU E is manufactured and calibrated in order to perform accurately at

ambient temperatures from -25 to +70 °C. The unit incorporates three highly

accurate accelerometers and three Micro-Electro-Mechanical-Structures (MEMS)

angular rate gyros. This unit achieves high reliability by using solid state sensors

with no moving parts and the proven MRU electrical and mechanical construction.

A special mounting bracket  for outdoor mounting of the MRU E is available.

This bracket protects the MRU from weather and sea spray.

Output variables

The MRU E outputs roll, pitch and heave together with linear acceleration in 3-axes.

PFreeHeave® algorithm

The PFreeHeave algorithm uses past measurements to output a correct and phase

free heave from the MRU. PFreeHeave has an advantage in long swell conditions and

for applications that can utilize a heave signal that is delayed some minutes, typically

seabed mapping applications.

External inputs

The MRU E accepts input of external speed and heading information on separate

serial lines or Ethernet for improved accuracy in heave, roll and pitch during turns and

accelerations.

For time synchronization the MRU accepts a 1-second time pulse (1PPS) input.

Digital I/O protocols

For this 5th generation MRU data is available through both Ethernet interface and

serial lines enabling easy distribution of MRU data to multiple users on board the vessel.

Output protocols for commonly used survey equipment are available on two individually

configurable serial lines and Ethernet/UDP.

FEATURES

• 0.010° roll and pitch dynamic accuracy

• Outputs real-time heave, roll, pitch and linear acceleration measurements

• Outputs on RS-232. RS-422 and Ethernet

• High output data rate (200 Hz)

• Each MRU delivered with Calibration Certificate

• No limitation in mounting orientation

• Lever arm compensation to two individually configurable monitoring points

• Meets HCA requirements

• Small size, light weight and low power consumption

• Selectable communication protocols in the Windows based MRU configuration

software

• 2-year warranty