Calibrating the Pitch and Roll

You need to calibrate the pitch and roll of the sensors when placed on the trawl doors.

Before you begin

Tip: Some trawl door manufacturers measure the pitch and roll offsets themselves and write them on the doors. Check on trawl doors.

About this task

A sensor pocket is usually welded to the door at a 15 to 20 degree vertical angle. This means that when trawl doors are vertical, the sensors will already have a pitch angle and maybe a roll angle. You need to calculate these angles and offset them in order to have 0° of pitch and roll when doors are vertical.

When calibrating the pitch and roll on Mosa2, you can select between three calibration types:
  • Automatic: select if you do not know the offsets. In this case, the doors need to be taken out and placed on the ground in order to calibrate the pitch and roll.
  • Manual: select if you already know the pitch and roll offsets, for example if they are written on the doors.
  • Import offset: select if you need to apply the same offsets as those from a previous installation, using the *.A2C configuration file (for example when replacing the sensor). See Exporting Sensor Configuration to know how to get the configuration file

Procedure

  1. Remove all rigging, shackles and attachment points from the doors.
  2. Remove the net gear attached to the door.
  3. Using a crane or forklift, place the door on a flat surface, such as a dock or similar location.
  4. Using the necessary rigging, hang doors with angles as close to 0 degree as possible on the vertical and horizontal plane. Use a carpenter level to help you.
  5. Insert the sensor in the pockets on the doors.
  6. Connect the sensor to the Dock or Configuration Cable to connect to Mosa2.
  7. From Mosa2, go to Measurements page and click in Motion.
  8. Check on the bottom of the window that the pitch and roll of the door are close to 0 degree.
  9. From Opening Angle, enter the angle between the door and the sensor (horizontal plane) in degrees. If you do not know the angle, ask the manufacturer for the angle of attack. If you cannot know the angle, you can put 35° but be aware that a wrong angle impacts pitch and roll measurements.
  10. Select the Calibration type:
    • Automatic: make sure the doors are in vertical position, then click Calibrate.
    • Manual: enter the offset values manually, then click Apply offset.
    • Import offset: click Import offset from config file and select the *.A2C configuration file from a previous installation.
  11. When the calibration is finished, click .


    Automatic calibration

    Manual calibration


    Import offset
  12. If you need to update the Accelerometer coefficients, download the last XML test file from MASP and connect in Expert mode.

Results

The sensor is calibrated.