KONGSBERG BWMS system operation and maintenance

Explicit interaction: The on duty driver actively presses the "I'm on watch" button on the bridge deck panel or triggers it through a connected motion sensor (such as an infrared motion detector).

Implicit interaction: Read user input from navigation devices (radar, ECDIS, autopilot) connected to BWMS, such as turning the radar's azimuth knob, changing the display scale of the electronic chart, or adjusting the heading setting of the autopilot. Once any interaction is captured, the internal timer is immediately reset to 0.

When the timer accumulates to the set "first level delay" threshold and no interaction occurs, the system determines to enter the "potential unmanned" state.

6.2 Classification alarm transfer process

Stage 1- Local Reminder: The bridge alarm panel emits a buzzing sound (approximately 85dB) and flashes a red light, while displaying "Bridge Unattended - Please Respond". At this time, the on duty driver should press the 'Acknowledge' button on the dashboard or operate any networked navigation device within 30 seconds. If successful, the timer will reset and everything will return to normal.

Stage 2- Call Captain: After the local reminder timeout, the system automatically triggers the output relay, connects the sound alarm installed in the captain's bedroom/dining room, and sends text to the captain's portable reminder device (if integrated). The captain can respond remotely through a dedicated "takeover" button or rush to the bridge for confirmation. After the response, the system will reset and will no longer continue with the upgrade.

Stage 3- Call the backup navigator: If the captain does not respond within the set time, BWMS activates the third level output and sends an alarm to the residences of the first and second officers until someone responds.

6.3 Manual call backup function

During regular duty hours, if the duty driver needs to temporarily leave the bridge building (such as the restroom or retrieve documents) or feels unwell, they can press the 【 Call Backup 】 button on the dashboard. This will immediately bypass stages 1 and 2 and directly call the backup navigator with the highest priority to come and provide support. This operation is not considered an alarm fault, but it is recorded in the ship safety log.

Common troubleshooting and repair cases

7.1 Fault 1: Frequent false alarms on bridge deck panels (triggered when no one is present)

Phenomenon: Even though VDR playback shows that there is always someone operating the bridge, the system still prompts "Unattended" every few minutes.

Possible reasons:

The installation position of the motion sensor is unreasonable, covering blind spots or being too far away from the main operating position.

Implicit interaction signal not properly connected - radar/CDIS did not send heartbeat or button pulses to BWMS.

If the timer is set too short (e.g. 5 seconds), the driver will be judged as pausing if they do not check the chart normally for a few seconds.

Solution steps:

Check the "Activity Sources" page in MOS-33 to see which interaction device was last detected. If 'None' is displayed, it indicates that BWMS has not received any external input.

Temporarily increase the first level delay of the timer to 45 seconds (for testing purposes) and observe if frequent alarms still occur. If not reported, the original set value is too short and should be set to 15-20 seconds according to the actual working pace.

Check sensor wiring: The infrared motion detector should be installed near the driver's head when seated normally, and avoid the air conditioning outlet (to avoid mistaking airflow for movement). The detector output normally open contact should be connected to the DI terminal of RDi-32.

For integration with radar/ECDIS, it is necessary to ensure that the baud rate of the serial communication between devices (NMEA 0183 or NMEA 2000) matches, and the message format is "$IIACK *". Data can be captured using the "Communication Monitoring" tool within MOS.

7.2 Fault 2: Alarm transfer cannot trigger the captain's cabin alarm

Phenomenon: The local alarm on the bridge tower prompts normally, but after exceeding the time limit, there is no sound or light signal at the captain's location.

Possible reasons:

The output relay (RDo-16 corresponding channel) is damaged or the wiring is loose.

The captain's cabin alarm itself is malfunctioning (such as a burnt buzzer).

The 'Level 1 output' is not correctly associated with a specific physical output point in MOS.

Solution steps:

Enter MOS-33 "Output Test" mode and force the relay of the corresponding port on RDo-16 to be activated. If you can hear the sound of the relay action and measure its contact continuity with a multimeter, then the output board is normal; Otherwise, replace the DPU.

Check if there is any open or short circuit in the cable from the output terminal to the captain's cabin alarm. Measure the control voltage at the alarm terminal (should be 18-32V). If there is no voltage, search for the intermediate junction box.