Information concerning scaling factor and number of decimals is programmed on each channel board, and is connected to the system bus at the same time as the measured value. It is possible to program eight different factors with a 3-bit binary code, and the number of decimals can be 0, 1 or 2.
The display is normally dark and is only lit up when a push-button for manual measuring has been depressed, the displayed value will follow the fluctuations of the signal. When the push-button is released, the value will remain unchanged for about five seconds.
Alarm measuring systems on vessels are crucial for monitoring and ensuring the safety and proper functioning of various shipboard systems. These systems typically include sensors, control units, and alarm displays, all working together to detect abnormal conditions and alert the crew. Here’s a detailed overview of the operation of alarm measuring systems on vessels:
1. Components of Alarm Measuring Systems
Sensors and Transducers:
- Measure physical parameters such as temperature, pressure, level, flow, and electrical parameters.
- Types include thermocouples, pressure transducers, level sensors, flow meters, and current/voltage sensors.
Control Units:
- Receive signals from sensors.
- Process data to determine if parameters are within acceptable ranges.
- Compare readings against preset thresholds.
Alarm Displays and Panels:
- Visual and audible indicators to alert the crew.
- Located on the bridge, engine room, and other critical areas.
- Can include mimic panels, computer screens, and integrated alarm management systems.
2. Operation Process
Data Collection:
- Sensors continuously monitor various parameters.
- Data is transmitted to control units in real-time.
Data Processing:
- Control units process the data to check for deviations from normal conditions.
- Signal conditioning may be performed to filter noise and convert signals to a usable format.
Alarm Triggering:
- If a parameter exceeds or falls below the preset threshold, the control unit activates an alarm.
- Types of alarms include visual signals (lights), audible signals (horns, sirens), and text messages on display panels.
Crew Notification:
- Alarms are designed to be easily noticed by the crew.
- May include redundancy (e.g., multiple alarms for the same condition) to ensure alerts are not missed.
Response and Acknowledgment:
- Crew must acknowledge the alarm, often by pressing a button or entering a code.
- Immediate actions are taken to address the issue, following established procedures.
- Alarms are logged for later review and analysis.
3. Types of Alarm Systems on Vessels
Fire and Smoke Detection Systems:
- Detect fire, smoke, and high temperatures.
- Essential for preventing and responding to onboard fires.
Engine and Machinery Monitoring Systems:
- Monitor engines, generators, and other machinery.
- Parameters include temperature, pressure, lubrication, and vibration levels.
Bilge and Ballast Systems:
- Monitor water levels in bilge and ballast tanks.
- Prevent flooding and maintain vessel stability.
Navigation and Bridge Systems:
- Monitor navigation equipment, autopilot, and radar systems.
- Ensure safe navigation and collision avoidance.
Cargo Monitoring Systems:
- Monitor conditions in cargo holds and tanks.
- Important for transporting hazardous materials and ensuring cargo integrity.
4. Maintenance and Testing
Regular Inspections:
- Routine checks to ensure sensors and alarm units are functioning correctly.
- Includes calibration of sensors and verification of alarm set points.
Functional Testing:
- Simulating alarm conditions to test system response.
- Ensures alarms trigger appropriately and crew can respond correctly.
Documentation and Logging:
- Keeping records of alarm events, maintenance activities, and system tests.
- Helps in troubleshooting and improving system reliability.
5. Regulations and Standards
- Compliance with international maritime safety regulations (e.g., SOLAS, MARPOL).
- Adherence to standards set by classification societies (e.g., DNV GL, ABS).
- Regular audits and inspections by maritime authorities to ensure compliance.
By effectively monitoring critical parameters and alerting the crew to any deviations, alarm measuring systems play a vital role in maintaining the safety and operational efficiency of vessels. Proper maintenance, regular testing, and adherence to regulatory standards are essential to ensure these systems function correctly.
