Detail

Control system is an arrangement of elements interconnected and interacting in order to maintain, or to affect in a prescribed manner, some condition of a body, process or machine, which forms part of the system where as automation involves self-acting or self-regulating apparatus, process, or system that generally through the employment of mechanical or electrical devices that replace human observation, effort, and decision-making.

On a ship there are many parameters that needs to be controlled or monitored including: temperatures, pressure, level, viscosity, flow control, position of vessel, speed, torque control, voltage, current, machinery status (on or off), and equipment status (open or closed).

In the drive to become more efficient with reduced staff on board it called for an automatic control and monitoring system for the ship that enabled unattended operation of machinery spaces. Vessels capable of safe operation at any period of time qualify as UMS (Unattended Machinery Space) ships.

A modern automation and control system is a fully integrated system covering many aspects of the ship operation that includes the propulsion plant operation, power management operation on the auxiliary engines, auxiliary machinery operation, cargo on-and-off-loading operation, navigation and administration of maintenance and purchasing of spares.

Propulsion (Main Engine) and Power (Auxiliary Engines) Monitoring & Control
Monitoring and control of the ships propulsion and power is essential for its efficiency and safety and there are many systems and parameters to consider like: fuel consumption, combustion temperature, engine temperature, diesel engine safety and start/stop, generator voltage and frequency control, generator load in KW and %, load control, torque, heavy consumers logic, control of diesel electric propulsion, thrusters monitoring and control etc..

Auxiliary Machinery Monitoring and Control
Auxiliary machinery monitoring and control covers several systems like: main sea & fresh water cooling system – pumps, system pressure, temp. etc., Potable and fresh water control, Air compressors, Bilge & sludge control – Tank level, pumps, Fuel oil system – Tank levels, temp., viscosity, flow, purifiers, heaters etc., Other cooling systems, Boiler or steam system – pumps, valves, pressure temp. etc., Air Conditioning, ballast water treatment, exhaust gas treatment equipment.Cargo & Ballast Monitoring & Control
For safe on and off loading of cargo, especially on tankers, this process is closely monitored and many times incorporates functions like: Level gauging, Control of cargo pumps, Valve control, Ballast & ballast pump control, Heeling control, Remote monitoring of temperature, pressure, and flow. When cargo like stogie and cigars are being transported, sometimes, humidity-controlled Cigar Lockers are also used.

Condition based monitoring
In order to further improve the ships efficiency many equipment manufacturers are looking into feeding the main control and monitoring system with opportunities for condition-based monitoring. This would further improve the possibilities of preventing breakdowns on board.

Components include:

Master controller is used in a cascade control system. It provides an output which acts as a variable desired value for a slave controller.

Control stations spaces in which the ship radio or the main navigating equipment or the emergency source of power is located, or where the fire recording or fire control equipment is centralized, (SOLAS). Centralized control station is a propulsion control station fitted with instrumentation, control systems and actuators to enable propulsion and auxiliary machinery be controlled and monitored, and the state of propulsion machinery space be monitored, without the need of regular local attendance in the propulsion machinery space. Remote control station is a location fitted with means of remote control and monitoring.

Automation is done either in form of closed or open loop. Closed-loop are self-regulating control system, that maintains the desired operation by comparing the controlled variable to the set point. The difference between actual and desired outputs creates an error signal. That error signal is fed back to the control elements, which act upon it to reduce the error signal within an acceptable tolerance band. An example of such control is the regulation of the voltage and frequency of the ship, electrical generators under varying load conditions. Open-loop on the other hand do not employ the feedback principle. Such systems are self-acting but not self-regulating and are used in automated systems where system operation can be predicted with a high degree of certainty.

Integrated monitoring system combines of all the individual control systems in a plant into a single computer-controlled system. This would include all aspects of navigation, cargo control, machinery control and also administrative systems on a ship.

Engine automation system is a modular, embedded control system for control and monitoring of diesel and gas engines. The system facilitates fundamental engine safety functions, engine monitoring and control of fuel injection and ignition functionalities. The system also includes start/stop logics and speed/load control.