In an electrical switchboard vertical section, vertically adjacent pairs of cubicle doors are mounted by common hinge blocks located adjacent door corners and releaseably, latchingly corners. Horizontally aligned pairs of hinge and latch blocks additionally serve as mounts for instrument compartments located in the spaces available between vertically adjacent doors; these compartments slidingly accomodating drawout instrument drawers.

Requirements for Unattended Machinery Space (UMS) ShipFire PrecautionA) Arrangement should be provided on UMS ship to detect and givealarmin case offire.a) In theboilerair supply casing and uptake.b) In scavenge space of propulsion machinery.B) In engines of power 2250 Kw and above or cylinders having bore more than 300mm should be provided with oil mist detector forcrankcaseor bearing temperature monitor or either of two.Protection against FloodingBilge well in UMS ship should be located and provided in such a manner that the accumulation of liquid is detected at normal angle of heel and trim and should also have enough space to accommodate the drainage of liquid during unattended period.

In case of automatic starting of bilgepump, the alarm should be provided to indicate that the flow of liquid pumped is more than the capacity of the pump.Control of Propulsion Machinery from Navigation BridgeThe ship should be able to be controlled from bridge under all sailing conditions. The bridge should be able to controlthe speed, direction of thrust, and should be able to change the pitch in case of controllable pitchpropeller.Emergency stop should be provided on navigating bridge, independent ofbridge controlsystem.

The remote operation of the propulsion should be possible from one location at a time; at such connection interconnected control position are permitted.The number of consecutive automatic attempt which fails to start the propulsion machinery shall be limited to safeguard sufficient starting air pressure.Centralized control & instruments are required in Machinery SpaceCentralized control system should be there so that engineers may be called to the machinery space during emergencies from wherever they are.Automatic Fire DetectionAlarms anddetectionshould operate very rapidly and effectively. It should be placed at numerous well sited places for quick response of the detectors.

Fire Extinguishing SystemThere should be arrangement for fire extinguishing system other than the conventional hand extinguishers which can be operated remotely from machinery space. The station must give control of emergency fire pumps,generators, valves, extinguishing media etc.Alarm SystemA comprehensive alarm system must be provided for control & accomodation areas.Automatic Start of Emergency GeneratorArrangement forstarting of emergency generatorand automatic connection to bus bar must be provided in case ofblackoutcondition. Apart from that following points are also to be noted.1) Local hand control of essential machineries likesteering, emergency generator starting, emergency start for main engine etc.2) Adequate settlingtankstorage capacity.3) Regular testing & maintainence of machinery alarms & instruments.

Within the environment of a marine plant there are many parameters which need to be controlled or monitored including: temperatures, pressure, level, viscosity, flow control, speed, torque control, voltage, current, machinery status (on/ off), and equipment status (open/ closed).

In olden times it was the role of the watch keeping engineers to monitor and control the machinery plant. This was achieved by periodically taking rounds around the engine room and manually inspecting the condition of the running machinery. Often the engineer was totally dependent on his natural senses, frequently supported by only the minimum of widely distributed simple monitoring devices.The demand to reduce manning level led to the development of automatic control arrangements for the engine room plant which enabled unattended operation of machinery spaces. With vessels capable of safe operation for any period of time in this mode, those ships were qualified as UMS (Unattended Machinery Space) ships.In these types of ships, all the control systems and monitoring facilities are grouped together in an Engine Control Room and the ship machinery can also be controlled from this station.Initially the control room was located in the engine room, with extended monitoring and alarm systems to the bridge and in the accommodation while the ship is running in UMS. But as of recent development, ships are built with the engine control room adjacent to the bridge.In the latest trend, the control room uses the total integrated systems for all aspects of ship operation which includes engine room operation, cargo operation, navigation, and general administration.Bridge Control of Main EngineBridge control of Main Engines:Automatic control of the starting of the main engine can be done from the bridge as well as in Engine control room. The automatic controls employed in starting the engine is by the following sequence:1. Automatic control used in correctly positioning of the cam shaft.2. Admitting starting air3. Admitting fuel4. Starting air shut off5. Speed adjustment to the value requiredThus the engine is started and the various parameters like temperature, pressure, flow and tank level have to measured at every watch to make sure that the engine is running safely.Temperatures of lube oil, JCW, exhaust gas, etc. are measured.Pressures of lube oil, JCW, fuel oil, and starting air etc. are measured.Flow of fuel oil is measured while running.Tank levels of Heavy fuel oil, diesel oil, and lube oil are measured.For measuring the parameters we make use of the transducers, in turn sending the input signal to the automatic control system. Boiler Control SystemBoiler control systems:Automatic control of boiler is also done from the engine control room. The automatic systems employed in controlling the following:1. Boiler system (open / closed feed)2. Steam pressure3. Steam temperature4. Water level5. Feed water level6. Feed pump7. Feed water temperature8. Fuel oil system9. Air heater10. Smoke density11. Force draught fanThus if any of the above automatic system fails it give alarm and trips the boiler for a safe operation. Turbine and Reduction GearIn case of the steam propulsion ship the steam from the boiler enters in to the turbine and in turn it is coupled with reduction gear so some of the automatic controls used are.1. Controlling the speed of the rotation of the turbine in turn it controls the speed of the ship.2. Bleeder valve control3. Lube oil temperature control.4. Over speed trip control.5. Condensate system. Diesel GeneratorThis is employed in automatic starting and stopping of the auxiliary generator from the engine control room. So of the automatic control used are:1. Starting and stopping of the engine according to the load demand.2. Synchronization of incoming generator.3. Closing the circuit breaker4. Load sharing between the alternators5. Maintaining the supply frequency and voltage.6. Engine and alternator fault protection7. Preferential tripping of non-essential loads.Turbo GeneratorIn case if the steam propulsion ships they use turbo Generators for generating the power. In this type the small Steam turbines are coupled with the alternators and the automatic controls used are8. Reset governor trip level.9. Reset emergency stop valve.10. Staring auxiliary lube oil pump11. Staring the circulating pump12. Apply gland steam13. Starting extraction pump14. Staring the air ejector15. Opening the steam valve.These are some of the automation commonly used in marine environment.

Electro pneumatics is now commonly used in many areas of Industrial low cost automation. They are also used extensively in production, assembly, pharmaceutical, chemical and packaging systems. There is a significant change in controls systems. Relays have increasingly been replaced by the programmable logic controllers in order to meet the growing demand for more flexible automation. Electro-pneumatic control consists of electrical control systems operating pneumatic power systems. In this solenoid valves are used as interface between the electrical and pneumatic systems. Devices like limit switches and proximity sensors are used as feedback elements.

Electric control excels when absolute accuracy of movement is required or when continuous motion is needed. Electric servo control is useful in such diverse applications as CNC spindle controls in machining centers and in lift and locate applications in assembly operations.

Hydraulics is the choice for heavy loads when immediate motion is required. Forces are by far the highest of the three technologiesupwards of 100 tons. Hydraulics allows full velocity to be achieved quickly.

Pneumatics is chosen because speed and force are easily and continuously controllable over a wide range. This technology is positions, fluid power is extremely accurate and repeatable. For more than three positions, pneumatics can give about +/-1mm.

Closed-loop control systems are also called feedback control systems are very common in process control and electronic control systems. Feedback systems have part of their output signal fed back to the input for comparison with the desired set point condition. The type of feedback signal can result either in positive feedback or negative feedback.In a closed-loop system, a controller is used to compare the output of a system with the required condition and convert the error into a control action designed to reduce the error and bring the output of the system back to the desired response. Then closed-loop control systems use feedback to determine the actual input to the system and can have more than one feedback loop.Closed-loop control systems have many advantages over open-loop systems. One advantage is the fact that the use of feedback makes the system response relatively insensitive to external disturbances and internal variations in system parameters such as temperature. It is thus possible to use relatively inaccurate and inexpensive components to obtain the accurate control of a given process or plant.However, system stability can be a major problem especially in badly designed closed-loop systems as they may try to over-correct any errors which could cause the system to loss control and oscillate.

Analog deviceis usually a combination of both analogmachineand analogmediathat can togethermeasure,record, or reproduce continuousinformation, for example, the almost infinite number of grades oftransparency,voltage,resistance,rotation, orpressure. In theory, the continuous information (alsoanalog signal) has an infinite number of possiblevalueswith the only limitation onresolutionbeing theaccuracyof the analog device. Example of analog device is amplifier, op-amp, transistor, transducer.

A digital device is an electronic device which uses discrete, numerable data and processes for all its operations.Example of digital device is adder, multiplexer, encoder, decoder.

Fault detection and isolationis a subfield ofcontrol engineeringwhich concerns itself with monitoring a system, identifying when afaulthas occurred, and pinpointing the type of fault and its location. Two approaches can be distinguished: A direct pattern recognition of sensor readings that indicate a fault and an analysis of the discrepancy between the sensor readings and expected values, derived from some model. In the latter case, it is typical that a fault is said to be detected if the discrepancy orresidualgoes above a certain threshold. It is then the task of fault isolation to categorize the type of fault and its location in the machinery. Fault detection and isolation (FDI) techniques can be broadly classified into two categories. These include Model-based FDI and Signal processing based FDI.