Lesson 28　CONTROL SYSTEMS I 轮机英语课件.ppt

Lesson 28 CONTROL SYSTEMS I Control systems on board ship are either automatic or remote or a combination of these. The term ‘automation’, or automatic control, generally is taken to mean the operation of a machine by a self-regulating mechanism that that senses the performance of the machine and, using a process called feedback, compares it with the intended performance, and then adjusts the machine to reduce the difference between actual and intended performance. In a full automatic control system, a computer is used to supervise, analyze, record and display the conditions of the machines, and then to make necessary decisions and take necessary actions. Remote control means that the system is being controlled by the operator who is situated remote from the system. Examples are steering gear, watertight door system, tanker cargo control, bridge control of engine, etc. The combination of automatic control and remote control results in the centralized control(集中的控制) of main and auxiliary machinery. Modern engine room has machinery control rooms from where every possible operation will be performed remotely. The operation state and parameters of working condition of machines can be recorded, displayed and controlled automatically or manually in the rooms. An alarm system enables the monitoring of certain measured variables(变量). Where a fault condition is located, audible and visual alarms are given and a print-out of the fault and the time of occurrence is produced. The modern improvement of control systems and the reliability of the equipment used have resulted in machinery space remaining unattended(无人看管的) for long periods. In order to ensure the safety of the ship and its equipment during UMS (Unattended Machinery Spaces无人机舱) operation, certain essential functions must be provided. Those are bridge control, machinery control room control, alarm and fire protection, and emergency power. UMS are mainly unattended overnight and during this time the br