Control valves of a CO2 system may be located within the pro

Operation of the valve control release on a fixed CO2 system must immediately ______.

A.release CO2 to the protected space

B.secure all mechanical ventilation in the protected space

C.sound the rig’s general alarm signal for a fire

D.sound an alarm in the ballast control room

第一组

An automatic system usually consists of a control system and an information system. A control system is a system which measures the condition of some entity and, with the information, governs the state of a variable; i.e., speed, temperature, pressure, position, etc. The open-loop system is the simplest form. a control system may assume. It is distinguished from the closed-loop system by the lack of an input which measures the state of the controlled variable; such an input is called a feedback. In modern ships the open-loop system has practically disappeared and the closed-loop system which operates with a feed-back is extensively used. An information system serves the parallel function of monitoring system or plant performance. The monitoring function may serve a number of purposes; specifically it may indicate values of controlled variables to guide remote control operations, warn of off-limit conditions and provide record of performance. In many cases a visual and audible alarm may be provided to warn of off-limit conditions on board ship and, associated with this, the important variables will be recorded on demand. The automatic control system can be more sophisticated by incorporating digital-processing equipment, that is, a computer. This computer is usually fed with signals from all sensors. It scans the values of the sensors and generates alarm signals for off-limit conditions, acting as a super-supervisor. Sometimes, it can even make necessary and take the necessary action to optimize performance without human intervention.

The closed-loop system differs from the open-loop system by

A.the lack of a feedback

B.the presence of a feed back

C.the lack of a computer

D.the presence of a computer

Which of the listed pressure control valves would be used to establish the maximum operating pressure of a hydraulic system?

A.Pressure-reducing valve

B.Unloading valve

C.Counterbalance valve

D.Pressure-relief valve

Which statement is TRUE concerning the placard entitled Discharge of Oil Prohibited ________．

A.It is required on all vessels

B.It may be located in a conspicuous place in the wheelhouse

C.It may be located at the bilge and ballast pump control station

D.All of the above

Before performing any maintenance on a hydraulic system storing energy in an accumulator, you should

A.pressurize the system to test for leaks

B.bleed off all pressure within the system

C.operate the machine until it reaches normal temperature

D.disconnect the pump pressure control switch

Where normal delivery at the port of destination is prevented by some cause beyond the control of the master，and the master may and must deal with the cargo for the benefit of its owners by landing it，carrying it，or transshipping it，as may seem best，the Shipowner may then charge the cargo owners with ______ to cover the expenses thus incurred in their interests．

A.pro rata freight

B.advance freight

C.dead freight

D.back freight 答案

●An Embedded System is a (72)designed for specific control functions within a larger system.

(72) A． computer

B． program

C．computer system

D．tool

Valves on steam-smothering lines to cargo tanks shall be set with ______．

A.The master control valve shut and valves to individual cargo tanks shut

B.The master control valve open and valves to individual cargo tanks shut

C.The master control valve shut and valves to individual cargo tanks open

D.All valves open