Page 344 - Introduction to Marine Engineering

318 Instrumentation and control

The ultimate goal in the centralised control room concept will be to
perform and monitor every possible operation remotely from this
location. This will inevitably result in a vast amount of information
reaching the control room, more than the engineer supervisor might
reasonably be expected to continuously observe. It is therefore usual to
incorporate data recording and alarm systems in control rooms. The
alarm system enables the monitoring of certain measured variables over
a set period and the readings obtained are compared with some
reference or desired value. Where a fault condition is located, i.e. a
measured value different from the desired value, audible and visual
alarms are given and a print-out of the fault and the time of occurrence
is produced. Data recording or data logging is the production of
measured variable information either automatically at set intervals or on
demand. A diagrammatic layout of a data logging and alarm monitoring
system is shown in Figure 15,42.

Unattended machinery spaces

The sophistication of modern control systems and the reliability of the
equipment used have resulted in machinery spaces remaining un-
attended for long periods. In order to ensure the safety of the ship and
its equipment during UMS operation certain essential requirements
must be met:

1. Bridge control. A control system to operate the main machinery must
be provided on the bridge. Instrumentation providing certain basic
information must be provided.
2. Machinery control room. A centralised control room must be provided
with the equipment to operate all main and auxiliary machinery
easily accessible.
3. Alarm and fire protection. An alarm system is required which must be
comprehensive in coverage of the equipment and able to provide
warnings in the control room, the machinery space, the accommoda-
tion and on the bridge. A fire detection and alarm system which
operates rapidly must also be provided throughout the machinery
space, and a fire control point must be provided outside the
machinery space with facilities for control of emergency equipment.
4. Emergency power. Automatic provision of electrical power to meet the
varying load requirements. A means of providing emergency
electrical power and essential lighting must be provided. This is
usually met by the automatic start up of a standby generator.