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Instrumentaon and control systems
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REEDS MARINE ENGINEERING AND TECHNOLOGY
INSTRUMENTATION
AND CONTROL SYSTEMS
S O
%%*arx .
\
■ t r * +
> () \\ s B u K V
EDS MARINE ENGINEERING AND TECHNOLOGY SERiES
1.1 Mathematics for Marine Engineers
1.2 Applied Mechanics for Marine Engineers
1.3 Applied Heat for Marine Engineers
1.4 Naval Architecture for Marine Engineers
1.5 Ship Construction for Marine Students
. 6 Basic Electrotechnology for Marine Engineers
. 7 Advanced Electrotechnology for Marine Engineers
. 8 General Engineering Knovvledge for Marine Engineers
. 9 Steam Engineering Knovvledge for Marine Engineers
. 10 Instrumentation and Control Systems
. 11 Engineering Dravvings for Marine Engineers
. 12 Motor Engineering Knowledgefor Marine Engineers
. 13 Ship Stability, Resistance and Povvering
.14 Stealth WarshipTechnology
. 15 Electronics, Navigational Aids and RadioTheory for
llectrotechnical Offìcers
10
ÌRiNG AND TECHNOLOGY
INSTRUMENTATION
AND CONTROL
SYSTEMS
Revised by Gordon Boyd
Leslie Jackson
A D LA R D C O LE S N A U T IC A L
BLOOMSBURY
LONDON • NEYV DELHI • NE\V YORK • SYDXEY
Published by Adlard Coles Nautical
an imprint of Bloomsbury Publishing Plc
50 Bedford Square, London WC1B 3DP
www.adlardcoles.com
Copyright® Gordon Boyd and Adlard Coles Nautical 1970,1975,1979,1992,2013
Rrst edition published byĩhom as Reed Publications 1970
Second edition 1975
Third edition 1979
Reprinted 1985
Pourth edịtiọn 199?
Re printed 20.00,200) . . .
Reprinted by Adlard Coles Nautical 2003,2006,2009,2010 (tvvice) and 2011
• > ,
This fifch edition published by Adlãrd Coles Nauticaỉ in 2013
Print ISBN 978-1 -4081 -7559-0
ePDF ISBN 978-1-4081 -7560-6
ePub ISBN 978-1-4081-7135-6
All rights reserved. No part of this publication may be reproduced in any form or
by any means - graphic, electronic or mechanical, including photocopying, recording,
taping or information srorage and retrieval systems - vvithout the prior permission
in writing of the publishers.
The right of the author to be identified as the author of this work has been asserted by him
in accordance with the Copyright, Designs and Patents Act, 1988.
A CIP cataỉogue record for this book is available from the British Library.
This book is prođuced using paper that is made from wood grown in managed.
sustainable forests. It is natural, renewable and recyclable.The logging and manuíacturing
processes conform to the environmental regulations of the country of origin. O f course
if that's Brazil, congratulations, you're holding a souvenir of the rainforest.
Typeset in Myriad Pro 10/14 by Nevvgen Knowledge Works (P) Ltd., Chennai, India
Printed and bound in Great Britain by CPI Group (UK) Ltd. Croydon CR0 4YY
Note: while all reasonable care has been taken in the publication of this book, the publisher
takes no responsibility for the use of the methods or Products described in the book.
CONTENTS
PREFACE ix
INTRODUCTION 1
Historical 1
Utilisation 2
Economy 2
Saíety 2
Terminology 3
Comparison of Systems 4
Control Loops 5
System 6
Analogue 7
Digital 8
Computers 8
Microprocessors and Microcomputers 8
1 TEMPERATURE MEASUREMENT 9
Mechanical Thermometry 9
Electrical Thermometry 11
TestExam ples 18
2 PRESSURE MEASUREMENT 20
Atmospheric Pressure 20
Mercury Manometer 22
Mercury Barometer 23
Aneroid Barometer 24
Displacement of an Elastic Sensing Element 25
Differential Pressure Cell (D/P Cell) 27
Piezoelectric PressureTransducer 28
Strain Gauge 32
Test Examples 35
3 LEVEL MEASUREMENT 36
Direct Methods 36
Iníerential Methods 38
Non-contact Level Measurement 43
Test Examples 45
4 FLOW MEASUREMENT 46
Quantity Meters 46
Rate of Flow Meters 46
• Contents
Integrators 47
Square Root Extraction 47
Iníerential-Rotational 48
lnferential-Differential Pressure 51
Ultrasonic and Nudeonic 57
Test Examples 57
OTHER MEASUREMENTS 58
Speed-Tachogenerator 58
Torque-Power 60
Viscometer 61
Photo-Electric Cells 62
O ilinW aterSensor 64
Smoke Density Detector 64
Oil Mist Detector 65
pH Sensor 66
Heat (Fire) Detector 67
Flame Detector 68
Gas Explosion - Detector Meter 68
Gas Analysis 69
Relative Humidity 72
Water Analysis 72
Hall Effect Sensor 74
Other Encoders 74
Mass Air-Flow Measurement 75
Instrument Calibration: Testing and Adjustment 76
Test Examples 77
TELEMETERING 78
PneumaticTransmitters 79
ElectricalTransmitters 81
Electronic Force-Balance System 84
Voltage-CurrentTransducer 85
Receivers 86
Potentiometric Pen Recorder 87
X/Recorder 88
Position Motors (dc) 88
Position Motors (ac) 89
CurrentTransm ission:4-20m A 90
Test Examples 90
Contents • vi
7 ELECTRONIC DEVICES 92
Semi-Conductors 92
Rectiíiers 95
Amplifìers 102
Analysis of Transistor Behaviour 104
Oscillators 113
Other Devices 116
TestExam ples 119
8 FINAL CONTROLLING ELEMENTS 120
Correcting Units 120
Servo-Motors 125
TestExam ples 130
9 PROCESS CONTROLTHEORY 131
Terminology 131
Response of Detection Elements 139
TestExam ples 158
10 PNEUMATiC CONTROL PRINCIPLES 160
Pneumatic Two-Step Control Technique 160
TheRelay 161
Pneumatic Proportioal ControlTechnique 162
StackType Controller Principle (P Action) 164
Pneumatic Proportional Plus Integral ControlTechnique 165
Pneumatic Proportional Plus Derivative Control Technique 168
Pneumatic Compound Controller (P + l + D) 170
AirSupplies 171
TestExam ples 172
11 ELECTRONIC CONTROL PRINCIPLES 173
Operational Ampliíiers 173
TestExam ples 192
12 ACTUAL CONTROLLER TYPES 194
Mechanical Controller 194
Mechanical-Hydraulic Controller (Governor) 195
Electro-Pneumatic Controller 196
Electronic Controller (1) 197
Electronic Controller (2) 199
Electronic Controller (3) 200
Pneum aticC ontroller(l) 202
Pneumatic Controller (2) 204
Pneumatic Controller (3) 206
• Contents
Integrators 47
Square Root Extraction 47
Iníerential-Rotational 48
lnferential-Differential Pressure 51
Ultrasonic and Nucleonic 57
Test Examples 57
OTHER MEASUREMENTS 58
Speed-Tachogenerator 58
Torque-Power 60
Viscometer 61
Photo-Electric Cells 62
Oil in Water Sensor 64
Smoke Density Detector 54
Oil Mist Detector 65
pH Sensor 66
Heat (Fire) Detector 67
Flame Detector 68
Gas Explosion - Detector Meter 68
Gas Analysis 69
Relative Humidity 72
Water Analysis 72
Hall Effect Sensor 74
Other Encoders 74
Mass Air-Flow Measurement 75
Instrument Calibration:Testing and Adjustment 76
Test Examples 77
TELEMETERING 78
PneumaticTransmitters 79
ElectricalTransmitters 81
Electronic Force-Balance System 84
Voltage-CurrentTransducer 85
Receivers 86
Potentiometric Pen Recorder 87
XY Recorder 88
Position Motors (dc) 88
Position Motors (ac) 89
CurrentTransmission: 4-20 mA 90
Test Examples 90
Contents • vii
7 ELECTRONIC DEVICES 92
Semi-Conductors 92
Rectifiers 95
Amplifiers 102
Analysis of Transistor Behaviour 104
Oscillators 113
Other Devices 116
TestExam ples 119
8 FINAL CONTROLLING ELEMENTS 120
Correcting Units 120
Servo-Motors 125
TestExam ples 130
9 PROCESS CONTROLTHEORY 131
Terminology 131
Response of Detection Elements 139
Test Examples 158
10 PNEUMATIC CONTROL PRINCIPLES 160
Pneumatic Two-Step Control Technique 160
TheRelay 161
Pneumatic Proportioal Control Technique 162
Stack Type Controller Principle (p Action) 154
Pneumatic Proportional Plus Integral Control Technique 165
Pneumatic Proportional Plus DerivativeControlTechnique 168
Pneumatic Compound Controller {P + 1+ D) 170
AirSupplies 171
TestExam ples 172
11 ELECTRONIC CONTROL PRINCIPLES 173
Operational Ampliíiers 173
TestExam ples 192
12 ACTUAL CONTROLLER TYPES 194
Mechanical Controller 194
Mechanical-Hydraulic Controller (Governor) 195
Electro-Pneumatic Controller 196
Electronic Controller (1) 197
Electronic Controller (2) 199
Electronic Controller (3) 200
Pneumatic Controller (1) 202
Pneumatic Controller (2) 204
Pneumatic Controller (3) 206
iii • Contents
Pneum aticController(4) 207
Pneumatic Controller (5) (Fuel—Air Ratio) 209
Pneumatic Controller (6) (Viscosity) 210
Electrical Positional Control 211
TestExam ples 211
\ TYPICAL CONTROL CIRCUITS 213
Steam Plant 213
IC Engine Plant 221
General Plant 231
Test Examples 243
1 KINETIC CONTROL SYSTEMS 245
Kinetic Control System 245
Servo-Mechanism 245
Position Systems 245
Speed Systems 251
Thyristor Speed Control 253
Governor Systems 254
Mathematical Aspects 256
Test Examples 258
; CONTROL SYSTEM ANALYSIS 260
The Systems Approach 260
System Order 263
Component Adịustment 281
Test Examples 283
. LOGIC AND COMPUTING 284
Analogue Computers 284
Logic Circuits 289
Digital Computer 300
Data Processing 306
Computer Control 309
TestExamples 310
PECIMEN EXAMINATION QUESTIONS 312
Class Three (DTp - SCOTVEC) 312
Class Two ( DTp - SCOTVEC) 313
Class One (DTp - SCOTVEC) 317
ONC - OND (BTEC & SCOTVEC) 323
HNC (BTEC & SCOTVEC) 326
HND (BTEC & SCOTVEC) 333
1DEX 341
This book aims to bridge the gap betvveen the mathematical treatm ent often used by the
specialist control engineer and the descriptive literatureoí a particular manuíacturer.
It is vvritten primarily for those with a general engineering background who have had
little experience in instrumentation and control.
The work íavours marine engineering but students and engineers in other Industries
should find it a useíul book as the subject has a common basis. Text and examples
cover the requirements of Department forTransport(M aritim e and Coastguard Agency)
for examinations as administered by the Scottish Qualitìcations Authority - and all
Business and Technician Education Council (BTEC) and SCOTVEC - syllabuses and
examinations for all marine engineer officers and cadets as deíined by STCW 95 REG.
111/2 & 3. Requirements for content of B. Eng. in Marine Engineering are also covered.
Some examples are included for purposes of analysis and understanding and it should
be noted that although some represent long-established practices they can still be
found in Service.
Full use has been made of simpliíied diagrams and the work is presented from basic
principles, using analogues vvhere appropriate.
The introduction is followed by Chapters 1-5 on variable measurement in instrumentation.
Chapters 6-8 on telemetering, electronic devices and fìnal controlling elements link
instrumentation to control. Chapters 9-14 cover theory, practice and components
of process and kinetic control systems. Chapters 15 and 16 are intended to develop
a broader knovvledge of the subject and, by necessity, have a more analytic and
mathematical approach.
A selection of test examples are included at the end of each chapter and specimen
examination questions are added at the end of the book.
The reader should refer to manuíacturers' instruction manuals to obtain a full and
detailed description of a specific or particular component.
Instrumentation has alvvays been an integral part of technology. Development íronr
simple level indicators, Bourdon tubes, moving iron and moving coil meters, etc. ha:
been rapid. Progress in electrics and electronics has led to centralised recording anc
display stations with associated data Processing, computing and control systems
Application to control with the requirement of accurate measuring (sensors), variablí
converting (transducers) and remote signal transmission (telemetering) has involvec
a close relation betvveen measuring, Processing and control systems. The advantagí
of electrical signal transmission is apparent in the development of instrumentation
Modular designs and interchangeable plug-in sub-assemblies have improved servicinc
of electronic units. Digital operation has replaced analogue operation in man)
applications.
The Watt governor (1788) was one of the first practical applications. Instability wa:
recognised in the nineteenth century in hunting of steam engine speed and ship
steering gears, and much analysis followed. Development in engineering plant anc
bridge equipm ent is likely to remain in a State of continuous improvement.
The third quarter of the tvventieth century saw more complex systems which wer«
mainly pneumatic and hydraulic, being replaced by development in electronics
Accelerated progress in digital electronics meant that the final quarter of that centur'
saw the establishm ent of Computer control.
These developm ents led to much greater unmanned operations of many shipboart
activities to the extern that prolonged operation of sophisticated vessels could no
be achieved with current manning levels without computer-based autom ation.The'
have also enabled more sophisticated operations from entertainment systems, t<
process plant control, survey processes, electric propulsion and dynamic positioning
• Instrumentation and Control Systems
/stems are generally classĩtĩed by their field of operation. Process control such as
‘mperature, flow, level and pressure; kinetic control such as displacement, velocity
nd acceleration, etc.
le degree of utilisation in marine practice varies a great deal. Individual control
ops, from simple to íairly complex, have been in use for many years. Centralised data
indling has been a relatively recent innovation. Ship's Controls havedeveloped rapidly
ith improved reliability. There are many links betvveen localised instrumentation
id control, the centralised data handling system and an integrated Central control
stem. This requires that Computer technology is involved in the interíace betvveen
easurement and control. Computer control has developed from small programmed
nctions to quite sophisticated, direct, digitally controlled processes. A modern
'mputer can be programmed not only to control machinery under all conditions but
ỈO to have start up, emergency and shutdown procedures.
Itomation results in more efficient operation and reduced manpovver in every case.
ere is increased initial cost due to specialised equipment provision vvhich leads
increased Insurance requirements and some increase in certain running costs, for
ample, staff training, skilled maintenance, etc. Overall running costs are reduced
cause of large cost savings in fuel and general maintenance, due to efficient
eration and close supervision, as well as staff reductions. The annual savings, taking
íactors into account, is vvell proven for controlled plants and the factor increases
:h increasing size of plant and machinery.
nost cases saíety is improved by monitoring and control.
}uirements for unmanned machinery spaces (UMS) are deíined by surveying
ieties.
Introduction • 3
Essential requirements for any UMS ship to sail at sea are enumerated in the SOLAS
1974 Chapter 11-1, regulations 46 to regulation 53. The main points discussed in this
chapter are as follows:
1. Bridge control of propulsion machinery
The bridge watchkeeper must be able to take em ergency control action. Control
and instrumentation must be as simple as possible.
2. Centralised control and Instruments are required in machinery space
Engineers may be called to the machinery space in an emergency and Controls
must be easily reached and fully comprehensive.
3. Automatic fìre detection system
Arrangement should be provided on an UMS ship to detect and give alarm in case
offire.
Alarm and detection system must operate very rapidly. Numerous well-sited and
quick-response detectors must be fitted.
4. Fỉre extinguishing system
In addition to conventional hand extinguishers a control fire station remote from
the machinery space is essential. The station must give control of emergency
pumps, generators, valves, ventilators, extinguishing media, etc.
5. Alarm system
A comprehensive machinery alarm system must be provided for control and
accommodation areas.
6. Automatic bilge high-level fluid alarms and pumping units
Sensing devices in bilges with alarms and hand or automatic pump cut in devices
must be provided.
7. Automatic start emergency generator
Such a generator is best connected to separate em ergency bus bars.The primary
íunction is to give protection from electrical blackout conditions. Local hand
control of essential machinery. Adequate settling tank storage capacity. Regular
testing and maintenance of instrumentation.
This topic involves a great deal of specialist technical language and so explanations
of specialised terminology appear in several places in the book. In this section some
general terms relating to control and instrumentation are introduced.