MARINE ELECTRICAL AND ELECTRONICS TECHNOLOGY
INTRO TO
AUTOMATION
TABLE OF CONTENT
No.
T it le
Page
Overview of an Automation System
2
1 .1
Definition of automation system
2
1 .2
How automation arises?
2
1 .3
W hy we need automation?
3
1 .4
W ho needs automation?
3
1 .5
W here does automation apply to?
3
1 .6
Benefits of automation.
3
1 .7
Examples of automation
4
1 .8
Automated system
4
1 .9
Sensor
7
1 .1 0
Processor
11
1 .1 1
Actuator
14
1.
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Chapter 1 - Intro to Automation
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1. OVERVIEW OF AUTOMATION SYSTEM
1.1 Definition of automation system
- The ability of a system or device to perform work intelligently with minimum or without
human supervision or intervention.
1.2 How automation arises?
MANUAL REPETITIVE
MECHANIZATION
AUTOMATION
Manual Repetitive
Similar work done over and over again using physical strength with minimum or without
tools.
Ex: Loading and unloading of rice pack from padi field to truck.
Mechanization
Work is done by machine under direct supervision.
Ex: Filling machine fills rice into sacks, conveyor belt transfers the sacks to another man
to load it into a truck.
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Automation
Work is done by machine intelligently with minimum or without human supervision.
Ex:
- Auto filling of rice pack to ensure even quantity per sack;
- Intelligent Conveyor system that do auto sorting for accepting and rejecting
packages; and
- Robotics arm to do lifting and transferring works.
1.3 Why we need automation?
- Increase product standards with consistent quality.
- Higher throughput.
- Reduce labour dependencies.
1.4 Who needs automation?
- Small and medium industries (SMI),
- Multi-national companies (MNC),
1.5 Where does automation apply to?
- Assembly line,
- Test and finishing packaging (repetitive process),
- Hazardous environment.
- On board a modern ship.
- Etc.
1.6 Benefits of automation?
- Cost reduction in terms of labour requirement.
- Increase efficiency in terms of quality and quantity.
- Flexible to market demand (faster and flexible) i.e. changes in product and changes in
process.
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- Reliable: automation processes can sustain long hours but still maintain its desired
performance (consistent quality and durability).
- High repeatability: output from the automatic machine can be scheduled and control
accordingly.
- Safe: automated machines reduce and minimize human contact or interaction in
hazardous environment.
- A solution for labour shortage.
1.7 Examples of automation
- Industrial environment: conveyor system, pick and place system, ship control and
monitoring system (SCAMS), fire fighting system, CCTV and security alarm system, etc.
- Domestic environment: automatic door/gate, washing machine, smart house, etc.
- Commercial environment: building automation system (BAS), lifts and escalators,
automatic teller machine (ATM), supervisory control and data acquisition (SCADA), etc.
- Public utilities: traffic lights, etc.
1.8 Automated system.
- Automated system functions by the motion of specific hardware controlled by dedicated
software.
- What is hardware?
: It is the physical element in the automated system such as
sensors, keyboard, monitor, PLC, PC, etc.
- What is software?
: It comprises of sets of instruction that tell PLC or PC what to
do.
It can be written in ladder diagram, codes of certain computer
languages, logic presentation, etc.
- How automation works? : Automated system responds upon the processing of its
instruction or programme.
The system should know its environment by having input
signals from various sensors.
The input signals exist in the form of compressed fluid,
incompressible fluid (pneumatic/hydraulic), or electrical.
The relationship between input and output, and elements
associated with them are as below.
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- Input elements: electrical, pneumatic, and hydraulic. (sensor)
- Ex.:
- Output elements: electrical, pneumatic, and hydraulic. (actuator)
- Ex.:
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- Processing element: electrical, pneumatic, and hydraulic. (processor)
- Ex.:
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1.9 Sensor.
- Definition: Sensors are parts of a control system which is responsible for collecting and
preparing process status data and passing it to the processor.
- Functions:
 The ability to control a process or machine is dependent on the ability to sense
what is happening.

A sensor in an automated system is a device that can:
o Detect the presence of objects
o Detect the difference between objects sensed (whether metallic or nonmetallic)
o Measure temperature
o Measure flow rate
o Measure force
o Measure velocity
o Measure position
o Measure acceleration
- Distinguishing features of sensors:
 Contact sensor: Are the most widely used form of actuator motion or
positioning sensing. It is achieved with mechanically operated valves such as
roller valves, plunger valves, one way trip valves, whisker valves and etc.
 Contactless sensors: must be chosen wherever physical contact of the
sensing mechanism with the object to be detected is either impossible or
undesirable. Such applications range from food processing, liquid sensing,
extreme lightweight object sensing (ex: paper sheet), to the sensing of gauge
hands on pressure gauge or weighing machines, and strip material correction
when being rolled onto reels for powder storage in tanks and silos.
- Signal: represent information and may take the form of a value or curve of a physical
variable, and may refer to the transmission, processing or storage of information.


Analogue signals: is a signal where various data are assigned point for point to a
continuous value range of the signal parameter. The data content can therefore
assume any desired value within certain limits.
Example: pressure gauge
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
Further example: temperature range of thermometer, reading on tachometer,
speedometer in motor vehicles.

Digital signals: used in control systems that have one or two possible levels or
conditions; therefore they are binary signals. We can represent this signal in
numerical form by assigning one of the levels a value of ‘1’and the other a value of
‘0.’ i.e. the two values in a binary system.
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

Further example: counter, digital measuring equipment.
Types of input and output signals:
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
A sensor may be incorporated with transmitter or converters in order to produce an
output signal type different from the input signal type.
- Selection criteria for sensors:
 In selecting a sensor for a particular problem, various physical and technical
factors must be considered in order to determine the most suitable sensor for the
problem. Below is a list of evaluation criteria which must be weighted differently in
accordance with the task in hand.
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1.10
Processor.
- Definition: the signal which are fed to the inputs from the signal generators (sensors)
are processed and fed to the outputs.
- Functions: signal processing is carried out in the processor by means of various basic
functions. The basic functions in the field of signal processing comprise of:
 Logic function: AND, OR, NOT, NOR, NAND gates.
 Timing function: is carried out by means of functional elements to delay, shorten
and expand signals.
 Memory function: is carried out with functional element, e.g. double pilot valves
and self holding circuits (electrical/pneumatic).
- Type of signal processing:
 Pneumatic signal processing
o Logic function
The pneumatic AND element is the ‘two pressure valve’. The pressure valve has
two inlets ‘X’ and ‘Y’ and one outlet ‘A’.
o Timing function
Timing function in pneumatic system is done by a pneumatic timer.
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o Memory function
5/2 way directional control valve, air operated (double pilot valve.

Electrical signal processing (ex: relays)
o Logic function
In electrical signal processing, two normally-open contact are connected in a
parallel basis to produce an OR function.
o Timing function
Time relay (switch-on delay timing characteristic).
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Time relay (switch-off delay timing characteristic).
o Memory function
Dominating Reset

Dominating Set
Electronic signal processing
In an electronic hard-wired-programmed control, contacts (N/O, N/C, etc) are
replaced by electronic functional element. The sequence is determined by the
functions of the modules (NOR, AND, etc) and the wiring, If alternations are
required, the effort involved is considerable. In order to avoid these disadvantages,
programmable logic control (PLC) were developed and built in the USA (1970).
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1.11
Actuator.
- Definition: The signal from the processor are amplified if necessary and passed on to
the actuators. The desired actions are finally carried out in a process by the actuators.
These actions might for example, be the generation of movements, of works of the most
varied types (mechanical, electrical, thermal) or of reports of important process statues,
etc.
- The motion generated by the actuators might be:
 Linear motion
o Ex: pneumatic cylinder
 Rotary motion
o Ex: Electric motor
 Generation of large forces
o Hydraulic cylinder
- Hydraulic is best suited for the generation of large forces. It may be used
to control machines such as hydraulic presses, lathes and grinders and is
commonly found in automation control systems.
- the generation of large forces involves the following energy conversion:
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LED 21303 – Automated System
Chapter 1 - Intro to Automation
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