1. PROGRAMMABLE LOGIC CONTROLLER (PLC) AND AUTOMATION
EJ501
EJ501
PROGRAMMABLE LOGIC CONTROLLER (PLC) AND AUTOMATION
SBO/ PMM/ EJ501/ Jun2011

2. UNIT 1 INTRODUCTION TO AUTOMATION SYSTEM
EJ501
UNIT 1 INTRODUCTION TO AUTOMATION SYSTEM
Objective ;
Understand automation system
Understand type of automation
Comparison type of automation
Understand relays, contactors, electromechanical timer and electromechanical counter (symbol, building diagram, operation and application examples)
Develop simple logical control/ automation sequence
SBO/ PMM/ EJ501/ Jun2011

3. UNIT 1 INTRODUCTION TO AUTOMATION SYSTEM
EJ501
UNIT 1 INTRODUCTION TO AUTOMATION SYSTEM
Automation System
Automation is the use of control systems and information technologies to reduce the need for human work in the production of goods and services.
In the scope of industrialization, automation is a step beyond mechanization.
Whereas mechanization provided human operators with machinery to assist them with the muscular requirements of work, automation greatly decreases the need for human sensory and mental requirements as well
Type of Automation system :
fixed/ hardwired automation
programmable automation
flexible automation
SBO/ PMM/ EJ501/ Jun2011

4. UNIT 1 INTRODUCTION TO AUTOMATION SYSTEM
EJ501
UNIT 1 INTRODUCTION TO AUTOMATION SYSTEM
Fixed/ Hardwired Automation
Custom-engineering, special – purpose equipment to automate a fixed sequence of operations.
High production rates, inflexible product design
Programmable Automation
Equipment designed to accommodate a specific class of product changes.
Batch production, medium volume
Flexible Automation
Design to manufactured a variety of product or parts
Low production rates, varying product design and demand
SBO/ PMM/ EJ501/ Jun2011

5. UNIT 1 INTRODUCTION TO AUTOMATION SYSTEM
EJ501
UNIT 1 INTRODUCTION TO AUTOMATION SYSTEM
Comparison Types of Automation
Automation
When to consider
Advantages
Disadvantages
Fixed
High demand volume, long product life cycle
maximum efficiency
low unit cost
large initial investment
inflexibility
Programmable
Batch production, products with the different options
flexibility to deal with changes in product
low unit cost for large batches
new product requires long set up time
high unit cost relative to fixed automation
Flexible
Low production rates, varying demand, short product life cycles
flexibility to deal with design variations
customized product
high unit cost relative to fixed or programmable automation
SBO/ PMM/ EJ501/ Jun2011

6. UNIT 1 INTRODUCTION TO AUTOMATION SYSTEM
EJ501
UNIT 1 INTRODUCTION TO AUTOMATION SYSTEM
Relays
Define
A relay is usually an electromechanical device that is actuated by an electrical current. The current flowing in one circuit causes the opening or closing of another circuit. Relays are like remote control switches and are used in many applications because of their relative simplicity, long life, and proven high reliability. Relays are used in a wide variety of applications throughout industry, such as in telephone exchanges, digital computers and automation systems. Highly sophisticated relays are utilized to protect electric power systems against trouble and power blackouts as well as to regulate and control the generation and distribution of power. In the home, relays are used in refrigerators, washing machines and dishwashers, and heating and air-conditioning controls
Symbol
SBO/ PMM/ EJ501/ Jun2011

7. UNIT 1 INTRODUCTION TO AUTOMATION SYSTEM
EJ501
UNIT 1 INTRODUCTION TO AUTOMATION SYSTEM
Building Diagram
SBO/ PMM/ EJ501/ Jun2011

8. UNIT 1 INTRODUCTION TO AUTOMATION SYSTEM
EJ501
UNIT 1 INTRODUCTION TO AUTOMATION SYSTEM
Relay
Diagram
Bottom View
SBO/ PMM/ EJ501/ Jun2011

9. UNIT 1 INTRODUCTION TO AUTOMATION SYSTEM
EJ501
UNIT 1 INTRODUCTION TO AUTOMATION SYSTEM
How does a relay work?
All relays contain a sensing unit, the electric coil, which is powered by AC or DC current. When the applied current or voltage exceeds a threshold value, the coil activates the armature, which operates either to close the open contacts or to open the closed contacts. When a power is supplied to the coil, it generates a magnetic force that actuates the switch mechanism. The magnetic force is, in effect, relaying the action from one circuit to another. The first circuit is called the control circuit; the second is called the load circuit.
There are three (3) basic functions of a relay:
On/Off Control: Example: Air conditioning control, used to limit and control a “high power” load, such as a compressor.
Limit Control: Example: Motor Speed Control, used to disconnect a motor if it runs slower or faster than the desired speed.
Logic Operation: Example: Test Equipment, used to connect the instrument to a number of testing points on the device under test.
SBO/ PMM/ EJ501/ Jun2011

10. UNIT 1 INTRODUCTION TO AUTOMATION SYSTEM
EJ501
UNIT 1 INTRODUCTION TO AUTOMATION SYSTEM
Operation
When no voltage is applied to pin 1, there is no current flow through the coil. No current means no magnetic field is developed, and the switch is open. When voltage is supplied to pin 1, current flow though the coil creates the magnetic field needed to close the switch allowing continuity between pins 2 and 4.
SBO/ PMM/ EJ501/ Jun2011

11. UNIT 1 INTRODUCTION TO AUTOMATION SYSTEM
EJ501
UNIT 1 INTRODUCTION TO AUTOMATION SYSTEM
Type of Relay / Application Examples
This is a Single Pole Single Throw (SPST) relay. Current will only flow through the contacts when the relay coil is energized.
This is a Single Pole Double Throw (SPDT) relay. Current will flow between the movable contact and one fixed contact when the coil is DEenergized and between the movable contact and the alternate fixed contact when the relay coil is energized. The most commonly used relay in car audio, the Bosch relay, is a SPDT relay.
This is a Double Pole Single Throw (DPST) relay. When the relay coil is energized, two separate and electrically isolated sets of contacts are pulled down to make contact with their stationary counterparts. There is no complete circuit path when the relay is DEenergized.
SBO/ PMM/ EJ501/ Jun2011

12. UNIT 1 INTRODUCTION TO AUTOMATION SYSTEM
EJ501
UNIT 1 INTRODUCTION TO AUTOMATION SYSTEM
Type of Relay / Application Examples
This relay is a Double Pole Double Throw (DPDT) relay. It operates like the SPDT relay but has twice as many contacts. There are two completely isolated sets of contacts.
This is a 4 Pole Double Throw (4PDT) relay. It operates like the SPDT relay but it has 4 sets of isolated contacts.
SBO/ PMM/ EJ501/ Jun2011

13. UNIT 1 INTRODUCTION TO AUTOMATION SYSTEM
EJ501
UNIT 1 INTRODUCTION TO AUTOMATION SYSTEM
Figure : Relay Contact Configuration
Single Pole – relay have 1 common
Double Pole – relay have 2 common
Single Throw – relay have NC or NO
Double Throw – relay have NC and NO
SBO/ PMM/ EJ501/ Jun2011

14. UNIT 1 INTRODUCTION TO AUTOMATION SYSTEM
EJ501
UNIT 1 INTRODUCTION TO AUTOMATION SYSTEM
Pin no 1 – Common
Pin no 2 – NC
Pin no 3 – NO
Figure : Wiring of relay
SBO/ PMM/ EJ501/ Jun2011

15. UNIT 1 INTRODUCTION TO AUTOMATION SYSTEM
EJ501
UNIT 1 INTRODUCTION TO AUTOMATION SYSTEM
Contactors
Define
Contactors are used to indicate an open or closed path of current flow. Contacts are shown as normally open (NO) or normally closed (NC). Contacts shown by this symbol require another device to actuate them.
Symbol
SBO/ PMM/ EJ501/ Jun2011

16. UNIT 1 INTRODUCTION TO AUTOMATION SYSTEM
EJ501
UNIT 1 INTRODUCTION TO AUTOMATION SYSTEM
Building Diagram
SBO/ PMM/ EJ501/ Jun2011

17. UNIT 1 INTRODUCTION TO AUTOMATION SYSTEM
EJ501
UNIT 1 INTRODUCTION TO AUTOMATION SYSTEM
Operation
Normally Open Contact
In the following illustration the circuit is first shown in the de-energized state. The contacts are shown in their normally open (NO) state. When the relay is energized, the contacts close, completing the path of current and illuminating the light. The contacts have been highlighted to indicate they are now closed.
Normally Open Contact
SBO/ PMM/ EJ501/ Jun2011

18. UNIT 1 INTRODUCTION TO AUTOMATION SYSTEM
EJ501
UNIT 1 INTRODUCTION TO AUTOMATION SYSTEM
Operation
Normally Close Contact
In the following illustration the contacts are shown as normally closed (NC), meaning the contacts is closed when the relay is de-energized. A complete path of current exists and the light is on. When the relay is energized, the contacts open turning the light off.
Normally Close Contact
SBO/ PMM/ EJ501/ Jun2011

19. UNIT 1 INTRODUCTION TO AUTOMATION SYSTEM
EJ501
UNIT 1 INTRODUCTION TO AUTOMATION SYSTEM
Electromechanical Timer
Define
Electromechanical timers are used to start or stop a machine or other device at preset or delayed intervals. They consist of both electrical and mechanical components, and often feature an electric motor that drives one or more gears. They typically accept electric or electronic inputs to operate a mechanical output such as rotating wheels or knobs.
SBO/ PMM/ EJ501/ Jun2011

20. UNIT 1 INTRODUCTION TO AUTOMATION SYSTEM
EJ501
UNIT 1 INTRODUCTION TO AUTOMATION SYSTEM
Symbol Electromechanical Timer
Contact symbols determine the time of timer action:-
On-delay action - TR energized, contacts change state after set time interval
Off-delay action - TR de-energized, contacts change state after set time interval
SBO/ PMM/ EJ501/ Jun2011

21. UNIT 1 INTRODUCTION TO AUTOMATION SYSTEM
EJ501
UNIT 1 INTRODUCTION TO AUTOMATION SYSTEM
Electromechanical Counter
Define
Electromechanical counters are used to detect, totalize, and indicate a sequence of events. They typically accept electric or electronic inputs to operate mechanical outputs such as rotating wheels or knobs. These devices may count UP and/or DOWN, support multiple functions, and provide reset capabilities.
SBO/ PMM/ EJ501/ Jun2011

22. UNIT 1 INTRODUCTION TO AUTOMATION SYSTEM
EJ501
UNIT 1 INTRODUCTION TO AUTOMATION SYSTEM
Symbol Electromechanical Counter
SBO/ PMM/ EJ501/ Jun2011

23. UNIT 1 INTRODUCTION TO AUTOMATION SYSTEM
EJ501
UNIT 1 INTRODUCTION TO AUTOMATION SYSTEM
Simple Logical Control/ Automation Sequence
SBO/ PMM/ EJ501/ Jun2011

24. UNIT 1 INTRODUCTION TO AUTOMATION SYSTEM
EJ501
UNIT 1 INTRODUCTION TO AUTOMATION SYSTEM
SBO/ PMM/ EJ501/ Jun2011

25. UNIT 1 INTRODUCTION TO AUTOMATION SYSTEM
EJ501
UNIT 1 INTRODUCTION TO AUTOMATION SYSTEM
Relay
Contactor
SBO/ PMM/ EJ501/ Jun2011

26. UNIT 1 INTRODUCTION TO AUTOMATION SYSTEM
EJ501
UNIT 1 INTRODUCTION TO AUTOMATION SYSTEM
3ph Starter/1ph Motor
SBO/ PMM/ EJ501/ Jun2011

27. EJ501
THANK YOU
SBO/ PMM/ EJ501/ Jun2011