Automation could be achieved with the aid of Industrial Controller PLC. PLC basic Programming are discussed in this presentation.Case studies are available and solutions for those questions will be updated in next presentation.

1. PRESENTED BY
S.VALAI GANESH, AP/MECHANICAL
RAMCO INSTITUTE OF TECHNOLOGY

2. AGENDA

3. INTRODUCTION TO AUTOMATION
Automation or automatic control, is the
use of various control systems for operating
equipment such as machinery, processes in
factories, boilers and heat treating ovens,
switching on telephone networks, steering
and stabilization of ships, aircraft and other
applications and vehicles with minimal or
reduced human intervention. Some
processes have been completely automated.

4. INTRODUCTION TO AUTOMATION
Automation has been achieved by
various means including mechanical,
hydraulic, pneumatic, electrical,
electronic devices and computers,
usually in combination. Complicated
systems, such as modern factories,
airplanes and ships typically use all
these combined techniques.

5. INTRODUCTION TO AUTOMATION
ADVANTAGES
•Replaces hard physical or monotonous work
•Tasks in hazardous environments, such as
extreme temperatures, or atmospheres that are
radioactive or toxic can be done by machines
•Faster production and cheaper labor costs
•Automation can be maintained with simple quality
checks
•Can perform tasks beyond human capabilities

6. INTRODUCTION TO AUTOMATION
LIMITATIONS
•As of now, not all tasks can be
automated
•Some tasks are more expensive to
automate
•Initial costs are high
•Failure to maintain a system could result
in the loss of the product

7. AUTOMATION COMPANIES

8. INTRODUCTION TO AUTOMATION
EXAMPLE 1 OPENING AND CLOSING DOORS

9. INTRODUCTION TO AUTOMATION
EXAMPLE 2 ESCALATORS

10. INTRODUCTION TO AUTOMATION
EXAMPLE 3 TAP OPENING

11. INTRODUCTION TO AUTOMATION
• PNEUMATICS
• HYDRAULICS

12. INTRODUCTION TO AUTOMATION
A programmable Logic Controller (PLC) is
defined as a digital electronic device that uses a
programmable memory to store instructions and to
implement functions such as logic, sequencing, timing,
counting and arithmetic in order to control machines
and processes
PLCInput from
devices
Output to
devices
Control
Program
PLC

13. LADDER LOGIC PROGRAMMING
Ladder diagram is a graphical method for
representing and programming an event driven sequential
process.
ELEMENTS OF LADDAR DIAGRAM
Relays
Motors
Solenoids
Lamps or indicators
Switches

14. LADDER LOGIC PROGRAMMING
• Ladder diagrams are specialized schematics
commonly used to document industrial control logic
systems.
• They are called "ladder" diagrams because they
resemble a ladder, with two vertical rails (supply
power) and as many "rungs" (horizontal lines) as
there are control circuits to represent.
• If we wanted to draw a simple ladder diagram
showing a lamp that is controlled by a hand switch,
it would look like this:

15. LADDER LOGIC PROGRAMMING
• The left and right uprights represent power. If we
connect the left and right uprights through a load,
power can flow through the rung from the left
upright to the right upright
• Ladder logic diagrams are read from left-to-right,
top-to-bottom.
• Rungs are sometimes referred to as networks

16. LADDER LOGIC PROGRAMMING
• Most inputs to a PLC are simple devices that are either on
(true) or off (false). These inputs are sensors and switches
that detect part presence, empty or full status, and so on.
• Contacts can be thought of as switches. The two basic
kinds of switches are normally open and normally closed:
– A normally open switch does not pass current until it
closed
– A normally closed switch allows current flow until it
closed

17. LADDER LOGIC PROGRAMMING
• Coils are output symbols. There are many
types of real-world output devices: motors,
lights, pumps, counters, timers and relays
• The PLC examines the contacts (inputs) in the
ladder and turns the coils (outputs) on or off,
depending on the condition of the inputs

18. LADDER LOGIC PROGRAMMING
• Programmable control is based on the basic logic
function (AND, OR, NOT) to form the instruction.
• Parallel contacts are equivalent to an OR gate.
• Series contacts are equivalent to an AND gate.
• Normally-closed contacts are equivalent to a NOT
gate (inverter).

19. LADDER LOGIC PROGRAMMING

20. LADDER LOGIC PROGRAMMING

21. LADDER LOGIC PROGRAMMING

22. LADDER LOGIC PROGRAMMING

23. LADDER LOGIC PROGRAMMING

24. LADDER LOGIC PROGRAMMING

25. LADDER LOGIC PROGRAMMING

26. LADDER LOGIC PROGRAMMING

27. LADDER LOGIC PROGRAMMING

28. LADDER LOGIC PROGRAMMING

29. LADDER LOGIC PROGRAMMING
RULES TO BE FOLLOW WHILE DRAWING LADDAR DIAGRAM
(a) The vertical lines of diagram represent the
power rails between which the circuits are connected.
(b) Each rung of ladder defines one operation
in the control process.
(c) The ladder diagram must be read from left
to right and top to bottom.
(d) In RUN mode, PLC goes through entire
ladder program to the end. Then it came back to start position

30. LADDER LOGIC PROGRAMMING
RULES TO BE FOLLOW WHILE DRAWING LADDAR DIAGRAM
(e) Each rung must start with at least one input
and one output
(f) Electrical devices are shown in their normal
condition.
(g) A Particular device can appear more than
one rung in a ladder. Some identification number is used to
identify device in each situation.
(h) All inputs and outputs are identified by their
addresses, the notation used depending on the PLC
manufacturer.

31. LADDER LOGIC PROGRAMMING

32. PROGRAMMING 1
Draw the ladder rungs to represent:
(a) Two switches are normally open and both have to be closed for a
motor to operate.
(b) Either of two, normally open, switches have to be closed for a coil
to be energized and operate an actuator.
(c) A motor is switched on by pressing a spring-return push button
start switch, and the motor remains on until another spring-return
push button stop switch is pressed.
(d) A lamp is to be switched on if there is an input from sensor A or
sensor B.
(e) A light is to come on if there is no input to a sensor.
(f) A solenoid valve is to be activated if sensor A gives an input.

33. PROGRAMMING 2
Develop the ladder diagram for block
opening and closing door operation. Sensor is
placed in front of doors. The door will remain in
open for 10 seconds whenever person cross the
door.

34. PROGRAMMING 3
Develop the ladder diagram for bus opening
and closing door operation. When driver press the
button door will open and driver press the same
button for second time door will close.

35. PROGRAMMING 4
Given two push-to-ON buttons (PB1,PB2),
Red and Green lamps, develop a ladder diagram to
meet the following objectives.
(a) When PB1 is pushed, RED lamp should be ON
and it will continue to be ON till PB2 is pushed
(b) When PB2 is pushed, GREEN lamp should be
ON and it will continue to be ON till PB1 is pushed
(c) If PB1 and PB2 both are pushed
simultaneously, both light should be OFF.

36. PROGRAMMING 5
Given four normally open switches (P1,P2,S1
and S2) with DC motor (M). Draw a PLC program
to satisfy following objectives:
When P1 is pushed the cycle shall start. The cycle
shall continue to remain ON until P2 is pushed.
When S1 is pushed and S2 is not pushed then
Motor is ON clockwise direction.
When S2 is pushed and S1 is not pushed then
Motor is ON counter clockwise direction.
When P2 is pushed the program stops

37. MCQ
1. The two binary states can be defined as:
(a) “high” or “low”
(b) “on” or “off”
(c) 1” or “0”
(d) all of these
2. A gate can have one or more
outputs but
only one input. (True/False)

38. MCQ
3. The ______ table shows the resulting output
for each possible gate input conditions.
a. input status c. data
b. output status d. truth
4. A light that is "off" or a switch that is "open"
would normally be represented by a binary 1.
(True/False)
5. The OR function, implemented using contacts,
requires contacts connected in series. (True/False)

39. MCQ
6. With an AND gate, if any input is 0, the output
will be 0. (True/False)
7. The symbol shown is that of a(an)
_________ .
(a) AND gate
(b) OR gate
(c) NAND gate
(d) inverter

40. MCQ
9. The basic rule for an XOR function is that if
one or the other, but not both, inputs are 1 the
output is 1. (True/False)
10. A NAND gate is an AND gate with an inverter
connected to the output. (True/False)
8. Which of the following gates is commonly used
for the comparison of two binary numbers?
(a) NAND
(b) NOR
(c) XOR
(d) NOT

41. MCQ
11. Which gate logic shown represents the Boolean
equation: ( A + B ) C = Y
(a) (b)
(c) (d)

42. MCQ
12. The correct Boolean equation for the
combination logic gate circuit shown is:
a. Y = A B C D c. Y = ( A + B ) ( C + D )
b. Y = ( AB ) + ( CD ) d. Y = ( AB ) + ( CD )

43. MCQ
13. The correct Boolean equation for the
combination logic gate circuit shown is:
a. Y = ( A + B + C ) D c. Y = ( AB + C ) D
b. Y = ( A + B ) ( C + D ) d. Y = ( ABC ) D

44. MCQ
14. The correct Boolean equation for the
combination logic gate circuit shown is:

45. MCQ
15. The correct Boolean equation for the ladder
logic program shown is:
a. Y = (A B) + (CD) c. Y = A + B + C + D
b. Y = (A+B ) (C+D) d. Y = ABCD

46. SOLUTIONS ?
SEE IN NEXT PRESENTATION