lecture1 plc
TRANSCRIPT
04/08/23 FACULTY OF TECHNOLOGY MANAGEMENT - PGD 2008
1UNIVERSITI TUN HUSSEIN ONN MALAYSIAUNIVERSITI TUN HUSSEIN ONN MALAYSIAUNIVERSITI TUN HUSSEIN ONN MALAYSIA
BDA 2811MECHANICAL ENGINEERING PRACTICE IV
PROGRAMMABLE LOGIC CONTROLLER (PLC)
Prepared by: Saliana binti Sanusi
DEPARTMENT OF MANUFACTURING & INDUSTRIAL ENGINEERINGFACULTY OF MECHANICAL & MANUFACTURING ENGINEERING
Learning Outcome
After finish this task, students are able to:• Write PLC definition
• List PLC language and program
• Identify input/output address and device classification
• Draw PLC configuration & structure
• Design simple program & assemble input/output devices with single output
What is PLC?
• Definition:
A programmable logic controller (PLC) is a
specialized computer used to control
machines and process
• It uses a programmable memory to store instructions and specific functions that include on/off control, timing, counting, sequencing, arithmetic and data handling.
How does PLC look like?
PLC system
PLC configuration (training kit)
OUTPUT TERMINALS
INPUT/OUTPUT CARD
INPUT TERMINALS V+ TERMINALEARTH TERMINAL
PERIPHERAL PORT
RS 232 CABLE
PLC
POWER SWITCH
Courtesy from OMRON PLC
Processor (CPU)
• Is a ‘brain’ of the PLC• Consists of microprocessor for
implementing the logic and controlling the communications among the modules
• Designed so the desired circuit can be entered in relay ladder logic form
• The processors accepts input data from various sensing devices, executes the stored user program and send appropriate output commands to control devices
Memory System
• The memory system stores both the control and data from the equipment connected to the PLC.
• For storage of programs, present PLC use semiconductor memory devices such as RAM or a programmable read-only memory (ROM)
PLC can process dataPLC can memory
But how we communicate with PLC?
Can PLC talks to us?
How can we tell PLC what we want?
PLC Language
• It is a medium where we can write program• To program means set command or to instruct
the PLC what to do• There are several programming methods, such
as ‘Ladder Diagram’, ‘Statement List’, ‘Mnemonic Code’, ‘Functional Block’ and ‘Block Diagram’
• Several software available in markets are such as OMRON with CX-programmer, SIEMENS with TISOFT, FESTO with FST and Allen-Bradley with RSLogix
Input/Output (I/O) Units• I/O units form the interface between the PLC and
outside devices. • This unit received any input signal, converts it
into low voltage signal and sent it to the processor.
• The processor determines and interprets the data due to the program.
• Then the processor sent the data to the output unit.
• The output unit produce out the output signal and sent it to the output device
• For easy assessment, every input/output has their own adddress.
PLC applications
Automatic Storage Process Control
Food & Beverages Wrapping & Packaging
Quality Control
Machine System
Automotive Assembly
Parking System
Automated Material Handling
Advantages of PLC control system
• Eliminates much of the hard wiring that was associated with conventional relay control circuit
• More flexibility• Increased reliability• Communications capability• Faster response time• Easier to troubleshoot• Lower costs
Limitation
• PLC is not suitable for analogue application
PLC Language
• Concentrate on ‘ladder logic diagram’
• A ladder diagram is a means of graphically representing the logic required in a relay logic system.
0V, COMMON24 V+
RUNG
BRANCH
INPUT OUTPUT
Ladder Logic Structure
RAIL
Ladder Logic Symbols & IO Address
INPUT OUTPUT
Normally Open contact
Normally Close contact
Normally Open contact
Normally Close contact
Timer & Counter
IP address: 0.00 to 0.15 IP address: 1.00 to 1.15
Sensor Cylinder
Limit Switch Buzzer
Push button Solenoid
Simple Application
SwitchLamp 1
Lamp 2
Solenoid
The ladder logic program
0.04
1.07
1.10
1.15
In actual……
DC supply
Relay
Lamp 2Lamp 1
AC supply
Solenoid
Switch
Hardwire Circuit
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15
CPU
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15
Switch
Lamp 1 Lamp 2 Solenoid
24+V
0V, common
• Assignment 1 & lab report submit on/before 14 AUGUST 2009 to En Omar.
TIPS: assignment 1
• Host having reset button
• Using latching for each group of contestants
• Just a simple circuit
You may access the lab on any time (refer to the schedule outside the room)
Print out your program (drawing using cx-programmer) using printer in the lab.