PLC Workshop 1-2 Day
April 7, 2023 | Author: Anonymous | Category: N/A
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DAY - 1
PLC WORKSHOP
Basics of Programmable Logic Controllers
SAJID ALI
Presentation Sequence Basics of PLCs
Functions of PLCs Applications of PLCs Components of PLCs Programming Devices Symbols Programming modes PLC program creation Documentation PLC addressing Programming logic functions Q&A
Functions of PLC
Symbols
Applications of PLC
Components of PLC
Programming Devices
PLC Program creation
Programming Modes
Documentation PLC addressing
Programming Logic Functions
Q&A
Programmable Logic Controllers PLC( programmable logical controller) is a computer type device used in an industrial environment to analogue control various of machines or processes through digital or inputstypes and outputs. PLCs are similar to computers except, computers are optimised for calculation and display, PLCs are optimised for control tasks and the industrial environment. Thus PLCs are: •
Rugged and designed to withstand vibrations, temperature, humidity and noise.
•
Have interfacing for inputs and outputs already inside the controller. controller.
•
Easily programmed and have an easily understood programming language which primarily concerned with logic and switching operations
Why PLCs
PLC is a microprocessor based, reprogrammable reprogrammable device that is used for Industrial Automation
In addition to the programming flexibility PLCs offer other advantages over traditional control systems. These advantages include:
high reliability small space requirements computing capabilities reduced costs ability to withstand harsh environments expandability
History Conventional control panel At
the outset of industrial
revolution, especially during sixties and seventies, relays were used to operate automated machines, and these were interconnected using wires inside the control panel. In
some cases a control panel covered an entire wall.
History Disadvantages of Conventional control panel z
Too many wiring work.
z
Difficult to modify and troubleshoot => Long down down time.
z
Power consumption can be quite high
z
Drawings are usually not updated.
z
Lifetime of relay contacts wa was s limited, so some relays had to be replaced. If replacement was required, machine had to be stopped st opped and production too.
z
z z z
Also, it could happen that there was not enough room for necessary necessary changes. As far as maintenance, electricians had to be very skillful in finding errors.
When a problem occurs, hold-up time is indefinite, usually long.
History
In the late 1960's PLCs were first introduced. The primary reason for designing such a device was eliminating the large cost involved in replacing the complicated relay based machine control systems. Bedford Associates (Bedford, MA) proposed something called a Modular Digital Controller (MODICON) to a major US car manufacturer. Other companies at the time proposed computer based schemes, one of which was based upon the PDP-8. The MODICON 084 brought the world's first PLC into commercial production.
In the mid70's the dominant PLC were Modicon and A-B PLCs. The AMD 2901 and 2903 were quite popular in these PLCs
Communications abilities began to appear in approximately 1973. The first such system was Modicon's Modbus. The PLC could now talk to other PLCs and they could be far away from the actual machine they were controlling. They could also now be used to send and receive varying voltages to allow them to enter the analog world.
History
The 80's saw an attempt to standardize communications with General Motor's manufacturing automation protocol (MAP). It was also a time for reducing the size of the PLC and making them software programmable through symbolic programming on personal computers instead of dedicated programming terminals or handheld programmers.
The 90's have seen a gradual reduction in the introduction of new protocols, and the modernization of the physical layers of some of the more popular protocols that survived the 1980's. The latest standard (IEC (IEC 1131-3) 1131-3) has tried to merge PLC programming languages under one international standard.
History A d v a n t ag ag e s o f P L C b a s e ed d c o n t r o l s y s t em em
Compared to a conventional process control system, number of wires needed for connections is reduced by 80% Diagnostic functions of a PLC controller allow for fast and easy error detection. Change in operating sequence or application of a PLC controller to a different operating process can easily be accomplished by replacing a program through a console or using a PC software (not requiring changes in wiring, unless addition of some input or output device is required).
Needs fewer spare parts.
It is much cheaper compared to a conventional system, especially in cases where a large number of I/O instruments are needed and
when operational functions are complex. Reliability of a PLC is greater than that of an electro-mechanical relay or a timer. timer.
PLC Architecture Typically a PLC system has five basic components. These are the processor unit, memory,, the power supply unit unit,, input/output input/output unit, memory interface section and the programming device. Figure shows the basic arrangement. Programming Device
Memory
Input Interface
Processor Power Supply
Output Interface
PLC Architecture
PLC Architecture CPU The processor unit or central processing unit (CPU) is the unit containing the microprocessor and this interprets the input signals and carries out the control actions, according to the program stored in its memory, communicating decisions as a action signals to the output.
Power Supply Unit The power supply unit is needed to convert the main a.c. voltage to the low d.c. voltage (5V,24V etc) necessary for the processor and the circuits in the input and output interface modules.
PLC Architecture Programming Device The Programming device is used to enter/edit the required program into the memory of the processor. The program is developed in the device and then transferred to the memory unit of the PLC.
Memory Unit Program is stored in memory unit, and is used for the control actions to be exercised by the microprocessor.
Input and Output Sections The input and output sections are where the processor receives information form external devices and communicates information to external devices
PLC Architecture The essential elements of a CPU are:
Registers A register is a byte (8 bits), word ( 16 bits ) or long word (32 bits) of memory which is part of the microprocessor as opposed to general purpose memory. A register is used for temporary storage of data and addresses within the CPU.
ALU The ALU performs arithmetic and logical operations such as addition and subtraction on data stored in registers. re gisters.
Control Unit The control unit is basically a set of counters and logic gates which is driven by the block. Its function is to control the units within the microprocessor to ensure that operations are carried out in the correct order.
Functions of PLCs
Functions of PLC: Function of a PLC is to provide a reprogrammable, reliable, upgradable control solution for Industrial Automation The function of an input module is to convert incoming signals into signals, which can be processed by the PLC, and to pass these to the central control unit. The reverse task is performed by an output module. This converts the PLC signal into signals suitable for the actuators
Applications of PLCs PLCs ...over 1,000,000 applications world wide Woodworking
Overview
Conveyor systems Pump controls
Filling plants
Vacuum suction systems/elevators
Application examples examples
Applications of PLC are wide ranging ranging as it is designed for Industrial Applications
As the Industry is diversified so is the application of of PLC.
A reliable controller for every machine & system .
Where frequent process changes are required. In harsh environments.
Where the whole plant is to be controlled by central controller with multiple loops.
Accurate Timer and counter functions, memory memory setting and resetting, mathematical computing operations when required.
For reliable, accurate and economical automation
Control of a Sequence (Conveyor Unit)
Here a PLC is controlling the conveyor unit (Diversion & Speed)
PLC is getting info from: Sensors for workpiece detection Sensors for conveyor speed detection
And controlling: 1.
2.
Diversion device (pneumatic based) Conveyor speed
Monitoring a Chemical Plant
Here a PLC is controlling a process PLC gathers information from level sensors According to the level definition of the reservoirs opens or closes the respective valves All of the actions are executed according to the program that is written in the PLC PLC can also control the flowrate of the fluids.
Interface Control in CNC machine
A CNC machine requires a variety of sequential control applications like:
Coolant on / off Door open / close Tool changing Vise / chuck open / close
Interface control in CNC machine machine
Program
Program
PLC Interface Control Control
CNCController
A PLC is used here in connection with CNC the controller that enables machine to execute the fore stated steps
Machine Tool Tool
Replacing Relays by PLC
Replacing Relays by PLC Continue:
Components of a PLC Basics of PLC
Hardware
Power supply Processor Input module Output module Special modules
Temperature sensing Motor control
Software
PLC programming software Linking software HMI development software
Functions of PLC
Symbols
Applications of PLC
Components of PLC
Programming Devices
PLC Program creation
Programming Modes
Documentation PLC addressing
Programming Logic Functions
Q&A
Components of a PLC
The Base For PLC
Components of a PLC
The Power Supply Mounted On The Base Plate
Components of a PLC
The Processor Module Mounted on the Base Plate
Components of a PLC
The Input Module Mounted on the Base Plate
Components of a PLC
The Output Module Mounted on the Base Plate
Block Diagram of PLC
Types of PLC There are two types of PLC 1) Fixed PLC PLC
Fixed PLC combine all of the main components into a single unit that contains the CPU, input/output sections, and power supply. The number of inputs and outputs cannot be expanded. 2) Modular PLC PLC
A PLC configuration in which each component is split into a separate unit. A modular PLC lets you have as many inputs and outputs as you want.
PLC Available in market Following models of PLC are commonly available in the market.
Basics of PLC
Functions of PLC
Symbols
Applications of PLC
Components of PLC
Programming Devices
PLC Program creation
Programming Modes
Documentation
PLC addressing
Programming Logic Functions
Q&A
Programming Devices
Processor Module can be programmed via
PLC programmer Hand Held Programmer
Processor Module can give output to
Computer
Printer HMI panel Computer
It can communicate with other devices as well
Basics of PLC
Functions of PLC
Symbols
Applications of PLC
Components of PLC
Programming Devices
PLC Program creation
Programming Modes
Documentation
PLC addressing
Programming Logic Functions
Q&A
Programming languages Basics of PLC
Ladder Diagram
Function Block Diagram
Instruction List
Structured Text
Sequential Function Chart
Functions of PLC
Symbols
Applications of PLC
Components of PLC
Programming Devices
PLC Program creation
Programming Modes
Documentation
PLC addressing
Programming Logic Functions
Q&A
Ladder diagram
A graphic programming language Derived from relay logic Contact the right Rails to the left and These contact rails are connected to switching elements
Function block diagram
Graphical Method of programming
Various Function blocks are provided for the ease of programmer, e.g.
Logic Functions
Math Functions
Special Functions
Functions blocks are interconnected into networks, to form a PLC program.
Even Ladder Diagram can be used with function blocks
Instruction List
Instruction list is a textual assembler-type language Instruction list is formulated from control instructions consisting of an operator and an operand.
LD
Part_TypeA
OR
Part_TypeB
AND
Part_present
AND
Drill_ok
ST
Sleeve_in
Structured Text
Structured text programming is similar to high-level language
Loops, control statements and function blocks can be used
Structured text enables the formulation of numerous applications, beyond pure function technology,
algorithmic problems (Control)
data handling (data analysis, processing of complex data structures etc.).
Sleeve_in :- (Part_TypeA (Part_TypeA OR Part_TypeB) And Part_present AND Drill_ok;
Sequential Function Chart
Used for structuring of sequence-oriented control programs.
The elements SFC are
steps,
transitions,
alternative and
parallel branching.
Hierarchical structure of a control program is developed.
Why there are a number of programming options for a PLC? To gain popularity!
Basics of PLC
Functions of PLC
Symbols
Applications of PLC
Components of PLC
Programming Devices
PLC Program creation
Programming Modes
Documentation PLC addressing
Programming Logic Functions
Q&A
Procedure for Creating a PLC Program Specification:
Design:
Description of the solution
Realization:
Description of the task
Implementation of the solution
Integration / commissioning:
Incorporating into environment and testing
Documentation
One important and crucial component of a system is documentation, Documentation is required for Maintenance
Expansion of the system Troubleshooting
PLC Program creation
Individually these are: Problem description Documentation Positional sketch or technology pattern Circuit diagram Terminal diagram Printouts of control programs in SFC, FBD etc.. inputs and outputs Allocation list of inputs Additional documentation
PLC addressing Basics of PLC
Input and output Assignment
Electrical and pneumatic circuit diagrams
Functions of PLC
Symbols
Applications of PLC
Components of PLC
Programming Devices
PLC Program creation
Programming Modes
Documentation
PLC addressing
Programming Logic Functions
Q&A
PLC addressing Memory Area Structu Structure re OF FA FATEK PLC
PLC addressing Memory Area Structu Structure re OF FA FATEK PLC
PLC addressing Memory Area Structure OF SIEMENS PLC
PLC addressing Memory Area Structure OF SIEMENS PLC
PLC addressing Memory Area Structure OF SIEMENS PLC z Physical Input Contacts()These are the external physical inputs contacts of the PLC. Its Address in Siemens PLC P LC is I0….. In and for Fatek PLC is X0….Xn.
z Physical Output Coils()These are the external physical Outputs Coils/Relays of the PLC. Its Address in Siemens PLC is Q0….. Qn and for Fatek is Y0….Yn.
PLC addressing Memory Area Structure PLC Internal Relay ()()Do not have any specific function, and they can be freely used within the program (except those assigned to Input or Output Cards and Special I/O Cards). Known as M area in Fatek PLC. Retentive M(M800-1399), Internal Relay(M0-799) and Special relays (M1912-2001) Work Area/Data Register (D) (D) – – can be used only in the program; not for I/O exchange with external I/O terminals. D (D0-D4095), R(R0-4168)
PLC addressing Memory Area Structure PLC
–
Step Relays (S) relays (S) These are the step of PLC. Known as Retentive S(S500-999) and S(0-499) of Fatek PLC. Timers(T)/ Counters(C)-
I/O Assignment
The I/O assignment table indicates which PLC inputs are connected to which input devices And which PLC outputs drive which output devices. The assignment of internals, including timers and counters also takes place here.
Electrical and pneumatic circuit diagrams
Integration of PLC with mechanical system.
the electrical circuit is
replaced with the ladder diagram of PLC and is connected to the pneumatic circuit accordingly
Here a solenoid operated valve is connected to the PLC.
Basics of PLC
Functions of PLC
Symbols
Applications of PLC
Components of PLC
Programming Devices
PLC Program creation
Programming Modes
Documentation
PLC addressing
Programming Logic Functions
Q&A
Programming of logic functions Ladder Diagram representation ntation use • A graphical represe by engineers for their relay logic. •
Adopted by PLC PLC makers as a programming language due to its simplicity.. Thus the term Ladder simplicity Programming shown in figure.
• Fatek PLC programmer
WinProLadder.
Symbols of Ladder Diagram
Symbols of Ladder Diagram
Y0
X0
X0
This is is a representation of a relay coil. coil. The number represents the relay.
This is a normally open contact symbol. It will will be closed if the coil of the same number is energised. This is a normally closed contact symbol. It will open upon the energising of the coil of the same number
SIMATIC S7-200 SIMATIC S7-200
S7-200 Second Generation Overview 221 (10CPU I/O Points)
CPU 222 (14 I/O Points)
224 (24) CPU I/O Points)
Overview
CPU 224XP (24 I/O Points) Points)
CPU 226 (40 I/O Points) Points)
Built-in Features Overview
CPU Status
I/O Point
LEDs
Status LEDs
Cartridge Slot
Internal: - Power Supply - Super Capacitor - Clock
(224(XP),226)
Communication Port(s)
24V Sensor Power Output
Removable Terminal Blocks
(224(XP),226)
Snap-On Clip
for DIN Rail Mounting
Mounting Holes for Panel Installation
Please sit infront of Individual PCs and Open WinProLadder placed on DeskTop. Practice on Simple Ladder Logic Programming
Review on Logic Gates NOT Gate, OR Gate, Nor Gate, And Gate, Nand Gate, XOR Gate, Multiplexers Multiplexe rs Etc. Equation & Truth Truth Table of Gates Practice Session
Programming of logic functions
Basic Logic Functions
Not
Or
And Memory
The figure is showing the relay logic for AND and OR operation
(NOT Gate) Negation (NOT
The output signal assumes the value 1, if the input signal has the value 0 and vice versa.
(NOT Gate) Negation (NOT Exercise 1:
Lamp H1 is illuminated as long as switch S1 is not actuated; It is extinguished, if the switch is closed. The purpose of S1 is therefore to switch off the lamp.
(NOT Gate) Negation (NOT Solution:
AND-Operation
The output signal only assumes the value 1, if all input signals have the value 1.
AND-Operation Exercise 2:
Lamp H1 is to be switched on only if the two switches S1 and S2 are actuated.
AND-Operation Solution:
NAND-Operation
The output signal only assumes the value 1, if all input signals have the value 1.
NAND-Operation Exercise 3:
The output signal only assumes the value 1, if all input signals have the value 1.
Lamp H1 is to be switched on only if the two switches S1 and S2 are actuated.
NAND-Operation Solution 3:
OR-Operation
The output signal assumes the value 1, if at least one input signal has the value 1.
OR-Operation Example 4:
Lamp H1 is to be switched on, if at least one switch, S1 or S2 is actuated.
OR-Operation Solution 4:
NOR-Operation
The output signal assumes the value 1, if at least one input signal has the value 1.
NOR-Operation Example 5:
Lamp H1 is to be switched on, if at least one switch, S1 or S2 is actuated.
NOR-Operation Solution 5:
Exclusive OR-Operation
The output signal assumes the value 1, if at least one input signal has the value 1.
Exclusive OR-Operation Example 6:
Lamp H1 is to be switched on, if at least one switch, S1 or S2 is actuated.
Exclusive OR-Operation Solution 6:
Memory Function
The standard function block SR
a dominant setting flipflop (bistable with preferredmemory status 1). A 1-signal at S1 sets the value of Q1 A 1-signal at R only only brings output Q1 to value 0
The standard function block RS
a dominant resetting flipflop (bistable memory with
preferred status 0).
Memory Function
Exercise:
If sensor B1 has a 1-Signal, this indicates an error status in the system. A horn H1 is sounded . The horn can only be switched off by actuating push-button S1. It is possible to switch off the horn, even if the B1signal continues to be applied.
Memory Function
DAY-2 Programming Techniques • •
• • •
Symbolic Addressing Latches Timers Single Shot Pulse Counters
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Symbolic Addressing
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Symbolic Addressing
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Latches Latch circuit is used to maintain the status of output based on two execution conditions. These conditions are SET & RESET. condition is true, outputWhen turns ON and stay ON,When untilSET reset condition is true. RESET condition is true, output turns OFF and stay OFF, until SET condition is true. SET condition RESET condition
Output National Institute of Design & Analysis
Latches
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Latches
92
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TIMER
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TIMER
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TIMER
95
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Timers and Creating Delay A timer is activated when its execution condition goes ON. If the execution condition remains ON long enough for TIM to time down to zero, the output for the TC number used will turn ON and will remain ON, until TIM is reset. TIM measures in units of 0.1 second from the Set Value. Input Condition
Output T1
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Timers and Creating Delay
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DELAY ON TIMER
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DELAY ON TIMER
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DELAY ON TIMER
EXAMPLE:: Write a program to on a motor after 10 seconds EXAMPLE When switch S1 is on
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DELAY ON TIMER Solution:
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DELAY OFF TIMER EXAMPLE: Write a program to on a motor for 100 seconds When switch S1 is on.
102
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DELAY OFF TIMER Solution:
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Retentive or Accumulating timer
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Retentive or Accumulating timer Example:
105
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TIMER
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Single-Shot Circuit
This circuit is used to keep the ON time of an input signal.
Input Signal Output T1
T1
107
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Single-Shot Circuit
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COUNTER
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COUNTER
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COUNTER
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COUNTER
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COUNTER EXAMPLE: Write a program to count a number of samples ( box, apples, bottles etc) up to 10 and then stop the conveyor motor.
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COUNTER
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COUNTER
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COUNTER
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Retentive or Accumulating timer EXAMPLE: Write a program to count the existing bottles on a conveyor belt by using S1 at the entrance and S2 at outlet. If bottles are 4 then on alarm AL1. Use S3 pushbutton for reset.
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COUNTER
118
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