Components of a simple PC

Hard driveVideo USB Network

Outside

world

Hard drive

controller

Video

controller

Memory

USB

controller

Network

controller

CPU Computer internals

(inside the “box”)

"von Neumann" ArchitectureMemory

Input ALU Output

Control

Unit

Data Flow

Address Flow

Control Flow

CPU Mikro Computer,

Single Chip Computer

Minimal Configuration of a Microcomputer System

MemoryClock Power

Supply(ROM, RAM)Generator

InputCPU Output

(I/O)

Address Bus

Data Bus

Control Bus

Out

In

I/O Bus

mainmemory

I/O bridge

bus interface

ALU

register file

CPU chip

system bus memory bus

memorybridgebus interface

disk controller

graphicsadapter

USBcontroller

mouse keyboard monitor

disk

I/O bus Expansion slots forother devices suchas network adapters.

Moore’s LawMoore’s Law

START

ECHIVALENTA FUNCTIONALA

SISTEM CU

CIRCUITE IN

LOGICA CU L

+ 24 V

START

SISTEM IN

LOGICA CU FUNCTII

PORT

INTRARI

PORT

IESIRI

STOP

LOGICA CU

FUNCTII CABLATE

L

STOP

L

LOGICA CU FUNCTII

PROGRAMATEPORT

INTRARI

PORT

IESIRI

History Of Microcontrollers

• Microprocessors came before Microcontrollers

• November 1971– Intel introduced the world's first single chip microprocessor, the Intel

4004 4004

• April of 1972– First 8-bit microprocessor appeared on the market under a name 8008

• April of 1974– 8080 became available– Addressed 64Kb of memory, had 75 instructions, and cost $360

• MOS Technology - WESCON exhibit ( 1975)– a pivotal event in the history of microprocessors – Announced the 6501 and 6502 at $25 each

What Are Microcontrollers?

• Microprocessor – Microcontroller what's the diff?

• Microprocessors can not stand alone

– instruction decoder, ALU, address/data/ctl. busses, timing logic, (CPU)

– Has no capability to interact with the outside world– Has no capability to interact with the outside world

• memory, I/O ports, UARTS, etc. must be added to make it useful

• Microcontrollers are small computing systems on a single chip

– Central Processing Unit (CPU)

– Program memory

– Random Access Memory (RAM)

– EEPROM - Electrically Erasable Programmable Read Only Memory

– A variety of peripheral devices

• USARTs, Timer/Counters, ADC, DAC, I/O Ports, CANs, SPIs, etc., etc.

What Are Microcontrollers?So, what’s all the excitement about?

• They are inexpensive- even in single pieces• You can design complex functionality in a small

package• Microcontrollers can be viewed as a universal • Microcontrollers can be viewed as a universal

building block• There are a lot of free tools to work with

Microcontrollers• And – The thing I like the best - Next Slide!

Microprocessors:

• CPU for Computers

• No RAM, ROM, I/O on CPU chip itself

• Example：Intel’s

Many chips on mother’s board

General-purpose microprocessor

CPU

General-

Purpose

Micro-

processor

RAM ROM I/O

PortTimer

Serial

COM

Port

Data Bus

Address Bus

General-Purpose Microprocessor System

Many chips on mother’s board

• A smaller computer

• On-chip RAM, ROM, I/O ports...

• Example：Motorola’s, Intel’s, Zilog’s and PIC 16X

Microcontroller:

RAM ROM

I/O

PortTimer

Serial

COM

PortMicrocontroller

CPU

A single chip

Microprocessor

• CPU is stand-alone,

RAM, ROM, I/O, timer

are separate

• designer can decide on

the amount of ROM,

Microcontroller

• CPU, RAM, ROM, I/O

and timer are all on a

single chip

• fix amount of on-chip

ROM, RAM, I/O ports

Microprocessor vs. Microcontroller

the amount of ROM,

RAM and I/O ports.

• expansive

• versatility

• general-purpose

ROM, RAM, I/O ports

• for applications in which

cost, power and space are

critical

• single-purpose

Block Diagram

On-chip

RAM

On-chip

ROM for

program

code Timer 0

Interrupt

Control

External interrupts

Timer 1

Timer/Counter

Counter

Inputs

CPU

4 I/O PortsSerial

PortOSCBus

Control

TxD RxDP0 P1 P2 P3

Address/Data

Microprocessor – Basic concept

CPU

containsCCUALU

data registers

CONTROLADDRESS

BOOTROM

Used at

Instruction(program)

ROMTransducers

KeyboardScreenUART

Parallelinterface

DataRAM

data registersand

pointer registers

DATA

Microprocessor, by-itself, completely useless – must have external peripherals toInteract with outside world

Used at startup

ROMinterface

etc

Microcontroller – Basic concept

CPU

containsCCUALU

data registers

CONTROLADDRESS

BOOTROM

Used at startup

Instruction(program)

ROMTransducers

UARTParallelinterface

Etc

DataRAM

data registersand

pointer registers

DATA

Microcontroller – put a limited amount of most commonly used resources “inside” the chip

What is a PLC?

• PLC is a digitally operating apparatus

which uses a programmable memory for the

internal storage of instructions for

CONTROLERELE LOGICE PROGRAMABILE

implementing specific functions such as

logic, sequencing, timing, counting and

arithmetic to control, through digital or

analog input/output modules, various types

of machine or processes.

PLC History• More recently electricity has been used for control and early electrical control was based on relays.

• These relays allow power to be switched on and off without a mechanical switch.

• It is common to use relays to make simple logical control decision.

• The development of low cost computer has brought • The development of low cost computer has brought the most recent revolution the Programmable Logic Controller (PLC).

• PLC was developed to replace relays in 1960s. Cost dropped and became popular by 1980s.

• The advent of PLC has become the most common choice for manufacturing controls.

How does PLC differs from a personal computer?

• A Programmable Logic Controller (PLC) is a

specialized computer, designed to be used for

industrial control.

• Programmable Logic Controllers are sometime

called programmable controllers (PC) but are more

commonly called PLCs.commonly called PLCs.

• A PLC looks different from a standard personal

computer.

• For a start, a PLC doesn’t have a keyboard or a

monitor.

• The following pictures show several PLCs.

Advantages of Using PLCs in Automated Food Industrial

• PLCs have been gaining popularity on the factory floor

and will probably remain predominant. Most of this is

because of the advantages they offer.

• Cost effective for controlling complex system.

• Flexible and can be reapplied to control other systems

quickly and easily.

• Reliable components make these likely to operate for • Reliable components make these likely to operate for

years before failure.

• Troubleshooting aids make programming easier and

reduce downtime.

• Ease to setup and program.

• PLC are tough enough to keep working in even the

dirtiest production environment.

Advantages of Using PLCs in Automated Food Industrial

• Programming the PLC is easier than wiring the relay

control panel.

• The PLC can be reprogrammed (conventional

controls must be rewired).

• Computational abilities allow more sophisticated

control.

• PLCs take less floor space than relay control panels.• PLCs take less floor space than relay control panels.

• Maintenance of the PLC is easier, and reliability is

greater.

• The PLC can be connected to the plant computer

systems more easily than relays can.

The use of PLC in manufacturing

Timer and Timer and CounterCounter

Switches and Switches and SensorsSensors

ProcessesProcesses

PLCPLC

SoftwaSoftwarere

Motor Motor ControlControl Field I/OField I/O

Operator Operator InterfaceInterface

CommunicationCommunication

ConnectoConnectorr

PLCs

Keyence, Keyence, JapanJapan Omron, JapanOmron, JapanMitsubishi, Mitsubishi,

..\P L C\Carte net\eBook_PLC.exe ..\..\..\KIT\PLC Sim\PLCAutomationTrainer\PLC Automation Trainer\PLCTrainer Demo.exe

JapanJapan Omron, JapanOmron, JapanMitsubishi, Mitsubishi, JapanJapan

Allen Bradley, Allen Bradley, USAUSA

Siemens AG, Siemens AG, GermanyGermany

Schneider, Schneider, GermanyGermany

Location of the PLC in the control architecture

Entreprise Network

Control Bus(e.g. Ethernet)

Engineerstation gateway

Control Station 2

CO

M1

CO

M 2

CP

U

Operatorstation

PLC PLCPLC

CO

M1

1

SupervisorStation

directly connectedI/O

I/O

I/O

I/O

I/O

CP

U

Sensor Bus (e.g. ASI)

Field Bus (proprietary)

Field Stations

Control Station with Field Bus

direct I/O

I/O

Field DevicesFB

gateway

gateway

I/O

I/O

I/O

I/O

CP

U

CO

M

I/O

I/O

I/O

CO

M

CP

U

CO

M

CO

M

CO

M

I/O

Field Bus (standard)

CP

U

CO

M 2

I/O

I/O

I/O

CP

U

CO

M

CO

M

I/OCP

UPLC

small PLClocal intelligence

PLC

CO

M

CO

M1

ANSI/ISA 95 standard

the ANS/ISA standard 95 defines terminology and good practices

Enterprise Resource PlanningBusiness Planning & LogisticsPlant Production Scheduling

Operational Management, etc.

ManufacturingOperations & Control

Level 4

Level 3

Source: ANSI/ISA–95.00.01–2000

Manufacturing Execution System

Control & Command System

Operations & ControlDispatching Production, Detailed Product

Scheduling, Reliability Assurance,...

Levels2,1,0

BatchControl

ContinuousControl

DiscreteControl

Busses and processors in industrial plants

Operator panelMimic boarddisk

process bus (500m .. 3 km)

Process pictures

Process Data Base

Logging

workstation bus

instrument bus(mimic board)

open network:TCP/IP, ...

stationstation

PLC nodes(multi-processors)

fieldbus

plant (Werk, usine)

Ppool

transducers

controlstations

valve thermo-couple motorposition

station bus

(0,5.. 30 m)

node bus

sensor bus

directly coupled input/output

P P C

I/O MEM I/O

P P C P

MEM BC

M

sensor bus

(30m..2 km)

Example: Production management system

transportation manufacturing

scheduling maintenance quality control

plant network

productionplanning

enterprise network

celltransportationcell control

manufacturingcell control

floor network

robotcontrolle

r

millingmachine

rail-guidedvehicle

cell

Example: ABB Industrial IT (redundant system)

engineeringworkplace

Firewall

Plant Network / Intranet

Client/server Network

3rd party

applicatio

n server

applicationserver

aspectserver

Workplaces(clients)

Enterprise Optimization

(clients)

MobileOperator

connectivityserver

Control Network

3rd party

controllers,

servers etc

Serial, OPCor fieldbus

Field Bus Field Bus

ProgrammableLogic ControllerAC 800C

Redundant

AC 800M

touch-screen

Decentralized Control System (DCS)

engineeringworkstation

operatorworkstation

data logger

controller controller controller controller

control bus

plant

field bus

all controllers can communicate as peers (without going through a central master), restricted only by throughput and modularity considerations.

Note: Honeywell's "DCS™" stands for "Distributed Control System", it is not a decentralized control system, but a control system for the process industry.

General PLC architecture

CPUReal-Time

Clockflash

EPROMROM

buffers

serial portcontroller

Ethernet

parallel bus

ethernetcontroller

RS 232

analog- digitalfieldbus external

extensionbus

signal conditioning

power amplifiers

relayssignal

conditioning

analog-digital

converters

digitalanalog

convertersDigital Output

DigitalInput

fieldbuscontroller

externalI/Os

field bus direct Inputs and Outputs

PLC’s Component

• Many PLC configurations are available, even from a

single vendor.

• But, in each of these are common components and concepts.

• The most essential components are:

• CPU Module:

• Input Modules:

• Output Modules

PLC Operation

CONSOLA DE

PROGRAMARE

MEMORIA

PROGRAM

UNITATEA CNTRALĂ MODULE

DE

IEŞIRE

MODULE DE

INTRARE

MODULE

SPECIALE

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