Mechatronics Session 6 Microcontroller n PLC

8/17/2019 Mechatronics Session 6 Microcontroller n PLC

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SESSION OUTCOMES

At the end of 6th session, Students will be able to:

1$ !n%erstan% the %igital control s#stem composition

&ase% on Microcontrollers' Cs

2$ !n%erstan% interacing issues in %igital architecture

&ase% on Microcontrollers ' Cs


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Role of Digital Control Architecture in a MechatronicSystem


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*ole o Microcontroller' C in a Digital Control Architecture

+ Stores data+ Processes arithmetic/logic functions+ Used for data acquisition+ Essentially used in embedded control systems


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CPU, MICROPROCESSOR, MICROCONTROER

Microprocessor:CPU on a chip (memory, power source etc. need

to be eternally arranged!

Used for PCs, "es#tops, $aptops etc.

Microcontroller:

Computer on a Chip (usually de%oid of display!

Used for embedded control systems


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MICRO CONTROER

&he 'icrocontroller, which is a single C containingspeciali)ed circuits and functions that are applicable to

'echatronic system design

e.g. Microchi!"s PIC, Motorola"s #$%C&&, an' Intel"s$()#


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Applications:-

+ *ome appliances+ Entertainment equipment+ &elecommunication equipment+ +utomobiles

+ &ruc#s,+ +irplanes+ &oys+ ffice equipment

All of these !o*erful an' interesting 'e+ices arecontrolle' y microcontrollers an' the soft*arerunning on them-


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Microcontroller based Digital Control Architecture: Composition


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Microcontroller Board


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Microcontroller ATmega328P

Operating Voltage ./

Input Voltage

(recommended) 01&2/Input Voltage

(limit)#12(/

Digital I/O Pins &3 4of *hich # !ro+i'e P5M out!ut6

PWM Digital I/O

Pins

#

Analog Input Pins #

D urrent per I/O

Pin2( mA

D urrent !or

3"3V Pin

.( mA

#las$ Memor%72 89 4ATmega72$P6

of *hich (-. 89 use' y ootloa'er

&'AM 2 89 4ATmega72$P6

P'OM & 89 4ATmega72$P6

loc &peed M%:

Microcontroller Specifications

http://www.atmel.com/Images/doc8161.pdfhttp://www.atmel.com/Images/doc8161.pdf


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+ digitally operating electronic apparatus which uses a programmablememory for the internal storage of instructions by implementing specific

functions such as logic sequencing, timing, counting, and arithmetic to

control, through digital or analogue input/output modules, %arious types of

machines or processes.

Programmable Logic Controller


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PC /ERSUSMICROCONTROER

ARDUINO

MICROCONTROER

PRO;RAMMA9E O;ICCONTROER 4%ITAC%I6

Pin &7ED

US9connect

or

9arrel


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PLC vs. Microcontroller

Micro controller

• C!, *AM, *OM, 'O an% timer areall on a single chip

• i-e% amount o on.chip *OM, *AM,

'O ports• or applications in /hich cost, po/er

an% space are critical• single.purpose (control.oriente%)• o/ processing po/er • o/ po/er consumption• 0it.le"el operations•

nstruction sets ocus on control an%&it.le"el operations• #picall# '16 &it• #picall# single.c#cle't/o.stage

pipeline

Programmable Logic Controller + C! is stan%.alone, *AM,

*OM, 'O, timer are separate+ %esigner can %eci%e on the

amount o *OM, *AM an% 'O

ports$

+ e-pensi"e+ "ersatilit#+ general.purpose+ 3igh processing po/er + 3igh po/er consumption

+ nstruction sets ocus onprocessing.intensi"e operations

+ #picall# 2'64 5 &it+ #picall# %eep pipeline (.27

stages)


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Digital Control Architecture: Meaning of nterfacing

+ nteracing is re8uire% to resol"e incompati&ilit# &et/een the

microprocessor an% peripheral %e"ices "i9$ sensors, :e#&oar%,

actuators etc$

+ eripheral %e"ices ma# either suppl# input to or recei"e output

signals rom the microprocessor$

+ 0ut usuall# peripheral %e"ices cannot &e %irectl# interace% to

microprocessor %ue to lac: o compati&ilit# in signal orms an%

le"els$

+ ;er# commonl# use% interaces are<

(i) eripheral interace a%apter e$g$ Motorola MC627

(ii) As#nchronous Communications nterace a%apter e$g$ MC67


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Certain actions that are oten re8uire% o an interace circuit<

!" #lectrical Buffering$ solation: 0uering is re8uire% to isolate

microprocessor rom the peripheral %e"ices /hich operate at higher

po/er$ 0uering %e"ices pro"i%es isolation an% 'or current' "oltage

ampliication$

%" &iming Control: s#nchroni9ation o %ata transer rate &et/een

microprocessor an% the peripheral %e"ices$ Handshake lines are special

lines use% or the purpose$

'" Code con(ersion: or e$g$ an ED %ispla# ma# re8uire %eco%er to

con"ert 0CD output rom Microprocessor into &inar# co%e to operate a =.

Segment ED %ispla#$

Digital Control Architecture: nterfacing issues


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Digital Control Architecture: nterfacing issues contd)*

+" Serial to parallel and (ice (ersa data transfer: microprocessor is

recei"ing serial %ata transer an% it nee% to output in parallel %ata transer

mo%e to the peripheral %e"ices or "ice."ersa, an interace is re8uire%$

" Con(ersion from Analogue to Digital and -ice.(ersa


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Selection o Micro Controller

-actors of selecting micro controllers

+ o of inputs / out put pins+ nterfaces required+ 'emory requirements+ &he number of interrupts required

+ Processing speed required+ low cost+ 0ersatility+ ease of programming,

+ small si)e


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Tem!erature Control

+ he temperature sensors gi"es a "oltage proportional to temperature$+ he output rom the temperature sensor is connecte% to the ADC+ he micro controller is programme% to con"ert temperature into 0CD

output /hich can s/itch on the elements o a 2.%igit se"en.element

%ispla#$+ 0ecause o luctuations in the temperature, a storage register is use% to

hol% %ata i$e$ =43C2=, lip.lop$

Case Stud/: &emperature Measurement S/stem Control


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Case Stud/: #M0 controlled 1obot


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&han2 3 4 5ueries, if an/

Mechatronics Session 6 Microcontroller n PLC

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