Wilamowski B.M., Irwin J.D. The Industrial Electronics Handbook. Second Edition: Industrial Communication Systems

Подождите немного. Документ загружается.

Communication Aspects of IEC 61499 Architecture 55-17

and.port.number.of.the.remote.server.is.also.required,.and.this.INIT+.event.will.result.in.the.client.

establishing.a.TCP.connection.with.the.RCV.FB.. e.SEND.FB,.upon.receiving.an.REQ+.event,.

sends.the.data.(16-bit.words).available.on.its.SD_x.input.ports.and.simultaneously.asks.for.the.

return.data,.using.the.“read/write.multiple.registers”.Modbus.function.(function.code.23-17.hex).

•

. e.RCV.FB,.upon.receiving.the.message.sent.by.the.client,.places.the.received.data.on.its.RD_x.

data.output.ports.and.emits.an.IND+.event.

•

. e.server.device.must.then.make.the.return.data.available.on.the.RCV.SD_x.input.ports.and.

emit.the.RSP+.event..Upon.receiving.this.event,.the.RCV.FB.then.replies.to.the.“read/write.mul-

tiple

.registers”.request.. e.SEND.FB,.upon.receiving.the.reply.message,.places.the.received.data.

on.its.RD_x.output.ports.and.emits.the.CNF+.event.

.the.RSP+.event.is.delayed.beyond.a.certain.timeout,.the.SEND.FB.will.emit.an.RSP−.event.

Since

.the.IEC.61499.FBs.do.not.use.the.same.remote.memory.data.model.as.the.Modbus.protocol,.

with.the.mapping.proposed.above.it.is.not.necessary.to.specify.the.Modbus.register.addresses.. ese.are.

assumed.to.always.start.at.0,.and.the.number.of.registers.to.read.(write).is.the.same.as.the.number.of.data.

outputs.(inputs).on.the.SEND.FB..Note.that.the.number.of.input.words.of.the.SEND.FB.must.match.the.

number.of.output.words.in.the.RCV.FB,.and.vice.versa.

Similar

.SEND. and.RCV. FBs. are.used. for.the. transmission. of. Boolean. data.. However,. since. the.

Modbus.protocol.does.not.include.a.function.that.allows.simultaneous.reading.and.writing.of.Boolean.

data,.these.must.only.send.data.either.from.the.SEND.FB.to.the.RCV.FB.(using.the.Modbus.function.

“Write.Multiple.Coils,”.code.15-0F.hex).or.from.the.RCV.FB.to.the.SEND.FB.(using.the.Modbus.func-

tion

.“Read.Coils,”.code.01-01.hex).

.above.communication.assumes.that.the.server.device.also.supports.IEC.61499..However,.cur-

rently

.many.remote.terminal.units.(RTUs).support.the.Modbus.protocol,.but.do.not.implement.IEC.

61499..To.allow.a.controller.device.to.communicate.with.these.legacy.RTUs,.SEND.FBs.are.used.that.

connect.directly.to.these.legacy.Modbus.server.devices.. ese.RCV.FBs.require.additional.parameters.

when.the.function.is.initialized.in.order.to.specify.the.Modbus.function,.data.address,.and,.when.read-

ing

.data,.the.number.of.registers.to.use.when.transferring.data.to/from.the.legacy.Modbus.server.

55.10 Communication via the CIP

In. this. section,. we. show.how.another. communication. network,. based. on.CIP,. can. be. used. in. our.

example..CIP.has.originally.been.developed.as.application.layer.for.Rockwell.Automation’s.CAN-based.

DeviceNet.and.their.controller.network.ControlNet..With.the.development.for.the.industrial.Ethernet.

EtherNet/IP.and.the.sensor.actuator.bus.CompoNet,.the.CIP.specication.was.further.unied.and.pro-

vides

.a.common.application.layer.for.these.four.networks..CIP.is.a.multimaster.system.and.therefore.

well-suited.for.the.application.in.a.distributed.control.system.

Interface

.of.IEC.FBs.for.CIP.was.dened.in.the.compliance.prole.[25]..More.implementation.details.

can.be.found.in.[26,27].

INIT

REQ

Data

Event

SD_1

SEND_1

RCV_1

INITO

INIT INITO

IND

RD_1

CNF

FIGURE 55.14 Producer–consumer.pair.implemented.in.MODBUS.

55-18 Industrial Communication Systems

For.the.exchange.of.real-time.application.data,.CIP.provides.the.means.of.so-called.implicit.messages..

Implicit.messages.have.a.connection-oriented.uni-.or.multicast.producer/consumer.messaging.model.

(i.e.,.similar.to.publish/subscribe.model)..In.general,.eldbuses.feature.a.cyclic.execution.behavior..In.

dierence,.CIP.allows.the.so-called.application-triggered.message.production.behavior,.which.ts.very.

well.to.the.event-triggered.execution.model.of.IEC.61499..CIP.furthermore.provides.QoS.mechanisms.

that.can.be.utilized.for.simplifying.an.IEC.61499.application,.as.certain.communication.errors.can.be.

handled.at.CIP.stack.level.. ese.QoS.mechanisms.are

. 1..Sequence counter:.Each.message.is.identied.with.an.increasing.sequence.number,.which.allows.

the.detection.of.wrong.message.order.and.lost.messages.

. 2.. Production inhibit timer:.With.this.value,.the.minimum.time.between.two.messages.can.be.speci-

ed

.on.the.producer’s.side.. is.allows.to.bound.the.network.trac.

. 3..Expected packet rate:. is.rate.gives.the.consumer.an.estimation.of.how.oen. messages. will.

arrive.. is.can.be.used.to.determine.if.the.producer.was.lost.

.CIP.producers.do.not.keep.track.of.and.do.not.request.an.acknowledgment.from.consumers,.the.

producer.has.no.CIP.means.for.detecting.the.loss.of.consumers.

With

.these.basic.assumptions,.the.behavior.of.the.CIP_SEND_1.and.the.CIP_RCV_1.communication.

FBs.(Figure.55.15).is.as.follows:

•

. e.device.containing.the.CIP_SEND_1.FB.initializes.this.FB.with.an.INIT+.event.. e.FB.will.

create.a.CIP.assembly.object.with.the.given.ID..To.this.assembly.object,.the.CIP_RCV_1.can.now.

connect.. e.size.of.the.data.and.the.meaning.of.the.data.are.dened.by.the.number.of.inputs.

and.their.data.types..As.CIP.uses.the.same.data.types.as.IEC.61499,.namely.the.data.types.of.IEC.

61131-3,.the.CIP.data.encoding.mechanisms.can.be.directly.used.

•

. Aer.the.CIP_SEND_1.set.up.its.side.of.the.communication,.the.CIP_RCV_1.can.establish.the.

connection.. is.is.again.triggered.with.an.INIT+.event.. e.ID.input.has.to.specify.the.address.

of.the.device.and.the.assembly.object.to.connect.to.(i.e.,.the.assembly.object.created.by.the.CIP_

SEND_1).

.As.a.result,.the.CIP.stack.is.congured.for.a.consumer,.and.a.unicast.CIP.connection.

between.the.two.devices.is.established..As.the.application.cannot.guarantee.that.the.CIP_SEND_1.

is.initialized.before.the.CIP_RCV_1,.the.implementation.has.to.be.robust.enough.to.handle.this.

case.(e.g.,.automatic.retry.to.establish.the.connection).

•

. On.triggering.the.REQ.event.of.the.CIP_SEND_1,.the.input.data.are.encoded.into.the.CIP.net-

work

.format,.and.the.message.is.sent..With.a.CNF.event,.the.IEC.61499.application.is.informed.

on.the.success.of.this.procedure..No.information.on.the.consumer.side,.such.as.if.the.data.have.

been.received.and.processed.is.given.

•

. On.receiving.a.message,.the.CIP.stack.will.inform.the.CIP_RCV_1.FB.. ere.the.data.is.decoded.

and.placed.on.the.outputs.. e.application.is.then.notied.with.an.IND.event.

•

. rough.INIT.events,.the.connection.can.be.closed.from.both.sides..If.the.connection.is.closed.

from.the.CIP_SEND_1.side,.the.CIP_RCV_1.will.be.informed,.otherwise.not.

INIT

REQ

SD_1

INIT INITO

IND

RD_1

Data

Event

CIP_SEND_1

CIP_RCV_1

INITO

CNF

FIGURE 55.15 Producer–consumer.pair.implemented.with.CIP.

Communication Aspects of IEC 61499 Architecture 55-19

 is.investigation.shows.that.CIP.ts.very.well.to.the.execution.and.object.model.of.IEC.61499.

Our

.exam

ple

.made.the.assu

mption

.that.all.devi

ces

.on.the.CIP.netw

ork

.are.IEC.6149

9-enabled

cont

rol

. devi

ces.

. Howe

ver,

. seve

ral

. adva

ntages

. can. be. gain

. from. comb

ining

. lega

. CIP. devi

ces

with.IEC.6149

9-enabled

.devi

ces.

.Two.die

rent

.appl

ication

.scen

arios

.shou

.be.cons

idered:

.rst.IEC.

6149

9-enabled

.CIP.slav

.devi

.(i.e

.prog

rammable

.I/O.devi

ces)

.and.seco

.use.stan

dard

.CIP.slav

devi

ces

.from.IEC.6149

.devi

ces.

.In.the.rst.case

.the.CIP.inte

rface

.of.the.IEC.6149

.devi

.woul

be.spec

ied

.by.util

izing

.the.CIP.FBs,.and.with.this.mech

anism

.the.inte

rface

.can.be.adap

ted

.to.the.

spec

ic

.IEC.6149

.appl

ication

.runn

ing

.in.the.devi

ce.

.On.the.othe

.end.of.the.comm

unication,

.a.CIP.

mast

.devi

.(e.g

.a.PLC).woul

.inte

ract

.with.the.IEC.6149

.devi

.in.the.same.way.as.with.any.othe

CIP.slav

.devi

ce.

.Howe

ver,

.the.use.of.IEC.6149

.allo

.to.pre-

process

.I/O.data.and.to.prov

ide

.high

leve

.info

rmation

.to.the.PLC.. is.use.case.is.an.impo

rtant

.step.towa

.a.full

.dist

ributed

.cont

rol

syst

.as.desc

ribed

.by.IEC.6149

.In.the.seco

.use.case

.the.IEC.6149

.cont

rol

.devi

.will.take.the.

plac

.of.the.PLC,.and.the.CIP.comm

unication

.FBs.will.mimi

.the.beha

vior

.of.a.CIP.mast

er.

.Howe

ver,

in.cont

rast

.to.the.exis

ting

.PLC.inte

rface

.wher

.the.netw

ork

.data.are.pres

ented

.to.the.appl

ication

.as.a.

at.memo

.regi

on,

.IEC.6149

.allo

.a.stru

ctured

.acce

.to.the.data

. is.is.achi

eved

.by.repr

esenting

each.sla

.dev

ice

.as.a.sep

arate

.FB.. is.all

ows

.to.lev

erage

.exi

sting

.inv

estments

.in.pla

nts

.and.I/O.dev

ice

deve

lopment,

.or.to.exte

.dumb.I/O.modu

les

.by.addi

.own.CPUs

. ere

fore

.this.will.be.an.impo

rtant

part.of.an.IEC.6149

9-based

.cont

rol

.envi

ronment.

Both

.use.case

.are.not.spec

ic

.to.the.CIP.envi

ronment.

. ey.can.be.appl

ied

.to.any.eld

bus

.syst

used.in.industrial.control.systems.

55.11 Impact of Communication Semantics

appli

cation Behavior

One.word.of.caution.however..Traditional.control.applications.running.on.a.single.controller.periodi-

cally

.or.cycl

ically

.read.from

.and.writ

.to,.all.the.remo

.devi

ces

.conn

ected

.to.the.netw

ork

.bus.(eve

when.no.chan

ges

.to.the.stat

.of.thes

.devi

ces

.is.requ

ired);

.so.if.the.netw

ork

.sue

.a.tran

sient

.erro

.dur-

.one.peri

od/cycle,

.the.appl

ication

.will.natu

rally

.reco

ver

.in.the.next.peri

od/cycle,

.when.a.new.netw

ork

mess

age

.is.gene

rated.

.In.cont

rast,

.an.IEC.6149

.appl

ication

.is.even

.orie

nted,

.so.it.will.typi

cally

.only.

gene

rate

.a.netw

ork

.mess

age

.when.the.PUBL

ISH

.or.SEND.FBs.rece

ive

.an.REQ.even

.or.when.an.RCV.

FB.rece

ives

.an.RSP.even

.Whil

.this.may.be.consi

dered

.an.adva

ntage

.due.to.the.lowe

.tra

.impo

sed

on.the.netw

ork,

.it.also.has.the.draw

back

.that.the.appl

ication

.beco

mes

.much.more.susc

eptible

.to.tran

sient

.com

munication

.err

ors

.tha

.may.occ

.on.thi

.sam

.net

work.

Consider,

.for.exam

ple,

.the.syst

.in.Figu

.55.1

.Now.imag

ine

.that.a.CR.even

.gene

rated

.by.FB.Logi

does.not.reac

.the.NEW.even

.inpu

.of.Logi

.due.to.a.tran

sient

.comm

unication

.erro

.on.the.netw

ork

used.by.the.publ

ish

.and.subsc

ribe

.CR2.FBs.. e.resu

.will.be.that.all.the.ligh

.conn

ected

.to.Logi

.will.

be.corr

ectly

.swit

ched

.o,.and.no.ligh

.conn

ected

.to.Logi

.will.be.lit.to.cont

inue

.the.chas

ing

.seque

nce.

.may.conc

lude

.that.due.to.the.asyn

chronous

.even

t-based

.arch

itecture

.used.by.IEC.6149

.appl

ica-

tions,

.thes

.are.more.susc

eptible

.to.netw

ork

.fail

ures.

.Neve

rtheless,

.this.does.not.mean.that.the.appl

ica-

tion

.will.fail.at.the.smal

lest

.netw

ork

.inte

rference.

.In.fact

.many.comm

unication

.proto

cols

.incl

ude

.erro

dete

ction

.and.corr

ection

.algo

rithms.

.If.the.comm

unication

.proto

col

.used.betw

een

.the.CR2.PUBL

ISH

and.SUBS

CRIBE

.FBs.incl

udes

.erro

.dete

ction

.and.corr

ection

.mech

anisms,

.the.IEC.6149

.appl

ication

will.not.be.aec

ted

.by.the.tran

sient

.netw

ork

.fail

ure.

.Howe

ver,

.note.that.in.the.pres

ence

.of.fail

ures,

.the.

exact.semantics.of.the.communication.service.interface.FBs.is.not.specied.by.the.IEC.61499.standard,.

as.well.as.the.choi

.of.whic

.spec

ic

.impl

ementation

.of.the.comm

unication

.serv

ice

.inte

rface

.FBs.will.

aec

.how.the.IEC.614

.app

lication

.wil

.rea

.whe

.in.the.pre

sence

.of.tra

nsient

.net

work

.fai

lures.

.mess

age

.deli

very

.sema

ntics

.in.the.pres

ence

.of.fail

ures

.may.gene

rally

.be.clas

sied

.into.thre

clas

ses:

.“at.most.once

,”

.“at.leas

.once

,”

.and.“exa

ctly

.once

.”

.Alth

ough

.the.“exa

ctly

.once

”

.sema

ntics

.are.

usua

lly

.the.pref

erred

.sema

ntics,

.due.to.the.high

.numbe

.of.mess

ages

.requ

ired,

.some

times

.sema

ntics

55-20 Industrial Communication Systems

with.lower.guarantees.are.sucient..For.example,.when.switching.on.a.siren.to.warn.of.the.occurrence.

of.an.ala

rm,

.the.“at.lea

.onc

e”

.sem

antics

.wou

.be.su

cient.

Another

.issu

.is.that.of.even

.orde

ring.

.If.two.even

.are.gene

rated

.insid

.one.devi

.in.the.orde

.EV1,.

EV2,.thes

.are.not.guar

anteed

.to.arri

.at.anot

her

.devi

.in.the.same.orde

.If.an.appl

ication

.reli

.on.

the.orde

ring

.of.even

.to.corr

ectly

.exec

ute

.its.algo

rithms,

.care.shou

.be.take

.to.choo

.comm

unica-

tion

.ser

vice

.int

erface

.FBs.who

.imp

lementation

.gua

rantees

.mes

sage

.del

ivery

.in.the.sam

.ord

er.

Some

.impl

ementations

.of.the. comm

unication

.serv

ice

.inte

rface

.FBs. may. allo

.qual

ity

.of.serv

ice

(QoS

)

.para

meters

.to.be.spec

ied.

.Othe

.may.have.xed.QoS.para

meters.

.In.conc

lusion,

.one.shou

.be.

care

ful

.of.the.exac

.sema

ntics

.impl

emented

.by.the.serv

ice

.inte

rface

.FBs.as.thes

.may.aec

.the.outc

ome

of.the.IEC.614

.con

trol

.app

lication.

55.12 Failures in Distributed applications

Although.distributed.applications.may.have.many.advantages,.they.are.not.without.their.drawbacks..

One.of.thes

.as.was.disc

ussed

.prev

iously,

.is.the.fact.that.the.comm

unication

.netw

ork

.may.exhi

bit

fail

ures

.that.will.aec

.the.outc

ome

.of.the.appl

ication

.exec

ution.

.Anot

her

.is.the.fail

ure

.of.the.devi

ces

exec

uting

.the.con

trol

.log

.its

elf.

When

.writ

ing

.an.indu

strial

.stre

ngth

.cont

rol

.appl

ication,

.usua

lly

.all.fail

ure

.mode

.of.the.cont

rolled

proc

ess

.must.be.take

.into.acco

unt,

.so.that.the.physi

cal

.mach

inery

.unde

.cont

rol

.alwa

.rema

ins

.in.a.

safe.stat

.Like

wise,

.the.fail

ure

.of.the.cont

rolling

.devi

ces,

.i.e.,.the.PLCs.exec

uting

.the.logi

.and.the.com-

unication

.net

works

.lin

king

.the

.mus

.als

.be.tak

.into.acc

ount.

For

.appl

ications

.that.run.on.a.singl

.PLC,.usua

lly

.eith

.the.cont

rol

.appl

ication

.fail

.comp

letely

.when.

the.exec

uting

.PLC.fail

.or.it.does.not.fail.at.all..Comp

lete

.fail

ures

.of.the.cont

rol

.appl

ication

.are.usua

lly

hand

led

.by.ext

ernal

.saf

ety

.dev

ices.

However,

.when.writ

ing

.a.dist

ributed

.appl

ication,

.one.must.be.care

ful

.of.how.this.appl

ication

.may.fail

as.it.may.have.part

ial

.fail

ures

.when.one.or.more

.but.not.all,.of.the.PLCs.that.are.exec

uting

.the.dist

rib-

uted

.cont

rol

.appl

ication

.fail

.Even.more.like

.is.the.possi

bility

.of.fail

ure

.of.the.comm

unication

.netw

ork

that.con

nects

.the.dis

tributed

.PLC

Now,

.to.over

come

.part

ial

.fail

ures

.of.a.dist

ributed

.appl

ication,

.the.appl

ication

.itse

.must.be.awar

.of.

this.scen

ario

.and.be.prep

ared

.to.take.appr

opriate

.acti

.when.it.occu

rs.

.Howe

ver,

.in.orde

.to.do.so,.it.

must.rst.be.able.to.iden

tify

.the.fact.that.a.part

ial

.fail

ure

.occu

rred

.(be.it.on.the.comm

unication

.netw

ork

or.anot

her

.exec

uting

.devi

ce).

. is.iden

tication

.may.be.done.eith

.at.the.appl

ication

.leve

.or.by.the.

communication.service.interface.function.blocks.(SIFBs).

IEC

.6149

.comm

unication

.SIFB

.typi

cally

.indi

cate

.the.pres

ence

.of.fail

ures

.by.emit

ting

.local.even

while.thei

.QO.outp

.is.set.to.fals

.Howe

ver,

.as.was.state

.prev

iously,

.the.capa

city

.of.a.comm

unication

SIFB.to.dete

.the.fail

ure

.and.cons

equently

.emit.the.even

.depend

.on.the.unde

rlying

.comm

unication

.pro-

ocol.

.For.examp

le,

.some.prot

ocols

.inclu

.“keep.aliv

e”

.mess

ages

.that.are.excha

nged

.even.when.no.data.

need.to.be.tran

smitted

.so.that.the.lack.of.thes

.mess

ages

.may.be.safe

.assu

med

.to.be.the.resu

.of.a.fail

ure.

When

.comm

unication

.SIFB

.are.not.able.to.iden

tify

.fail

ures,

.then.thes

.will.need.to.be.iden

tied

.at.

the.appl

ication

.leve

.One.simpl

.mean

.of.doin

.this.is.to.con

gure

.the.cont

rol

.appl

ications

.to.peri

odi-

cally

.call.the.PUBL

ISH

.and/

.CLIE

.(or.SEND

.as.in.our.exam

ple)

.SIFB

.even.when.no.new.data.

need.to.be.tran

smitted.

.Anot

her

.possi

bility

.is.the.impl

ementation

.of.hand

shakes

.and.time

outs

.at.the.

appl

ication

.lev

el.

55.13 Conclusion

 e.FBs.of.IEC.61499.are.a.powerful.architectural.model.for.abstract.yet.executable.specication.of.

dist

ributed

.cont

rol

.syst

ems.

.It.can.be.furt

her

.exte

nded

.by.addi

.comm

unication

.over.any.part

icular

netw

ork

.proto

col.

.Inte

rfaces

.to.the.proto

col

.need.to.be.impl

emented

.in.libr

aries

.of.CIFB

.Adva

nced

sow

are

.tool

.can.mak

.add

ing

.the.exp

licit

.com

munication

.sea

mless

.and.hid

den

.fro

.the.use

Communication Aspects of IEC 61499 Architecture 55-21

references

. 1.. IEC. 61499-1:. Function. Blocks—Part. 1. Architecture,. 1st. edn.,. International. Electrotechnical.

Commi

ssion,

.Gen

eva,

.Sw

itzerland,

.2005.

. 2.. FBDK—F

unction

.Blo

.De

velopment

.Ki

.Onlin

.ww

w.holobloc.com,

.2008.

. 3.. ICS-Tr

iplex.

.ISaGRAF—IEC.61131.and.IEC.61499.so

ware,

.cite

.2008..Avai

lable

.fro

.htt

p://www.

isagraf.com/

. 4.. V..Vyat

kin

.and.J..Cho

uinard,

.On.comp

arisons

.of.the.ISaGRAF.implem

entation

.of.IEC.61499.wit

FBDK.and.oth

.implem

entations,

.in.Sixth

IEEE International Conference on Industrial Informatics,

2008. INDIN 2008,

.Daej

eon,

.Ko

rea,

.Ju

.2008.

. 5.. nxtCon

trol

.we

bsite:

.ht

tp://www.nxtcontrol.com/

. 6.. K.. ramb

oulidis,

.Dev

elopment

.of.dist

ributed

.indu

strial

.cont

rol

.app

lications:

. e.CORFU.fram

work,

.in.Fou

rth IEEE International Workshop on Factory Communication Systems,

.Vas

teras,

.Swe

den.

Augus

.2002.

. 7.. T..Str

asser

.et.al.

.Fra

mework

.for.dis

tributed

.indu

strial

.aut

omation

.and.con

trol

.(4D

IAC),

.in.Six

IEEE International Conference on Industrial Informatics, 2008 (INDIN’08),

.Dae

jeon,

.Kor

ea,

.Jul

13–

16,

.200

. 8.. FBenc

.we

bsite:

.ht

tp://www.ece.auckland.ac.nz/∼vyatkin/ench/

. 9.. W..Dai

.A..Shih,.and.V..Vyat

kin,

.Dev

elopment

.of.dist

ributed

.indu

strial

.aut

omation

.system

.and.

debug

ging

. func

tionality

. bas

. on. the. Open. Sour

. OOO

NEIDA

. Wor

kbench,

. in. Aus

tralasian

Conference on Robotics and Industrial Automation,

.Auc

kland,

.Ne

.Ze

aland,

.2006.

. 10.. PROFACTOR. Produktionsforschungs. GmbH,. 4DIAC-RTE. (FORTE):. IEC. 61499. Compliant.

Runt

ime

.Env

ironment,

.30/10/2007,.2007;.ht

tp://www.fordiac.org

. 11.. L.H..Yoo

ng,

.P..Roo

.V..Vyat

kin,

.and.Z..Salcic,.Syn

chronous

.exec

ution

.for.IEC.61499.func

tion

bloc

ks,

.in.Pro

ceedings Fih IEEE Conference on Industrial Informatics (INDIN’07),

.Vienna,.Aus

tria,

Jul

.23–27,.2007,.pp

.1189–1194.

. 12.. G..Ceng

.and.K..Akes

son,

.Denit

ion

.of.the.exec

ution

.mode

.use

.in.the.FUBER.IEC.61499.run-

tim

.envir

onment,

.in.Sixth

IEEE International Conference on Industrial Informatics, 2008 (INDIN

2008),

.Daej

eon,

.Ko

rea,

.Ju

.13–16,.2008.

. 13.. K.. ramb

oulidis

.and.A..Zou

pas,

.Rea

l-time

.Java.in.cont

rol

.and.aut

omation:

.A.mode

.driv

.deve

opment

.app

roach,

.in.Tent

h IEEE International Conference on Emerging Technologies and Factory

Automation,

.Ca

tania,

.It

aly,

.Sep

tember

.19–22,.2005.

. 14.. G..Dou

kas

.and.K.. ramb

oulidis,

.A.rea

l-time

.Linux.exec

ution

.envir

onment

.for.func

tion-block

bas

. dist

ributed

. cont

rol

. app

lications,

. in. ir

d IEEE International Conference on Industrial

Informatics (INDIN’05),

.Per

th,

.Au

stralia,

.Augu

.10–12,.2005.

. 15.. P..Tat

.and.V..Vyat

kin,

.Pro

posing

.a.nov

.IEC61499.Runt

ime

.Fram

ework

.implem

enting

.the.cyc

lic

exec

ution

.sem

antics,

.in.INDIN 2009

.Ca

rdi,

.U.K.,.Jun

.2009.

. 16.. V.. Vyatkin,. IEC 61499 Function Blocks for Embedded Control Systems Design,. Instrumentation.

Societ

.of.Am

erica,

.Res

earch

.Tr

iangle

.Pa

rk,

.NC,.2007.

. 17.. H.-M..Hani

sch

.and.V..Vyat

kin,

.Achie

ving

.reco

ngurability

.of.aut

omation

.system

.by.using.the.

new.inter

national

.sta

ndard

.IEC.61499:.A.deve

loper’s

.view

.in.Int

egration Technologies for Industrial

Automated Systems,

.R..Zura

wski

.(ed

.),

.CRC.Pr

ess/Taylor

.&.Fra

ncis,

.Bo

.Ra

ton,

.FL,.Ju

.2006.

. 18.. A..Zo

itl,

.Re

al-Time Execution for IEC 61499,

.ISA,.Res

earch

.Tr

iangle

.Pa

rk,

.NC,.2008.

. 19.. IEC.611

31-3

.Int

ernational

.Sta

ndard,

.Pro

grammable

.Con

trollers—Part

.1:.Gen

eral

.inf

ormation,

2.0.ed.,.In

ternational

.Ele

ctrotechnical

.Co

mmission,

.Gen

eva,

.Sw

itzerland,

.2003.

. 20.. IEC. 61499.Com

pliance

. Pro

le

.for.fea

sibility

. demon

strations,

. htt

p://www.holobloc.com/doc/ita/

index.htm

. 21.. Mod

bus

. App

lication

. Pro

tocol

. Spe

cication,

. v1.1b,.Mod

bus-IDA,

. Decem

ber

. 28,. 2006,. avai

lable

fro

.ht

tp://www.Modbus-IDA.org

. 22.. A..Swales,.Open.Modbus/TCP.Specication,.Schneider.Electric,.March.29,.1999.

55-22 Industrial Communication Systems

. 23.. Modbus.Messaging.on.TCP/IP.Implementation.Guide.v1.0b,.Modbus-IDA,.October.24,.2006,.avail-

able

.fr

.ht

tp://www.Modbus-IDA.org

. 24.. MOD

BUS

.over.Seri

.Line.Spe

cication

.and.Imp

lementation

.Guide.V1.02,.Mod

bus-IDA,

.2006,.

avai

lable

.fr

om:

.ht

tp://www.Modbus-IDA.org

. 25.. IEC. 61499. Com

pliance

. Pro

le

. for. CIP. bas

. communic

ation

. func

tion

. bloc

ks,

. htt

p://www-ist.

massey.ac.nz/functionblocks/CIPCompliance.htm

. 26.. F..Wee

huizen,

.A..Bro

wn,

.C.K..Sünder

.and.O..Hummer

-Koppendorfer,

.Imp

lementing

.IEC.61499.

communic

ation

. wit

. the. CIP. pro

tocol,

. in. Pro

ceedings 12th IEEE International Conference on

Emerging Technologies and Factory Automation (ETFA’07),

.Pa

tras,

.Gr

eece,

.Sep

tember

.25–28,.2007.

. 27.. F..Wee

huizen

.and.A..Zoi

tl,

.Using.the.CIP.pro

tocol

.wit

.IEC.61499.communic

ation

.func

tion

.bloc

ks,

in. Pro

ceedings of the Fih IEEE International Conference on Industrial Informatics (INDIN’07),

Vienna,.Au

stria,

.Jun

.23–27,.2007,.Vo

.1,.pp

.261–265,.ISB

.1-4244-0864-4.

56-1

56.1 Introduction

 e.Internet.and.its.applications.can.be.seen.as.an.integral.part.of.the.actual.social.development.stage..

Witho

.any.doub

.the.Inte

rnet

.has.chan

ged

.comm

unication

.and.info

rmation

.retr

ieval.

. is.is.enab

led

by.a.rapi

dly

.deve

loping

.set.of.tech

nologies

.and.easy

-to-use

.appl

ications,

.suit

able

.for.near

.all.situa

tions

of.ever

.day.life

.On.the.othe

.hand

.the.broa

.and.incr

easing

.appl

ication

.rang

.has.in.turn.adva

nced

tech

nology

.deve

lopment.

. e.comm

.and.stab

.basis.for.Inte

rnet

.Appl

ications

.is.the.Tran

smission

Cont

rol

.Proto

col/Internet

.Proto

col

.(TCP

/IP)

.as.the.gene

ral,

.alwa

.and.ever

ywhere

.avai

lable—in

.this.

sens

.ubi

quitous—communication

.pla

tform.

Internet

.Tech

nologies

.is.a.comm

.term.for.thos

.tech

nologies

.that.repr

esent

.the.appl

ication-related

laye

.5–7.of.the.Open.Syst

.Inte

rconnection

.(OSI

)

.comm

unication

.mode

.[HZ8

0],

.rely

ing

.on.IP.pro-

col

.on.laye

.3.and.the.TCP.or.User.Data

gram

.Proto

col

.(UDP

)

.proto

cols

.at.laye

.4..Alth

ough

.it.woul

be.tech

nically

.possi

ble,

.in.most.case

.a.clea

.sepa

ration

.of.thes

.laye

.insid

.a.spec

ic

.appl

ication

.is.not.

easy.to.achi

eve.

.Howe

ver,

.this.migh

.be.an.addi

tional

.bene

t,

.since.the.slim.appl

ication

.stru

ctures

.make.

appl

ication

.dev

elopment

.for.Int

ernet

.use.rat

her

.eas

.appl

ication

.of.Inte

rnet

.tech

nologies

.is.trem

endously

.inu

enced

.by.the.deve

lopment

.of.the.Worl

Wide.Web..Espe

cially,

.Web.brow

sers

.prom

ise

.to.be.able.to.disp

lay

.near

.ever

.type.of.data.with

out

.any.

addi

tional

.sow

are.

. ey.are.avai

lable

.for.ever

.comp

uting

.plat

form,

.are.easy.to.inst

all

.or.are.alre

ady

an.inte

gral

.part.of.oper

ating

.syst

ems.

. ey.are.easy.to.use.and.prov

ide

.acce

.not.only.to.stat

.cont

ent

like.the.trad

itional

.Web.page

.but.also.to.dyna

mic

.cont

ent

.incl

uding

.mult

imedia.

. e.actu

.tren

like.Web.2.0.oer.adva

nced

.tech

nologies

.as.well.as.plat

forms

.for.soci

.inte

rconnections

.up.to.comp

lete

virt

ual

.comm

unities

.like.“Sec

ond

.Life

.”

.Of.cour

se,

.the.tren

.sket

ched

.abov

.also.crea

.draw

backs.

 e.prob

lem

.that.is.ment

ioned

.most.oen.is.secu

rity.

.But.with

out

.any.doub

.Inte

rnet

.tech

nologies

.have.

chan

ged

.hum

.lif

Industrial Internet

56.1. Introduction.....................................................................................56-1

56.2

. Appl

ication

.of.Int

ernet

.Tec

hnologies

.in.Ind

ustry......................56-2

56.3

. Tech

nologies.....................................................................................56-3

Transport.and.Communication.Related.

Technologies. •. Technologies.for.Information.Description.

andPresentation. •. Technologies.for.Server-Side.and.Client-Side.

Functions

56.4. Application.Examples.....................................................................56-8

Description.Technologies. •. Browser-Based.Applications. •. .

Machine–Machine.Communication.UsingWebServices

56.5. Conclusions.and.Outlook.............................................................56-12

Acronyms...................................................................................................56-12

References...................................................................................................56-13

Martin

Wollschlaeger

Dresden University

of Tec

hnology

Thilo Sauter

Austrian Academy

of Sci

ences

56-2 Industrial Communication Systems

56.2 application of Internet technologies in Industry

 e.trend.of.applying.Internet.technologies.in.dierent.application.areas.can.hardly.be.stopped.. e.

promising.features.like.instant.and.ubiquitous.information.access.without.any.additional.eorts,.no.

costs.for.soware.installation.and.maintenance,.and.nally.the.manifold.de.facto.standards.lead.to.a.

spreading.application.of.Internet.technologies.also.in.industrial.application,.characterized.by.the.term.

“Industrial.Internet.”

.application.of.Internet.technologies.seems.to.solve.most.major.problems.in.the.industrial.

automation.domain..Exchange.and.presentation.of.information.is.greatly.simplied.by.applying.those.

methods.and.technologies.that.are.well.known.from.application.in.general.IT.systems..Because.of.

communication.system.independence,.Internet.technologies.seem.to.perfectly.t.the.requirements.for.

vertical.integration.in.automation..Especially,.the.trend.to.use.Ethernet-based.systems.at.the.factory.

oor.will.simplify.the.steps.needed.for.seamless.integration.of.automation.systems.and.company.IT.

systems.. is.will.reduce.the.eorts.for.data.communication,.conversion,.and.presentation,.thus.nally.

reducing.complexity.and.costs.for.such.systems..In.addition,.the.adoption.of.Internet.technologies.

introduces.new.concepts.and.oers.new.chances.for.tasks.in.dierent.stages.of.an.automation.system’s.

life.cycle..Especially,.Web.technologies.are.state.of.the.art.and.have.developed.into.de.facto.standards.

(see.Figure.56.1).

Browsers

.and.servers.exist.for.nearly.every.platform;.they.are.widely.accepted.by.different.classes.

of.users..The.browser.as.a.platform-independent.application.framework.should.allow.re-using.soft-

ware

.components..Finally,.location.independence,.multiple.client.access,.and.easy.installation.of.

software.components.are.in.the.users’.focus..On.the.other.hand,.this.“promised.land”.has.some.

drawbacks,.which.mostly.encompass.dealing.with.the.heterogeneity.of.the.different.technologies.

with.typically.very.short.life.cycles.

However,

. the. application. in. industrial. automation. produces. some. additional. requirements. for.

the.eective.use.of.Internet.technologies..Besides.commonly.mentioned.requirements.like.real-time.

aspects,.communication.structures,.and.security.aspects,.in.addition.the.availability.and.maturity.of.

the.technologies,.as.well.as.the.acceptance.and.the.knowledge.of.users.and.developers.have.to.be.consid-

ered.

.Finally,.the.selection.of.suitable.technologies.or.technology.combinations.appears.to.be.dicult..

It.is.mainly.based.on.the.use.cases.to.be.addressed.by.an.Industrial.Internet.application,.but.also.on.the.

automation.and.IT.systems’.design,.and.on.considerations.regarding.the.total.cost.of.ownership.(TCO).

On-line

data

Data

base

Static

text

Picture

Multi-

media

Forms

(D)COM

CORBA

Client

SOAP

(de facto) standards

Dierent types of data

from dierent sources

***

FIGURE 56.1 Internet.and.Web.technologies.as.de.facto.standards.

Industrial Internet 56-3

A.systematic.solution.for.this.problem.should.develop.specic.application.scenarios,.clearly.iden-

tify

.technical.requirements.for.the.intended.application.functions,.the.features.of.the.system.compo-

nent

.where.the.function.will.be.implemented,.and.the.location.where.the.component.is.implemented.

inside.the.system.. is.may.lead.to.dierent.combinations..For.all.relevant.combinations,.the.technical.

details.of.the.information.ows.have.to.be.specied.and.the.requirements.for.the.technologies.have.to.be.

rened.. is.establishes.a.list.of.criteria.by.which.the.technologies.have.to.be.evaluated.

56.3 technologies

It.is.obvious.that.an.evaluation.process.as.the.one.mentioned.above.is.not.possible.without.knowing.

communication.paradigms.and.technologies.in.detail.. e.most.common.communication.paradigm.

used.by.Internet.applications.is.client–server.communication.. e.server.provides.the.data,.while.the.

client.retrieves.the.data.and.displays.it..Typically,.conrmed.services.are.used.. e.sequence.can.be.

described.by.the.well-known.service.primitives.(see.Figure.56.2).. e.client.issues.the.request.by.invok-

ing

.the.service.at.an.appropriate.service.access.point.(SAP)—service.primitive—..req—the.server.is.

informed.by.an.indication.(.ind),.executes.the.service,.and.prepares.the.answer.. e.server.passes.the.

answer.to.the.client.as.response.(.rsp)..Finally,.the.client.gets.the.answer.together.with.the.conrmation.

(.cnf).from.the.service,.and.can.now.use.the.data.. us,.from.an.architectural.point.of.view,.a.client.layer.

and.a.server.layer.can.be.distinguished.in.Industrial.Internet.systems.

.further.specialization.of.the.functional.components.involved.in.the.communication.scenarios.leads.

to.more.sophisticated.architectures.. e.separation.of.application.and.data.leads.to.the.well-known.

three-tier-architecture.(Figure.56.3),.which.can.be.further.subdivided.concerning.application.logic,.

data.source,.and.communication.server.component.(Figure.56.4)..All.types.of.architectural.examples.

can.be.found.in.industrial.applications.. us,.for.the.dierent.functions.the.components.of.the.architec-

ture

.have.to.provide,.dierent.technologies.exist—all.assembled.within.the.term.Internet.Technologies.

Internet

.technologies.can.be.grouped.by.function.. e.following.functional.clusters.can.be.distinguished:

•

. Transport.and.communication.related.technologies

•

. Technologies.for.information.description.and.presentation

•

. Technologies.for.server-side.and.client-side.functions

Client layer

Client

e.g., Web browser

Request

Response

Server

e.g., Web server

Application

Documents

Server layer

.req

.cnf

.ind

.rsp

FIGURE 56.2 Basic.architecture.and.communication.paradigm.of.Industrial.Internet.applications.

56-4 Industrial Communication Systems

56.3.1 transport and Communication related technologies

 e.transport.and.communication.related.technologies.cover.well-known.application.protocol.deni-

tions

.for.a.wide.variety.of.Internet.technologies.. ey.include.specic.technologies.for.use.in.mes-

sage-related

.applications,.like.Simple.Mail.Transfer.Protocol.(SMTP).[SMTP82],.Post.Oce.Protocol.

(POP).[POP94],.Internet.Message.Access.Protocol.(IMAP).[IMAP03],.and.Network.News.Transfer.

Protocol.(NNTP).[NNTP06]..Typically,.e-mail.applications.use.these.protocols.in.order.to.access.

messages.

Within

.the.Industrial.Internet,.this.type.of.message.transfer.can.be.used.to.asynchronously.trans-

fer

.data.between.applications,.mostly.in.the.upper.layers.of.the.automation.pyramid.(see.Chapter.13),.

mainly.in.Manufacturing.Execution.Systems.(MES).layer.and.in.Enterprise.Resource.Planning.(ERP).

layer..It.is,.for.example,.possible.to.use.such.protocols.and.application.to.inform.MES.or.ERP.functions.

Server

e.g., Web server

Server

Data server

Client layer

Data layer

Server layer

Documents

Data

Client

e.g., Web browser

Application layer

Server

Application server

Application

logic

FIGURE 56.4 Multitier.architecture.

Client

e.g., Web browser

Server

e.g., Web server

Server

Data server

Client layer

Data layer

Server layer

Documents

Data

FIGURE 56.3 ree-tier.architecture.