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

Подождите немного. Документ загружается.

45-8 Industrial Communication Systems

 e.two.parity.bits.for.the.ID.are.calculated.using.the.following.equations:

P0 ID0 ID1 ID2 ID4

= ⊕ ⊕ ⊕ . (45.2)

P1 ID1 ID ID ID= ⊕ ⊕ ⊕3 4 5

(45.3)

45.5.4 Data Field

 e.data.eld.is.the.rst.part.of.the.response.. e.response.can.also.be.generated.in.the.master.by.the.

slav

.task.and.can.consi

.of.one.to.eigh

.data.byte

.As.desc

ribed

.abov

.the.ID.dete

rmines

.the.numbe

of.byte

.unle

.anot

her

.leng

.is.indi

cated.

. e.signa

.are.tran

smitted

.in.the.data.byte

.star

ting

.with.

the.leas

.signi

cant

.bit.(LSB

.A.data.byte.consi

sts

.of.a.star

.bit,.eigh

.data.bits

.and.a.stop.bit..A.pari

bit.is.not.tra

nsferred.

45.5.5 Checksum

 ere.is.a.distinction.in.LIN.between.a.so-called.classic.checksum.and.an.enhanced.checksum.. e.

LIN.proto

col

.versi

.1.3.uses.the.clas

sic

.chec

ksum.

.LIN.versi

.2.x.uses.the.enha

nced

.chec

ksum

.and.

incl

udes

.the.PID

. e.enh

anced

.che

cksum

.is.onl

.use

.for.the.IDs.0x0

–0x3B

.(0–

59).

45.5.6 Frame Length

 e.minimum.and.the.maximum.header.and.frame.length.are.specied.in.the.LIN.specication.. e.

maxi

mum

.valu

.are.140%.of.the.mini

mal

.time

.An.unde

.run.of.the.mini

mum

.time

.is.not.pos-

ble

.beca

use

.they.exac

tly

.corr

espond

.to.at.leas

.the.nece

ssary

.bit.time

.Tabl

.45.3.summ

arizes

.thes

para

meters.

45.5.7 time-triggered Data transmission

Modern.automotive.networking.solutions.favor.the.time-triggered.model.for.message.scheduling.so.

that.the.over

all

.timi

.of.mess

ages

.in.the.syst

.can.be.dete

rministic.

.In.a.time

-triggered

.netw

ork,

mess

ages

.are.tran

smitted

.agai

nst

.a.pred

ened

.mess

age

.sche

dule

.tabl

.and.ther

.is.a.noti

.of.a.glob

cloc

.to.ensu

.prop

.time.sync

hronization.

. e.Flex

Ray

.netw

ork

.is.an.exam

ple

.of.such.an.autom

otive

time

-triggered

.netw

ork.

.Sinc

.LIN.is.a.subn

etwork

.that.can.be.used.in.conj

unction

.with.larg

.netw

orks

in.a.sys

tem,

.LIN.sup

ports

.tim

e-triggered

.ope

rations.

LIN

.cont

rols

.the.time

-triggered

.tran

smission

.by.using.sche

dule

.tabl

es,

.whic

.are.impl

emented

.in.

the.mast

er.

. us,.the.syst

.can.be.dete

rministic,

.that.is,.the.time.when.a.mess

age

.is.tran

smitted

.can.

be.exac

tly

.pred

icted

.and.guar

antees

.the.peri

odicity

.of.signa

ls.

. e.sche

dule

.tabl

.den

.a.time.slot.for.

ever

.sch

eduled

.fra

me,

.as.are.des

cribed

.in.the.LDF.by.the.sys

tem

.desi

gner.

TABLE 45.3 Nominal.and.Maximum.

Tran

smission

.Tim

.of.Hea

ders

.and.Fra

mes

Name

Header_Nominal

34.T

Bit

Response_Nominal

10*(N.

Data

.+.1).T

Bit

Frame_Nominal

Header_Nominal

.+.T

Response_Nominal

Header_Maximum

1.4*T

Header_Nominal

Response_Maximum

1.4*T

Response_Nominal

Frame_Maximum

Header_Maximum

.+.T

Response_Maximum

LIN-Bus 45-9

45.5.8 Frame types

 ere.are.three.dierent.ways.of.transmitting.frames.on.the.LIN.bus:.unconditional,.event-triggered,.

and.sporadic.frames..Diagnostic.frames.are.also.supported.

45.5.8.1

Unconditional Frame

Unconditional

.frame.transfer.signals.may.use.the.IDs.0x0–0x3B.(0–59)..Every.frame.can.have.only.one.

transmitter.(publisher).but.one.or.several.receivers.(subscribers).. e.setup.of.the.frame.is.described.

in.the.LIN.description.le..Unconditional.frames.can.be.transferred,.as.shown.in.the.relationships.of.

Figure.45.4.

45.5.8.2

Event-triggered Frame

.unconditional.frame.can.be.considered.as.the.normal.LIN.frame..LIN2.0.also.denes.a.so-called.

event-triggered.frame..Event-triggered.frames.improve.the.response.time.of.the.master–slave.system.by.

mapping.unconditional.frames.with.rare-event.data.of.multiple.slaves.into.one.event-triggered.frame..

 is.reduces.the.cycle.time.of.the.time.schedule.table.because.the.master.does.not.have.to.poll.the.slave.

nodes.individually..Several.frame.IDs.can.be.dened.as.“event.triggered”.within.the.network..If.the.

master.requests.such.an.“event-triggered”.frame,.all.corresponding.slaves.will.begin.to.transmit.their.

data..However,.corresponding.slave.nodes.only.provide.their.frame.response.when.the.values.in.their.

data.elds.have.changed..But,.multiple.slaves.can.provide.a.frame.response.to.a.single.event-triggered.

frame..To.enable.the.master.to.recognize.which.slave.node.has.responded,.the.rst.byte.of.the.associated.

unconditional.frames.have.to.contain.their.frame.ID.

.more.than.one.slave.can.answer,.by.updating.data.in.the.frame,.it.is.possible.that.a.collision.can.

occur.on.the.bus.line.. e.master.recognizes.such.a.collision.situation.and.resolves.it.by.switching.auto-

matically

.to.the.so-called.collision.resolving.schedule.table.. e.table.will,.at.a.minimum,.contain.the.

associated.unconditional.frames.and.it.will.be.a.member.of.schedule.table.set.

45.5.8.3

Sporadic Frame

.sporadic.frames.were.introduced.in.the.LIN.version.2.0.for.better.utilization.of.bandwidth.. is.

method.provides.some.dynamic.behavior.to.the.otherwise.static.LIN.protocol.. ey.are.in.principle.

placeholders.in.the.time.schedule.table.in.which.the.master.can.send.several.dierent.messages.that.

carry.signals.that.seldom.change,.for.example,.commands.. e.master.sends.the.message.only.if.a.signal.

carried.by.this.message.is.changed..Hence.the.time.slot.can.remain.empty.. e.assignment.of.the.uncon-

ditional

.frames.to.the.sporadic.frame.takes.place.in.the.LIN.description.le..Figure.45.8.shows.a.simple.

example..In.slot.three,.the.master.can.transfer.either.the.unconditional.frame.“Master.Command”.or.

“Outdoor.Temperature”.or.it.can.leave.the.slot.empty.

Slot 1 Slot 2 Slot 3 Slot 4

Window

status

Mirror

status

Master

command

Keyboard

status

Empty

slot

Outdoor

temperature

FIGURE 45.8 Principle.of.sporadic.frames.

45-10 Industrial Communication Systems

45.5.9 Diagnostic Frame

Diagnostic.frames.always.carry.transport.layer.data.. ere.are.two.types,.the.master.request.frame.

(MRF).and.the.slave.response.frame.(SRF).. e.transmitter.is.always.the.master.. e.MRF.has.the.ID.

0x3C.(60).and.always.has.eight.data.bytes..It.is.the.“go-to-sleep”.command.if.the.rst.byte.carries.0x00,.

otherwise.it.carries.a.transport.layer.protocol.. e.SRF.transfers.the.slave.response.of.the.transport.layer.

protocol.to.the.master..It.has.the.ID.0x3D.(61).and.also.has.eight.data.bytes.

45.6 Network and Status Management

 e.network.and.the.status.management.features.are.very.simple.. e.network.management.feature.

supports.only.the.“wake-up”.and.“go-to-sleep”.signals.. e.corresponding.slave.state.diagram.is.shown.

in.Figure.45.9.. e.slave.node.enters.the.Initializing.state.aer.power-on,.reset.or.wake-up..In.the.opera-

tional

.mode.state.that.the.slave.node.can.transmit.and.receive.frames..In.the.bus.sleep.mode.state,.the.

node.is.normally.in.power.save.mode.. e.bus.line.is.set.to.the.recessive.level.(logical.1)..Any.node.can.

send.a.wake-up.request.for.the.cluster..Each.slave.node.can.detect.the.wake-up.request.and.listen.for.bus.

commands.for.a.short.period.. e.master.node.can.also.wake-up.and.send.frame.headers.to.establish.

the.cause.of.the.wake-up.

.slave.nodes.enter.the.bus.sleep.node.if.they.receive.the.go-to-sleep.command.from.the.master.or.

if.the.bus.is.inactive.for.a.minimum.of.4.s..Bus.inactivity.means.no.transitions.between.logical.0.and.1.

bit.values.and.so.covers.the.IDLE.state.and.a.short.circuit.condition.with.V

SUP

.or.GND.

For

.status.management.each.slave.node.monitors.its.communication.. e.slave.provides.two.status.

bits.for.status.management.within.its.own.node:.error_in_response.and.successful_transfer..If.it.detects.

an.error.(bit.error,.framing.error,.or.checksum.error),.it.sets.the.response_error.signal.. is.is.carried.

as.a.one.bit.scalar.signal.in.an.unconditional.frame.to.the.master.. e.position.in.the.frame.is.dened.

in.the.LDF..Based.on.this.single.bit,.the.master.node.can.interpret.the.error.states.as.listed.in.Table.45.4.

Initializing

Bus sleep

mode

Operational

mode

Go-to-sleep

command

Wake up

signal

Reset or power on

FIGURE 45.9 Slave.node.state.diagram.

TABLE 45.4 Interpretation.of.the.Response_error.

Signal.by.the.Master.Node

Response_error Interpretation

False e

.slave.node.is.

operating.correctly

True e

.slave.node.has.

intermittent.problems

.slave.node.did.not.answer e.slave.node,.bus,.

ormaster.node.has.

serious.problems

LIN-Bus 45-11

 e.successful_transfer.status.is.set.when.a.frame.has.been.successfully.transferred.by.the.slave,.that.

is,.a.frame.has.either.been.received.or.transmitted.

45.7 transport Layer Protocol

 e.LIN.transport.layer.provides.a.data.transfer.between.master.and.slave.node.for.diagnostic,.slave.node.

conguration,.and.identication.purposes..It.achieves.segmentation/desegmentation.and.ow.control.. e.

diagnostics.message.transfer.is.compatible.with.CAN-based.diagnostic.protocols..Typically.diagnostics.

are.performed.from.a.tester.where.a.LIN.master.can.pass.the.received.tester.requests.to.the.relevant.LIN.

slaves..A.LIN.slave.receives.requests,.routes.them.to.the.appropriate.service,.and.constructs.the.response.

LIN

.version.2.0.denes.a.transport.layer.protocol.that.was.deduced.from.the.ISO.15765-2.protocol.

[ISO15765-2]..It.tunnels.Keyword.Protocol.2000.(KWP-2000).and.Unied.Diagnostic.Services.(UDS),.

as.dened.in.ISO.15765-2.and.ISO.14229-1.[ISO14229-1],.and.provides.the.conguration.and.diagnostic.

service.for.LIN.slaves.. erefore,.the.full.transport.layer.specication.does.not.have.to.be.implemented.

in.all.slave.nodes;.LIN.version.2.1.species.three.diagnostic.classes.as:

Class 1

.supports.single.frame.transport.protocol.only,.with.fault.indication.by.signals.

Class 2

.provides.node.identication.support,.implementing.the.multi-frame.transport.protocol,.

but.supporting.only.the.UDS/KWP-2000.“read.by.identier”.service.

Class 3

.slave.nodes.are.the.most.complex.nodes.. ey.execute.additional.tasks.beyond.the.basic.

sensor.and.support.the.services:.diagnostic.session.control,.input/output.control,.read/clear.

diagnostic.trouble.code.information,.as.well.as.optional.ash.programming.features.

.transport.layer.protocol.uses.two.diagnostic.frames:.the.MRF.and.the.SRF.. e.MRF.(ID.=.0x3C).

is.the.diagnostic.request,.where.the.master.transmits.both.the.frame.header.and.the.frame.response.to.

a.slave.node.. e.SRF.(ID.=.0x3D).represents.the.diagnostic.response,.where.the.master.transmits.the.

header,.and.a.slave.transmits.the.response.to.the.master.that.contains.the.answer.of.the.preceding.MRF..

 e.protocol.uses.single.frames.(SF),.but.for.multi-frame.support,.rst.frames.(FF).and.consecutive.

frames.(CF).are.mapped.into.the.eight.data.bytes.of.a.LIN.frame..A.MRF.is.always.transmitted.to.all.

slave.nodes.(broadcast.trac).. erefore,.the.slave.node.address,.the.so-called.node.address.for.diag-

nostics

.(NAD).is.stored.in.the.rst.data.byte.. e.second.data.byte.stores.the.protocol.control.informa-

tion

.(PCI).of.the.transport.layer.and.the.third.data.byte.stores.the.service.identier.(SID).dened.in.the.

standards.ISO.15765-3.(KWP-2000).[ISO15765-3].and.ISO.14229-1.(UDS).[ISO14229-1].

.simple.example.for.use.of.a.single.frame.transport. protocol.is.the.node.conguration.service.

“assign.NAD”.(see.Figure.45.10)..With.this.service,.the.slave.nodes.in.a.cluster.can.assign.a.unique.NAD..

Initial

NAD

Initial

NAD

PCI

0×06

PCI

0×01

SID

0×B0

RSID

0×F0

Supplier ID

LSB

0×FF

Supplier ID

MSB

0×FF

Function ID

LSB

0×FF

Function ID

MSB

0×FF

new NAD

0×FF

MRF

assign NAD

request

SRF

positive

assign NAD

response

Master

Slave

ID = 0×3C

ID = 0×3D

FIGURE 45.10 e.“assign.NAD”.service.as.an.example.for.a.single.frame.

45-12 Industrial Communication Systems

 eidentication.of.the.slaves.is.provided.by.the.LIN.Product.Identication,.where.a.32.bit.value.

iden

ties

.the.suppl

ier

.ID,.the.func

tion

.ID,.and.the.vari

ant.

. e.data.eld.of.the.“ass

ign

.NAD”.requ

est

(it.is.a.MRF).carr

ies

.the.foll

owing

.info

rmation:

.rst.byte.is.the.init

ial

.NAD.(old.NAD)

;

.high.nibb

.of.

seco

.byte.is.the.ID.of.SF.(0x0

);

.low.nibb

.of.seco

.byte.is.the.data.leng

.plus.one.(for.the.SID.or.

RSID

);

.thir

.byte

.the.SID.(0xB

0—assign

.NAD)

;

.byte.four.and.ve.is.the.suppl

ier

.ID;.byte.six.and.seve

is.the.func

tion

.ID.and.byte.eigh

.is.the.new.NAD..If.the.NAD,.the.suppl

ier

.ID,.and.the.func

tion

.ID.

matc

.the.slav

.answ

ers

.to.the.head

.of.the.SRF.with.a.posi

tive

.“ass

ign

.NAD”.resp

onse.

. e.thir

.byte.

carr

ies

.the.resp

onse

.serv

ice

.iden

tier

.(RSI

D).

. e.SID.+.0x04

.repr

esents

.a.posi

tive

.ackn

owledgment

(her

.0xF0.for.posi

tive

.assi

.NAD.resp

onse).

45.8 Conguration

As.stated.earlier,.a.LIN.cluster.can.be.congured.using.automated.tools.that.use.the.CLD.to.describe.the.

clus

ter,

.in.an.LDF..A.rst.step.is.to.crea

.a.clus

ter

.mess

age

.stra

tegy

.to.comp

letely

.desc

ribe

.the.requ

ired

comm

unication

.betw

een

.all.unit

.in.the.clus

ter.

.A.list.of.all.fram

.is.gene

rated

.that.incl

udes

.fram

.IDs,.

publ

ishers

.and.subs

cribers,

.data.cont

ent,

.etc..A.sche

dule

.tabl

.can.also.be.desc

ribed

.for.the.clus

ter.

All.of.the

.par

ameters

.are.des

cribed

.by.the.LDF

LIN2.x

.also.den

.the.“o-

the-shelf”

.appr

oach

.for.a.dyna

mic

.con

guration,

.whic

.aor

.a.simpl

plug

-and-play

.feat

ure

.for.the.slav

.node

. is.appr

oach

.is.base

.on.the.node.con

guration

.and.iden

ti-

cation

.serv

ices.

. e.main.serv

ices

.for.the.node.con

guration

.are.the.abov

e-mentioned

.“assi

.NAD”.

as.well.as.the.“assi

.fram

.ID”.(LIN

2.0)

.and.“assi

.fram

.ID.rang

e”

.(LIN

2.1)

.serv

ices.

.With.the.latt

serv

ice,

.one.can.assi

.and.cha

nge

.the.pro

tected

.ide

ntier

.of.a.fra

me.

.more.iden

tical

.slav

.node

.are.used.in.a.clus

ter

.(e.g

.damp

.motor

.in.an.air-

conditioning

.syst

em),

the.addr

ess

.con

ict

.can.be.reso

lved

.via.a.slav

.node.posit

ion

.dete

ction

.(SNP

.proc

edure

.only

.One.

possi

ble

.algo

rithm

.is.the.Bus.Shut.Meth

.(als

.call

.“coo

l-LIN”)

.that.is.desc

ribed

.in.the.pate

.WO.

03/0

94001

.A1.[WO0

3].

.Anot

her

.algo

rithm

.is.the.Extr

.Wire.Dais

.Chai

.meth

od.

.(In.this.area

.ther

are.mor

.pat

ents,

.e.g

.[US

59].)

45.9 relationship between SaE J2602 and LIN2.0

In.March.of.2004,.the.SAE.approved.the.SAE.J2602.recommended.practice.for.the.use.of.LIN,.based.

upon.the.rel

eased

.LIN

2.0

.spe

cication.

.SAE.J260

.reco

mmended

.prac

tice

.narr

ows

.down.some.of.the.choi

ces

.allo

wed

.in.the.LIN2

.spec

ication

.to.ensu

.a.grea

ter

.degr

.of.inte

roperability

.and.to.prov

ide

.a.mini

mum

.leve

.of.perf

ormance

char

acteristics

.amo

.SAE.J26

.com

pliant

.nod

es.

.most.signi

cant

.die

rences

.in.impl

ementing

.an.SAE.J260

.comp

liant

.LIN.netw

ork

.and.a.LIN2

comp

liant

.netw

ork

.are.in.the.diag

nostics

.and.netw

ork

.con

guration

.supp

ort

.as.well.as.the.rest

riction

on.a.singl

.bus.spee

.of.10.4

.kbps.that.allo

.tigh

tening

.of.the.physi

cal

.laye

.spec

ications.

.It.was.

deci

ded

.that.the.LIN2

.diag

nostics

.requ

irements

.shou

.be.optio

nal

.for.SAE.J260

.impl

ementations.

Usag

.of.the.netw

ork

.con

guration

.meth

ods

.were.also.simpl

ied

.and.furt

her

.spec

ied,

.part

icularly

.the.

incl

usion

.of.a.dev

ice

.nod

.numb

.(DN

.as.a.par

.of.the.sla

.nod

.add

ress

.(NA

D).

45.10 Conclusion

 is.chapter.has.introduced.the.LIN.bus.concepts.and.has.provided.an.insight.into.the.LIN.specica-

tions,

.high

lighting

.some.of.the.more.impo

rtant

.tech

nical

.deta

ils.

.LIN.has.now.been.esta

blished

.as.the.

de.facto.netw

ork

.tech

nology

.for.the.impl

ementation

.of.simpl

.and.cost

-eective

.equi

pment

.clus

ters

.in.

the.vehi

cle.

.Toda

.nume

rous

.vehi

cles

.empl

.LIN.in.the.body

/convenience

.area

.of.the.vehi

cle.

.LIN.

will.succ

eed

.into.the.futu

.as.it.has.many.adva

ntages

.in.that.it.is.simpl

.to.engi

neer,

.with.many.sup-

orting

.desig

.tools

.Hard

ware

.comp

onents

.are.read

ily

.avai

lable,

.the.impl

ementations

.are.very.cost.

LIN-Bus 45-13

eective,.and.there.is.no.protocol.license.required.. e.main.versions.are.LIN1.3.and.LIN2.0,.and.in.

fut

ure

.LIN

2.1

.as.wel

.If.nod

.are.use

.wit

.di

erent

.LIN.ver

sions

.wit

hin

.a.clu

ster,

.the.mas

ter’s

.ver

sion

lev

.mus

.be.at.the.sam

.ver

sion

.lev

.or.at.a.hig

her

.ver

sion

.lev

.tha

.any.sla

.nod

. e.mas

ter

.has.to.

res

pect

.th

.di

verse

.pr

operties

.of.th

.sl

ave

.no

des.

references

[Grz05]. A.. Grzemba,. C. v.d.. Wense:. LIN-Bus—Systeme,. Protokolle,. Tests. von. LIN-Systemen,. Tools,.

Har

dware,

.Ap

plikationen;

.Fra

nzis-Verlag,

.Mün

chen,

.Ger

many;

.2005;.ISB

.3-7723-4009-1.

[ISO14229-1]

.Road.vehic

les—Diagnostic

.system

s—Part

.1:.Diag

nostic

.serv

ices;

.Int

ernational

.Sta

ndard

ISO.14229-1.6,.Is

sue

.6,.2001-02-22.

[ISO15765-2]

.Road.vehic

les—Diagnostics

.on.Con

troller

.Are

.Netw

ork

.(CAN)—Par

.2:.Netw

ork

.lay

serv

ices;

.In

ternational

.St

andard

.ISO.15765-2.4,.Is

sue

.4,.2002-06-21.

[ISO15765-3]

.Road.vehic

les—Diagnostics

.on.cont

roller

.are

.netw

ork

.(CAN)—Par

.3:.Imp

lementation

.of.

diag

nostic

.ser

vices;

.In

ternational

.St

andard

.ISO.15765-3.5,.Is

sue

.5,.2002-12-12.

[ISO9141]

. Road. vehic

les—Diagnostic

. system

s—Requirement

. for. inter

change

. of. digit

. Info

rmation;

Int

ernational

.St

andard

.ISO9141,.1st.edn.,.1989.

[LIN1.0]

.LIN.Sp

ecication

.Pac

kage

.Re

vision

.1.0,.1999,.ww

w.lin-subbus.org

[LIN1.3]

.LIN.Sp

ecication

.Pac

kage

.Re

vision

.1.3..De

cember

.12,.2002..ww

w.lin-subbus.org

[LIN2.0]

.LIN.Sp

ecication

.Pac

kage

.Re

vision

.2.0..Sep

tember

.23,.2003..ww

w.lin-subbus.org

[LIN2.1]

.LIN.Sp

ecication

.Pac

kage

.Re

vision

.2.1..No

vember

.24,.2006..ww

w.lin-subbus.org

[TR0363]

.TR0363— e.LIN.Ph

ysical

.La

yer;

.Re

.2.0;Ju

.7,.2008;.Te

chnical

.Rep

ort;

.nxp.

[US59]

.Au

tomatic

.no

.congura

tion

.wi

.ident

ical

.no

des;

.U.S..pa

tent

.5,914,957.

[WO03]

.Meth

.for.Addres

sing

.the.user

.of.a.bus.system.by.mea

.of.identic

ation

.ows;.pat

ent

.WO.

03/094001.A1;.2003-11-13;.or.U.S..pa

tent

.7,0918,76.

46-1

46.1 Introduction

Prosafe.is.a.comprehensive.and.integrated.solution.with.the.aim.to.support.safe.communication.in.

eld

bus

.net

works

.(Fi

gure

.46.

1).

.Pro

safe

.com

prises

.the.fol

lowing

.pri

nciples

.[1]

•

. Inte

gration

.of.safe

ty-related

.appl

ications

.into.stan

dard

.solu

tions

.with

out

.any.impa

.for.the.latt

ones

•

. Stan

dard

.and.safe

.data.coex

ist

.in.the.same.netw

ork—Probus

.(see.Chap

ter

.32).or.Pro

net

(see.Chap

ter

.40)—

without

.modi

cation

.of.the.stan

dard

.prot

ocols.

•

. Safe

. data. is. tran

smitted

. betw

een

. safe

. equi

pment—controllers

. (F-H

ost)

. and. devi

ces

(F-D

evice)—using

.the.high

est

.inte

grity

.leve

.(SIL.3.or.PL.“e”).requ

ired

.by.curr

ent

.appl

ications

.in.

facto

.and.pro

cess

.auto

mation.

•

. Conguration,. parameterization,. diagnosis,. and. maintenance. of. safety. devices. is. performed.

using.engi

neering

.tools.that.are.simil

.to.thos

.empl

oyed

.in.stan

dard

.appl

ications,

.thus.faci

litat-

ing

.the.dev

elopment

.and.int

egration

.pro

cess.

46.1.1 Standardization Framework

 e.development.of.safety-related.systems.for.factory.and.process.automation.is.a.complex.task,.which.

invo

lves

.the.empl

oyment

.of.mult

iple

.and.inte

rrelated

.stan

dards.

.Figu

.46.2.pres

ents

.a.sele

ction

.of.the.

most.rel

evant

.one

.deve

lopment

.of.Pro

safe

.was.perf

ormed

.base

.on.two.stan

dards:

.IEC.6150

.[2].and.EN.50159

-1,

now.IEC.6228

0-1

.[3]..IEC.6150

.outl

ines

.the.requ

irements

.when.elec

trical/electronic/programmable

elec

tronic

.syst

ems

.are.used.to.perf

orm

.safe

.func

tions

.(fur

ther

.deta

ils

.can.be.foun

.in.Chap

ter

.2),.

Prosafe

46.1. Introduction.....................................................................................46-1

Standardization.Framework. •. Black.Channel.Principle

46.2. Prosafe.Communication..............................................................46-3

Error-Detection.Requirements. •. Error.Types.and.Safeguards. •. .

Cyclic/Acyclic.Communication. •. Cyclic.Communication.

PDU. •. Virtual.Consecutive.Number. •. Time-Out.with.

Receipt. •. Code.Name.for.Sender/Receiver. •. Data.Consistency.

Check. •. Detected.Safety.Data.Failures

46.3. Deployment....................................................................................46-11

Power.Supplies.and.Electrical.Safety. •. IncreasedImmunity. •. .

Installation.Guidelines. •. Wireless.Transmission.

andSecurity. •. Response.Time

Acronyms...................................................................................................46-14

References

...................................................................................................46-14

Ron Mitchell

RC Systems

Max Felser

Bern University of

Appl

ied

Sci

ences

Paulo Portugal

University of Porto

46-2 Industrial Communication Systems

Standard CPU

Pronet

F-gateway

Remote I/O

PA-link

Limit switch

(F-Device)

Standard

controller

Laser scanner

(F-Device)

Drives

Probus-PA

ASI-safe

Robot

DP-link

F-Modules in a

remote I/O device

Probus-DP

Coexistence of standard and safety communication

Safety CPU

(F-Host)

Combination

possible

FIGURE 46.1 e. Prosafe. approach.. (Adapted. from. PROFIsafe—Safety. technology. for. PROFIBUS. and.

PROFINET—System.description,.PROFIBUS.Nutzerorganisation.e.V..PNO,.2007.)

Product standards

IEC 61486

Safety

functions (e.g,

light curtains)

IEC 61784-4

Security

(profile-specific)

IEC 61784-5

Installation guide

(profile-specific)

IEC 61784-3-3

(Profisafe)

Functional safety

communication

profile 3

IEC 61158 series/

61784-1, -2

Fieldbus for use in

industrial controls

systems

IEC 61508

Functional safety

(basic standard)

IEC 61326-3-1

EMC and

functional

safety

Safety-related standards Fieldbus-related standards Profisafe

Factory Process

IEC 61918

Installation guide

(common part)

IEC 60204-1

Safety of electrical

equipment

US: NFPA 79

Valid also in process industries, whenever applicable

IEC 62061

Functional safety

for machinery

(SRECS)

Design objective

Applicable standards

IEC 62443

Security

(common part)

IEC 61131-6

Safety for PLC

IEC 61800-5-2

Safety functions

for drives

ISO 12100-1 and ISO 14121

Safety of machinery — Principles for design and risk

assessment

US: ISA-84.00.01

DE: VDI 2180

IEC 61511

Functional safety — safety instrumented systems

for the process industry

Non-electrical

Electrical

ISO 13849-1, -2

Safety-related parts

of machinery

(SRPCS)

SIL based

PL based

Design of safety-related electrical, electronic and

programmable electronic control systems

(SRECS) for machinery

FIGURE 46.2 Overview.of.safety.standards.for.factory.and.process.automation..(Adapted.from.PROFIsafe—Safety.

technology.for.PROFIBUS.and.PROFINET—System.description,.PROFIBUS.Nutzerorganisation.e.V..PNO,.2007.)

Prosafe 46-3

while.EN.50159-1.denes.the.requirements.needed.to.support.safe.communication.between.safety-

.equipment..Many.of.the.solutions.employed.by.Prosafe.are.based.on.EN.50159-1.proposals,.

the.“black.channel”.principle.being.the.most.relevant.example..Nowadays,.Prosafe.is.part.of.a.series.

of.standards.related.to.eldbus.systems—IEC.61158.[4].and.its.companion.IEC.61784.[5]..Within.

this.series,.the.IEC.61784-3.[6].denes.a.set.of.proles.to.support.safe.communication.in.eldbus.

networks..Prosafe.is.standardized. as.IEC.61784-3-3.[7],. resulting. from.additional. specications.

proposed.within.IEC.61784-3.to.encompass.Probus.and.Pronet.networks..According.to.its.devel-

opers

.[1],.it.is.certied.for.use.in.safety-related.applications.up.to.SIL.3.(Safety.Integrity.Level,.IEC.

61508.or.IEC.62061).or.PL.“e”.(Performance.Level,.ISO.13849-1).. is.certication.is.also.extended.

to.wireless.networks.such.as.IEEE.802.11.and.Bluetooth,.but.with.additional.security.requirements.

(see.Section.46.3.4).

46.1.2 Black Channel Principle

 e.“black.channel”.principle.is.based.on.the.following.requirement:.the.transmission.of.safety.data.

is.performed.independently.of.the.characteristics.of.the.transmission.system,.e.g.,.medium,.topology,.

communication.stack,.network.devices,.etc.,.and.without.trusting.the.internal.safety.mechanisms.

provided.by.it..In.order.to.achieve.this.goal,.its.implementation.is.undertaken.as.an.additional.layer—

the safety layer—on

.top.of.the.application.layer.. e.safety.layer.considers.that.safety.data.are.subject.

to.various.threats.(i.e.,.errors),.and.for.each.one.denes.a.set.of.defense.measures.in.order.to.protect.

this.data.[3].(see.Section.46.2.2)..In.the.Prosafe.case,.the.safety.layer.is.implemented.as.a.safety.

prole.(Figure.46.3).. erefore,.safety.data.are.encapsulated.in.standard.Pronet.or.Probus.frames,.

jointly.with.standard.data,.and.transmitted.in.accordance.with.the.usual.rules.dened.by.the.com-

munication

.protocol.

46.2 Prosafe Communication

From.the.beginning,.the.Prosafe.solution.was.subject.to.certain.design.constraints:.compatibility.with.

existing.Probus/Pronet.physical.layers,.interoperability.with.existing.devices,.and.compatibility.

with.existing.modular.devices..Any.solution.must.attempt.to.guarantee.the.error-free.delivery.of.data,.

or.the.detection.of.data.with.errors,.between.communicating.devices,.such.as.a.PLC.(F-Host).and.an.I/O.

Safety

application

Safety

application

Standard

application

Standard

application

Profisafe

layer

Profisafe

layer

Black

channel

Standard protocol Standard protocol

Standard data

Safety data

Profinet, Profibus

FIGURE 46.3 Black. channel. approach.. (Adapted. from. PROFIsafe—Safety. technology. for. PROFIBUS. and.

PROFINET—System.description,.PROFIBUS.Nutzerorganisation.e.V..PNO,.2007.)

46-4 Industrial Communication Systems

device.(F-Device)..Implementation.of.the.error-detection.mechanism.as.separate.rmware.layers.in.the.

communicating.devices.allowed.these.constraints.to.be.met.

46.2.1 Error-Detection requirements

 e.requirement.for.being.able.to.designate.a.system.as.capable.of.operating.at.SIL.3.is.that.the.system.

must.exhibit.a.failure.rate.less.than.10

−7

/h.. is.failure.rate.is.for.the.entire.system..However,.a.system.is.

made.up.of.several.components.and.it.must.be.determined.what.each.component.is.allowed.to.contrib-

ute

.to.the.overall.system.failure.rate.. ere.were.no.precedents.for.safety.systems.involving.digital.com-

munication

.systems.. e.IEC.61508.species.the.contributions.to.the.overall.system.failure.rate.as.35%.

for.sensors,.15%.for.logic.controllers,.and.50%.for.actuators.. erefore,.the.Working.Group.developing.

the.Prosafe.specications.chose.a.maximum.of.a.1%.contribution.allowed.for.Prosafe.. is.percent-

age

.contribution.was.deducted.from.the.contribution.of.the.logic.controller.and.is.now.specied.in.IEC.

61784-3..As.one.can.see.in.Figure.46.4,.this.results.in.a.required.failure.rate.for.the.Prosafe.contribution.

of.only.10

−9

/h.(10

−2

.×.10

−7

46.2.2 Error types and Safeguards

Various.errors.can.occur.when.messages.are.transmitted,.whether.due.to.hardware.failures,.extraor-

dinary

.electromagnetic.interference,.or.other.inuences..A.message.can.be.lost,.occur.repeatedly,.be.

inserted.from.somewhere.else,.appear.delayed.or.in.an.incorrect.sequence,.and/or.show.corrupted.data..

In.the.case.of.safety.communication,.there.may.also.be.incorrect.addressing—a.standard.message.erro-

neously

.appears.at.an.F-Device.and.pretends.to.be.a.safety.message..Dierent.transmission.rates.may.

additionally.cause.storage.eects.to.occur..Of.the.numerous.error.types.and.safeguards.known.from.

literature,.Prosafe.concentrates.on.those.shown.in.Figure.46.5.

Although

.it.can.be.detected.by.use.of.the.consecutive.number.technique,.an.additional.error.type.

was.identied.for.Pronet.communication—that.of.the.failure.of.revolving.memory.in.switches..Since.

there.is.little.control.of.what.Ethernet.switches.a.customer.actually.uses,.some.COTS.(commercial,.o-

the-shelf)

.switches.may.be.unreliable.and.lead.to.revolving.memory.failures.as.shown.in.Figure.46.6..

Accidental.“jumping”.of.the.send.pointer,.for.example,.can.cause.emptying/sending.of.the.entire.queue.

of.messages.

46.2.3 Cyclic/acyclic Communication

Cyclic.data.exchange.between.a.controller.and.its.eld.devices.utilizes.a.one-to-one.communication.

relationship.as.shown.in.Figure.46.7.. is.gure.illustrates.that.a.controller.(F-Host).can.operate.any.

mix.of.standard.and.safety.devices.(F-Devices).connected.to.the.same.network..Safety.tasks.and.

Sensor

Logic operations

Actuator

Bin. O

50%

14%

Safety integrity level (SIL) 3: 10

–7

(PROFIsafe-Portion: 1% = 10

–9

/h)

SIL3

35%

Bin. I

Anal. I

FIGURE 46.4 Prosafe.contribution.to.system.failure.rate..(Adapted.from.Specication.PROFIsafe—Prole.for.

safety.technology,.Version.1.30,.June.2004,.Order.No:.3.092,.PROFIBUS.International.)