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

Подождите немного. Документ загружается.

31-16 Industrial Communication Systems

. 34.. J..Pimentel,.J..Proenza,.L..Almeida,.G..Rodríguez-Navas,.M..Barranco,.and.J..Ferreira..Dependable.

aut

omotive

.CAN.netw

orks.

.In.Aut

omotive Embedded Systems Handbook,

.N..Nav

.and.F..Simo

not-

Lion

.(ed

s.).

.CRC.Pr

ess,

.Bo

.Ra

ton,

.FL,.2009.

. 35.. J..R..Pimen

tel

.and.J..A..Fon

seca.

.FlexCAN:.A.exible.arc

hitecture

.for.highl

.depend

able

.embe

dded

app

lications.

.In.RTN 2004—

ird International Workshop on Real-Time Networks sattelite Held in

Conjunction with the 16th Euromicro International Conference on Real-Time Systems,

.Cat

ania,

.Ita

ly,

June.2004.

. 36.. G..Rodr

íguez-Navas

.and.J..Pro

enza.

.Ana

lyzing

.ato

mic

.bro

adcast

.in.TTCAN.netw

orks.

.In.Pro

ceedings

of the Fih IFAC International Conference on Fieldbus Systems and eir Applications

.(FET 2003)

Aveir

.Po

rtugal,

.2003,.pp

.153–156.

. 37.. G..Rodr

íguez-Navas,

.J..Pro

enza,

.and.H..Han

sson.

.An.UPPAAL.mode

.for.for

mal

.veric

ation

.of.

mas

ter/slave

.cloc

.sync

hronization

.over.the.cont

roller

.are

.netw

ork.

.In.Pro

ceedings of the Sixth

IEEE International Workshop on Factory Communication Systems,

.Tur

in,

.It

aly,

.2000.

. 38.. M..Rucks..Opt

ical

.lay

.for.CAN..In.Pro

ceedings of the First International CAN Conference,

.Vol

.2,.

Mainz,.Ger

many,

.1994,.pp

.11–18,.CiA.

. 39.. J..Runo

.P..Verí

ssimo,

.and.G..Arr

oz.

.A.Col

umbus’

.egg.idea.for.CAN.medi

.red

undancy.

.In.Dige

st of

Papers,

.the

29th International Symposium on Fault-Tolerant Computing Systems,

.Madis

on,

.WI,.June.

1999,.pp

.286–293,.IEEE.

. 40.. J..Runo

.P..Verí

ssimo,

.G..Arr

oz,

.C..Almeid

.and.L..Rodigues..Fau

lt-tolerant

.bro

acast

.in.CAN..

In.Digest of Papers,.28th International Symposium on Fault Tolerant Computer Systems,.Munich,.

Germ

any,

.pp

.150–159,.1998.

. 41.. V..Sil

va,

.J..Ferr

eira,

.and.J..Fon

seca.

.Dyn

amic

.top

ology

.man

agement

.in.CAN..In.Pro

ceedings of the

11th IEEE International Conference on Emerging Technologies and Factory Automation,

. Prague

Czech.Rep

ublic,

.2006,.IEEE.

. 42.. K.. Tinde

. and. A.. Burn

. Gua

ranteeing

. mess

age

. lat

encies

. on. cont

roller

. are

. netw

ork

. (CAN)..

In.Pr

oceedings of the First International CAN Conference,

.Ma

inz,

.Ger

many,

.1994,.pp

.1–11.

32-1

32.1 Introduction

 e.Probus.(PROcess.FIeld.BUS).was.dened.by.a.consortium.of.dierent.manufacturers.and.research.

inst

itutions

.in.Germ

any

.more.than.20.year

.ago.and.den

.from.the.begi

nning

.as.an.open.nati

onal

stan

dard

.DIN.1924

.It.is.a.simpl

.eld

bus

.base

.on.an.exte

nded

.token.passi

.and.objec

t-oriented

serv

ices

.to.prov

ide

.dist

ributed

.cont

rol

.base

.on.a.simpl

ied

.and.adapt

.versi

.of.ISO.6950

.manu

fac-

turing

.mess

age

.spec

ication

.(MMS

)

.call

.the.eld

bus

.mess

age

.spec

ication

.(FMS

.But.the.indu

stry

did.not.want.a.dist

ributed

.syst

.and.adopt

.a.simpl

.remo

.I/O.syst

.with.cent

ralized

.cont

rol.

So.the.Pro

bus-FMS

.was.exte

nded

.with.an.appl

ication

.proto

col

.for.dece

ntralized

.peri

phery

.(DP).we.

call.here.Pro

bus

.DP..To.cope.with.the.requ

irements

.of.proc

ess

.autom

ation,

.addi

tional

.den

itions

.for.

tran

smission

.medi

.and.func

tion

.bloc

.are.adde

.and.coll

ected

.unde

.the.name.Pro

bus

.PA..All.thes

den

itions

.were.brou

ght

.to.the.Euro

pean

.stan

dard

.EN50

170-2.

.Fina

lly,

.the.Versi

ons

.PA.and.DP.are.

today.part.of.the.inte

rnational

.stan

dard

.IEC.6115

.[IEC

58]

.and.IEC.6178

.[IEC

84-1]

.unde

.the.desig

na-

tion

.“Fam

ily

.3”.with.subd

ivisions

.3/1.and.3/2.. e.func

tionality

.of.Pro

bus

.DP.can.furt

her

.be.spli

.in.

thre

.leve

ls:

.DPV0.for.simpl

.remo

.I/O,.DP-V

.for.addi

tional

.acyc

lic

.data.exch

ange,

.and.DP-V

.for.

high

-performance

.func

tions

.like.isoc

hronous

.cycl

.and.broa

dcast

.data.exch

ange.

.Tabl

.32.1.show

thei

.assi

gnment.

.“PRO

FIBUS

.Nutze

rorganisation”

.(PNO

.repr

esenting

.the.inte

rested

.ente

rprises

.and.inst

itutes

.in.this.

tech

nology,

.was.foun

ded

.as.earl

.as.1989.in.Germ

any.

.Pro

bus

.is.toda

.supp

orted

.by.Pro

bus

.&.Pro

net

Inte

rnational

.(PI)

.an.umbr

ella

.orga

nization

.form

.out.of.more.than.30.Regi

onal

.Pro

bus

.Asso

ciations

(RPA

)

.on.all.cont

inents

.like.the.PNO.for.Germ

any

.or.the.PTO.repr

esenting

.the.Nort

.Amer

ican

.mark

et.

Probus

32.1. Introduction.....................................................................................32-1

32.2

. Physi

cal

.Tra

nsmissions...................................................................32-2

Asynchronous.(RS-485). •. Manchester.Bus.Powered. •. Fiber.Optics

32.3. Fieldbus.Data.Link...........................................................................32-5

Services. •. Framing. •. Media.Access

32.4. DP.System.........................................................................................32-7

DP-Master.Class.1:.Controllers. •. DP-Master.Class.2:.Engineering.

Stations. •. DP-Slaves:.Field-Devices. •. Application.Relations

32.5. Cyclic.Data.Exchange:.MS0—Relation........................................32-9

Device.Model. •. Initialization.and.Supervision.of.the.Relation. •. .

Status.of.the.Controller.and.Fail-Safe.Functionality. •. Diagnostics.

ofthe.Field-Device. •. Distributed.Database. •. Synchronization.

ofthe.Applications

32.6. Acyclic.Data.Exchange:.MS1/MS2.Relations.............................32-10

Variables. •. Device.Model.including.Identication.

andMaintenance. •. Alarm.Handling. •. Procedure.Calls

32.7. Application.Proles.......................................................................32-12

References...................................................................................................32-12

Max Felser

Bern University of

Appl

ied

Sci

ences

Ron Mitchell

RC Systems

32-2 Industrial Communication Systems

Support.for.the.Probus.technology.is.provided.by.more.than.30.competence.centers.(PICC).and.certica-

tion

.trai

nings

.are.oer

.by.trai

ning

.cent

ers

.(PIT

C).

. e.confo

rmance

.of.prod

ucts

.to.the.stan

dard

.and.the.

inte

roperability

.of.the.die

rent

.prod

ucts

.is.veri

ed

.and.test

.by.the.test.labo

ratories

.(PIT

.avai

lable

.in.all.

majo

.mark

ets.

32.2 Physical transmissions

Probus.provides.dierent.versions.of.layer.1.as.transmission.technology.listed.in.Table.32.2.

32.2.1 asynchronous (rS-485)

RS485.transmission.technology.is.simple.and.cost-eective.and.primarily.used.for.tasks.that.require.

high.tran

smission

.rate

.Shie

lded,

.twis

ted

.pair.copp

.cabl

.with.one.condu

ctor

.pair.is.used

.Deta

ils

to.RS.485.inst

allation

.are.desc

ribed

.in.[P21

12,P8022,P8032].

. ebu

sstructure

.allo

.addi

tion

.or.

TABLE 32.1 Properties.of.the.Communication.Family.CPF.3.for.Probus

Layer Prole.CP3/1 Prole.CP3/1 Prole.CP3/2

Application Manufacturing

.aut

omation Motion

.cont

rol Process

.aut

omation

.(Pro

bus

.PA)

.link IEC.61158.subs

.DP-V0.

async

hronous

.tran

smission

IEC

.61158.subs

.DP-V2.

async

hronous

.tran

smission

IEC

.61158.subs

.DP-V1.

synchr

onous

.tran

smission

Physical RS485 RS485 MBP

Plastic

.ber P

lastic

.ber

lass

.ber G

lass

.ber

PCF

.ber PCF.ber

TABLE 32.2 Transmission.Technologies.(Physical.Layer).at.Probus

MBP RS485 RS485-IS Fiber.Optic

Data

.tran

smission Digital,

.bit-

nchronous,

Manc

hester

.encodin

Digital,

.dieren

tial

signal

.accordin

.to.

RS485,.NRZ

Digit

al,

.dieren

tial

signal

.accordin

toRS485,.NRZ

Opt

ical,

.digit

al,

.NRZ

Tran

smission

.rate

31.25

.kb/s 9.6–12,000.kb/s 9.6–1,500.kb/s 9.6–12,000.kb/s

Dat

.sec

urity Preamble,

.erro

protected,

.sta

rt/end

delimiter

HD.=.4,.Par

ity

.bit,.

star

t/end

.delimit

.=.4,.Par

ity

.bit,.

star

t/end

.delimit

.=.4,.Par

ity

.bit,.

star

t/end

.delimit

Cable Shielded,

.twi

sted

.pair.

copper

hielded,

.twi

sted

.pair.

copper

.cab

.type.A

Shielde

.twi

sted

4-wire,.cab

.type.A

Mul

timode

.glas

.ber

sing

lemode

.glas

ber

.PCF,.plas

tic

Remote

.fee

ding Optional

.avai

lable

.over.

signal.wire

vailable

.over.

addition

.wire

vailable

.over.

addition

.wire

vailable

.over.hyb

rid

line

Pro

tection

.type

Intrinsic

.saf

ety

(EEx.ia/ib)

one Intrinsic

.saf

ety

(EExib)

Topology Line

.and.tre

.top

ology

with.termin

ation;

also.in.comb

ination

Line

.top

ology

witht

ermination

Line

.top

ology

witht

ermination

Star

.and.ring.

topo

logy

.typic

al;

line.top

ology

possib

Number

ofsta

tions

.to.32.sta

tions

.per.

segmen

.tota

.of.max..

126.per.netw

ork

.to.32.sta

tions

.per.

segmen

.wit

hout

repea

ter;

.up.to.126.

stat

ions

.wit

.repe

ater

.to.32.sta

tions

persegm

ent;

.up.to.

126.sta

tions

.wit

repea

ter

.to.126.sta

tions

per.netw

ork

Number

ofrepe

aters

Max.

.4.repe

ater Max.

.9.repe

ater

.wit

signal.refr

eshing

Max.

.9.repe

ater

.wit

signal.refr

eshing

Unlimited

.with.signal.

refres

hing

.(time.

delay.of.signa

Probus 32-3

removal.of.stations.or.the.step-by-step.commissioning.of.the.system.without.inuencing.other.sta-

tions.

.Subs

equent

.expa

nsions

.(wit

hin

.den

.limi

ts)

.have.no.eec

.on.stat

ions

.alre

ady

.in.oper

ation.

Various

. tran

smission

. rate

. can. be. sele

cted

. betw

een

. 9.6.kb/s. and. 12.Mb/s

. One. unif

orm

. spee

. is.

sele

cted

.for.all.devi

ces

.on.the.bus.when.comm

issioning

.the.syst

em.

. e.maxi

mum

.perm

issible

.line.

leng

.dep

ends

.on.the.tra

nsmission

.rat

.and.is.lis

ted

.in.Tab

.32.

All

.devi

ces

.are.conn

ected

.in.a. bus.stru

cture

.(lin

e).

.Up.to.32.stat

ions

.(mas

ters

.or.slav

es)

.can.be.

conn

ected

.in.a.singl

.segm

ent.

. e.begi

nning

.and.end.of.each.segm

ent

.is.tte

.with.an.acti

.bus.

term

inator.

.Both.bus.term

inators

.have.a.perm

anent

.powe

.supp

.to.ensu

.erro

r-free

.oper

ation.

. e.

bus.term

inator

.is.usua

lly

.swit

ched

.in.the.devi

ces

.or.in.the.bus.term

inator

.conn

ectors.

.If.more.than.

32st

ations

.are.impl

emented

.or.ther

.is.a.need.to.expa

.the.netw

ork

.area

.repe

aters

.must.be.used.to.

link.the.ind

ividual

.bus.seg

ments.

Dierent

cabl

type

(typ

desig

nation

A–D)

for

die

rent

appl

ications

are

avai

lable

the

mark

for.conn

ecting

.devi

ces

.eith

.to.each.othe

.or.to.netw

ork

.elem

ents

.(e.g

.segm

ent

.coup

lers,

.link

.and.

repe

aters).

When

.conn

ecting

.the.stat

ions,

.alwa

.ensu

.that.the.data.line

.are.not.reve

rsed.

.Alwa

.use.a.

shie

lded

.data.line.(typ

.A.is.shie

lded)

.to.ensu

.high.inte

rference

.immu

nity

.of.the.syst

.agai

nst

elec

tromagnetic

.emis

sions.

. e.shie

.shou

.be.grou

nded

.on.both.side

.wher

.poss

ible

.and.larg

area

.shie

.clam

.used.for.grou

nding

.to.ensu

.good.cond

uctivity.

.Furt

hermore,

.alwa

.ensu

.that.

the.data.line.is.laid.sepa

rately

.and,.wher

.poss

ible,

.away.from.all.powe

.cabl

es.

.Never.use.spur.line

for.tran

smission

.rate

.≥1.5.Mb/s..Comm

ercially

.avai

lable

.conn

ectors

.supp

ort

.dire

.conn

ection

.of.the.

inco

ming

.and.outg

oing

.data.cabl

.in.the.conn

ector.

. is.disp

enses

.with.the.need.for.spur.line

.and.

the.bus.conn

ector

.can.be.conn

ected

.and.disc

onnected

.at.the.bus.at.any.time.with

out

.inte

rrupting

data.comm

unications.

. e.type.of.conn

ector

.suit

able

.for.RS48

.tran

smission

.tech

nology

.depe

nds

.on.

the.degr

.of.prot

ection.

.A.9-pi

.D-Su

.conn

ector

.is.prim

arily

.used.for.prot

ection

.rati

.IP.20.. e.

pref

erred

.solu

tion

.for.prot

ection

.rati

.IP.65/6

.is.the.M12.circ

ular

.conn

ector

.in.acco

rdance

.with.

IEC.947-

5-2.

 ere

.exi

sts

.a.con

guration

.of.int

rinsically

.saf

.RS4

.sol

utions

.wit

.simp

.dev

ice

.int

erchangeabil-

ity.

. e.spec

ication

.of.the.inte

rface

.stip

ulates

.the.leve

.for.curr

ent

.and.volt

age

.that.must.be.adhe

red

.to.

by.all.stat

ions

.in.orde

.to.ensu

.safe.func

tioning

.duri

.inte

rconnection.

.An.elec

tric

.circ

uit

.perm

its

maxi

mum

.curr

ents

.at.a.spec

ied

.volt

age.

.When.inte

rconnecting

.acti

.sour

ces,

.the.sum.of.the.cur-

ents

.of.all.stat

ions

.must.not.exce

.the.maxi

mum

.perm

issible

.curr

ent.

.An.inno

vation

.of.the.RS48

5-IS

conc

ept

.is.that

.in.cont

rast

.to.the.FISC

.mode

.whic

.only.has.one.intr

insically

.safe.sour

ce,

.all.stat

ions

now.rep

resent

.act

ive

.sou

rces.

TABLE 32.3 Transmission.Range.and.Range.

for.Cab

.Typ

Transmission.Rate.(kb/s)

Range.per.

Segment.(m)

9.6,

.19.2,.45.45,.93.75 1,200

187.5 1,000

500 400

1,500 200

3,000,

.6,000,.12,000 100

.values.refer.to.cab

.type.A.wit

.the.fol

lowing

prop

erties:

Impe

dance

. 135.to.165.Ω

Cap

acity

.. ≤30.pf/m

.resis

tance

. ≤110.Ω./km

Wir

.diam

eter

. >0.64.mm

Core.cross-s

ection

. >0.34.mm

32-4 Industrial Communication Systems

32.2.2 Manchester Bus Powered

Manchester.Bus.Powered.(MBP).stands.for.transmission.technology.with.the.following.attributes:

•

. Man

chester

.Co

ding

.(M

)

•

. Bus.Po

wering

.(B

MBP

.is.syn

chronous

.tra

nsmission

.wit

.a.de

ned

.tra

nsmission

.rat

.of.31.

.kb/

.and.Man

chester

.cod

ing.

 is.tra

nsmission

.tec

hnology

.is.fre

quently

.use

.in.pro

cess

.auto

mation

.as.it.sat

ises

.the.key.dem

ands

.of.

the.che

mical

.and.pet

rochemical

.ind

ustries

.for.int

rinsic

.saf

ety

.and.bus.pow

ering

.usin

.two

-wire

.tec

nology.

. is.mea

.tha

.Pro

bus

.can.als

.be.use

.in.pot

entially

.exp

losive

.are

.wit

.the.att

ribute

.int

rin-

sically

.sa

fe.

.int

rinsically

.saf

.tra

nsmission

.tec

hnology

.of.MBP.is.usu

ally

.lim

ited

.to.a.spe

cic

.seg

ment

.(e

dev

ices

.in.haz

ardous

.are

as)

.of.a.pla

nt,

.whi

.are.the

.lin

ked

.to.the.RS4

.seg

ment

.(co

ntrol

.sys

tem

.and.

eng

ineering

.dev

ices

.in.the.con

trol

.roo

.ove

.seg

ment

.cou

pler

.or.lin

ks.

.Seg

ment

.cou

plers

.are.sign

con

verters

.tha

.mod

ulate

.the.RS4

.sign

als

.to.the.MBP.sign

.lev

el.

. es

.are.tra

nsparent

.fro

.the.

bus.pro

tocol

.sta

ndpoint.

.In.con

trast,

.lin

.hav

.the

.own.int

rinsic

.int

elligence.

. ey.map.all.the.el

dev

ices

.con

nected

.to.the.MBP.seg

ment

.as.a.sing

.sla

.in.the.RS4

.seg

ment.

. er

.is.no.lim

.to.the.

tra

nsmission

.rat

.in.the.RS4

.seg

ment,

.so.tha

.fas

.net

works

.can.als

.be.imp

lemented

.usin

.el

dev

ices

.wi

.MB

.co

nnection,

.e.

g.,

.fo

.co

ntrol

.ta

sks.

Tree

.or.lin

.str

uctures

.(an

.any.com

bination

.of.the.two

)

.are.net

work

.top

ologies

.sup

ported

.by.

Pro

bus

.wit

.MBP.tra

nsmission.

.In.a.lin

.str

ucture,

.sta

tions

.are.con

nected

.to.the.tru

.cab

.usi

tree.adapters.. e.tree.topology.is.comparable.to.the.classic.eld.installation.method.. e.multi-core.

mas

ter

.cab

.is.rep

laced

.by.the.two

-wire

.bus.mas

ter

.cab

le;

.the.el

.dis

tributor

.ret

ains

.its.fun

ction

.of.

con

necting

.the.el

.dev

ices

.and.det

ecting

.the.bus.ter

minator

.imp

edance.

.Whe

.usi

.a.tre

.top

ol-

ogy,

.all.el

.dev

ices

.con

nected

.to.the.el

dbus

.seg

ment

.are.wir

.in.par

allel

.in.the.el

.dis

tributor.

In.all.cas

es,

.the.max

imum

.per

missible

.spu

.lin

.len

gths

.mus

.be.tak

.int

.acc

ount

.whe

.cal

culat-

ing

.the.ove

r-all

.lin

.len

gth.

.In.int

rinsically

.saf

.app

lications,

.a.spu

.lin

.has.a.max

imum

.per

missible

len

gth

.of.30.m.

.shi

elded

.two

-wire

.cab

.is.use

.as.the.tra

nsmission

.med

ium.

. e.bus.tru

.cab

.has.a.pas

sive

.lin

ter

minator

.at.eac

.end

.whi

.com

prises

.an.RC.ele

ment

.con

nected

.in.ser

ies

.wit

.R.=.100.Ω.and.C.=.2.μF..

 e.bus.ter

minator

.is.alr

eady

.int

egrated

.in.the.seg

ment

.cou

pler

.or.lin

.Whe

.usin

.MBP.tec

hnology,

inc

orrect

.con

nection

.of.a.el

.dev

ice

.(i.

e.,

.pol

arity

.rev

ersal)

.has.no.ee

.on.the.fun

ctionality

.of.the.bus.

as.th

ese

.de

vices

.ar

.us

ually

.t

ted

.wi

.an.au

tomatic

.po

larity

.de

tection

.fu

nction.

.numb

.of.sta

tions

.tha

.can.be.con

nected

.to.a.seg

ment

.is.lim

ited

.to.32..How

ever,

.thi

.numb

may.be.fu

rther

.de

termined

.by.th

.pr

otection

.ty

.se

lected

.an

.bu

.po

wering

.(i

.an

y).

.int

rinsically

.saf

.net

works,

.bot

.the.max

imum

.fee

.vol

tage

.and.the.max

imum

.fee

.cur

rent

.are.

de

ned

.wit

hin

.str

ict

.lim

its.

.But.the.out

put

.of.the.sup

ply

.uni

.is.lim

ited

.eve

.for.non

intrinsically

.saf

.net

works.

. e.FIS

.mod

.con

siderably

.simp

lies

.the.pla

nning,

.ins

tallation,

.and.exp

ansion

.of.Pro

bus

net

works

.in.po

tentially

.ex

plosive

.ar

eas.

32.2.3 Fiber Optics

Some. eldbus. application. conditions. place. restrictions. on. wire-bound. transmission. technology,.

suc

.as.tho

.in.env

ironments

.wit

.ver

.hig

.ele

ctromagnetic

.int

erference

.or.whe

.par

ticularly

lar

.dis

tances

.nee

.to.be.cov

ered.

.Fib

er-optic

.tra

nsmission

.ove

.be

r-optic

.con

ductors

.is.sui

table

in.suc

.cas

es.

. e.tra

nsmission

.cha

racteristics

.sup

port

.not.onl

.sta

.and.rin

.top

ology

.str

uctures

but.als

.lin

.str

uctures.

.In.the.sim

plest

.cas

.a.be

r-optic

.net

work

.is.imp

lemented

.usi

.ele

ctrical/

optical

.tra

nsformers

.tha

.are.con

nected

.to.the.dev

ice

.and.the.be

.opt

ics

.ove

.a.RS4

.int

erface.

 is.all

ows

.you.to.swi

tch

.bet

ween

.RS4

.and.be

r-optic

.tra

nsmission

.wit

hin

.a.pla

nt,

.dep

ending

.on.

the.cir

cumstances.

Probus 32-5

32.3 Fieldbus Data Link

 e.Probus.Communication.Proles.Family.(CPF3).uses.a.uniform.medium.access.protocol.. is.pro-

tocol

.is.implemented.by.layer.2.of.the.OSI.reference.model.and.is.called.eldbus.data.link.(FDL).. is.

also.includes.the.handling.of.the.transmission.protocols.and.telegrams.and.the.detection.and.correction.

of.transmission.errors.

32.3.1 Services

Probus.layer.2.operates.in.a.connectionless.mode..In.addition.to.logical.peer-to-peer.data.transmis-

sion,

.it.provides.multi-peer.communication.(broadcast.and.multicast).

Table

.32.4.lists.all.available.FDL.services.. e.services.are.called.up.by.the.higher.order.layers.via.the.

service.access.points.(SAPs)..In.DP,.a.precisely.dened.function.is.assigned.to.each.service.access.point..

Several.service.access.points.can.be.used.simultaneously.for.all.active.and.passive.stations..A.distinction.

is.made.between.source.access.points.(SSAPs).and.destination.service.access.points.(DSAPs).

32.3.2 Framing

Another.important.task.of.layer.2.is.to.ensure.the.detection.of.transmission.errors..All.telegrams.have.

a.Hamming.Distance.of.HD.=.4.. is.is.achieved.through.compliance.with.the.international.standard.

IEC.870-5-1,.through.special.telegram.start.and.end.delimiters,.slip-free.synchronization,.a.parity.bit,.

and.a.check.byte..An.example.of.Probus.frames.is.shown.in.Figure.32.1..If.a.receiver.detects.transmis-

sion

.errors.the.frame.is.deleted.. e.sender.repeats.the.transmission.automatically.. e.details.of.the.

mechanism.are.also.explained.in.[F06].

Every

.station.is.assigned.one.unique.address.in.the.range.of.0–126.. e.address.0.is.typically.reserved.

for.engineering.tools.and.the.address.126.is.the.default.address.for.devices.. e.value.127.addresses.all.

stations.on.the.network.

SD1 DA SA FC FCS ED

Frame without data:

Token frame:

Short acknowledge:

SD1 = 0 × 10 Start delimitter 1

SD2 = 0 × 68 Start delimitter 2

SD4 = 0 × DC Start delimitter 4

ED = 0 × 16 End delimitter

SC = 0 × E5 Short confirmation

DA = Destination address

SA = Source address

FC = Function code

PDU = Protocol data unit

FCS = Frame check sequence

LE = Length

LEr = Length repeated

Frame with variable length:

LEr SD2 DA SA FC PDU (=1 – 246 bytes)

FCS ED

SD4 DA SA

SD2

FIGURE 32.1 Example.of.Probus.frames.

TABLE 32.4 List.of.Available.FDL.Services

Name Service

SDN Send

.data.with.no.acknowledge

SDA Send

.data.with.acknowledge

SRD Send

.and.request.data

MSRD Send

.and.request.data.with.multicast.reply

CS Clock

.synchronization

32-6 Industrial Communication Systems

32.3.3 Media access

 e.Probus.medium.access.control.(MAC).includes.the.token-passing.procedure,.which.is.used.by.

complex.bus.stations.(masters).to.communicate.with.each.other.and.the.master–slave.procedure.used.

by.complex.bus.stations.to.communicate.with.the.simple.peripherals.(slaves).

.token-passing.procedure.ensures.that.the.bus.access.right.(the.token).is.assigned.to.each.master.

within.a.precisely.dened.timeframe.. e.token.message,.a.special.telegram.for.passing.the.token.from.

one.master.to.the.next.master.must.be.passed.around.the.logical.token.ring.once.to.all.masters.within.a.

(congurable).maximum.token.rotation.time..In.Probus,.the.token-passing.procedure.is.only.used.for.

communication.between.complex.stations.(masters).

.master–slave.procedure.permits.the.master.(the.active.station).which.currently.owns.the.token.to.

access.the.assigned.slaves.(the.passive.stations).. is.enables.the.master.to.send.messages.to,.or.retrieve.

them.from.the.slaves.. is.method.of.access.allows.implementation.of.the.following.system.congurations:

•

. Pure.master–slave.system.with.just.one.master.polling.the.slaves

•

. Pure.master–master.system.with.token.passing.and.no.slaves

•

. A.hybrid.system.combining.multiple.masters.passing.the.token.and.polled.slaves.(Figure.32.2)

.system.startup,.every.master.listens.to.the.bus.and.watches.the.transmissions..If.the.bus.is.idle.a.

timer.is.started;.the.timer.is.set.as.a.multiple.of.the.unique.station.address.n.as.shown.in.formula.(32.1)..

 e.timer.of.the.master.with.the.lowest.address.expires.rst.and.this.master.has.the.rst.token.as.shown.

Master

Bus is “Idle”

n = 1 Time-out time = 8T

Master 1 sends token

n = 2 Time-out time = 10T

n = 3 Time-out time = 12T

FIGURE 32.3 Generation.of.the.rst.token.

Master

Slave

Master

Token

FIGURE 32.2 Hybrid.system.with.two.masters.and.ve.slaves.

Probus 32-7

in.Figure.32.3..He.signals.this.to.the.other.stations.by.sending.the.token.to.himself.. e.active.master.

star

.to.pol

.all.add

resses

.to.det

ect

.add

itional

.sta

tions

.on.the.bus

t t n t

TIMEOUT SLOT SLOT

6 2= +

(32.1)

where

SLOT

.=.maximum.time.to.answer.to.a.poll.request.

.an.addi

tional

.mast

.dete

cts

.tra

.on.the.bus.he.has.to.list

.to.all.token.fram

.and.coll

ect

.the.list.

of.all.addr

essed

.mast

ers.

.As.soon.as.he.has.a.comp

lete

.and.stab

.list

.he.clai

.the.token.for.hims

elf.

When.the.acti

.mast

.poll

.him.he.repl

ies

.that.he.is.read

.to.get.the.token.and.that.it.will.be.incl

uded

in.the.toke

.rin

.toke

.is.passed.from.one.mast

.to.the.othe

.in.an.incr

easing

.orde

.of.the.stat

ion

.addr

ess

.numb

er.

For.ever

.bus.is.den

.a.targ

.toke

.rota

tion

.time.(TTR

T).

.When.the.acti

.stat

ion

.sends.the.toke

.it.

star

.a.time

.reduc

ing

.the.TTRT

.When.the.toke

.gets.back,.the.rest.of.the.time.is.the.maxi

mum

.toke

hold.time.for.this.node..Duri

.this.time

.the.acti

.stat

ion

.can.comm

unicate

.with.all.slav

.stat

ions

.in.a.

mast

er–slave

.comm

unication

.rela

tionship

.and.to.all.mast

.stat

ions

.in.a.mast

er–master

.comm

unication

rela

tionship.

.a.Pro

bus,

.DP.syst

.the.con

guration

.tool.ensu

res

.that.the.TTRT.is.larg

.enou

.that.the.mast

can.poll.assig

ned

.slav

.in.one.token.hold.time

.More.deta

iled

.desc

riptions

.and.form

ulas

.may.be.foun

at.[CM

TV02,V04,

.and.KHU

08].

32.4 DP System

DP.supports.the.implementation.of.both.mono-master.and.multi-master.systems.. is.aords.a.high.

degr

.of.exi

bility

.duri

.syst

.con

guration.

. e.spec

ications

.for.syst

.con

guration

.den

.the.

foll

owing:

•

. Numbe

.of.sta

tions

•

. Assig

nment

.of.sta

tion

.add

resses

.to.the.I/O.add

resses

•

. Data.int

egrity

.of.I/O.dat

•

. e.for

mat

.of.dia

gnostic

.mes

sages

•

. e.bus.par

ameters

.use

[P02]

. expl

ains

. all. thes

. para

meters

. in. deta

. and. [WG0

. give

. an. exam

ple

. of. a. comm

ercial

impl

ementation.

Each

.DP.syst

.is.made.up.of.die

rent

.devi

.type

.wher

eby

.a.dist

inction

.is.made.betw

een

.thre

type

.of.dev

ices:

•

. DP.mas

ter

.cla

.1.(DP

M1)—controllers

•

. DP.mas

ter

.cla

.2.(DP

M2)—engineering

.sta

tions

•

. DP.sla

ves

.(DP

S)—eld

.dev

ices

32.4.1 DP-Master Class 1: Controllers

 is.is.a.central.controller.that.cyclically.exchanges.information.with.the.distributed.stations.(slaves).

at.a.spec

ied

.mess

age

.cycl

.Typi

cal

.DPM1.devi

ces

.are.prog

rammable

.logi

.cont

rollers

.(PLC

.or.PCs..

ADPM

.has.acti

.bus.acce

.with.whic

.it.can.read.meas

urement

.data.(inp

uts)

.of.the.eld.devi

ces

.and.

writ

.the.setp

oint

.valu

.(out

puts)

.of.the.actu

ators

.at.xed.time

. is.cont

inuously

.repe

ating

.cycl

.is.

the.basi

.of.the.auto

mation

.fun

ction.

.the.case.of.mono

-master

.syst

ems,

.only.one.mast

.is.acti

.on.the.bus.duri

.the.oper

ation

of.the.bus.syst

em.

. is.sing

le-master

.is.the.cent

ral

.cont

rol

.comp

onent.

. e.slav

.are.dece

ntrally

coup

led

.to.the.mast

.over.the.tran

smission

.medi

. is.syst

.con

guration

.enab

les

.the.shor

test

bus.cycl

.time

32-8 Industrial Communication Systems

In.multi-master.operation,.several.masters.are.connected.to.one.bus.. ey.represent.either.indepen-

dent

.subsystems,.comprising.one.DPM1.and.its.assigned.slaves,.or.additional.conguration.and.diag-

nostic

.devices.. e.input.and.output.images.of.the.slaves.can.be.read.by.all.DP.masters,.while.only.one.

DP.master.(the.DPM1.assigned.during.conguration).can.write-access.the.outputs.

32.4.2 DP-Master Class 2: Engineering Stations

Devices.of.this.type.are.engineering,.conguration,.or.operating.devices.. ey.are.implemented.during.

commissioning.and.for.maintenance.and.diagnostics.in.order.to.congure.connected.devices,.evaluate.

measured.values.and.parameters,.and.request.the.device.status..A.DPM2.does.not.have.to.be.perma-

nently

.connected.to.the.bus.system.. e.DPM2.also.has.active.bus.access.

32.4.3 DP-Slaves: Field-Devices

A.slave.is.a.peripheral.(I/O.devices,.drives,.HMIs,.valves,.transducers,.analysis.devices),.which.reads.in.

process.information.and/or.uses.output.information.to.intervene.in.the.process.. ere.are.also.devices.

that.solely.process.input.information.or.output.information..As.far.as.communication.is.concerned,.

slaves.are.passive.devices,.they.only.respond.to.direct.queries.. is.behavior.is.simple.and.cost-eective.

to.implement.(in.the.case.of.DP-V0.it.is.already.completely.included.in.the.hardware).

32.4.4 application relations

 e.dierent.types.of.devices.may.enter.dierent.communication.relations.to.each.other.(Figure.32.4):

MM:

.Exchange.of.parameters,.conguration.data,.and.diagnostics.between.a.DPM1.and.a.DPM2

MS0:

.Cyclic.data.exchange.of.a.DPM1.controller.with.a.eld-device.(DP.slave)

MS1:

.Acyclic.data.exchange.between.a.DPM1.controller.and.a.eld-device.(DP.slave)

MS2:

.Acyclic.data.exchange.between.a.DPM2.engineering.station.and.a.eld-device.(DP.slave)

User-

program

Process

image

MS0 MS1

MS0 MS1 MS2

PROFIBUS FDL

Slave

Application

programmer’s

interface (API)

Communications

platform

Communications

platform

PROFIBUS FDL

Field device

Comm-FB

(IEC 61131-3)

e.g., Proxy-FB

(IEC 61131 -3)

Device type

manager (DTM),

(EDD-interpreter)

Field-device-

tool (FDT)

MS2

PROFIBUS FDL

Master class 1 (DPM1) Master class 2 (DPM2)

FIGURE 32.4 Device.types.and.relations.

Probus 32-9

32.5 Cyclic Data Exchange: MS0—relation

 e.central.control.(DPM1).performs.the.following.functions:

•

. Read

.inp

.inf

ormation

.fro

.the.sla

ves

.cyc

lically

•

. Writ

.out

put

.inf

ormation

.to.the.sla

ves

.cyc

lically

.bus.cycl

.time.shou

.be.shor

ter

.than.the.prog

ram

.cycl

.time.of.the.cent

ral

.autom

ation

.syst

em,

whic

.is.app

roximately

.10.ms.for.man

.app

lications.

32.5.1 Device Model

Every.eld-device.is.composed.of.modules,.which.are.located.in.slots..Every.module.can.have.one.or.

seve

ral

.chan

nels.

. ese.modu

les

.may.be.real.physi

cal

.modu

les

.or.only.virt

ual

.orga

nization

.unit

. e.

con

guration

.and.numbe

.and.versi

.of.modu

les

.may.be.xed.or.vari

able.

. e.possi

ble

.modu

les,

.orde

and.para

meters

.are.desc

ribed

.in.the.Gene

ric

.Stati

.Desc

ription

.(GSD

)

.le,.whic

.is.prov

ided

.by.the.

manu

facturer

.of.the.dev

ice

.and.use

.by.the.con

guration

.tool.of.the.con

troller

.to.sup

port

.the.eng

ineer

in.the.pla

nning

.of.the.Pro

bus

.sys

tem.

32.5.2 Initialization and Supervision of the relation

Data.communication.between.the.DPM1.and.its.assigned.slaves.is.automatically.handled.by.the.DPM1.

in.a.den

ed,

.recu

rring

.sequ

ence.

. e.user.den

.the.assig

nment

.of.the.slav

e(s)

.to.the.DPM1.when.con-



guring

.the.bus.syst

em.

. e.user.also.den

.whic

.slav

.are.to.be.incl

uded

.or.excl

uded

.in.the.cycl

user.dat

.com

munication.

Data

.comm

unication

.betw

een

.the.DPM1.and.the.slav

.is.divi

ded

.into.thre

.phas

es:

.para

meteriza-

tion,

.con

guration,

.and.data.tran

sfer.

.Befo

.the.mast

.incl

udes

.a.DP.slav

.in.the.data.tran

sfer

.phas

a.chec

.is.run.duri

.the.para

meterization

.and.con

guration

.phas

.to.ensu

.that.the.con

gured

.set-

oint

.con

guration

.matc

hes

.the.actu

.devi

.con

guration.

.Duri

.this.chec

.the.devi

.type

.form

at,

and.leng

.info

rmation

.and.the.numbe

.of.inpu

.and.outp

uts

.must.also.corr

espond.

. is.prov

ides

.the.

user.with.reli

able

.prot

ection

.agai

nst

.para

meterization

.erro

rs.

.In.addi

tion

.to.user.data.tran

sfer,

.whic

.is.

autom

atically

.exec

uted

.by.the.DPM1

.the.user.can.also.requ

est

.that.new.para

meterization

.data.are.sent.

to.the.sla

ves.

For

.safe

.reas

ons,

.it.is.nece

ssary

.to.ensu

.that.DP.has.eec

tive

.prot

ective

.func

tions

.agai

nst

.inco

rect

.para

meterization

.or.fail

ure

.of.tran

smission

.equi

pment.

.For.this.purp

ose,

.the.DP.mast

.and.the.

slav

.are.tte

.with.moni

toring

.mech

anisms

.in.the.form.of.time.moni

tors.

. e.moni

toring

.inte

rval

.is.

den

.dur

ing

.con

guration.

.DPM1.uses.a.Data

_Control_Timer

.to.moni

tor

.the.data.comm

unication

.of.the.slav

es.

.A.sepa

rate

.time

.is.used.for.each.slav

. e.time.moni

tor

.is.trip

ped

.if.no.corr

ect

.user.data.tran

sfer

.is.exe-

uted

.with

.the.moni

toring

.inte

rval.

.In.this.case

.the.user.is.noti

ed.

.If.the.autom

atic

.erro

.hand

ling

(Auto_Clear.=.True).is.enabled,.the.DPM1.exits.the.operate.state,.switches.the.outputs.of.the.assigned.

slav

.to.the.fai

l-safe

.sta

te,

.and.shi

s

.to.the.cle

.mod

.slav

.uses.the.watc

hdog

.cont

rol

.to.dete

.erro

.of.the.mast

.or.of.the.tran

smission.

.If.no.data.

comm

unication

.with.the.mast

.occu

.with

.the.watc

hdog

.cont

rol

.inte

rval,

.the.slav

.autom

atically

swit

ches

.its.out

puts

.to.the.fai

l-safe

.sta

te.

.addi

tion,

.acce

.prot

ection

.is.requ

ired

.for.the.inpu

.and.outp

uts

.of.the.slav

.oper

ating

.in.mult

master

.syst

ems.

. is.ensu

res

.that.only.the.auth

orized

.mast

.has.dire

.acce

ss.

.For.all.othe

.mast

ers,

.the.

slav

.pro

vide

.an.ima

.of.the

.inp

uts

.and.tha

.can.be.rea

.wit

hout

.acc

ess

.rig

hts.