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

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42-1

42.1 Introduction and Overview

 e.KNX.standard.describes.an.extensive.open.system.concept.for.distributed.home.and.building.auto-

mation

.and.cont

rol.

.KNX.cove

.the.full.scop

.of.rela

ted

.appl

ications,

.incl

uding

.ligh

ting,

.shad

ing,

.shut

ters

.and.blin

ds,

.heat

ing,

.cool

ing,

.vent

ilation,

.and.air.cond

itioning

.(HVA

C),

.and.remo

.mete

.read

ing.

All.rele

vant

.comm

unication

.medi

.are.supp

orted.

. e.KNX.spec

ication

.resu

lts

.from.a.form

.merg

of.thre

.tech

nologies

.dedi

cated

.to.this.area

.Euro

pean

.Inst

allation

.Bus.(EIB

.Bati

bus,

.and.Euro

pean

Home.Sys

tem

.(EH

S).

Signicant

.part

.of.the.KNX.speci

cation

.are.publ

ished

.as.Euro

pean

.stan

dards,

.main

.the.EN.50090.

fami

.but.also.EN.1332

1-1:2006

.and.EN.1332

1-2:2006.

.KNX.techn

ology

.is.also.cove

red

.by.ISO/

IEC

.14543

3-x

.(200

6/2007),

.whic

.has.been.publ

ished

.as.GB/Z.2096

5-2007

.by.the.Stan

dardization

.Admi

nistration

of.Chin

.as.well

.KNX.Asso

ciation

.is.a.for-

prot

.orga

nization

.gove

rned

.by.Belg

ian

.law..Its.membe

.are.most

manu

facturers

.and.deve

lopers

.of.home.and.buil

ding

.elec

tronic

.devi

ces,

.buil

ding

.serv

ices

.equi

pment,

and.rela

ted

.sow

are.

. ey.can.free

.make.use.of.pate

nts

.held.by.fell

.KNX.membe

.in.cert

ied

.KNX.

prod

ucts

.if.this.is.nece

ssary

.to.make.them.KNX.comp

atible.

. e.main.task.of.the.KNX.Asso

ciation

.is.

to.main

tain

.the.syst

.mast

.spec

ication

.freq

uently

.refe

rred

.to.as.the.“KNX.Hand

book.”

.More

over,

the.asso

ciation

.is.resp

onsible

.for.the.deve

lopment

.and.main

tenance

.of.a.manu

facturer-independent

PC-ba

sed

.comm

issioning

.tool,.trad

emark

.lice

nsing

.(bou

.to.conf

ormance

.test

s),

.and.the.cert

ication

of.trai

ning

.cent

ers

.and.test

ing

.labo

ratories.

.Also

.the.asso

ciation

.main

tains

.part

nership

.prog

rams

.for.

nati

onal

.ass

ociations,

.use

.clu

bs,

.and.sci

entic

.par

tners.

KNX

.is.more.than.just.a.simpl

.netw

ork

.proto

col

.spec

ication.

.Besid

.mere

.den

ing

.how.data.

is.tran

sferred,

.the.stan

dard

.incl

udes

.rule

.and.den

itions

.of.how.a.KNX.syst

.is.mana

ged

.and.how.

devi

ces

.imp

lemented

.by.di

erent

.ven

dors

.hav

.to.beh

ave

.to.ach

ieve

.int

erworking.

KNX

42.1. Introduction.and.Overview...........................................................42-1

42.2

. Medi

um-Independent

.Lay

ers........................................................42-2

42.3

. Medi

um-Dependent

.Lay

ers...........................................................42-5

42.4

. Runt

ime

.Int

erworking....................................................................42-6

42.5

. Devi

ces............................................................................................42-11

42.6

. Con

guration.................................................................................42-12

42.7

. Conc

lusion

.and.Out

look..............................................................42-12

Abbreviations.............................................................................................42-13

References

...................................................................................................42-13

Wolfgang Kastner

Vienna University

of Tec

hnology

Fritz Praus

Vienna University

of Tec

hnology

Georg

Neugschwandtner

Vienna University

of Tec

hnology

Wolfgang Granzer

Vienna University

of Tec

hnology

42-2 Industrial Communication Systems

Certainly,.the.user applications.that.implement.the.desired.automation.and.control.functionality.are.

cent

ral

.comp

onents

.with

.a.KNX.syst

em.

.Howe

ver,

.thei

.inte

rnal

.stru

cture

.and.impl

ementation

.is.up.to.

the.devi

.manu

facturer

.and.thus.not.den

.by.the.KNX.stan

dard.

. e.comm

unication system,

.on.the.

othe

.hand

.whic

.speci

es

.the.servi

ces

.that.are.used.by.the.user.appl

ications

.to.comm

unicate

.with.each.

othe

.is.part.of.the.KNX.speci

cation.

. e.KNX.prot

ocol

.stac

.is.based.on.the.ISO/

OSI

.refe

rence

.mode

Sinc

.die

rent

.comm

unication

.medi

.are.supp

orted,

.the. proto

col

. stac

.is. divi

ded

.into.a.medi

um-

dependent

.and.a.mediu

m-independent

.part

.Whil

.the.form

.cons

ists

.of.the.phys

ical

.laye

.and.the.lowe

leve

.of.the.data.link.laye

.(DL)

.the.latt

.incl

udes

.the.uppe

.leve

.of.the.DL.that.is.comm

.for.all.media

a.lean.netw

ork

.laye

.(NL).and.tran

sport

.laye

.(TL).as.well.as.the.appl

ication

.laye

.(AL)

. e.sessi

.and.

prese

ntation

.laye

.are.le.empt

.In.addi

tion

.to.data.exch

ange

.over.the.netw

ork,

.the.KNX.prot

ocol

.speci

cation

.also.cove

.loca

.poin

t-to-point

.conn

ections

.to.KNX.devi

ces,

.for.exam

ple,

.via.EIA-

232

.or.USB.

.inte

rworking and application model

.spec

ies

.how.data.are.repr

esented

.in.KNX.and.how.they.are.

acce

ssible

.via.the.netw

ork.

.Data

points,

.asso

ciated

.with.func

tional blocks

.(FBs

.are.a.cent

ral

.conc

ept

.in.

this.mode

.A.KNX.data

point

.may.be.rela

ted

.to.a.sens

.valu

e/actuator

.stat

.(e.g

.inpu

.and.outp

ut)

.or.it.

may.be.a.para

meter

.that.cont

rols

.the.beha

vior

.of.the.user.appl

ication.

. e.nece

ssary

.asso

ciation

.betw

een

data

points

.is.esta

blished

.via.bind

ings.

.KNX.also.spec

ies

.the.appl

ication interface

.that.is.pres

ented

.to.

user.appl

ications

.for.inte

racting

.with.remo

.data

points.

. e.inte

rworking

.and.appl

ication

.mode

.as.

well.as.the.comm

unication

.syst

.need.sche

mes

.for.con

guration and maintenance.

. ere

fore,

.KNX.

also.spec

ies

.rela

ted

.reso

urces

.and.mana

gement

.proc

edures

.(toge

ther

.with.the.func

tionality

.of.the.

server.entities.within.the.devices.that.handle.them).. is.includes,.for.example,.services.for.setting.up.

the.user.appl

ications,

.for.con

guring

.the.nece

ssary

.bind

ings,

.and.for.init

ializing

.the.comm

unication

syst

.of.a.devi

.(e.g

.addr

ess

.assig

nment).

.To.achi

eve

.this

.die

rent

.con

guration

.mode

.are.den

ed.

Finally,

.KNX.also.spec

ies

.vari

ous

.devi

.mode

.with.die

rent

.feat

ures,

.main

.rega

rding

.supp

orted

con

guration

.proc

edures.

.Pro

les

.den

.whic

.part

.of.the.KNX.spec

ication

.have.to.be.impl

emented

and.ensu

.inte

rworking

.of.devi

ces

.with.the.same.pro

.that.are.prov

ided

.by.die

rent

.manu

facturers.

 e.conf

ormance

.test

.den

.in.the.KNX.spec

ication,

.whic

.are.the.basis.for.KNX.comp

liance

.cert

cation,

.are.als

.bas

.on.the

.pro

les.

42.2 Medium-Independent Layers

 e.medium-independent.part.of.the.KNX.network.protocol.includes.the.upper.level.of.the.DL,.the.NL,.

TL,.and.the.AL.. e.DL.den

.servi

ces

.to.send.and.recei

.fram

.over.the.netw

ork.

.Ackn

owledgment

.is.

avail

able

.as.an.opti

.for.some.netw

ork

.media

. e.two.most.impo

rtant

.servi

ces

.den

.are.L_Da

.for.

peer

-to-peer

.data.fram

.tran

sfer

.and.L_Po

ll_Data

.for.a.mast

.coll

ecting

.data.from.slav

.in.a.so-ca

lled

poll

ing

.grou

.Furt

hermore,

.the.DL.den

.a.gene

ric

.addr

essing

.schem

.that.is.comm

.to.all.avail

able

netw

ork

.media

. is.addr

essing

.schem

.dist

inguishes

.betw

een

.four.die

rent

.kind

.of.addr

esses.

.Firs

each.node.has.a.so-ca

lled

.indi

vidual

.addr

ess.

. e.assi

gnment

.and.stru

cture

.of.the.indi

vidual

.addr

ess

.are.

based.on.the.loca

tion

.of.the.devi

.with

.the.thre

e-level

.topo

logy

.that.is.used.in.KNX..In.this.topo

logy,

the.netw

ork

.segme

nts

.at.the.lowe

.leve

.are.call

.line

.Depe

nding

.on.the.netw

ork

.mediu

.die

rent

devi

ces

.can.be.used.to.over

come

.phys

ical

.rang

.rest

rictions

.with

.a.line..On.the.twis

ted-pair

.mediu

brid

ges

.(or.repe

aters,

.a.trad

itional

.KNX.term.that.does.not.rela

.to.thei

.func

tion

.with.resp

ect

.to.the.OSI.

laye

rs)

.can.be.used.to.exte

.the.phys

ical

.leng

.of.a.line..A.line.can.cont

ain

.up.to.256.devi

ces.

.Up.to.16.

line

.can.be.inte

rconnected

.by.main

lines

.to.form.an.area..Rout

ers

.link

ing

.the.line

.to.the.main.line.are.

refe

rred

.to.as.line

couplers

.(LC)

.Agai

.up.to.15.main.line

.can.be.inte

rconnected

.by.a.comm

.back

bone

line

.usin

.rout

ers

.call

.back

bone couplers

.(BC)

. e.enti

.addr

ess

.spac

.is.refe

rred

.to.as.a.domai

. e.

resu

lting

.topo

logy

.is.show

.in.Figu

.42.1.(bri

dges

.are.labe

led

.“B”)

.addr

ess

.mult

iple

.node

.at.the.same.time

.they.can.be.arra

nged

.into.so-ca

lled

.comm

unication

.grou

ps.

Each.grou

.has.a.dedic

ated

.grou

p address

.that.is.two.octe

.long

.Grou

.addr

esses

.are.glob

ally

.den

.for.

the.whol

.doma

in,

.that.is,.they.are.inde

pendent

.of.the.phys

ical

.loca

tion

.of.the.grou

.memb

ers.

.Devi

ces

may.be.part.of.more.than.one.grou

KNX 42-3

In.addition.to.individual.and.group.addresses,.KNX.also.denes.the.use.of.polling addresses.allow-

ing

.a.device.to.request.status.data.from.up.to.15.other.nodes.with.minimal.protocol.overhead.. is.

communication.scheme.is.useful.for.high-frequency.node.liveness.checking.and.rests.upon.the.service.

L_Poll_Data..It.is.limited.to.a.single.physical.segment..Finally,.to.avoid.interference.between.dif-

ferent

.KNX.installations.on.open.media,.KNX.supports.the.use.of.domain addresses.

.network layer.(NL).uses.the.services.provided.by.the.DL.and.oers.four.dierent.NL.services:.

a. unicast. service. (N_Data_Individual),. a. multicast. service. (N_Data_Group),. a. domain-wide.

broadcast.service.(broadcast.within.a.single.domain;.N_Data_Broadcast),.and.a.system.broadcast.

service.(broadcast.across.domain.borders;.N_Data_SystemBroadcast)..For.all.four.services,.the.

individual.address.of.the.sender.is.used.as.the.source.address.. e.destination.address.type.depends.on.

the.used.service:.for.unicast.communication,.the.individual.address.of.the.receiver.is.used,.while.for.

multicast.communication,.the.group.address.of.the.destination.group.is.used.. e.broadcast.services.are.

implemented.by.using.a.DL.group.address.of.“0.”.Additionally,.the.NL.introduces.a.hop count,.which.is.

decremented.and.examined.by.routers.and.repeaters.to.perform.ltering.based.on.the.amount.of.elapsed.

hops.of.a.packet.

.TL.uses.the.NL.services.and.enriches.them.by.providing.a.connection-oriented.unicast.service.

(T_Data_Connected)..Using.this.service,.a.device.is.able.to.establish.a.reliable.unicast.connection.

to.another.device.. e.state.machine.used.implements.an.acknowledgment.mechanism.where.data.

packets.are.retransmitted.in.case.of.negative.or.absent.acknowledgments.. e.other.NL.services.are.

transparently. passed. through. (T_Data_Individual,. T_Data_Group,. T_Data_Broadcast,.

and.T_Data_SystemBroadcast).

The

.AL.on.top.of.the.protocol.stack.supports.a.multitude.of.AL.services..Generally,.these.ser-

vices

.can.be.divided.into.two.different.service.classes..The.first.one.is.dedicated.to.exchanging.

process.data.(process data communication)..Beside.other.rarely.used.opportunities.to.exchange.

process.data.in.KNX.(e.g.,.using.the.polling.mechanism),.the.most.important.ones.are.the.group

communication

. services. (A_GroupValue_Read. and. A_GroupValue_Write).. Since. they.

are.based.on.T_Data_Group,.they.are.multicast.services..The.second.class.of.services.is.used.

for.configuration.and.maintenance.tasks.(management communication)..It.includes.services.for.

uploading.user.applications,.assigning.individual.and.group.addresses.and.accessing.diagnostic.

information.

KNX

.denes.dierent.frame.formats.depending.on.the.communication.medium.and.service.. e.

most.commonly.encountered.format.by.far.is.the.twisted-pair.standard data frame.L_Data,.shown.at.

the.top.of.Figure.42.2.

.frame.starts.with.the.control.octet.. is.octet.indicates.the.frame.format.(Frame.Type).and.

contains.the.priority.eld..It.also.holds.a.repeat.ag.that.is.set.for.retransmitted.frames.. e.following.

Backbone line

Domain A

Line

Main line

Line Line

Area

Domain B

FIGURE 42.1 Topology.

42-4 Industrial Communication Systems

two.octets.specify.the.source.address..Regardless.of.the.used.communication.service,.this.is.always.

the.individual.address.of.the.sending.device.. e.succeeding.two.octets.identify.the.destination.of.

the.message.. e.address.type.(AT).bit.indicates.whether.the.destination.is.an.individual.address.or.

a.group.address..Together.with.the.hop.count.used.by.the.NL.and.the.frame.length,.the.AT.bit.makes.

up.the.last.octet.before.the.NL.payload.. e.value.of.the.Length.eld.is.the.number.of.NL.payload.

octets.minus.one.. e.frame.ends.with.a.check.octet.(FCS,.frame.checking.sequence),.which.holds.the.

vertical.odd.parity.of.all.preceding.octets.(each.Bit.is.calculated.as.the.logical.XOR.over.all.Bits.of.the.

same.signicance,.then.inverted).

.format.of.the.TL.protocol.data.unit.(TPDU),.that.is,.the.NL.payload,.is.shown.at.the.bottom.of.

Figure.42.2..On.KNX,.it.is.the.lowest.layer.PDU.whose.format.is.independent.of.the.communication.

medium.. e.width.and.alignment.of.the.AL.protocol.control.information.and.user.data.dier.depend-

ing

.on.the.TL.and.AL.service.type.as.well.as.the.size.of.the.AL.payload.

.standard.data.frame.supports.TPDUs.with.a.maximum.length.of.16.octets.. is.corresponds.to.

a.maximum.AL.payload.of.14.octets..For.the.transmission.of.longer.TPDUs,.the.extended data frame.

format.has.been.dened..It.is.shown.in.the.middle.of.Figure.42.2..Extended.frames.have.an.additional.

control.eld.(Extended.Control).as.their.second.octet..Besides.the.AT.Bit.and.the.hop.count,.this.octet.

contains.a.4.bit.eld.that.holds.additional.format.information.(Extended.Frame.Format).. e.length.

eld.is.expanded.from.4.to.8.bit.

Standard

.and.extended.data.frames.are.usually.followed.by.a.layer.2.acknowledgment.frame.sent.by.

the.receiver,.which.is.1.octet.long..If.group.addressing.is.used.on.the.twisted-pair.medium,.all.receiv-

ers

.send.this.frame.at.the.same.time;.negative.acknowledgments.will.cancel.out.positive.ones.. e.

L_Poll_Data.frame.format.(which.is.rarely.used).is.roughly.similar.to.L_Data,.with.the.master.

transmitting.a.request.consisting.of.the.control.and.address.part.followed.by.a.check.octet.and.the.slaves.

responding.with.one.octet.of.user.data.each.

.the.powerline.medium,.the.formats.of.standard.and.extended.data.frames.are.identical.to.those.

dened.for.twisted-pair.segments..However,.a.preamble.and.receiver.training.sequence.are.added.in.

Control

Octet 0 Octet 1 Octet 2 Octet 3 Octet 4 Octet 5 Octet 6

Source address Destination address

Address type

Length

Hop count

Control

Octet 0

Octet 1

Octet 2 Octet 3

Octet 4

Octet 5

Source address

Destination address

Octet 6

Address type

Length

Octet 7

Frame type

Ext. control

Octet 22 (max)

Check octet

...

Length

Hop count

Extended

frame

format

FCS

Sender:

Receiver(s):

...

control field

user data

control

field

TPDU

User data (payload)

Check octet

...

Length

FCSTPDU

User data (payload)

Repeated

Priority

Repeated

Priority

Sender:

Receiver(s):

TP1/PL110 standard data frame

TP1/PL110 extended data frame

TPDU

Individual

address

Individual

address

Individul

group

broadcast

address

Individual

group

broadcast

address

FIGURE 42.2 Frame.formats.

KNX 42-5

front,.and.the.domain.address.follows.as.a.postamble..Acknowledgment.frames.can.only.be.sent.by.

a.singl

.grou

.membe

. e.total.leng

.of.exte

nded

.fram

.(whi

.are.prac

tically

.neve

.used.on.this.

medi

um)

.is.lim

ited

.to.73.oct

ets.

.KNX.radi

.freq

uency

.(RF).fram

.form

.has.supp

orted

.TPDU

.long

.than.16.octe

.from.its.

ince

ption.

. ere

fore,

.the.die

rence

.betw

een

.stan

dard

.and.exte

nded

.data.fram

.does.not.exis

.on.this.

medi

um,

.and.a.slig

htly

.die

rent

.form

.is.used

. e.cEMI.fram

.form

.that.is.used.for.tunn

eling

.KNX.

data.ove

.IP.net

works

.is.simi

lar

.to.the.ext

ended

.dat

.fra

.for

mat

.as.des

cribed.

.addi

tion

.to.netw

ork

.proto

col

.mess

ages,

.the.KNX.stan

dard

.den

.the.use.of.so-c

alled

.exte

rnal

mess

ages

.whic

.are.spec

ied

.in.the.exte

rnal message interface

.(EMI

.EMI.spec

ies

.a.stan

dard

.proto

col

for.acce

ssing

.serv

ices

.of.the.KNX.netw

ork

.stac

.and.mana

gement

.serv

.enti

ties.

.Its.mess

ages

.can.be.

sent.via.vari

ous

.lowe

.laye

.proto

cols,

.whic

.are.also.part.of.the.KNX.spec

ication.

.EMI.is.main

.used.

for.loca

.poin

t-to-point

.conn

ections

.wher

.exte

rnal

.user.appl

ications

.comm

unicate

.with.a.conn

ected

bus.atta

chment

.unit.(BAU

.A.typi

cal

.exam

ple

.woul

.be.a.mana

gement

.clie

.like.a.work

station

.with.

a.USB.or.EIA-

232

.conn

ection

.to.a.devi

.that.prov

ides

.a.conn

ection

.to.the.KNX.bus.medi

um.

.Vari

ous

EMI.versi

ons

.that.die

.in.the.avai

lable

.serv

ice

.type

.and.in.the.used.enco

dings

.exis

.EMI1

.EMI2

.and.

cEMI.(com

mon

.EMI)

.In.cont

rast

.to.othe

.EMI.versi

ons,

.cEMI.is.also.used.for.KNXn

et/IP

.and.thus.the.

only.ver

sion

.to.be.use

.out

side

.the.con

text

.of.loc

.poi

nt-to-point

.con

nections.

42.3 Medium-Dependent Layers

 e.current.release.2.0.of.the.KNX.Handbook.species.three.dierent.physical.layers.for.communica-

tion.

.Comm

unication

.over.IP.netw

orks

.as.a.rst.clas

.medi

.is.incl

uded

.as.a.dra.spec

ication.

. e.

resu

lting

.four.optio

.are.desc

ribed

.in.the.foll

owing.

.All.medi

.can.be.depl

oyed

.and.combi

ned

.using.

rout

ers

.acc

ording

.to.an.int

egrator’s

.nee

Twisted

.Pair.1.(TP1

)

.is.the.olde

.and.stil

.most.popu

lar

.medi

.for.KNX..It.was.take

.from.EIB..

Asi

ngle-wire

.pair.(e.g.

.½.YCYM.2.×.2.×.0.8).is.used.for.both.data.and.powe

.tran

smission.

.A.TP1.segme

can.accom

modate

.up.to.256.devi

ces

.in.free.topo

logy.

.It.may.exte

.up.to.an.accum

ulated

.cabl

.leng

.of.

1000.m.and.must.cont

ain

.at.leas

.one.bus.powe

.supp

.unit.to.prov

ide

.the.link.powe

.of.abou

.30.V.DC..

 e.cont

ention

.prot

ocol

.bein

.used.is.carr

ier-sense

.mult

iple

.acces

.(CSM

.with.coll

ision

.avoi

dance

.by.

bit-

wise

.arbi

tration.

. e.domi

nant

.logi

cal

.0.is.enco

ded

.as.a.nega

tive

.volt

age

.impr

inted

.on.the.DC.supp

volt

age,

.wher

eas

.a.logi

cal

.1.corr

esponds

.to.the.idle.stat

.of.the.mediu

.Data.are.tran

sferred

.char

acter

orie

nted

.via.half

-duplex

.bidi

rectional

.comm

unication

.at.a.tran

smission

.rate.of.9600.bit/

.Char

acters

.con-

ain

.eigh

.data.bits

.even.pari

ty,

.and.one.stop.bit.(8e1).and.are.separ

ated

.by.a.mini

mum

.idle.peri

.of.2.bit.

time

.Data.fram

.of.varia

ble

.leng

.may.be.tran

smitted

.aer.a.line.idle.time.of.50.bit.time

.An.immed

ate

.ackn

owledgment

.fram

.may.foll

.aer.a.gap.of.15.bit.time

.TP1.is.the.only.mediu

.to.supp

ort

.poll

ing

.grou

ps.

.Doma

.addr

esses

.are.not.used.on.TP1.. e.Bati

bus

.twis

ted-pair

.mediu

.was.also.part.of.the.

KNX.stan

dard

.unde

.the.name.of.TP0,.but.was.remo

ved

.from.rele

ase

.2.0.

.desi

.of.the.KNX.RF.phys

ical

.laye

.and.DL.is.comp

atible

.with.Wire

less

.M-Bu

.a.Euro

pean

.mete

ing

.prot

ocol

.stan

dard,

.allo

wing

.tigh

.inte

gration.

.KNX.RF.oper

ates

.at.a.cent

.freq

uency

.of.868.

.MHz,.

which.is.located.within.the.band.reserved.for.SRDs.(Short.Range.Devices)..In.the.868.0–868.6.MHz.sub-

and,

.a.duty.cycl

.limi

tation

.to.less.than.1%.appl

ies.

.Data.are.tran

smitted

.at.a.data.rate.of.16.4.kbps.usin

freq

uency

.shi.keyi

.(FSK

)

.modu

lation

.and.Manc

hester

.enco

ding.

. e.KNX.RF.fram

.form

.is.based.

on.FT3.as.speci

ed

.in.IEC.6087

0-5.

.It.prov

ides

.the.capa

bilities

.of.the.exte

nded

.fram

.form

.as.descr

ibed

.in.

the.prev

ious

.sectio

.and.cont

ains

.addi

tional

.mediu

m-related

.info

rmation

.such.as.sign

.qual

ity

.or.batt

ery

stat

.Retr

ansmitters

.can.be.used.to.exte

.the.rang

.of.the.netw

ork.

.To.allo

.detec

tion

.and.elim

ination

of.dupl

icate

.fram

.that.can.occur.in.part

icular

.when.such.retr

ansmitters

.are.empl

oyed,

.the.TP1/

PL110

repe

.ag.is.repl

aced

.by.a.3.bit.link.laye

.fram

.numb

.(LFN

.KNX.RF.allo

.the.use.of.unid

irectional,

tran

smit-only

.devi

ces.

.Such.devi

ces

.are.chea

per

.to.prod

uce

.and.have.a.grea

tly

.exte

nded

.batt

ery

.life

time

due.to.reduc

.powe

.cons

umption,

.but.accom

modating

.them.requ

ires

.an.adap

ted

.addr

essing

.schem

 ere

fore,

.an.exte

nded

.addr

ess

.form

.comp

osed

.of.the.uniq

.seria

.numb

.of.the.devi

.conc

atenated

42-6 Industrial Communication Systems

with.either.the.KNX.individual.or.group.address.(correspondingly.referred.to.as.an.extended.individual.or.

an.exte

nded

.grou

.addr

ess)

.was.intr

oduced.

.Tran

smit-only

.devi

ces

.also.use.prea

ssigned

.grou

.addr

esses.

To.allo

.an.adeq

uate

.batt

ery

.life

time

.for.batt

ery

.driv

.bidi

rectional

.devi

ces

.as.well

.a.sync

hronous

.oper

tion

.mode.was.den

ed.

.In.this.mode

.devi

ces

.need.only.have.thei

.recei

vers

.enab

led

.duri

.cert

ain

.time.

wind

ows

.whic

.are.know

.by.all.node

.Also,.the.speci

cation

.incl

udes

.a.dra.for.exte

nding

.KNX.RF.to.

mult

iple

.chan

nels,

.die

rent

.sign

alling

.speed

.addi

tional

.freq

uency

.band

.and.prov

iding

.addi

tional

.fea-

ures

.for.powe

r-saving

.asyn

chronous

.recei

ver

.oper

ation.

KNX

.Powe

rline

.110.(PL1

10)

.uses.the.230.V/50.Hz.elec

trical

.powe

.supp

.netw

ork

.for.data.and.powe

tran

smission

.(in.comp

liance

.with.EN.5006

5-1).

.Half

-duplex

.bidi

rectional

.comm

unication

.is.supp

orted.

KNX.data.are.modu

lated

.using.spre

.freq

uency

.shi.keyi

.(SFS

.with.a.cent

.freq

uency

.of.110.kHz..

 e.signa

.is.injec

ted

.betw

een

.phas

.and.neut

ral

.and.is.supe

rimposed

.to.the.sinus

oidal

.osci

llation

.of.the.

main

.No.rest

rictions

.are.made.on.the.physi

cal

.topol

ogy

.of.the.inst

allation.

.Repe

aters

.can.be.inst

alled

in.thre

e-phase

.netw

orks

.if.passi

.phas

.coup

ling

.is.not.suc

ient.

.Owin

.to.the.rela

tively

.poor.tran

mission

.prop

erties

.of.the.main

.netw

ork,

.the.data.tran

smission

.rate.is.limi

ted

.to.1200.bit/

.Each.data.

link.octe

.is.code

.into.a.12.bit.char

acter

.(8.bit.data

.4.bit.erro

.corr

ection).

.Medi

.acce

.cont

rol

.is.

base

.on.a.slot

ted

.tech

nique

.to.redu

.the.prob

ability

.of.coll

isions:

.Aer.the.mini

mum

.silen

.peri

betw

een

.two.fram

.has.elap

sed,

.two.time.slot

.are.rese

rved

.for.pend

ing

.high

-priority

.tran

smissions,

foll

owed

.by.seve

.more.from.whic

.node

.with.pend

ing

.stan

dard-priority

.tran

smissions

.choo

.one.at.

rand

.as.thei

.star

ting

.time

.PL11

.was.take

.over.from.EIB.. e.EHS.powe

rline

.medi

.was.also.

part.of.the.KNX.standard.under.the.name.of.PL132,.but.was.removed.from.release.2.0.

Regarding

. the. tran

sportation

. of. KNX. tele

grams

. on. top. of. IP. netw

orks,

. KNXn

et/IP

. (for

merly

know

.as.EIBn

et/IP)

.curr

ently

.focu

ses

.on.scen

arios

.for.enha

ncing

.cent

ral

.and/

.remo

.mana

gement.

KNXn

et/IP

.spec

ies

.seve

ral

.serv

ice

.proto

cols.

. e.KNXn

et/IP

.Core

Services

.den

.the.pack

.stru

cture

and.meth

ods

.requ

ired

.for.disc

overy

.and.self

-description

.of.a.KNXn

et/IP

.serv

.and.for.sett

ing

.up.and.

main

taining

.a.com

munication

.cha

nnel

.bet

ween

.the.cli

ent

.and.the.ser

ver.

KNXnet/IP

.tunn

eling

.desc

ribes

.the.poin

t-to-point

.exch

ange

.of.KNX.data.over.the.IP.netw

ork.

.Its.main.

purp

ose

.is.to.repl

ace

.USB.or.EIA-

232

.conne

ctions

.betw

een

.KNX.netw

ork

.inte

rfaces

.and.PC.work

stations

.or.

serv

ers

.(e.g

.for.con

guration

.and.diag

nostics

.of.devi

ces

.on.the.KNX.netw

ork

.or.visu

alization)

.by.tunne

ling

L_Da

.fram

es.

.Ackn

owledgments,

.sequ

ence

.coun

ters,

.and.a.hear

tbeat

.mech

anism

.are.used.to.ensu

.the.

robu

stness

.expe

cted

.in.comp

arison

.with.such.a.trad

itional

.conne

ction.

.KNXn

et/IP

.rout

ing

.is.a.poin

t-to-mul-

tipoint

.prot

ocol

.for.rout

ing

.mess

ages

.betw

een

.KNX.line

.over.a.high-

speed

.IP.back

bone.

.KNXn

et/IP

.rout

ers

send.UDP/

.mult

icast

.mess

ages

.to.othe

.KNXn

et/IP

.rout

ers

.on.the.same.IP.netw

ork,

.which.in.turn.lte

the.mess

ages

.acco

rding

.to.thei

.dest

ination

.addr

ess

.or.grou

.addr

ess

.and.even

tually

.pass.them.to.the.“nat

ive”

KNX.segm

ent.

.KNXn

et/IP

.rout

ers

.can.repl

ace

.trad

itional

.KNX.LCs.and.BCs..KNXn

et/IP

.devic

e manage-

ment

.allo

.con

guration

.and.diag

nosis

.of.KNXn

et/IP

.tunne

ling

.inte

rfaces

.or.rout

ing

.devi

ces

.via.the.IP.

netw

ork.

.Withi

.all.thes

.thre

.serv

ice

.prot

ocols,

.the.actu

.KNX.data.is.carr

ied

.withi

.cEMI.mess

ages.

While

.KNXn

et/IP

.is.desig

ned

.for.devi

ces

.with.one.IP.and.one.“tra

ditional”

.KNX.netw

ork

.inte

rface,

the.upco

ming

.KNX.IP.is.also.inte

nded

.for.end.devi

ces

.that.are.sole

.conn

ected

.to.the.IP.medi

um.

A.typi

cal

.band

width

.of.10–1

.Mbps.for.IP.over.Ether

net

.allo

.the.inte

gration

.of.devi

ces

.requ

iring

high

.data.rate

.(e.g

.tele

communication

.and.mult

imedia),

.whic

.is.a.signi

cant

.impr

ovement

.com-

ared

.to.the.9.6.kbps.of.TP1..Larg

ely

.base

.on.KNXn

et/IP

.rout

ing,

.KNX.IP.will.also.incl

ude

.mech

nisms

.to.coun

teract

.possi

ble

.prob

lems

.arisi

.from.this.thro

ughput

.die

rence.

.Both.con

guration

.and.

runt

ime

.int

erworking

.rem

ain

.unc

hanged

.fro

.oth

.KNX.med

ia.

42.4 runtime Interworking

In.KNX,.runtime interworking.refers.to.the.denitions.that.enable.devices.to.communicate.for.the.pur-

pose

.of.exch

anging

.proc

ess

.cont

rol

.data

. e.comm

unication

.endp

oints

.of.a.KNX.devi

.appl

ication

rele

vant

.for.this.purp

ose

.(suc

.as.the.illu

minance

.leve

.meas

ured

.by.a.ligh

.sens

.or.the.cont

rol

.inpu

of.a.load.swit

ch)

.are.call

.grou

p objects

.(GOs

. e.KNX.AL.prov

ides

.serv

ices

.to.prop

agate

.chan

ges

.to.

KNX 42-7

these.GOs.using.the.at-most-once.multicast.service.Data_Group.provided.by.the.KNX.TL..For.this.

purpose,.it.maintains.an.association table.between.AL.service.access.points.(SAPs),.that.is,.GO.identi-

ers,

.and.TL.SAPs.(which.correspond.one-to-one.to.DL.group.addresses).. us,.a.group.address.describes.

a.group.of.GOs.in.a.communication.relationship.with.each.other..Every.node.is.aware.which.groups.it.

belongs.to.and.treats.messages.accordingly.

Usually,

.data.sources.will.actively.publish.new.data.via.the.AL.GroupValue_Write.service..If.a.user.

application.changes,.the.value.of.a.GO.and.A_GroupValue_Write.req.is.invoked,.the.network.stack.

determines.the.group.address.this.information.is.to.be.sent.to.. e.user.application.is.not.aware.of.the.

group.addresses.associated.with.a.GO.(implicit.addressing)..In.receivers.that.recognize.this.group.address.

as.one.of.their.own,.the.AL.generates.an.A_GroupValue_Write.ind.for.the.AL.SAPs.bound.to.this.

group.address,.providing.the.user.data.from.the.GroupValue_Write.PDU.(protocol.data.unit).. e.

application.environment.(KNX.application interface layer).updates.the.GOs.accordingly.and.noties.the.

user.application.. is.mechanism.allows.passing.a.piece.of.information.to.an.arbitrary.number.of.recipi-

ents

.by.way.of.a.single.message..For.a.single.receiver.only,.it.is.shown.in.Figure.42.3..GroupValue_Write.

is.an.unconrmed.service..Message.delivery.is.not.guaranteed..If.exactly-once.semantics.are.required,.

conrmations.have.to.be.obtained.by.the.user.application.

.this.mode.of.communication,.senders.do.not.need.to.know.which.nodes.will.actually.be.receivers.

of.their.messages.. e.knowledge.concerning.which.nodes.participate.in.any.particular.communica-

tion

.relationship.is.distributed.over.all.nodes.in.the.system..In.KNX,.it.has.traditionally.even.been.

impossible.(or.at.least.infeasible).for.any.node.to.determine.which.other.nodes.will.accept.and.process.

messages.to.any.specic.group.address.. is.pattern.is.sometimes.referred.to.as.the.producer/consumer.

3. User application recognizes

change of state at input port

KNX network stack

GO 2

Group addr.

GO 1

GO 3

KNX

network

User application

KNX network stack

GO 2

Group obj. ID

GO 1

GO 2

Group addr.

2/8/1

5/1/6

GO 1

4. User application updates

Application environment

recognizes group object

update

User application

Network stack recognizes

destination address of

L_Data

frame as one of its own

Network stack determines which

group object is associated with this

group address

10.

11. User app. performs associated

action (activates output signal)

12.

13. Lamp lights up

Group obj. ID

Network stack sends L_Data

frame (with GroupValue_Write

PDU) to this address

Application environment

updates appropriate group

object with value received

and notifies user application

Network stack looks up

group address associated

with this group object

Wall switch is

pushed

Device receives

signal

Signal energizes

relay

GO 1

GO 2

GO 3

1/1/2

4/7/3

2/8/1

associated group object

FIGURE 42.3 GroupValue_Write—end-to-end.overview.

42-8 Industrial Communication Systems

principle..Note.that.there.is.no.implicit.synchronization,.however..No.central.instance.exists.at.runtime.

tha

.wo

uld

.ma

nage

.su

bscriptions.

. e.me

chanism

.is.en

tirely

.pe

er-to-peer.

.the.net

work

.sta

ck,

.the.gro

.add

ress

.is.an.ent

irely

.opa

que

.ide

ntier

.tha

.bea

.no.rel

ation

.to.eit

her

.the.

con

tent

.of.the.mes

sage

.or.the.rec

eivers’

.ind

ividual

.add

resses.

.Sti

ll,

.sin

.KNX.gro

ups

.are.high

.sta

tic,

.gro

add

resses

.can.be.con

sidered

.ide

ntiers

.for.a.par

ticular

.cla

.of.info

rmation

.tra

veling

.thr

ough

.the.net

work.

Rec

eivers

.pic

.up.the.mes

sages

.if.this.cla

.of.info

rmation

.is.rel

evant

.to.the

.Esp

ecially

.in.the.con

text

.of.

Cont

roller

.Are

.Net

work

.tec

hnology,

.this.mec

hanism

.has.bee

.cal

led

.sub

ject-based

.add

ressing.

.pra

ctice,

.int

egrators

.act

ually

.assi

.gro

.add

resses

.bas

.on.the.inf

ormation

.pro

vided

.or.the.

fun

ction

.to.be.ee

cted

.by.the.ass

ociated

.GOs

.For.thi

.pur

pose,

.gro

.add

resses

.are.div

ided

.into.eit

her

two.el

.(5.and.11.bit.wid

.or.thr

.el

.(5,.3,.and.8.bit

. is.div

ision

.is.use

.for.hie

rarchical

.gro

up-

ing

.(e.

g.,

.site

-wide

.fun

ctions/panic

.ala

rm).

.No.bin

ding

.sta

ndard

.int

erpretation

.of.the.gro

up-address

spa

.is.sp

ecied

.by.th

.KN

.st

andard,

.ho

wever.

Since

.no.oth

.tra

nsport

.mec

hanism

.tha

.mul

ticast

.is.spe

cied,

.dat

apoints

.(i.

e.,

.GOs

)

.can

not

.be.

add

ressed

.ind

ividually

.unl

ess

.app

ropriate

.pro

visions

.are.mad

.at.con

guration

.tim

.It.als

.mea

.tha

pro

tocol

.se

curity

.me

chanisms

.ar

.mo

.di

cult

.to.im

plement.

While

. GroupValue_Write. is. the. mai

nstay

. of. KNX. com

munication,

. a. con

rmed

. AL. ser

vice

for.que

rying

.the.val

.of.a.GO.is.pro

vided

.as.wel

.It.inv

olves

.the.PDU

.GroupValue_Read,.rep

resenting

.the.que

.(re

quest),

.and.GroupValue_Response,.car

rying

.the.ans

wer

.(re

sponse).

.Bot

Gro

upValue_Read

.and.GroupValue_Response.aga

.use.mul

ticast

.com

munication

.via.gro

addresses.exclusively.. is.means.that.multiple.responses—with.dierent.values—may.be.prompted.

by.a.sing

.GroupValue_Read.PDU

.It.is.the.sys

tem

.int

egrator’s

.res

ponsibility

.to.pre

select

.a.nod

at.con

guration

.tim

.for.gen

erating

.the.res

ponse

.tha

.wil

.pro

vide

.a.mea

ningful

.ans

wer.

.It.als

.mea

tha

.gro

.memb

ers

.tha

.hav

.not.iss

ued

.the.rea

.req

uest

.wil

.rec

eive

.the.res

ponse(s),

.too..Act

ually,

a.Gro

upValue_Response

.is.con

sidered

.equ

ivalent

.to.a.GroupValue_Write.to.the.sam

.gro

add

ress

.by.a.ma

jority

.of.(n

.le

gacy)

.st

ack

.im

plementations.

. rs

. sigh

. thi

. com

munication

. con

cept

. qui

. clo

sely

. res

embles

. sha

red

. var

iables

. (di

stributed

sha

red

.mem

ory).

.How

ever,

.the

.are.sign

icant

.di

erences

.for.the.gen

eral

.cas

.Whi

.onl

.a.sing

gro

.add

ress

.can.be.assi

gned

.to.a.GO.for.tra

nsmitting

.Gro

upValue_Write

.PDU

.and.sen

ding

Gro

upValue_Response

.PDU

.(i.

e.,

.act

ing

.as.a.dat

.sou

rce,

.pro

viding

.inf

ormation

.to.oth

.dev

ices),

GOs.can.be.con

gured

.to.acc

ept

.Gro

upValue_Write

.PDU

.and.sen

.Gro

upValue_Read

.PDU

(i.

e.,

.act.as.a.dat

.sink

.tak

ing

.act

ions

.acc

ording

.to.the.inf

ormation

.rec

eived)

.for.mul

tiple

.des

tination

gro

.add

resses.

. is.is.act

ually

.a.key.desi

.fea

ture

.of.KNX

.whi

.all

ows

.ele

gant

.imp

lementation

.of.

site

-wide

.fun

ctions.

.By.inc

luding

.all.lig

ht-switching

.act

uators

.in.the.hou

.in.a.com

mon

.gro

.(be

sides

the.ind

ividual

.gro

ups

.the

.for

.wit

.wal

.swi

tches

.in.the.ind

ividual

.roo

ms),

.a.mas

ter

.swi

tch

.by.the.doo

can.easi

.tur

.the

.all.o.whe

.the.own

.is.lea

ving

.the.hou

se.

.Obv

iously,

.how

ever,

.a.GO.can

not

.tak

two.val

ues

.at.the.sam

.tim

.a.rea

.req

uest

.on.the.site

-wide

.gro

.wou

.be.mea

ningless.

. us

.a.gro

add

ress

.do

.no

.co

rrespond

.to.a.sin

gle

.ne

twork-wide

.va

lue.

Further

. situ

ations

. exi

. whe

. app

lying

. a. rea

. req

uest

. to. a. gro

. add

ress

. is. equ

ally

. fut

ile:

Gro

upValue_Write

.PDU

.are.not.onl

.use

.to.rep

ort

.tha

.the.val

.of.a.dat

.poi

.has.cha

nged

.but.

als

.fo

.al

.ki

nds

.of.co

mmands

.(e

.g.,

.in

crease

.ou

tput

.le

vel

.by.25

.of.th

.fu

.sc

ale).

Usually,

.a.GO.wil

.eit

her

.be.a.dat

.sou

rce

.or.a.dat

.sink

. er

.is.no.use.app

lying

.rea

.req

uests

.to.

a.GO.tha

.is.desi

gned

.for.acc

epting

.com

mands,

.and.nei

ther

.is.the

.any.in.ext

ernally

.att

empting

.to.

cha

nge

.the.sta

.of.a.GO.tha

.hol

.a.rea

l-world

.sta

.suc

.as.a.sen

sor

.val

ue.

.How

ever,

.KNX.als

.all

ows

GOs.to.be.bot

.dat

.sou

rce

.and.sink.at.the.sam

.tim

.Pos

sible

.app

lications

.are.GOs.whi

.rep

resent

.the.

abs

olute

.val

.of.a.“so

”

.dat

apoint

.(e.

g.,

.a.set.poi

nt)

.or.GOs.con

trolling

.act

uators

.suc

.as.rel

ays

.tha

.are.

simp

.and.rob

ust

.eno

ugh

.tha

.the.del

ivery

.of.a.sta

te-change

.req

uest

.can.be.equ

ated

.wit

.its.exe

cution

(no.mal

function

.is.ass

umed).

.How

ever,

.the.KNX.spe

cication

.con

tains

.a.rec

ommendation

.aga

inst

.thi

in.th

.in

terest

.of.cl

arity

.an

.ma

nageability.

Usually,

.it.is. ens

ured

.by.cho

osing

.the.pro

per

.bin

dings

.tha

.acc

ess

.vio

lations

.suc

.as.an.att

empt

to.cha

nge

.a.sen

sor

.val

.do.not.hap

pen.

.In.add

ition,

.it.is.det

ermined

.for.eac

.GO.at.bin

ding

.tim

.if.

KNX 42-9

GroupValue_Write.PDUs.should.be.sent;.if.GroupValue_Write.PDUs.should.lead.to.the.value.

of.the.GO.bei

.upd

ated;

.if.Gro

upValue_Read

.PDU

.sho

uld

.be.ans

wered;

.and

.exc

ept

.for.leg

acy

sta

.imp

lementations,

.if.Gro

upValue_Response

.PDU

.sho

uld

.be.tre

ated

.as.Gro

upValue_Write

PDU

.wit

.the.sam

.des

tination

.add

ress.

.Dev

ice

.app

lications

.com

.wit

.sen

sible

.def

aults

.and.usu

ally

pro

vide

.sep

arate

.GOs.for.com

mand

.inp

.and.sta

tus

.out

put,

.but.the.na

.res

ponsibility

.for.set

ting

.up.

the.pr

oper

.co

mmunication

.re

lationships

.re

mains

.wi

.th

.in

staller.

Enabling

.rea

d-back

.of.a.GO.tha

.is.act

ually

.a.dat

.sink.wou

ld,

.in.the

ory,

.als

.all

.che

cking

.if.mes

sages

.req

uiring

.exa

ctly-once

.del

ivery

.sem

antics

.wer

.del

ivered

.suc

cessfully

.by.the.at-

most-once

.tra

ns-

port

.ser

vice.

.How

ever,

.one.wil

.rat

her

.bin

.to.a.sta

tus

.fee

dback

.GO.ins

tead

.in.suc

.a.cas

.as.thi

.all

ows

che

cking

.suc

cessful

.exe

cution

.ins

tead

.of.del

ivery

.onl

.Usu

ally,

.the

.are.rea

sons

.besi

des

.a.fai

led

.tra

ns-

mission

.tha

.may.cau

.a.des

tination

.to.ign

ore

.a.mes

sage

.(e.

g.,

.win

.ala

.may.blo

.sun

blind

.ope

ra-

tion

.eve

.if.the.com

mand

.to.mov

.was.rec

eived

.pro

perly).

.If.suc

.exc

eptions

.are.to.be.cau

ght

.pro

perly,

end

-to-end

.st

atus

.fe

edback

.is.ma

ndatory

.an

yway.

.PDU

.can.be.sen

.wit

.di

erent

.pri

orities

.(as.pro

vided

.by.the.DL)

. e.com

mon

.con

guration

tool.(ET

.all

ows

.cho

osing

.the.pri

ority

.lev

.on.a.per.GO.basi

.amo

.the.low

.thr

ee;

.the.KNX.spe

ci-

cation

.su

ggests

.on

.usi

.th

.lo

wer

.tw

While

.the.AL.Gro

upValue

.serv

ices

.dea

.wit

.tra

nsferring

.new.valu

.fro

.one.GO.to.ano

ther,

.user.

app

lications

.sti

.need.to.agr

.on.how.to.int

erpret

.the

.valu

es.

.In.the.KNX.run

time

.int

erworking

.mod

el,

app

lications

.are.spl

.in.FBs.to.be.imp

lemented

.on.ind

ividual

.KNX.net

worked

.dev

ices.

.App

lication models

describing.the.interplay.of.FBs.are.typically.specied.for.a.single.application.domain.or.a.domain.sub-

structure

.(e.g

.hot.wat

.hea

ting)

.but.can.(an

.do).inc

lude

.poi

nts

.of.con

tact

.wit

.oth

.app

lications

.fro

the.sam

.or.oth

.dom

ains.

.Not

.tha

.the.ter

.“pr

ole”

.ref

ers

.to.some

thing

.di

erent

.in.KNX

FBs

.cor

relate

.dev

ice

.beh

avior

.wit

.act

ivity

.reg

arding

.the

.net

work

.com

munication

.end

points.

.In.

KNX

.com

munication

.end

points

.of.FBs.are.ter

med

.dat

apoints,

.irr

espective

.of.whe

ther

.the

.are.mes

sage

sou

rces

.or.sink

.for.the.exc

hange

.of.pro

cess

.con

trol

.dat

.bet

ween

.dev

ices

.dur

ing

.nor

mal

.ope

ration

.(inp

and.out

put

.dat

apoints)

.or.par

ameters

.tha

.are.onl

.cha

nged

.in.the.con

guration

.pha

se.

.Tra

ditionally,

par

ameter

.dat

apoints

.are.acc

essed

.fol

lowing

.a.man

ufacturer

.pro

prietary

.mem

ory

.map

ped

.mod

el,

.but.

rec

ent

.FB.de

nitions

.inc

lude

.pro

visions

.for.usin

.a.mor

.ope

.obje

ct-oriented

.mod

.(int

erface objects

and.pro

perties).

.Inp

.and.out

put

.dat

apoints

.may.als

.be.re

ected

.as.int

erface

.obje

.pro

perties

.(an

acc

essed

.via.uni

cast

.TL.ser

vices)

.or.imp

lemented

.usin

.the.TP1.mas

ter/slave

.pol

ling

.mec

hanism.

.In.

pra

ctice,

.how

ever,

.the.onl

.com

munication

.mec

hanism

.tha

.is.rel

evant

.for.inp

ut/output

.dat

apoints

.is.

the.gr

oup-object

.mo

del

.as.de

scribed

.in.de

tail

.ab

ove.

Standard

.dat

a point types

.(DP

Ts)

.de

.the.dat

.typ

.(e.

g.,

.int

eger)

.and.bit

-level

.enc

oding

.(e.

g.,

.two

’s

com

plement)

.of.bot

.inp

ut/output

.and.par

ameter

.dat

apoints.

. e.uni

.of.mea

surement

.to.be.ass

ociated

wit

.a.dat

apoint

.val

.and.ran

.res

trictions

.are.als

.re

ected

.in.the.DPT

.A.wid

.var

iety

.of.DPT

.exi

sts,

cov

ering,

.amo

.oth

ers,

.Boo

lean

.val

ues,

.sign

.and.unsi

gned

.int

egers

.of.mul

tiple

.wid

ths,

.tim

.dat

and.oa

ting-point

.val

ues.

.DPT

.may.als

.con

sist

.of.mul

tiple

.el

.(“s

tructured”

.DPT

s).

. us

.dep

end-

ing

.on.the.con

text

.and.AL.ser

vice

.use

.to.tra

nsport

.it,.a.sing

.DPT.can.rep

resent

.the.pre

sent

.val

.of.a.

dat

apoint

.tog

ether

.wi

.as

sociated

.st

atus

.in

formation

.or.a.co

mmand

.wi

.mu

ltiple

.pa

rameters.

Traditionally,

.the.met

.inf

ormation

.con

tained

.in.FB.de

nitions

.or.DPT

.is.no.lon

ger

.visi

ble

.at.the.

lev

.of.net

work

.mes

sages

.exc

hanged

.dur

ing

.nor

mal

.ope

ration.

.Jus

.as.for.gro

.add

resses,

.a.pro

ject

spe

cic

.(ex

ternal)

.dat

abase

.con

taining

.the.sem

antic

.inf

ormation

.is.req

uired

.for.int

erpreting

.mon

itored

com

munication.

.Suc

.a.dat

abase

.als

.mus

.con

tain

.dev

ice

.con

guration

.inf

ormation,

.sinc

.con

trol

inf

ormation

.in.KNX.is.usu

ally

.red

uced

.to.tri

gger

.inf

ormation.

.Ins

tead

.of.“ch

ange

.bri

ghtness

.lev

.to.

100

.tak

ing

.10.s.for.the.tra

nsition

.fro

.the.cur

rent

.lev

el,”

.a.typ

ical

.mes

sage

.wil

.say.“le

vel

.100

%”

.or.

may

.ev

.on

.“o

n,”

.wi

.th

.pr

ecise

.in

terpretation

.go

verned

.by.th

.de

vice

.co

nguration.

.EIB.(wh

ich

.can. be.reg

arded

.as.the.mai

.pre

decessor

.sys

tem

.to.KNX

.har

dly

.any.beh

avioral

asp

ects

.wer

.sta

ndardized

.at.all

.wit

.con

trol

.of.act

uators

.for.lig

.dim

mers

.and.moto

rized

.bli

nds

.bei

not

able

.exc

eptions.

.Dev

ices

.int

eracted

.chi

ey

.by.exc

hanging

.Boo

lean

.val

ues.

. is.con

cept

.act

ually

.was.

ver

.clo

.to.pow

ering

.tra

ditional

.ele

ctric

.cir

cuits

.on.and.o,.wit

.the.act

ual

.out

come

.dep

ending

.on.the.

42-10 Industrial Communication Systems

devices.connected..Consequently,.there.was.only.very.basic.type.compatibility.checking.even.at.setup.

tim

.lim

ited

.to.val

.enc

odings.

. er

.wer

.no.pro

visions

.to.pro

hibit

.bin

ding

.the.out

put

.of.a.mot

ion

det

ector

.to.the.sla

.ang

.adj

ustment

.inp

.of.a.sun

blind

.act

uator.

.Stil

.toda

.wit

.KNX

.int

egrators

.can.

bin

.GOs.ind

ividually

.and.wit

.min

imal

.res

trictions

.(fre

e binding)—taking

.the.res

ponsibility

.for.the.

dev

ices

.to.wo

.tog

ether

.as.in

tended.

Only

.rec

ently,

.the.key.fun

ction

.blo

cks

.for.the.ele

ctrical

.tra

.(li

ghting

.and.shu

tters/blinds

.sen

sors

.and.

act

uators)

.hav

.bee

.tho

roughly

.rev

ised.

.Par

ameters

.wer

.sta

ndardized;

.sti

ll,

.pro

cess

.dat

.exc

hange

.rem

ains

not.onl

.bac

kward

.com

patible

.but.ess

entially

.unc

hanged.

.Bes

ides

.lig

hting

.and.bli

nds,

.typ

ical

.EIB.app

lica-

tions

.inc

luded

.sim

ple

.roo

.tem

perature

.con

trol

.and.bas

.ene

rgy

.man

agement.

.As.the.foc

.of.KNX.has.

exp

anded

.bey

ond

.the.ele

ctrical

.tra

de,

.the.amo

unt

.of.int

erworking

.spe

cications

.has.inc

reased

.con

siderably.

Today,

.fun

ction

.blo

cks

.for.the.HVA

.dom

ain

.out

number

.all.oth

ers.

. ei

.de

nitions

.are.so.far.the.

onl

.one

.to.inc

lude

.max

imum

.and.typ

ical

.mes

sage

.gener

ation

.rat

es,

.all

owing

.the.net

work

.loa

.gener

ated

.by.dev

ices

.imp

lementing

.them.to.be.est

imated

.a.pri

ori

.and.serv

.as.a.gui

deline

.for.net

work

.pla

nning.

Mappings

.for.the.CHA

.(CE

CED

.Hom

.App

liances

.Int

eroperating

.Net

work)

.whi

.goo

.pro

les

spe

cied

.in.EN.505

.hav

.als

.bee

.dev

eloped

.but.are.not.con

tained

.in.the.KNX.Han

dbook.

.Mos

rec

ently,

.met

ering

.has.bee

.add

ed.

. e.spe

cication

.inc

ludes

.par

.of.the.M-B

.RF.pro

tocol

.sta

.as.

wel

.as.fun

ction

.blo

cks

.for.rep

resenting

.the.met

ering

.dat

.obt

ained

.thi

.way.wit

hin

.the.KNX.sys

tem,

ee

ctively

.de

ning

.a.gat

eway.

.A.simi

lar

.app

roach

.was.tak

.for.int

egrating

.Ope

n erm,

.a.pro

tocol

sta

ndard

.for.con

necting

.hom

.hea

ting

.app

liances

.and.roo

.the

rmostats:

.Ess

ential

.con

trol

.inf

ormation

was.mapped.to.KNX.FBs,.while.a.tunneling.mechanism.allows.Open erm.communication.as.usual.

What

.was.des

cribed

.so.far.is.the.tra

ditional

.mod

.of.run

time

.int

erworking,

.als

.kno

.as.“S-

Mode.”

Ano

ther

.mod

.has.bee

.desi

gned

.and.is.use

.for.HVA

.app

lications

.(al

though

.it.is.not.nec

essarily

lim

ited

.to.the

m).

.It.is.kno

.as.“LT

E”

.(lo

gical

.tag.ext

ended).

.Whi

.S-M

ode

.and.LTE.dev

ices

.can.coe

ist

.on.the.sam

.KNX.net

work,

.the

.mes

sage

.for

mats

.are.di

erent.

. er

efore,

.LTE.dev

ices

.add

itionally

imp

lement

.S-M

ode

.com

munication

.for.a.sub

set

.of.the

.fun

ctions.

.Ins

tead

.of.fre

.add

ressing

.and.bin

ing,

.LTE.use

.a.“ta

gged”

.assi

gnment

.sch

eme.

.In.it,.zon

ing

.inf

ormation

.is.sta

tically

.map

ped

.into.the.

gro

up-address

.spa

ce,

.de

ning

.a.xe

.cor

relation

.bet

ween

.cer

tain

.add

resses

.and.loc

ations

.(as.wel

.as.

dom

ain

.sub

structures).

.A.hie

rarchical

.str

ucture

.all

ows

.add

ressing

.sup

ersets

.of.des

tinations

.at.onc

. e.

gro

up-address

.ran

.was.qua

drupled

.by.mak

ing

.use.of.the.Ext

ended

.Fra

.For

mat

.el

. is.mea

tha

.th

.TP

1/PL110

.st

andard

.fr

ame

.fo

rmat

.ca

nnot

.be.us

.(s

.Fi

gure

.42

.2).

Although

.LTE.inp

ut/output

.dat

apoints

.are.con

nected

.via.mul

ticast

.com

munication,

.the

.mak

.use.of.

the.int

erface

.obje

ct/property

.con

cept

.(wh

ich

.is.oth

erwise

.onl

.use

.for.par

ameter

.dat

apoints)

.for.sen

ing

.sem

antic

.inf

ormation

.alo

ng.

.In.eve

.mes

sage,

.the.obje

.numb

.ide

ntifying

.the.fun

ction

.blo

and.the.pro

perty

.numb

.ide

ntifying

.the.dat

apoint

.wit

hin

.the.blo

.are.inc

luded.

.As.an.exa

mple

.of.

LTE.run

time

.int

erworking,

.con

sider

.a.roo

.tem

perature

.sen

sor

.sen

ding

.the.cur

rent

.mea

sured

.val

.to.

a.fa

ncoil

.co

ntroller.

Since

.the.sen

sor

.inc

ludes

.the.obje

.numb

.of.the.Roo

.tem

perature

.sen

sor

.(RT

.FB.and.the.pro

erty

.numb

.of.the.Tem

pRoom

.dat

apoint

.wit

.its.tra

nsmission,

.the.con

troller

.kno

.wha

.to.do.wit

.the.

val

.wit

hout

.fur

ther

.con

guration.

.To.est

ablish

.the.bin

ding

.bet

ween

.a.par

ticular

.sen

sor

.and.con

toller,

the.ins

taller

.set

.the.sam

.loc

ation

.tag.on.bot

.dev

ices.

. is.tag.uni

quely

.de

nes

.the.gro

.add

ress

.tha

the.se

nsor

.wi

.us

.as.th

.de

stination

.ad

dress

.an

.th

.co

ntroller

.wi

.li

sten

.fo

LTE

.als

.dis

tinguishes

.bet

ween

.rep

orting

.the.sta

.of.a.val

.and.ord

ering

.it.cha

nged.

.To.acc

om-

modate

. the

. cha

nges

. and. add

itions,

. the. AL. ser

vices

. GroupPropValue_Read/-Response,

GroupPropValue_Write,

.and.GroupPropValue_InfoReport.wer

.int

roduced.

.All.of.the

use.th

.Da

ta_Tag_Group

.TL.se

rvice,

.wh

ich

.wa

.de

ned

.fo

.th

.pu

rpose.

Finally,

.the.rec

ent

.add

ition

.of.a.le.sys

tem

.acc

ess

.and.bul

.dat

.tra

nsfer

.pro

tocol

.(e.

g.,

.for.tre

.log

tha

.is.cl

osely

.mo

deled

.on.FT

.de

serves

.me

ntion.