Schneider Electric Modbus Plus Network Bridge Multiplexer none Installation Guide

ModiconModbus Plus NetworkPlanning and Installation Guide890 USE 100 00 Version 3.0April 1996AEG Schneider Automation, Inc.One High StreetNorth Andove

890 USE 100 00xii ContentsAppendix AModbus Plus Transaction Elements 171. . . . . . . . . . . . . . . . . . . . . . . . . .A .1 Transaction T iming El

Estimating Network Performance890 USE 100 0085MODBUS PLUS NETWORKCPU1 2 3 4 5 6CPU CPU CPU CPU CPUFigure 36 Predicting Response TimePlanning LoadingOr

86 Estimating Network Performance890 USE 100 00The following steps can be used to calculate the data response time foran MSTR, and the acquisition tim

Estimating Network Performance890 USE 100 00873. Calculate the global data acquisition timeEach unit’s time to receive data from another unit’s Global

88 Estimating Network Performance890 USE 100 003.14 Estimating Throughput (W ith MSTR)Figure 37 shows a graph of the throughput per node as a function

Estimating Network Performance890 USE 100 0089Note that the network’s capacity is 20,000 registers/s. The throughputfor any node is 20,000 registers/s

90 Estimating Network Performance890 USE 100 003.15 Estimating Throughput (W ith Peer Cop)3.15.1 Estimating Total Communication TimeWith Peer Cop comm

Estimating Network Performance890 USE 100 0091The sending node A transmits its Specific Output data, containing PeerCop data to receiving node B. Node

92 Estimating Network Performance890 USE 100 003.16 Predicting Node Dropout Latency Time3.16.1 How the Network Handles Node DropoutsAll active nodes m

Estimating Network Performance890 USE 100 0093Addresses below the drop-outThis general formula is used to calculate the NDOL for each node withan addr

94 Estimating Network Performance890 USE 100 003.17 Estimating Latency for a Small NetworkHere is an example for estimating drop-out latency in a smal

Contents890 USE 100 00xiiiAppendix DInstalling Custom Cable Systems 207. . . . . . . . . . . . . . . . . . . . . . . . . . . .D .1 Overview 208. . . .

Estimating Network Performance890 USE 100 0095AbbreviationsTTT(n)Token Transmission Time (for node n)TRT Token Rotation TimeNDOL(n)Node Drop Out Laten

96 Estimating Network Performance890 USE 100 003.18 Estimating Latency for a Large NetworkHere is an example for estimating drop-out latency in a larg

Estimating Network Performance890 USE 100 0097AbbreviationsTTT(n)Token Transmission Time (for node n)TRT Token Rotation TimeNDOL(n)Node Drop Out Laten

98 Estimating Network Performance890 USE 100 003.19 Planning for Ring Join T imeNodes can be connected to the network while it is active, dynamicallyj

Estimating Network Performance890 USE 100 0099join and does not do so, approximately 2 ms must elapse before itsabsence can be assumed and the token p

100 Estimating Network Performance890 USE 100 003.20 Precautions for Hot Standby LayoutsA case exists in which a node can leave the network and rejoin

Estimating Network Performance890 USE 100 00101Caution: In the worst-case timing for this event, as much as15 s can be required for the ring to be rec

102 Estimating Network Performance890 USE 100 003.21 Guidelines for a Single Network3.21.1 Using MSTR FunctionsEach controller on the network should h

Estimating Network Performance890 USE 100 001033.21.2 Using Peer-to-Peer Communication TechniquesUse peer-to-peer passing of data where applicable, ra

104 Estimating Network Performance890 USE 100 003.21.4 Security Considerations in Node AddressingModbus Plus nodes can be addressed within the range 1

890 USE 100 00xiv ContentsIllustrationsFigure 1 Network Overview 3. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Fig

Estimating Network Performance890 USE 100 001053.21.6 Consistency in Node AddressingUse a consistent method for identifying node addresses. This willf

106 Estimating Network Performance890 USE 100 003.21.8 Controlling the Sequencing of MSTR FunctionsWhen you use multiple MSTR functions in a controlle

Estimating Network Performance890 USE 100 001073.21.1 1 Selecting Bridge Multiplexer Port ModesThe four Modbus ports on Bridge Multiplexers can be sep

108 Estimating Network Performance890 USE 100 003.22 Guidelines for Multiple NetworksIf your application’s data rate requirements are not met between

Estimating Network Performance890 USE 100 00109NETWORKANETWORKBDSDMDMDSDSDSDSDSDSDSDSDMDMDMDMDMDMDMDMDMDMDMDMDMDMDSDSDSDSDSDSDSBP85 BRIDGE PLUSFigure

110 Estimating Network Performance890 USE 100 003.22.2 Using Multiple Bridges Between NetworksIf your application will have heavy traffic between netw

Estimating Network Performance890 USE 100 00111You can plan your application so that high priority messages are passedthrough a dedicated bridge. Desi

112 Estimating Network Performance890 USE 100 003.23 Sample Communications Across NetworksFigure 44 shows two controllers on separate Modbus Plus netw

Estimating Network Performance890 USE 100 00113Step 4 When the peer processor in unit B acquires the token, it sends thedata response to the bridge. T

114 Estimating Network Performance890 USE 100 003.24 A Summary of Network Planning3.24.1 Analyzing Your NeedsAnalyze your application’s data communica

Contents890 USE 100 00xvFigure 31 Sample READ Communication 66. . . . . . . . . . . . . . . . . . . . . . . . . . . . .Figure 32 Sample GET LOCAL STAT

Estimating Network Performance890 USE 100 00115V Reduce queueing by reducing the number of communications to acontroller node, or by reducing the freq

Documenting the Network Layout890 USE 100 00117Chapter 4Documenting the NetworkLayoutV Documenting Your Network LayoutV Your Planning WorksheetsV Defi

118 Documenting the Network Layout890 USE 100 004.1 Documenting Your Network LayoutYour planning should include the preparation of documents thatdescr

Documenting the Network Layout890 USE 100 001194.2 W orksheets for Network PlanningFive kinds of worksheets are provided in this book to assist you in

120 Documenting the Network Layout890 USE 100 004.3 Defining Your Node RequirementsBefore you document your network layout, make a list of yourrequire

Documenting the Network Layout890 USE 100 00121MODBUS PLUS NETWORKNODE PLANNING WORKSHEETFACILITY / AREA :NETWORK NUMBER :PROJECT NAME : DATE :PROJECT

122 Documenting the Network Layout890 USE 100 004.4 Topology Planning W orksheetFigure 46 is an example of a completed Topology Planning Worksheet.The

Documenting the Network Layout890 USE 100 00123MODBUS PLUS NETWORKTOPOLOGY PLANNING WORKSHEETFACILITY / AREA : PROJECT NAME : DATE :PROJECT ENGR : TEL

124 Documenting the Network Layout890 USE 100 004.5 Estimating Cable LengthsAfter defining the network topology, consider the required cable lengthsbe

Documenting the Network Layout890 USE 100 001254.6 Reviewing Your Topology PlanReview your topology planning worksheet after you estimate the cablelen

890 USE 100 00xvi ContentsFigure 61 RR85 Repeater Rear Panel View 151. . . . . . . . . . . . . . . . . . . . . . . . . . . .Figure 62 RR85 Repeater In

126 Documenting the Network Layout890 USE 100 004.7 Detailing the Network Layout4.7.1 Overview of Your Detailed Planning W orksheetsYou have three wor

Documenting the Network Layout890 USE 100 00127MODBUS PLUS NETWORKCABLE ROUTING WORKSHEETFACILITY / AREA :NETWORK NUMBER :SHEET : OFSITES : TOPROJECT

128 Documenting the Network Layout890 USE 100 004.8 Network Planning W orksheetEach network planning worksheet can document up to eight sites. Useaddi

Documenting the Network Layout890 USE 100 00129Trunk Cable and TapsEstimate the length of the cable between sites. Each segment exceptthe first has a

130 Documenting the Network Layout890 USE 100 00MODBUS PLUS NETWORKNETWORK PLANNING WORKSHEETFACILITY / AREA :NETWORK NUMBER :SHEET : OFSITES : TOPROJ

Documenting the Network Layout890 USE 100 001314.9 Cable Routing W orksheetWherever possible, obtain a site layout for your plant facility and use itt

132 Documenting the Network Layout890 USE 100 00and cables. Use a larger scale on another sheet to show the overallnetwork layout.W orksheet Grid Area

Documenting the Network Layout890 USE 100 00133MODBUS PLUS NETWORKCABLE ROUTING WORKSHEETFACILITY / AREA :NETWORK NUMBER :SHEET : OFSITES : TOPROJECT

134 Documenting the Network Layout890 USE 100 004.10 Materials Summary W orksheetWhen your planning of the network layout and cable routing iscomplete

Documenting the Network Layout890 USE 100 00135Trunk Cable and TapsSummarize the amount of cable that will be required. Convert thenetwork cable lengt

Contents890 USE 100 00xviiFigure 91 Preparing the Cable 216. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Figure 92 Plac

136 Documenting the Network Layout890 USE 100 00MODBUS PLUS NETWORKMATERIALS SUMMARY WORKSHEETFACILITY / AREA :NETWORK NUMBER :PROJECT NAME : DATE :PR

Installing the Network Cable890 USE 100 00137Chapter 5Installing the Network CableV Overview of the Cable InstallationV Tools and Test Equipment Requi

138 Installing the Network Cable890 USE 100 005.1 Overview of the Cable InstallationThis chapter describes how to install the network trunk and dropca

Installing the Network Cable890 USE 100 001395.2 Tools and Test Equipment RequiredThe following tools and test equipment are required to install andch

140 Installing the Network Cable890 USE 100 005.3 Before You StartBefore routing the cable you should have a cable routing diagram thatshows:V Site lo

Installing the Network Cable890 USE 100 001415.4 Routing the CablesFigure 51 shows typical cable routing of the network trunk cablebetween tap locatio

142 Installing the Network Cable890 USE 100 00Refer to Figure 51. Route the cable between the site locations of thenode devices. Guidelines for cable

Installing the Network Cable890 USE 100 001435.5 Mounting the TapsBefore mounting each Tap, install the supplied grounding screw andnut into the Tap a

144 Installing the Network Cable890 USE 100 005.6 Connecting the Trunk Cables5.6.1 Cable Entry and Jumpers (Taps at Inline Sites)At each inline site,

Installing the Network Cable890 USE 100 001455.6.3 Connecting the W iresDetailed instructions for making the connections are enclosed in eachtap packa

iv Related Publications890 USE 100 00Related PublicationsRefer to the following publications for further information about theModbus Plus network and

146 Installing the Network Cable890 USE 100 005.7 Connecting the Drop Cable5.7.1 Connecting the Signal W iresDetailed instructions for making the conn

Installing the Network Cable890 USE 100 00147CABLETIEO BLUGNDW WOUTER SHIELDGROUNDWIREFigure 57 Drop Cable ConnectionsFigure 58 shows how to connect e

148 Installing the Network Cable890 USE 100 005.8 GroundingAt each tap, ensure that the drop cable’s ground wire is connected tothe tap’s grounding sc

Installing the Network Cable890 USE 100 001495.9 LabelingAfter the cable is installed, label the cable segments for ease in futuremaintenance of the n

150 Installing the Network Cable890 USE 100 005.10 Checking the Cable InstallationThis section describes how to visually inspect the cable and check i

Installing the Network Cable890 USE 100 00151V At each node device connector, check for an open circuit betweenpin 2 (a signal pin) and pin 1 (the out

Connecting an RR85 Repeater890 USE 100 00153Chapter 6Connecting an RR85RepeaterV Mounting MethodsV Mounting DimensionsV Installing the RepeaterV Readi

154 Connecting an RR85 Repeater890 USE 100 006.1 Mounting MethodsAs supplied, the RR85 Repeater’s bottom surface is fitted with pads formounting on a

Connecting an RR85 Repeater890 USE 100 001556.2 Mounting DimensionsMounting dimensions for the Repeater are shown in Figure 60. Thefigure shows the ou

156 Connecting an RR85 Repeater890 USE 100 006.3 Installing the RepeaterCaution: If you are replacing a Repeater on an active ModbusPlus network, the

Introducing the Modbus Plus Network890 USE 100 001Chapter 1Introducing the Modbus PlusNetworkV Introducing the Modbus Plus NetworkV Network Terminolog

Connecting an RR85 Repeater890 USE 100 00157Rear Panel V iewPower cableconnectorPowerswitchModbus Plusport 1 connectorPower selectorplug and fusePower

158 Connecting an RR85 Repeater890 USE 100 00If the cable segments are not labeled, or if you do not have a networklayout diagram, you can still conne

Connecting an RR85 Repeater890 USE 100 001596.4 Reading the Network IndicatorsThe layout of the Repeater indicators is shown in Figure 62.ModbusPlusPo

160 Connecting an RR85 Repeater890 USE 100 006.5 RR85 Repeater SpecificationsRR85 Repeater SpecificationsDescription Name RR85 Modbus Plus Network Re-

Connecting a BP85 Bridge Plus890 USE 100 00161Chapter 7Connecting a BP85Bridge PlusV Mounting MethodsV Dimensions (Panel/Shelf Models)V Dimensions (Ra

162 Connecting a BP85 Bridge Plus890 USE 100 007.1 Mounting MethodsBP85 models are available for mounting on a horizontal shelf orvertical panel, or f

Connecting a BP85 Bridge Plus890 USE 100 001637.1.3 Brid g e Plus ModelsP art Number Mounting MethodOperating Power(Nominal)Modbus PlusNetwork CableNW

164 Connecting a BP85 Bridge Plus890 USE 100 007.2 Dimensions (Panel /Shelf Models)Top V iewRear Panel V iew14.08 in (358 mm)12.83 in (326 mm)11.5 in

Connecting a BP85 Bridge Plus890 USE 100 001657.3 Dimensions (Rack Mount Model)Top V iewFrontPanelView19.0 in (483 mm)17.25 in (438 mm)3.47 in(88 mm)1

166 Connecting a BP85 Bridge Plus890 USE 100 007.4 Settin g the Modbus Plus AddressesBefore you apply power to the BP85, you must set the unit’s netwo

2 Introducing the Modbus Plus Network890 USE 100 001.1 Introducing the Modbus Plus Network1.1.1 Modbus Plus ApplicationsModbus Plus is a local area ne

Connecting a BP85 Bridge Plus890 USE 100 00167AddressSwitch Position12345678910111213141516171819202122232425262728293031321 2 3 4 5 6 7 8010101010101

168 Connecting a BP85 Bridge Plus890 USE 100 007.5 Connecting the Power CablesCaution: If y o u are replacing a Bridge Plus on an activenet w ork, the

Connecting a BP85 Bridge Plus890 USE 100 001697.5.3 Before You Apply PowerDo not apply power to the BP85 until you have completed the setup ofthe unit

170 Connecting a BP85 Bridge Plus890 USE 100 007.6 Connecting the Network CablesIf the cables and connectors are not in place, install them as describ

Connecting a BP85 Bridge Plus890 USE 100 001717.7 Applying PowerAfter you have set the address switches to the desired networkaddresses, and have conn

172 Connecting a BP85 Bridge Plus890 USE 100 007.8 Reading the Network IndicatorsThe layout of the Bridge Plus indicators is shown in Figure 67.Modbus

Connecting a BP85 Bridge Plus890 USE 100 00173V One flash/s The Bridge Plus node is offline after just being pow-ered up, or after hearing a message f

174 Connecting a BP85 Bridge Plus890 USE 100 00Modbus PlusNetworkNodeModbus PlusNetworkNode123222Figure 68 Modbus Plus Port Labels

Connecting a BP85 Bridge Plus890 USE 100 001757.10 BP85 Bridge Plus SpecificationsBP85 Bridge Plus S pecifications (Panel/Shelf Models)Description Nam

176 Connecting a BP85 Bridge Plus890 USE 100 00BP85 Bridge Plus Specifications (Rack Mount Model)Description Name BP85 Modbus Plus Network BridgePart

Introducing the Modbus Plus Network890 USE 100 003Modbus Plus networked devices, as well as with other devices at theserial ports.1.1.4 Network Exampl

Modbus Plus Transaction Elements890 USE 100 00177Appendix AModbus Plus TransactionElementsV Transaction Timing ElementsV The Message Format  HDLC Lev

178 Modbus Plus Transaction Elements890 USE 100 00A .1 Transaction T iming ElementsA .1.1 Token Holding TimeEachnode holds the networktoken for a mini

Modbus Plus Transaction Elements890 USE 100 00179SA85 and SM85 Network AdaptersTwo Registers 125 RegistersTransactionTypeAvailableTransactionsOneTrans

180 Modbus Plus Transaction Elements890 USE 100 00A .1.3 Data Response T imeWhen a node’s application program initiates a transaction, the timerequire

Modbus Plus Transaction Elements890 USE 100 00181ALL TIMING IS APPROXIMATE (NOT TO SCALE)ALL TIMING IS IN MILLISECONDSNOTES(R) = READ, (W) = WRITETRAN

182 Modbus Plus Transaction Elements890 USE 100 00A .2 The Message Format  HDLC LevelMessages appearing on the network contain three levels of protoc

Modbus Plus Transaction Elements890 USE 100 00183MAC/LLC DataThis field specifies the MAC level control packet for tokenrelatedoperations, and contai

184 Modbus Plus Transaction Elements890 USE 100 00A .3 The Message Format  MAC LevelAt the Medium Access Control (MAC) level, the network protocoldef

Modbus Plus Transaction Elements890 USE 100 00185Source AddressThe address of the node originating the message, in the range of 1 to64.MAC Function Co

186 Modbus Plus Transaction Elements890 USE 100 00A .4 The Message Format  LLC LevelAt the Logical Link Control (LLC) level, the message contains the

Preface iii890 USE 100 00PrefaceThe data and illustrations found in this book are not binding. Wereserve the right to modify our products in line with

4 Introducing the Modbus Plus Network890 USE 100 00BP85BRIDGEPLUSRR85REPEATERHOST DEVICENETWORKADAPTERBM85BRIDGEMULTIPLEXERMODBUS OR CUSTOMSERIAL DEVI

Modbus Plus Transaction Elements890 USE 100 00187A .4.1 LLC FieldsThe message contains the following LLC level fields:Master Output PathOne byte ident

188 Modbus Plus Transaction Elements890 USE 100 00For messages to a single Modbus slave device connected to a BridgeMultiplexer port: each nonzero by

Message Routing890 USE 100 00189Appendix BMessage RoutingV The Modbus Plus Message Routing PathV Modbus Address ConversionV Controller Bridge Mode Rou

190 Message Routing890 USE 100 00B .1 The Modbus Plus Message Routing PathA single Modbus Plus network can have up to 64 addressable nodedevices, with

Message Routing890 USE 100 00191Programmable ControllersFor programmable controllers, the last nonzero byte in the messagerouting specifies the netwo

192 Message Routing890 USE 100 00B .2 Modbus Address ConversionModbus devices use addresses of one byte in the range 1 ... 255.Modbus Plus nodes are a

Message Routing890 USE 100 00193RESERVEDRESERVED01646569707980255DIRECTATTACHADDRESSEXPLICITATTACHADDRESSIMPLICITATTACHADDRESSRESERVEDRESERVED01646579

194 Message Routing890 USE 100 00B .3 Controller Bridge Mode RoutingIf a Modbus message is received at the Modbus port of a controller thatis set to b

Message Routing890 USE 100 00195The routing path pointed to by the Modbus address is applied to themessage. Each path is five bytes in length:4x Free-

196 Message Routing890 USE 100 00B .4 Bridge Multiplexer RoutingModbus Address MapIf a Modbus message is received at a BM85 Modbus port, the address(1

Introducing the Modbus Plus Network890 USE 100 0051.2 Network TerminologyThe following terms are used in this guide to describe networkelements:Networ

Message Routing890 USE 100 001971 ... 64If the address is in the range 1 ... 64 (Direct Attach Address), themessage is routed to the specific node add

198 Message Routing890 USE 100 00B .4.1 Routing ExamplesFigure 77 illustrates message routing across two networks.MODBUS PLUS NETWORK (UP TO 64 NODES)

Message Routing890 USE 100 00199Here are examples of routing between peer, master, and slave devices.From To Routing PathCPU A (Primary) Slave A 5 2 0

Planning W orksheets890 USE 100 00201Appendix CPlanning W orksheetsThis appendix provides blank worksheets that you can use for planningyour Modbus Pl

202 Planning W orksheets890 USE 100 00C .1 Using the W orksheetsUse these worksheets to plan the layout of your network and tocoordinate the ordering

Planning W orksheets890 USE 100 00203MODBUS PLUS NETWORKNODE PLANNING WORKSHEETFACILITY / AREA :NETWORK NUMBER :PROJECT NAME : DATE :PROJECT ENGR : TE

204 Planning W orksheets890 USE 100 00NOTES :Figure 79 Node Planning: Notes

Planning W orksheets890 USE 100 00205MODBUS PLUS NETWORKTOPOLOGY PLANNING WORKSHEETFACILITY / AREA : PROJECT NAME : DATE :PROJECT ENGR : TEL :MAINTENA

206 Planning W orksheets890 USE 100 00NOTES :Figure 81 Topology Planning: Notes

Planning W orksheets890 USE 100 00207MODBUS PLUS NETWORKNETWORK PLANNING WORKSHEETFACILITY / AREA :NETWORK NUMBER :SHEET : OFSITES : TOPROJECT NAME :

6 Introducing the Modbus Plus Network890 USE 100 00Node Any device that is physically connected to the Modbus Plus cable.Figure 2 shows a network with

208 Planning W orksheets890 USE 100 00NOTES :Figure 83 Network Planning: Notes

Planning W orksheets890 USE 100 00209MODBUS PLUS NETWORKCABLE ROUTING WORKSHEETFACILITY / AREA :NETWORK NUMBER :SHEET : OFSITES : TOPROJECT NAME : DAT

210 Planning W orksheets890 USE 100 00NOTES :Figure 85 Cable Routing: Notes

Planning W orksheets890 USE 100 0021 1MODBUS PLUS NETWORKMATERIALS SUMMARY WORKSHEETFACILITY / AREA :NETWORK NUMBER :PROJECT NAME : DATE :PROJECT ENGR

212 Planning W orksheets890 USE 100 00NOTES :Figure 87 Materials Summary: Notes

Installing Custom Cable Systems890 USE 100 00213Appendix DInstalling Custom CableSystemsV OverviewV Tools and Test Equipment RequiredV Before You Star

214 Installing Custom Cable Systems890 USE 100 00D .1 OverviewThis chapter describes how to install the network cable system withoutthe use of Modicon

Installing Custom Cable Systems890 USE 100 00215D .2 Tools and Test Equipment RequiredAn installation tool (Modicon part number ASMBPL001) is availa

216 Installing Custom Cable Systems890 USE 100 00D .3 Before You StartBefore routing the cable you should have a cable routing diagram thatshows:V Sit

Installing Custom Cable Systems890 USE 100 00217D .4 Routing the CableFigure 88 shows typical cable drops to several network node devicesand a service

Introducing the Modbus Plus Network890 USE 100 0071.3 Overview of the Logical NetworkNetwork nodes are identified by addresses assigned by the user. E

218 Installing Custom Cable Systems890 USE 100 00V At each drop, allow sufficient cable for a service loop and strainreliefs.V At each drop, provide a

Installing Custom Cable Systems890 USE 100 00219D .5 Installing Connectors on Dual-Cable RunsAt each inline device site, an Inline Connector (AS-MBKT-

220 Installing Custom Cable Systems890 USE 100 00D .6 Installing Connectors W ith the ToolA tool is available from Modicon (part number ASMBPL001) f

Installing Custom Cable Systems890 USE 100 002211 2 3 1 2 3TERMINATINGCONNECTORASMBKT185INLINECONNECTORASMBKT085INSTALL ATEND POINTSINSTALL ATINLI

222 Installing Custom Cable Systems890 USE 100 00D .6.3 Preparing the CableRemove three inches (7.5 cm) of the cable’s outer jacket and shields asshow

Installing Custom Cable Systems890 USE 100 00223D .6.5 Determining the W iring DirectionThe wires must be inserted into the connector in the proper di

224 Installing Custom Cable Systems890 USE 100 00D .6.7 Replacing the CapCarefully replace the cap as shown in Figure 94 below. Make sure thecap is pr

Installing Custom Cable Systems890 USE 100 00225D .6.9 Completing the InstallationChecking W iring ContinuityOpen the tool, and remove the connector a

226 Installing Custom Cable Systems890 USE 100 00Installing the Cable TieUsing one of the cable ties supplied with the connector, tie the cabletightly

Installing Custom Cable Systems890 USE 100 00227D .7 Installing Connectors W ithout the ToolIf you are using the Modbus Plus connector installation to

8 Introducing the Modbus Plus Network890 USE 100 00Figure 4 shows the token sequences in two networks joined by aBridge Plus.NODEBRIDGEPLUSNETWORK 1NO

228 Installing Custom Cable Systems890 USE 100 00You will also need to know which type of network device (type ofModicon 984 controller or other devic

Installing Custom Cable Systems890 USE 100 00229D .7.4 Identifying the TerminalsRefer to Figure 99. Remove the screw that secures the connector cap.Re

230 Installing Custom Cable Systems890 USE 100 00123CABLE TO LEFTFOR984385, 485CABLE TO RIGHTFOR984685, 785WIRETERMINALTOWIREPRESS EACHWHITE WIRE AN

Installing Custom Cable Systems890 USE 100 00231If you are connecting an inline site, refer to Figure 101. Connect thesecond cable to the connector as

232 Installing Custom Cable Systems890 USE 100 00D .7.8 Completing the InstallationChecking W iring ContinuityLocate pins 1, 2, and 3 of the connector

Installing Custom Cable Systems890 USE 100 00233Installing the Cable TieUsing one of the cable ties supplied with the connector, tie the cabletightly

234 Installing Custom Cable Systems890 USE 100 00D .8 GroundingAll three conductors of the cable (signal wires and shield) shouldremain isolated from

Installing Custom Cable Systems890 USE 100 00235D .9 LabelingAfter the cable is installed, label the cable segments for ease in futuremaintenance of t

236 Installing Custom Cable Systems890 USE 100 00D .10 Checking the Cable InstallationThis section describes how to visually inspect the cable and che

Installing Custom Cable Systems890 USE 100 00237V At any connector, measure the resistance between pins 2 and 3 (thesignal pins). Measure this at the

Introducing the Modbus Plus Network890 USE 100 0091.4 Overview of the Physical NetworkThe network bus consists of twisted-pair shielded cable that is

Glossary890 USE 100 00241GlossaryacknowledgementAn LLC frame that indicates that a data frame has been receivedcorrectly.addressOn a network, the iden

242 Glossary890 USE 100 00Bridge PlusA Modicon device that interconnects two Modbus Plus networks.broadbandA network communications method supporting

Glossary890 USE 100 00243packet to the Physical Layer for transmission. Its two logicalentities are the MAC and LLC sublayers. See MAC and LLC .DIOSee

244 Glossary890 USE 100 00A code that is used to determine whether a frame was receivedcorrectly.

Glossary890 USE 100 00245frame descriptorA part of the host computer’s buffer structure that linkstransmitted or received data frames to appropriate p

246 Glossary890 USE 100 00LANLocal Area Network. An interconnection of devices in which datais transferred without the use of public communications se

Glossary890 USE 100 00247megabits per second. The network medium is shieldedtwisted-pair cable.Modbus IIAn industrial networking system that uses toke

248 Glossary890 USE 100 00Four kinds of Peer Cop communication can be transacted duringeach token pass: see Global Input, Global Output, SpecificInput

Glossary890 USE 100 00249segmentThe combination of: a continuous length of trunk cable connectinga pair of taps; the two taps; and the drop cables bet

250 Glossary890 USE 100 00systemA set of hardware devices and their associated software capable ofperforming the functions of information processing a

10 Introducing the Modbus Plus Network890 USE 100 00NETWORKTRUNKCABLENETWORKTRUNKCABLEDROPCABLETO NODETAP SHOWNWITHCOVER OPENCABLETIETERMINATIONJUMPER

Index890 USE 100 00239IndexBBM85 Bridge Multiplexer, description, 16BP85 Bridge Plus, description, 16bridgingModbus Plus networks, 32to serial devices

890 USE 100 00240 IndexNnetwork, deterministic timing, 23nodeaccess method, 18adding or deleting, 93connections, 8defined, 5types, 10node dropoutexamp

Introducing the Modbus Plus Network890 USE 100 00111.5 Major Components of the Network1.5.1 Programmable ControllersModicon controllers connect direct

12 Introducing the Modbus Plus Network890 USE 100 00Note: The address exchange can cause a momentary delay incommunication with the new primary unit w

Introducing the Modbus Plus Network890 USE 100 00131.5.3 DIO Drop AdaptersThe DIO Drop Adapter mounts in a housing at a remote site,communicating over

Contents890 USE 100 00vContentsChapter 1Introducing the Modbus Plus Network 1. . . . . . . . . . . . . . . . . . . . . . .1.1 Introducing the Modbus P

14 Introducing the Modbus Plus Network890 USE 100 001.5.4 Available Backplanes for DIO ApplicationsModicon backplanes are available in sizes from 2 ..

Introducing the Modbus Plus Network890 USE 100 00151.5.6 Network Adapters for Host ComputersAdapters are available for connecting host computers to th

16 Introducing the Modbus Plus Network890 USE 100 00Typical network adapter applications include:V User interfacesV Control, monitoring, and reporting

Introducing the Modbus Plus Network890 USE 100 00171.5.7 BM85 Bridge MultiplexerThe BM85 Bridge Multiplexer provides connection to Modbus Plus forup t

18 Introducing the Modbus Plus Network890 USE 100 001.5.9 RR85 RepeaterThe RR85 Repeater allows you to place more than 32 nodes on thenetwork and to i

Introducing the Modbus Plus Network890 USE 100 00191.6 How Nodes Access the Network1.6.1 How Your Application’ s Layout Affects Node AccessWhen the ne

20 Introducing the Modbus Plus Network890 USE 100 001.6.3 Point to Point Message TransactionsWhile a node holds the token, it sends its application me

Introducing the Modbus Plus Network890 USE 100 0021Global database applications include time synchronization, rapidnotification of alarm conditions, a

22 Introducing the Modbus Plus Network890 USE 100 001.7 Error Checking and RecoveryWhen a node sends a data message, it expects an immediateacknowledg

Introducing the Modbus Plus Network890 USE 100 00231.8 Designing for Process SpeedFigure 12 is an example of a hierarchical approach using Bridge Plus

890 USE 100 00vi ContentsChapter 1Introducing the Modbus Plus Network (Continued):1.11 Expanding the Network 28. . . . . . . . . . . . . . . . . . . .

24 Introducing the Modbus Plus Network890 USE 100 001.9 Designing for Deterministic I/O ServicingFigure 13 illustrates a network designed for determin

Introducing the Modbus Plus Network890 USE 100 00251.10 Using Peer Cop1.10.1 Peer Cop TransactionsPoint to point data can be transacted while a node h

26 Introducing the Modbus Plus Network890 USE 100 00Receiving DataNodes can be configured to receive two kinds of Peer Cop data:V Global Input Up to 3

Introducing the Modbus Plus Network890 USE 100 00271.10.2 A Peer Cop ExampleFigure 14 shows a network with three nodes that are handling PeerCop data

28 Introducing the Modbus Plus Network890 USE 100 00Node 7 has not been configured to receive Global Input from node 2,and ignores it. The node receiv

Introducing the Modbus Plus Network890 USE 100 00291.1 1 Expanding the Network1.1 1.1 Linear ExpansionThe simplest network configuration consists of t

30 Introducing the Modbus Plus Network890 USE 100 001.1 1.2 Using RR85 RepeatersIf your network requires more than 1500 ft (450 m) of cable, or moreth

Introducing the Modbus Plus Network890 USE 100 00311.1 1.3 Expanding Dual-cable NetworksOn dual-cable networks, repeaters must be placed between the s

32 Introducing the Modbus Plus Network890 USE 100 00NDNDNDND1500 ft CABLE MAX.1500 ftCABLEMAX.1500 ftCABLEMAX.1500 ft CABLE MAX.ND = NODE DEVICERR = R

Introducing the Modbus Plus Network890 USE 100 00331.12 Joining Modbus Plus Networks1.12.1 How the Bridge Plus OperatesThe BP85 Bridge Plus device con

Contents890 USE 100 00viiChapter 2Elements of Network Planning 41. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2.1 An Overview of Netwo

34 Introducing the Modbus Plus Network890 USE 100 00If a data message intended for a remote node is received at one of theBridge’s ports, the Bridge s

Introducing the Modbus Plus Network890 USE 100 0035When the first Bridge (22) receives the original message, it examinesthe routing field and determin

36 Introducing the Modbus Plus Network890 USE 100 00The types of devices used in your application determine how manyModbus Plus networks you can join.

Introducing the Modbus Plus Network890 USE 100 00371.13 Bridging Modbus Plus and Serial Devices1.13.1 How the Bridge Multiplexer OperatesThe BM85 Brid

38 Introducing the Modbus Plus Network890 USE 100 00Modbus master devices connected to the Bridge Multiplexer can accessany controller node on the Mod

Introducing the Modbus Plus Network890 USE 100 0039MODBUS PLUS NETWORK (UP TO 64 NODES)BM85BRIDGEMULTIPLEXERCPUIBM PCORJ478MODBUS= MODBUS PORTCOMPATIB

40 Introducing the Modbus Plus Network890 USE 100 00The application can then be downloaded using a utility supplied withthe development tools. The dow

Introducing the Modbus Plus Network890 USE 100 0041Figure 24 summarizes the layout of port devices in a typical BM85user-programmed application.MODBUS

Elements of Network Planning890 USE 100 0043Chapter 2Elements ofNetwork PlanningV An Overview of Network PlanningV Defining the Network ComponentsV De

44 Elements of Network Planning890 USE 100 002.1 An Overview of Network PlanningYou should consider the following factors in the layout of your Modbus

890 USE 100 00viii ContentsChapter 3Estimating Network Performance 51. . . . . . . . . . . . . . . . . . . . . . . . . . . .3.1 Overview 52. . . . . .

Elements of Network Planning890 USE 100 0045worksheets. You can make photocopies of them for use in documentingyour network.

46 Elements of Network Planning890 USE 100 002.1.1 Preparing a Network PlanThis chapter provides a focus for planning your Modbus Plus networkrequirem

Elements of Network Planning890 USE 100 0047V Bridge Plus You must define a network node address for each ofthe Bridge Plus device’s two network ports

48 Elements of Network Planning890 USE 100 002.2 Defining the Network ComponentsFigure 25 summarizes the components of the network cable system.TRUNK

Elements of Network Planning890 USE 100 00492.2.1 Modbus Plus Trunk CableCable specified for Modbus Plus trunk use is available from Modicon asthe fol

50 Elements of Network Planning890 USE 100 002.2.3 Modbus Plus TapA tap is required at each site on the trunk cable to provide connectionsfor the trun

Elements of Network Planning890 USE 100 00512.2.5 Modbus Plus Network GroundingEach tap has a grounding screw for connection to the site panel ground.

52 Elements of Network Planning890 USE 100 002.3 Defining the Network Layout2.3.1 Component LocationsThe maximum cable length allowed for the network

Elements of Network Planning890 USE 100 0053V In addition to the minimum separation, if the cable must crosspower wiring carrying over 480 volts, it m

54 Elements of Network Planning890 USE 100 00V Between nodes 2 ... 4, the difference between cables A and B is also600 ft (180 m). This exceeds the ma

Contents890 USE 100 00ix3.16 Predicting Node Dropout Latency Time 86. . . . . . . . . . . . . . . . . . . . . . . . . . .3.16.1 How the Network Handle

Estimating Network Performance890 USE 100 0055Chapter 3Estimating NetworkPerformanceV OverviewV Factors for PlanningV How Devices Interact on the Netw

56 Estimating Network Performance890 USE 100 00V A Summary of Network Planning

Estimating Network Performance890 USE 100 00573.1 OverviewThis chapter describes the major factors you should consider as youplan the layout of your M

58 Estimating Network Performance890 USE 100 00Your Options You can plan your network application as a single network, with alinear arrangement of nod

Estimating Network Performance890 USE 100 00593.2 Factors for PlanningWhen you plan an industrial communications strategy that willintegrate various c

60 Estimating Network Performance890 USE 100 003.2.3 Transaction RequirementsConsider the types and quantities of message transactions that mustoccur

Estimating Network Performance890 USE 100 00613.3 How Devices Interact on the NetworkMultiple data transfer and programming operations can occurconcur

62 Estimating Network Performance890 USE 100 00V Computer B in a programming or load/record/verify operation withcontroller 3V Plant personnel accessi

Estimating Network Performance890 USE 100 00633.4 Factors That Affect Performance3.4.1 Handling Multiple OperationsThe time that is required for a nod

64 Estimating Network Performance890 USE 100 00Two additional operations are occurring on the network. Computer B isin a programming or load/record/ve

890 USE 100 00x ContentsChapter 4Documenting the Network Layout 111. . . . . . . . . . . . . . . . . . . . . . . . . . .4.1 Documenting Your Network L

Estimating Network Performance890 USE 100 0065written by the incoming data, and cleared by a subsequent scan), or byusing transaction counters or othe

66 Estimating Network Performance890 USE 100 003.5 Communication Paths and QueueingWith multiple devices processing messages asynchronously on thenetw

Estimating Network Performance890 USE 100 00673.5.2 Path QuantitiesThe following paths are available in the various types of Modbus Plusdevices:CPU BM

68 Estimating Network Performance890 USE 100 00BP85 Bridge Plus QueueingMessages which must pass through multiple bridges will be queued (ifnecessary)

Estimating Network Performance890 USE 100 0069Transactions are handled in this way to prevent excessive delaysbetween requests and responses in your a

70 Estimating Network Performance890 USE 100 003.6 Reading and W riting with the MSTRThe MSTR instruction is a ladder logic function that provides acc

Estimating Network Performance890 USE 100 0071For example, in a data Read or Write operation, the Control Blocklayout is as follows:Register Content4x

72 Estimating Network Performance890 USE 100 003.7 A Sample MSTR CommunicationEvery Modbus Plus device has a peer processor that controls networkcommu

Estimating Network Performance890 USE 100 0073Step 4 At the end of the ladder logic scan in unit A, the incoming transac-tions are handled. The transa

74 Estimating Network Performance890 USE 100 003.8 Getting and Clearing Statistics3.8.1 Local Device StatisticsWhen you issue commands to Get Local St

Contents890 USE 100 00xiChapter 6Connecting an RR85 Repeater 147. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6.1 Mounting Methods 148.

Estimating Network Performance890 USE 100 0075The time required to process the complete communication would be:Time Range Average T ime W orst Case T

76 Estimating Network Performance890 USE 100 003.9 Reading and W riting Global Data3.9.1 Passing Global Data Between NodesUp to 32 registers of global

Estimating Network Performance890 USE 100 0077Step 1 When the peer processor in unit A acquires the network token, ittransmits any other application m

78 Estimating Network Performance890 USE 100 003.10 Loading Effects in Your ApplicationDuring the application, each node on the network can have a dif

Estimating Network Performance890 USE 100 0079During dequeueing at the destination, the receiving node will requestthe command again from the originat

80 Estimating Network Performance890 USE 100 003.1 1 Predicting Token Rotation TimeFigure 35 shows a graph of token timing as a function of the networ

Estimating Network Performance890 USE 100 0081The token rotation times shown in the figure are for data transactions,with no queueing at the destinati

82 Estimating Network Performance890 USE 100 003.12 Formula for Calculating Token RotationThe formula for calculating the average token rotation time

Estimating Network Performance890 USE 100 0083For example.consider twocases in which an MSTR is enabled everyscan, and the scan time is 20 ms.V Faster

84 Estimating Network Performance890 USE 100 003.13 Predicting MSTR Response TimeWhen you have calculated the average token rotation time on thenetwor