23809864 AB ProfibusScanner DOKU V10 e

7/28/2019 23809864 AB ProfibusScanner DOKU V10 e

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Application for Communication

Communication with Allen-Bradley ControlLogixControllers via PROFIBUS Scanner

Application with Sample Code


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Warranty, liability and support

Comm. with Third-Party Contr. (Allen-Bradley) ID No.: 23809864

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Note The Application Examples are not binding and do not claim to becomplete regarding the circuits shown, equipping and any eventuality.The Application Examples do not represent customer-specific solutions.They are only intended to provide support for typical applications. Youare responsible for ensuring that the described products are correctlyused. These Application Examples do not relieve you of the responsibilityof safely and professionally using, installing, operating and servicingequipment. When using these Application Examples, you recognize thatSiemens cannot be made liable for any damage/claims beyond theliability clause described. We reserve the right to make changes to theseApplication Examples at any time without prior notice. If there are anydeviations between the recommendations provided in these Application

Examples and other Siemens publications e.g. Catalogs then thecontents of the other documents have priority.

Warranty, liability and support

We do not accept any liability for the information contained in thisdocument.

Any claims against us based on whatever legal reason resulting fromthe use of the examples, information, programs, engineering and

performance data etc., described in this Application Example shall beexcluded. Such an exclusion shall not apply in the case of mandatoryliability, e.g. under the German Product Liability Act(Produkthaftungsgesetz), in case of intent, gross negligence, or injury oflife, body or health, guarantee for the quality of a product, fraudulentconcealment of a deficiency or breach of a condition which goes to the rootof the contract (wesentliche Vertragspflichten). However, claims arisingfrom a breach of a condition which goes to the root of the contract shall belimited to the foreseeable damage which is intrinsic to the contract, unlesscaused by intent or gross negligence or based on mandatory liability forinjury of life, body or health. The above provisions do not imply a change inthe burden of proof to your detriment.

Copyright 2006 Siemens A&D. It is not permissible to transfer orcopy these Application Examples or excerpts of them without firsthaving prior authorization from Siemens A&D in writing.

For questions about this document please use the following e-mail address:

mailto:[email protected]
mailto:[email protected]:[email protected]


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Foreword


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Foreword

Objective of the application

The demand for the connection of networks of different manufacturersincreases worldwide. For economic and technological reasons,interoperability is of greatest importance.

In this context, the products manufactured by Allen-Bradley/Rockwell are ofparticular interest. Together with a large number of partner companies,Allen-Bradley sells a broad portfolio of controllers, I/O devices and networkcomponents, which hold a considerable market share particularly in theUSA.

This application uses an example to show how SIMATIC S7 controllers canbe brought into contact with Allen-Bradley networks.

Main contents of this application

The widely ramified product range of both Allen-Bradley and Siemensmakes it impossible to comprehensively explain all possibilities in onesingle application. For this reason, this document focuses on one exampledescribing how an S7 PROFIBUS network can be connected to an Allen-Bradley ControlLogix network to enable a direct data exchange of the twoCPUs.

The following will be explained:

Which network technologies Allen-Bradley uses,

which products are available to establish the connection betweenAllen-Bradley and SIMATIC networks,

which technologies are used for the connection.

Delimitation

This application only includes introductory descriptions of

principles of programming Allen-Bradley ControlLogix controllers,

the use of the RsLogix 5000 configuration software for these controllers,

ladder logic as programming paradigm for PLC.

This application does not provide in-depth knowledge on these topics.


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Structure of the document

The documentation of this application is divided into the following mainparts.

Part Description

Application Description You are provided with a general overview of thecontents. You are informed on the usedcomponents (standard hardware and softwarecomponents and the specially created usersoftware).

Principles of Operation andProgram Structures

This part describes the detailed functionalsequences of the involved hardware and software

components, the solution structures and whereuseful the specific implementation of thisapplication. It is only required to read this part if youwant to familiarize with the interaction of thesolution components to use these components, e.g.as a basis for own developments.

Structure, Configuration andOperation of the Application

This part takes you step by step through structure,important configuration steps, startup and operationof the application.

Appendix This part of the documentation includes furtherinformation, e.g. bibliographic references,glossaries, etc.

Reference to Automation and Drives Service & Support

This entry is from the internet application portal of Automation and DrivesService & Support. Clicking the link below directly displays the downloadpage of this document.

http://support.automation.siemens.com/WW/view/en/23809864
http://support.automation.siemens.com/WW/view/en/23809864http://support.automation.siemens.com/WW/view/en/23809864


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Foreword


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Table of Contents

Table of Contents ......................................................................................................... 5Appl ication Descript ion ............................................................................................... 71 Automation Problem ...................................................................................... 71.1 General overview.............................................................................................. 7

1.2 Requirements ................................................................................................... 92 Automation Solution .................................................................................... 112.1 Overview of the overall solution...................................................................... 11

2.2 Description of the core functionality................................................................ 13

2.3 Required hardware and software components ............................................... 172.4 Performance data ........................................................................................... 19

2.5 Alternative solutions........................................................................................ 20Principles of Operation and Program Structures .................................................... 213 Basics on Working with Allen-Bradley Products....................................... 213.1 Controllers ...................................................................................................... 21

3.2 Networks......................................................................................................... 22

3.3 Configuration software.................................................................................... 23

3.4 The SST PROFIBUS scanner ........................................................................ 28

3.5 Variable management..................................................................................... 28

4 Functional Mechanisms of this Application ............................................... 314.1 Communication via data modules................................................................... 31

4.2 Limitation to I nt eger values....................................................................... 325 Explanations of the Example Program ....................................................... 335.1 Exchanged data.............................................................................................. 33

5.2 Details on programming the SIMATIC CPU 315 ............................................ 34

5.3 Programming the Allen-Bradley ControlLogix 5500 CPU ............................... 37

5.4 SST PROFIBUS scanner configuration.......................................................... 426 Modifications to the Example Program ...................................................... 446.1 Integrating several slaves ............................................................................... 446.2 Expanding the transferred variable ranges/data modules .............................. 446.3 Expanding the Allen-Bradley network............................................................. 45

6.4 Adaptation to other Allen-Bradley controllers ................................................. 45

6.5 Consistent transfer of larger data volumes ..................................................... 45

6.6 Transferring large data volumes ..................................................................... 46Structure, Configuration and Operation of the Application ................................... 477 Installation and Startup ................................................................................ 477.1 Installation of hardware and software............................................................. 47

7.1.1 Hardware installation...................................................................................... 47


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7.1.2 Installation of the standard software............................................................... 50

7.2 Installation of the application software............................................................ 508 Configuration ................................................................................................ 608.1 Configuring the SIMATIC configuration.......................................................... 60

8.2 Configuring the ControlLogix CPU.................................................................. 66

8.3 Configuring the SST PROFIBUS scanner...................................................... 689 Operation of the Application ....................................................................... 76Appendix and Literature ............................................................................................ 8010 Troubleshooting ........................................................................................... 8011 Literature ....................................................................................................... 8111.1 Bibliographic references................................................................................. 8111.2 Internet links ................................................................................................... 82


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Application Description

Automation Problem


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Content

You are provided with an overview of Allen-Bradley network componentsand technologies and connection options with SIMATIC networks. You areinformed on the used components (standard hardware and softwarecomponents and the user configurations created in the scope of theapplication).

The listed performance data show the performance of this application.

1 Automation Problem

You are provided with information on

... the classes of controllers and networks sold by Allen-Bradley, the optionsto establish a connection to SIMATIC networks and the motivation for sucha connection. In addition, it is explained which specific solution wasselected from the various solutions as an example.

1.1 General overview

Note From a legal point of view, Allen-Bradley is a subsidiary of Rockwell

Automation, which deals with the development and the application ofprogrammable controllers. The RSLogix configuration software forcontrollers, however, is sold by Rockwell.

To avoid confusion, the termAllen-Bradley designates all products soldby Rockwell and Allen-Bradley in this application.

Introduction

Allen-Bradley currently has a significant market share particularly in theUnited States. To serve the combination of different networks and the

increasingly desired interoperability, this application uses an example topresent an option to operate a Siemens PROFIBUS network in conjunctionwith an Allen-Bradley network.

Since a comprehensive product portfolio consisting of different classes ofcontrollers and networks has been developed and introduced to the marketby Allen-Bradley over the years, one single application cannot cover allpossible versions of Allen-Bradley products. For this reason, this documentonly focuses on one representative application.


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Al len-Bradley product range

The different controller classes which come into consideration for aconnection include (roughly sorted by ascending performance):

Table 1-1: Allen-Bradley controllers

Class Designation

Programmable logic controllers: PLC 5

SLC 500

MicroLogix

Programmable automation controllers:1

DriveLogix

SoftLogix (PC-based)

FlexLogix

ControlLogix

CompactLogix

Networks which are considered include (again sorted by ascending order ofperformance):

Table 1-2: Allen-Bradley networks

Network

Data Highway Plus (DH+)

DH-485ControlNet

DeviceNet

EtherNet/IP

Both controllers and networks greatly differ in their date of introduction,their performance and their market penetration. For this reason, a solutionwhich is valid for a large number of existing installations or which can easilybe adapted to other hardware/network combinations is presented for thisapplication.

Our example presents the use of a ControlLogix controller in conjunctionwith anyAl len-Bradley network.

1High-end controllers which are used when complex control processes/simulations, database

accesses, HMI functionalities or high computing power are required are referred to asprogrammable automation controllers by Allen-Bradley.


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Overview of the automation problem

The figure below provides an overview of the automation problem.

Figure 1-1: Overview of the automation problem

ABCPU

S7-300CPU

S7-300CPs

IOSST

PB-CP

PROFIBUS

DeviceNet*)

DeviceNet*)-Peripherie

Allen-Bradley SIMATIC

*) oder anderes Allen-Bradley-Netzwerk

SST PB-CP is an SST PROFIBUS communications processor, a plug-inmodule for ControlLogix controllers, which acts as a gateway toPROFIBUS. This will be referred to as PROFIBUS scanner in thefollowing.2

Description of the automation problem

This application solves the automation problem to provide a direct

communication of two CPUs of different manufacturers one S7-CPU andone Allen-Bradley ControlLogix CPU. It is assumed that both CPUs in theirrespective subnetworks any network such as DeviceNet for Allen-Bradley, PROFIBUS for S7 still communicate with their correspondingdistributed I/O and simultaneously perform control tasks in the distributedI/O.

In this application, the I/O devices are not directly included in thecommunication between the networks, but only indirectly via thecontrollers.3

1.2 Requirements

The ControlLogix controller communicates with its I/O devices and itsinput/output modules while the S7-CPU does the same within thePROFIBUS network. The possible connection of the ControlLogix controllerto other Allen-Bradley networks (DeviceNet, ControlNet, etc.), which can

2 We thus follow the manufacturers nomenclature.

3 An additional application describes the alternative that the SIMATIC CPU communicates

directly (i.e. not indirectly via the ControlLogix CPU) with the DeviceNet I/O devices with the aid

of an Anybus gateway (see \6\

). The corresponding application is currently being prepared andwill probably be published in fall 2006.


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take place simultaneously to the PROFIBUS communication, is not affected

by this.The PROFIBUS scanner coordinates PROFIBUS as master andcommunicates with the S7-CPU as slave.

Both controllers cyclically exchange variable blocks simulating the processvariables of a real automation problem. Importance is attached to aconsistent variable transfer.


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2 Automation Solution


... the solution selected for the automation problem.

2.1 Overview of the overall solu tion

A particularly simple model was selected for the communication betweenthe two subnetworks. A PROFIBUS scanner by SST/Woodhead (see \5\)is used to establish the connection.

This is a module which is inserted into the rack of the Allen-Bradley CPU,comparable to a CP in an S7 rack. The scanner acts as a master in

PROFIBUS and communicates with the S7-CPU as a slave.

Both controllers cyclically exchange data which are grouped in packets modules. These modules are mapped to virtual input/output ranges. Thismeans that the controllers identify the data packets as variables in their I/Oranges, the input variables of one controller acting as output variables ofthe other controller.

Diagrammatic representation

The system is installed on two separate racks, one for SIMATICcomponents and one for Allen-Bradley components, between which aPROFIBUS connection is created.

The following figure schematically shows the most important components ofthe solution in both racks:

Configuration of the SIMATIC rack

Figure 2-1: Component set of the SIMATIC rack

VOLTAGE

SELECTOR

DC 24 V

x 2

3 4

PS 307

5A SFATF

DC5V

FRCE

RUN

STOP

RUN

STOP

MRES

SIEMENS

x 2

3 4

CPU315-2 DP SM374IN/OUT 16

x 2

3 4

SM 374

Profibus network


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The SIMATIC rack includes the following components:

PS 307 power supply

S7 300-CPU (315-2)

SM374 simulator module

Configuration of the Allen-Bradley rack

Figure 2-2: Component set of the Allen-Bradley rack

A l l e n - B r a d l e y

Logix5500 DC INPUT DC OUTPUT SST Profibus SCANNER

DIAG NO STI C EL ECTR ONIC FU SINGCOMM SYS OK

COPN

RUN REM PROG

RUN I/O

RS232

BAT OK

POWER0 1 2 3 4 5 6 7

8 9 10 11 12 13 14 15

0 1 2 3 4 5 6 7

8 9 10 11 12 13 14 15

ST

FLT

ST

FLT

0 1 2 3 4 5 6 7

8 9 10 11 12 13 14 15

0 1 2 3 4 5 6 7

8 9 10 11 12 13 14 15

ST

Fuse

ST

Fuse

Profibus networkAllen-Bradley network (optional)

Slot: 0 1 2 3

The Allen-Bradley rack is equipped with the following modules:

1756-PA72/B Power supply

1756-L1M2 ControlLogix 5500 CPU

1756-IB16D Input module (digital inputs)

1756-OB 16E Output module (digital outputs)

SST-PFB-CLX-RLL PROFIBUS scanner, firmware version 5.01 orhigher

Used software

For the configuration of the SIMATIC CPU:

SIMATIC Step 7 Manager, version 5.3 or higher

For the configuration of the ControlLogix CPU:

RSLogix 5000 configuration software, version 13.03 or higher

RSLinx or RSLinx lite communication software, version 2.42 or higher(for RSLinx lite)


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For the configuration of the PROFIBUS scanner:

SST PROFIBUS Configuration Tool, version 3.6 or higher

Addi tional informat ion

A field PG is required for the configuration of the SIMATIC CPU.

The ControlLogix CPU and the PROFIBUS scanner can only be configuredvia an RS-232 interface. If the used field PG does not feature this interface,a second laptop with respective functionality is required.

2.2 Descript ion of the core functionality

Note The PROFIBUS scanner can be used in numerous ways, for example, asa PROFIBUS slave. For greater clarity, the documentation is limited tothe features actually used in this application, i.e. the use as a bus master.For a related documentation on the scanner, please refer to \2\.

In this application, two subnetworks are set up; one PROFIBUS DPnetwork with a SIMATIC CPU and an SM374 simulator module used for thesimulation of inputs and outputs and one Allen-Bradley network with oneinput and one output module.

Connection of the subnetworks

The connection between the two subnetworks is established by aPROFIBUS scanner by SST/Woodhead, which is inserted into the Allen-Bradley rack as a module, similar to a CP in the S7 environment.

The scanner is the only Allen-Bradley component which features aPROFIBUS interface and is thus physically connected to the SIMATICCPU. The scanner is logically configured as a master which cyclically pollsthe data of a slave here: the SIMATIC CPU or transfers the data to thisslave.4

4 Basically, the scanner can simultaneously communicate with several slaves; however, this

capability is not used in this application. Corresponding possible expansions of the applicationare described in chapters 6.1and 8.3.


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Data exchange via modules

In the application, the data exchange is limited to two modules (i.e. datapackets):

16 words from the Allen-Bradley CPU to the SIMATIC CPU(master slave),

6 words from the SIMATIC CPU to the Allen-Bradley CPU(slave master).

The data modules include simulated process data, counter values andswitch positions of the SM374 module.

Configuration of the modulesBasically, virtually any number of modules can be configured for thecommunication with a number of different slaves. However, the totalvolume of the data exchanged via the modules must not exceed 240 writtenor received data words per cycle and no individual module must be largerthan 16 words.

The data modules are from the output memory areas of the two CPUs andwritten into the input range of the respective other CPU. This is the actualPROFIBUS DP communication; in this application, the CPU configurationsadditionally ensure that the received values are routed to the outputmodules in their slots where they are displayed. But this only visualizes the

successful PROFIBUS communication.

Data consistency during the transfer

The transfer of the data packets between the CPUs is consistent, i.e., it isnot possible to modify the contents of one of the data packets between thestart and the completion of the transfer. This ensures that all elementswithin one transferred packet always represent the same system state.

It is, for instance, excluded that the system changes from state A to Bduring the transfer of the data so that one part of the data would still belongto state A and the other part already to B.

Consistency is always only ensured within one module. If several modulesare configured, the planner is responsible for ensuring the cross-moduledata consistency.

Overview of the data exchange

The figure below schematically shows the communication paths used inthis application.Table 2-1 explains the individual steps.


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Figure 2-3: Sequence of the data exchange

CPU 315-2 DP

Outputrange

Inputrange

SM374

DP

Logix5500

Input Output Profibusscanner

Inputrange

Inputrange

Inputrange

Outputrange

Outputrange

Outputrange

DP

SIMATIC

Allen-Bradley

16 words

n

o

u

p

q

r

s

t

v

w

6 words

Sequence of the core funct ionality

The following tables show the individual communication steps asschematically represented in Figure 2-3.

Table 2-1: Sequence of the core functionality: Communication from SIMATIC to Allen-Bradley

Action Note

1. Data from the input range of the SM 374 arecopied to the output range of the CPU 315.

The data are one data byte of whichthe value is determined by the switchpositions on the SM 374.

2. Together with further simulated process data, a

data module is prepared for the transfer viaPROFIBUS DP.

Data volume: 6 words

3. The CPU 315 transfers the data module inreply to the polling by the PROFIBUS scanner.

4. The data module received at the PROFIBUSscanner is copied to the input range of theControlLogix CPU.

5. The data are used to control the LEDs on theoutput module.

Data volume: One word, whichtransfers CPU 315 counter contentand SM 374 switch position.


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Table 2-2: Sequence of the core functionality: Communication from Allen-Bradley to SIMATIC

Action Note

6. A data module for the transfer to the CPU 315 isassembled in the ControlLogix from the inputrange of the input module and internalvariables.

7. The data module is transferred to thePROFIBUS scanner.

8. The module is transferred to the CPU 315 slaveby the scanner master.

Data volume: 16 words

9. The received data are copied to the input rangeof the CPU 315.

10. Parts of the data from the input range are usedto control the SM 374.

Note The individual steps are only represented in a logical order. It is in no wayensured that the actual order of the steps within a CPU cycle is identicalto the sequence in the table.

On the contrary: The clock cycles of S7-CPU and ControlLogix CPU arenot matched to one another and a PROFIBUS DP communication doesnot occur during each CPU cycle.

Advantages of this solut ion

The application of this solution is perfectly suited particularly due to the factthat its configuration is simple and not complicated:

The hardware additionally required to connect the two (assumed to bealready existing) subnetworks is limited to the PROFIBUS scanner.

The configuration overhead is also insignificant; it is basically limited to thedefinition of the new data modules in the ControlLogix CPU and theCPU 315 and the registration of the used hardware in the PROFIBUSscanner. To ensure the consistency of the transferred modules, only

standard blocks have to be used.The communication with several slaves can also be configured easily andquickly; the data are transferred at a speed that is sufficient for mostapplications.

See also chapters 2.5 and 6.1.


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2.3 Required hardware and software components

Note In the tables below, components not sold by Siemens are silhouetted ingray. The respectively specified sales sources are responsible for theirprocurement (see also page 18).

Hardware components

Table 2-3: Required hardware components

Component No. MLFB / Order number

Note

SIMATIC Field PG MStandard

1 6ES7712-0AA0.-0XXX

Or comparable PC with MPI

PS 307 load powersupply

1 6ES7307-1BA00-0AA0

Or comparable power source

SIMATIC S7-300 CPU315-2DP

1 6ES7315-2AG10-0AB0

Or SIMATIC NET PROFIBUSCP (CP 342-5)

SIMATIC MicroMemory Card 2 MB

1 6ES7953-8LlOO-0AA0

Or higher capacity

SM 374simulator module

1 6ES7374-2XH01-0AA0

Or DI8/DO8 module withdigital inputs/outputs

Power supply 1 1756-PA72/B Procurement via 1

ControlLogix 5500CPU

1 1756-L1M2 Procurement via 1

Input module 1 1756-IB16D Procurement via 1

Output module 1 1756-OB16E Procurement via 1

PROFIBUS scanner 1 SST-PFB-CLX-RLL

Procurement via 1

In addition, a PROFIBUS cable for connecting CPU 315 and PROFIBUSscanner and a null modem cable (RS232, 9-pin sub D plug) for configuringControlLogix controller and PROFIBUS scanner are required.

Standard sof tware components

Table 2-4: Required software components

Component No. MLFB / Ordernumber

Note

Simatic S7, Step 7V5.3 incl. SP3 (orhigher)

1 6ES7810-4CC07-0YA5

RSLogix 5000Standard Edition,V13.03 (or higher)

1 9324-RLD300DEE

German version, procurementvia 1


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Component No. MLFB / Order

number

Note

SST PROFIBUSConfiguration, V3.6 (orhigher)

1 Included in the scope ofdelivery of the PROFIBUSscanner; if not, procurementvia 2

Sources of supply for Germany:

1. Rockwell Automation regional office of Rockwell Int'l GmbHDsselbergerstrasse 1542781 Gruiten

GermanyTel: +49 2104 9600Fax: +49 2104 960 121(see also \4\

2. Woodhead Connectivity GmbHIm Gssle 970771 Leinfelden-Echterdingen,GermanyTel: +49 711 782374 0Fax: +49 711 782374 11(see also \5\)

Example files and projects

The following list includes all files and projects used in this example.

Table 2-5: Configurations included in the application

Component Note

23809864_DOKU_v10_e.pdf This document.

23809864_CODE_v10.zip Configurations for the application

The code archive 23809864_CODE_v10.zip includes the followingconfigurations:

Table 2-6: Configurations within the code archive

Configuration Note

23809864_allen_bradley_s7_v10.zip STEP 7 project

23809864_allen_bradley_rslogix_v10.zip Allen-Bradley configuration forRSLogix/ControlLogix CPU

23809864_allen_bradley_sst_v10.zip Configuration for SST PROFIBUSConfiguration Tool/PROFIBUSscanner

CPU315-2AF02.ZIP GSD file for CPU315-2DP (seechapter 5.4)


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2.4 Performance data

The presented technology for the data exchange between the CPUs issubject to the following restrictions:

The size of the exchanged data modules must not exceed 244 bytes forthe inputs and outputs of each individual slave.

The permissible total size of all data modules is 246 words for outputsand 248 words for inputs.

The size of each individual module for which the consistent transfer isstill ensured is 16 words.

A maximum of 35 modules (for inputs and outputs) can be defined.

The presented example is limited to the use with ControlLogixcontrollers, however, it can easily be adapted. Compare chapter 6.4.

The communication takes place between the CPUs. It is not possible todirectly access the I/O devices within the Allen-Bradley network.

If these key data represent serious restrictions, alternative solutions arelisted in chapter 2.5.

Please also observe that only integer variables are correctly transferredwith the suggested example. See chapter 4.2.


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2.5 Alternative solutions

The communication via the PROFIBUS scanner standard mechanismspresented in this document requires little hardware and configurationoverhead and provides a performance which is sufficient for manyapplications.

At the same time, however, the mechanism is subject to specific restrictionsas mentioned in chapter 2.4. If these key data do not meet therequirements, the following alternatives are available:

The consistent transfer oflarger data areas can be achieved byimplementing a protocol layer for the controllers, which causes a

segmentation of the data blocks into smaller, consistent modules andwhich puts the transferred modules together to form a consistent blockon the receiving end.Such a mechanism has been developed for the S7, e.g. in \5\. However,it would still have to be configured and tested on the Allen-Bradley side.

SST/Woodhead also sells scanner modules which are designed forother controllers such as PLC-5 and SLC 500, but which basicallyhave the same functionality as the used scanner. Compare \5\.

The company sells HMS networks gateways under the brand nameAnybus, which can link a large number of networks. These gatewaysinclude models which can connect other Allen-Bradley networks such

as DH+, DH 485 or ControlNet to PROFIBUS networks, see also \6\.For the use of these gateways, please refer to the application /3 (fall2006).5These gateways also allow direct communication with the Allen-BradleyI/O devices from the PROFIBUS network.

INAT GmbH sells Echochange gateways, which can establish theconnection from Ethernet/IP networks (Allen-Bradley) to other Ethernetnetworks, in particular Industrial Ethernet (SIMATIC). See /7/ (fall 2006)or \7\.

The actual PROFIBUS scanner can not only be operated as a masterbut also as a slave.

5 It has to be observed that this application is not subject to restrictions with regard to the used

Allen-Bradley networks since PROFIBUS is directly connected to the Allen-Bradley rack and nodistance has to be bridged between gateway and CPU.


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Principles of Operation and Program Structures

Basics on Working with Allen-Bradley Products


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Content

This part describes the detailed functional sequences of the involvedhardware and software components, the solution structures and whereuseful the specific implementation of this application.

It is required to read this part if you are interested in the interaction of thesolution components.

3 Basics on Working with Allen-Bradley Products


... the controllers, networks and configuration paradigms Allen-Bradley usesand the used nomenclatures. You are provided with a brief overview of theautomation work with Allen-Bradley products.

3.1 Controllers

Programmable logic controllers and programmable automation controllers

Allen-Bradley always divides its controllers into two groups: Programmablelogic controllers (PLCs) and programmable automation controllers

(PACs).PACs are used for demanding tasks. They combine PC and PLCfeatures.

The table below shows typical properties and fields of application of the twocontroller classes.

Table 3-1: Typical fields of application and use of PLCs and PACs

PLCs PACs

Control of inputs and outputs Advanced control algorithms

Logical interconnections Manipulation of comprehensivedatabases

Timing HMI functionality without using aseparate device

Communication Complex process simulation

Generation of reports Very high computing power andmemory requirements

Simple counting and math operations


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PLCsMembers of the PLC group are the controllers of the classes

PLC 5: The oldest still actively supported controllers. They can beroughly compared to S5 controllers regarding performance and also stillconsist of relatively large sized cards.

SLC 500: More modern controllers with smaller form factor andgenerally a higher performance. Its specifications can roughly becompared to an S7-300.

MicroLogix: Controllers aimed at the low price segment andcorrespondingly limited in their performance capability.

PACs and Logix platform

Currently, the following classes are sold:

CompactLogix: Controllers for compact applications

ControlLogix: High-performance controllers in compact form factor

SoftLogix: PC-based control solutions

FlexLogix: Low-level models as budget-priced alternatives toControlLogix controllers.

All PACs belong to the Logix platform, which is characterized by

standardized configuration, communication and visualization concepts.

3.2 Networks

In the course of the technical development, Allen-Bradley also developed anumber of protocols for communication.

Data Highway Plus (DH+, proprietary): The oldest still supportedprotocol by Allen-Bradley, originally developed for the work with PLC 5controllers. Serial communication via RS-422/RS-232 cables with up to57.6 Kbit/s and 99 network nodes.

DH-485 (proprietary): DH-485 is a further development of DH+ for multi-master operation. It was designed for use with SLC 500 PLCs andsupports up to 32 nodes on an RS-485 cable. The communication cantake place with up to 19.2 Kbit/s.

DeviceNet (open): A more modern protocol based on CAN technology.It is intended for linking sensors and actuators to modern controllers atprocess level.

ControlNet (open): A high-performance protocol based on coax andglass fiber connections developed for the communication at controllevel. The data rate is up to 5 Mbit/s.

Ethernet/IP (open): An adaptation of the Ethernet communication to theindustrial environment requirements.


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Nowadays, virtually every Allen-Bradley controller can communicate via

each of the offered networks with the aid of corresponding gateways, etc.

3.3 Configuration software

RSLogix 5000

The application with the aid of which ControlLogix and other Allen-Bradleycontrollers are configured is named RSLogix 5000; its functionalitybasically corresponds to the SIMATIC Manager. The current version is13.3. The figure below is a screen shot of the configuration user interface.

Figure 3-1: RSLogix 5000 screen shot

The left screen field includes the Project Tree which lists the componentsof the project hardware, program code and variables. The right screenfield changes depending on the component selected in the Project Tree;the figure shows a command sequence programmed in ladder logic (seebelow).


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Figure 3-2: RSLogix screen shot , tag table

In addition, RSLogix also provides further options for project management.The above screen shot shows a selected table of tags, which basicallycorresponds to the function of the variable table of the SIMATIC Manager.RSLogix also enables to access an online view of the current values of thetags in the viewed controller and to modify them in the process sequence if

required (forcing).

Ladder logic

Ladder logic is the programming paradigm preferred by Allen-Bradley, theCPUs are programmed with ladder logic by default also in RSLogix.

A chart is drawn, which consists of two vertical rails on the left and on theright. The two rails are connected by a row of horizontal rungs. (See Figure3-3 below.) A number of conditions and instructions is located on eachrung. The individual rungs are sequentially processed from top to bottomduring one program cycle. Due to this, the ladder logic bears a certainresemblance to a ladder diagram (LAD).

As an alternative, the ControlLogix controllers can also be programmedwith Structured Text, a text-oriented configuration language, which ratherfollows traditional programming languages or SCL.


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Figure 3-3: Screen shot of the ladder logic programming example as used in the RSLogix configurationsoftware.

Although many suppliers use ladder logic for the programming of theirPLCs, the details of the implementation always differ. This makes itnecessary to check the function of a ladder logic diagram in each individualcase.

Tasks, programs and routines

The configuration within the ControlLogix controller is hierarchically dividedinto tasks, programs and routines, which represent individual modulesstructuring both the program flow and the managed data.

The top programming level consists of the tasks. Aside from themain task, which always exists (comparable to OB 1 of S7), up to31 further tasks can be programmed. A priority is assigned to eachtask, the task with the highest priority is always executed. If severaltasks have the same priority, they share the available computingtime in the form of 1 ms time slices.Controller tags are variables which globally exist in all tasks.

Up to 32 programs can be defined within each task. Theseprograms are not executed concurrently as the tasks but strictlysuccessively in the order in which they are defined in the source

code.


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Each program has variables with a local range of validity in the form

of program tags. Programs can be divided into routines. The function of these

routines can be compared to S7 function blocks or procedures ofclassic programming languages.

A symbolic addressing of the variables ( via variable names) is the defaultfor the ControlLogix programming, the exact placing of the variables in thememory is left to the configuration software. But it is also possible toexplicitly assign specific memory locations to variables.

User-defined data types can be defined as structures.

RSLinxRSLinx is an application which cooperates closely with RSLogix andwhich provides communications services for this application. It acts as atype of driver with additional functions for diagnostics and configuration. Itcan, for example, provide an overview of the networks active nodes via theRSWho option.

Figure 3-4: RSLinx screen shot with an overview of the active modules in the Allen-Bradleyrack

Note RSLinx is automatically called by RSLogix, but it is not automaticallyterminated when stopping RSLogix. This may particularly cause that theserial interface is not enabled. In this case, the SST PROFIBUSConfiguration Tool (see page 27) can no longer communicate with thePROFIBUS scanner.If required, RSLinx must be manually terminated or the computer has tobe restarted.


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SST PROFIBUS Configuration Tool

The SST PROFIBUS Configuration Tool is a software with which thePROFIBUS scanner by SST/Woodhead is configured. The main function isto communicate to the PROFIBUS scanner which variable ranges (datamodules) are to be exchanged with which bus nodes.

Note It has to be observed that the SST PROFIBUS Configuration Tool wasnot developed by Rockwell/Allen-Bradley; thus, its interaction withRSLogix/RSLinx requires particular care.

Figure 3-5: SST PROFIBUS Configuration Tool screen shot

As illustrated above (Figure 3-5), the SST Configuration Tool shows atripartite screen. The left column includes a tree structure which lists theavailable bus node types, i.e., the models of known PROFIBUS mastersand slaves. As a further tree structure, the box on the right includes theactual scanner configuration consisting of branches in which the individualbus nodes are linked to the scanner and attached twigs which concern theexchanged data areas.

In the above example, the scanner is configured to communicate withexactly one slave, a CPU 315. Aside from three dummy entries, thescanner as master exchanges one input and one output data range withthis slave.


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A bar that can be used for network diagnostics is located in the bottom

screen field. It displays the found bus nodes and their properties.

3.4 The SST PROFIBUS scanner

The PROFIBUS scanner is one of many network gateways sold bySST/Woodhead. The gateways are used in the form of plug-in cards ormodules, which can connect different Allen-Bradley networks or controllersas master or slave to a PROFIBUS. In our application, a PROFIBUSMaster module (a scanner) is used together with a ControlLogix CPU.

The scanner is configured with a separate software. The configuration isused for the following tasks:

For the ControlLogix CPU, input/output modules are defined for thecommunication: As seen from the CPU, the scanner operates as anI/O module; the data packets to be exchanged (modules) aremapped to the I/O ranges of the CPU. (See below.)

The PROFIBUS configuration (bus addresses, baud rates, cycletimes) is defined and the exchanged data modules are assigned tothe slaves on the PROFIBUS.

3.5 Variable management

The main difference between the management of data and variables in

Allen-Bradley and SIMATIC is that the separation between memory areas(flags, input/output ranges, etc.) on the one hand and symbolic variableson the other hand is not so distinct.

Controller tags

Aside from procedure-local and temporary variables, the RSLogix softwareautomatically generates a set of controller tags, which are shown inFigure 3-6 as examples. Aside from the variables defined by the user inthis case the user-defined types Data_received and Data_to_sendwith their respective members the controller tags comprise also variablesautomatically generated by the system which correspond to the input/outputranges of the modules integrated in the rack.

These data areas are designated with Local:n:, n representing thenumber of the slot in which the respective module is located. The variablesof the scanner configured in slot 3 are also located in the Local:3: area.


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Figure 3-6: Variable management of the ControlLogix CPU with controller tags

Depending on the function of the module, the memory areas are furtherdivided into

C (Control),

I (Input),

O (Output) and

S (Status)

sections:

Table 3-2: Different sections of the controller tag fields

Design. Section

C Control

I Input

O Output

S Status

In the 1756-OB 16E output module in slot 2 of our configuration, the Osection is, for example, occupied by the process output image. Eachsection consists of an array containing the actual data designated withData. Local:2:O.Data.3 thus includes data bit 3 in the output rangeof the I/O module installed in slot 2, Local:3:S.Data[12] (note thesubtle distinction of the syntax!) data word 12 in the S section of module3.6

6 Depending on their use, the individual memory area elements can be specified in different

data types and addressed correspondingly. Mostly BOOL or INT (corresponds to WORD) areused.


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Structure of the controller tags area of the PROFIBUS scanner

The structure of the scanners input and output fields is as follows:

Table 3-3: Memory area structures of the scanner. The offset is specified in words.

Area Offset (words) Meaning

0 Register: Scanner Status

Input 1 Register: Command Reply

2 ... 247 (246 words) User data

0 Register: Issue Command

Output 1 Register: Command Value

2 ... 249 (248 words) User data

The sent and received data words can thus only start in the controller tagLocal:3:I:Data[2] or Local:3:O:Data[2] since the words 0 or 1are used as registers for the communication with the actual scanner.

The output words 0 and 1 are of particular importance. A new status can beentered in word 1; by setting word 0 to 1, a change to this status is thenactually performed.

Possible status values are:

Table 3-4: Scanner statuses (Command Value), specified in word 1 of the output range,change by setting bit 0 in word 0 (Issue Command).

Value Meaning

0 Not specified

1 Run

2 Clear

3 Clear status counter

4 Set scanner online

5 Read slave diagnostics

6 Acknowledge slave diagnostics

7 Set scanner offline

To commission the scanner after the configuration, first word 1 and thenword 0 of the output range have to be set to the value 1.

For detailed information on the contents of the command and statusregisters and of the status area, please also refer to \2\.

The exchange of the data modules between scanner and SIMATIC will beexplained in detail in chapter 4.1.


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Functional Mechanisms of this Application


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4 Functional Mechanisms of this Application


... the PROFIBUS communication mechanisms on which this application isbased.

4.1 Communication via data modules

The used PROFIBUS DP mechanism, which switches the communicationbetween a PROFIBUS master and the I/O modules configured as a slave,is based on the exchange of data modules.

This application is configured in such a way that

the SST PROFIBUS scanner acts as a master and

the CPU 315 operates as an intelligent slave.

The scanner takes the initiative of the communication.

Basically, any data can be exchanged between scanner and SIMATICCPU. The data are prepared by being displayed as input/output variableswhich are exchanged between master and slave as intelligent I/Odevices.

Figure 4-1 shows the principle of the communication:

Figure 4-1: PROFIBUS communication via data modules in the SIMATIC. Managing the process image inthe ControlLogix CPU is similar. (See chapter 3.5)

Backplane

bus

Profibus

CPU

DB DB Flags

Process image(I/O memory area of the CPU)

Physical variable ranges(e.g. SM 374)

Data modules from/to Profibuscommunications partners

Consistent copying(BLKMOV)

Daten areas of the CPU


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Data from the data blocks (or other memory areas of the CPU) are stored in

the process image. From there they are either transferred to the I/Omodules, or they are sent to the receivers as virtual I/O modules viaPROFIBUS. (Since the communications partners appear to the user as I/Omodules, they are also configured in the hardware configuration of theCPU.)

Data from outside pass the opposite way and are copied to data blocks orother memory areas for further use after having been included in theprocess image.

When copying, it has to be observed that it is performed consistently.Otherwise there is a risk that a new data module is received or sent duringcopying. This means that a part of the data would still have the old time

stamp, but the other part already the new one.

The figure shows the process for SIMATIC controllers. Basically, theprinciple of operation is identical for Allen-Bradley.

4.2 Limitation to Integer values

Note Due to the different internal data formats of the two controllers (bigendian or little endian), only integers (2 bytes or 1 word) are transferredcorrectly.

When transferring a sequence of individual bytes, a change of the byte

order may occur, high and low word are exchanged for longer data units(long int or real).

This problem cannot be solved without programming overhead. The datatransfer of the stream works correctly, but the problem is the assignment ofthe individual bytes to the variables to which they are associated. Thecorresponding information gets lost in the Profibus communication, whichonly sees a stream of individual bytes in the transferred data!


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5 Explanations of the Example Program


... the setup of the SIMATIC and Allen-Bradley configurations and theessential code sections.

5.1 Exchanged data

The functionality of the application is that master and slave (thusPROFIBUS scanner and CPU 315) exchange data.

Table 5-1 provides an overview of the exchanged data.

Table 5-1: Data exchanged in the application

Memory locationCPU 315

Datatype(S7)

Memory locationAl len-Bradley

Data typeAl len-Bradley

Address

offset

Remark

DB 1. From_CPU315.switches BYTE Switches SINT 0 (S7)

1 (AB)SM 374 switchposition

status BYTE Status SINT 1 (S7)0 (AB)

reserved INT 2-3

cycle_counter DWORD S7_cycles DINT 4-7 CPU 315program cyclecounter

DB 2. To_CPU315.counter_x INT Counter INT 0-1 Program cycle

counter of theAllen-BradleyCPU

ib16d INT ib16d_inputs INT 2-3 Status of theinputs of theIB16D module

scanner INT Scanner_status INT 4-5 Scanner status(internal variable)

active_slaves INT Active_slaves INT 6-7 Slaves detectedon the networkby the scanner

confirmations INT Confirmations INT 8-9 Receivedconfirmations(scanner networkvariable)

indications INT Indications INT 10-11 (Scanner networkvariable)

notOKINT

NotOK

INT 12-13


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Memory location

CPU 315

Data

type(S7)

Memory location

Al len-Bradley

Data type

Al len-Bradley

Address

offset

Remark

scanner_control BYTE Scanner_control SINT 14

speed REAL Speed REAL 16-19 Simulatedprocess variable

angle DINT Angle DINT 20-23

Please observe the exchange of the memory cells for status andswitches. Values that have not been correctly transferred (comparechapter 4.2and section 9) are italicized and only for demonstration!

See also the description of the data blocks and the following sections.

5.2 Details on programming the SIMATIC CPU 315

The programming of the CPU 315 is not very extensive. It only consists ofOB 1 and two data blocks DB 1 and DB 2, which have the user-definedstructures.


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OB 1

Figure 5-1: Programming of OB 1

The individual networks in OB 1 have the following function:


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Table 5-2: Programming of OB 1

Networkno.

Function

1. The received data module (configured to the memory area from inputbyte 5) is copied to DB 2 (volume: 24 bytes)

2. The counter_x variable from DB 2 is mapped to output byte 4.(These are the output LEDs of the SM 374); the switches variableof DB 1 (!) is copied to output byte 5 of the SM 374.)

3. The status of the switch on the SM 374 (input byte 4) is copied intothe switches variable in DB 1 anda program cycle counter(cycle_counter) is incremented.

7

4. The data from DB 1 are copied to the output data module (memory

area on output byte 6, volume: 8 bytes).

Note SFC 20, BLKMOV, is used for the copy operations since this ensuresconsistent data handling.

Note The switches variable is defined by the position of the lower eighttoggle switches on the SM 374 module. It has to be observed that theselector switch of the SM 374 (front panel center) is set to position8 Output, 8 Input.The display of the output LEDs is not determined by the current switch

positions, but by the values buffered in DB 1. For this reason, the displayalways lags one communication cycle behind the actual switch position.

Data blocks DB 1 and DB 2

DB 1 includes the data that are sent to the PROFIBUS scanner:

Figure 5-2: Structure of DB 1

Values are not written to the status variable.

reserved has only been inserted for demonstration purposes. The actualdata transfer in the modules is performed as a mere byte field withoutinternal structure. It is thus theoretically possible (even though rarelydesired) to write a structure to the data to be sent which differs from the

7

This variable is not synchronized with Data_to_send.Counter (see. Table 5-3); thevalues of both variables are independent of one another.


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one with which they were read. For instance, the sender can write a

sequence of four bytes which are read by the receiver as a doubleword.8

DB 2 comprises the variables which are received by the scanner:

Figure 5-3: Structure of DB 2

counter_x is a counter of the Allen-Bradley CPU which is incrementedevery 256 CPU program cycles.

ib16d indicates the status of the inputs in the IB16D digital input modulein the Allen-Bradley rack.

The variables scanner, active_slaves, confirmations,indications, notOK and scanner_control are diagnosticvariables the PROFIBUS scanner has reported to the Allen-Bradley CPUfrom where the variable values returned to the SIMATIC via the scanner.Primarily active_slaves is of interest. In this word, the addresses ofthe slaves are stored which the scanner has detected in its role as a master

on PROFIBUS. If, for example, bit 4 is set to TRUE, a slave with address4 has been detected on the bus. (The addresses 0 to 15 are encoded.)

speed and angle are two simulated process variables. They arecurrently not written to and only used to demonstrate that basically alsofloating point values, etc. can be transferred. Please observe chapter 4.2!

5.3 Programming the Allen-Bradley ControlLogix 5500 CPU

Ladder logic

The programming of the ControlLogix 5500 CPU was deliberately keptsimple. There is only one task which does not include any further sub-

programs or routines so that the necessary instructions are all executed inthe main task. Only controller tags with a global range of validity weredefined, but no module global or local variables.

The figures and tables below represent the function of the ladder logicprogram.

8

The loss of the data structure is also indicated by the fact that the copy commands from and tothe input/output ranges of the modules only copy memory areas, irrespective of their contents.


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Figure 5-4: P rogramming the main task, rung 0-2. The rung numbers are displayed on theleft as blue figures.

Table 5-3: Explanation of the ControlLogix main program inFigure 5-4

Rung Description

0. Incrementing the Counterauxiliary variable and theData_to_send.Counter

9variable to be transferred.

1. Reading the status of the inputs of the IB16D module

2. Copying the Scanner_status scanner diagnostic variable

9

This variable is not synchronized with cycle_counter (see. Table 5-2); the values of bothvariables are independent of one another.


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Figure 5-5: P rogramming the main task, rung 3-6 (continuation)

Table 5-4: Explanation of the ControlLogix main program inFigure 5-5 (continuation)

Rung Description

3. Copying the list of active slaves

4. Copying the further diagnostic variables

5. ...

6. ...


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Figure 5-6: P rogramming the main task, rung 7-10 (continuation)

Table 5-5: Explanation of the ControlLogix main program inFigure 5-6 and Figure 5-7 (end)

Rung Description

7. Copying the further diagnostic variables

8. Consistent copying of the data to be sent to the scanner

9. Consistent copying of the received data from the scanner

10. Representation of the Allen-Bradley counter

11. ... and of the switch position on the SM 374 module on the LEDs of theOB 16E output module

Figure 5-7: P rogramming the main task, rung 11 (end)


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Note The CPS commands (Synchronous Copy File) are used for steps 8and 9 since otherwise a consistent transfer would not be ensured. Itsfunction is analogous to SFC 20 of the SIMATIC.

Data structures

Figure 5-8: Overview of the defined controller tags

The structure of the user-defined data structures is shown below. Themeaning of the individual member variables corresponds to the SIMATICdata block descriptions, see also Figure 5-2 and Figure 5-3 and theaccompanying text. (Page 36)

Figure 5-9: User-defined data type for the data structure sent by S7

Please note that the order of the first two members Status andSwitches respectively is exchanged in the From_CPU315 structurecompared to the corresponding elements of DB 1 (compare Figure 5-2 ).This is the consequence of the different data formats of the controllersdiscussed in chapter 4.2.

S7_cycles is also not transferred correctly. A display of the variablevalues in hexadecimal representation illustrates the problem.


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Figure 5-10: User-defined data type for the data structure received by S7

5.4 SST PROFIBUS scanner configuration

The configuration of the PROFIBUS scanner basically consists of threesteps:

1. Defining the master (i.e. the actual scanner),

2. defining the slaves to which the master is connected,

3. configuring the data modules to be exchanged with the slaves.

The figure shows a screen shot section of the SST PROFIBUSconfiguration software with which the scanner is configured.

Figure 5-11: Overview of the PROFIBUS scanner configuration

The elements inserted inFigure 5-11 correspond to the three steps.

The top entry (under PROFIBUS DP, marked with Disconnected sincethere was no connection to the scanner at the time of the screen shot)marks the actual scanner.

The SIMATIC CPU is entered in the line below (highlighted). Since Allen-Bradley considers this is a third-party product, the controller has to beintroduced to the scanner by entering its configuration file (GSD file) inthe project. (See note page 72 andTable 8-6).

Finally, the exchanged data modules follow. The entries [003] and [004],the two only actually read and written blocks, are relevant.


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Note Although the entries [000] to [002] do not define user data, they mustnot be left out. The numbering of the modules corresponds to the (virtual)slots of the I/O modules in the S7 rack. In this rack, however, slots 0 to 2are occupied by the power supply and the actual CPU.In other words, the above blank entries are not defined and the scannerattempts to exchange data with the incorrect virtual slots andcommunication cannot be established.

Note The volume of the defined data areas is 32 bytes for both modules. (Thisis the maximum which can be consistently transferred.) The configureduser data volume, however, is only 8 bytes (SIMATIC to Allen-Bradley)or 24 bytes (Allen-Bradley to SIMATIC).


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Modifications to the Example Program


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6 Modifications to the Example Program


... how you can expand this application to adapt it to your requirements.

Note Specific instructions for the expansion and adaptation of your project arealso listed in chapter 8.

6.1 Integrating several slaves

To integrate more than one slave into the project, expand the PROFIBUS

scanner configuration correspondingly by making an entry for each slaveanalogous to the already configured CPU 315 and by assigning further datamodules to this entry.

Please observe that it might possibly be necessary to adapt the busparameters to maintain the communication. To do this, consult yourPROFIBUS documentation.

6.2 Expanding the transferred variable ranges/data modules

To expand the transferred data, two options are available:

Increase the size of the DBs (SIMATIC) and user defined types(Allen-Bradley) by the respective components. At the same time,ensure that the copying processes correspond to the new blocksizes in both controllers.10This procedure allows you to transfer a maximum of 32 bytes ineach direction in one module.

For larger data volumes, define several data modules for thetransfer.Define these modules analogously to the already defined modules.Changes have to be made in the configuration of the PROFIBUSscanner and in HW Config of the S7 project11. (See alsochapter 8.1) For the two controllers, the changes only result in an

increase in size of the usable I/O ranges.With this procedure, you can define up to 35 modules with a totalvolume of 244 bytes for input and output for each module.

10 Please ensure that the alignment of the elements of the data blocks corresponds in both

controllers. Refer also to the explanation of the reserved variable, page 36.

11 Data modules are handled as virtual I/O modules.


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6.3 Expanding the Allen-Bradley network

As long as you only want to use one CPU in your Allen-Bradley network,just proceed as if the PROFIBUS scanner did not exist when configuringthe network. The presence of the scanner only affects the ControlLogixCPU as an additional I/O module inserted into the rack; the scanner is notperceived as a network node and the Allen-Bradley internal networking isnot affected by this.

In other words, set up your network as if you used no PROFIBUS scanner.

In case of doubt, consult the Allen-Bradley documentation and comparableresources.

6.4 Adaptation to other Allen-Bradley control lers

The presented PROFIBUS scanner is only one model of the backplanemodules sold by SST/Woodhead. The following table lists the completecurrent product range.

Table 6-1: SST/Woodhead backplane modules for PROFIBUS

PLC class Order number Use

PLC 5 SST-PFB-PLC5 Master or slave

SLC 500 SST-PFB-SLC Master or slave

SST-PFB-SLC-ADP Only slave

ControlLogix SST-PFB-CLX-RLL Master or slave

Controllers other than ControlLogix PLCs are configured with thecorresponding module analogously to this application.

Anybus gateways (see /3/ and \6\) and other alternatives are available forthe other controllers.

6.5 Consistent transfer of larger data volumes

The size of an individual data module is limited to 32 bytes. This is

concurrently the largest unit for which the PROFIBUS scanner guaranteesa consistent transfer.

To transfer larger data blocks consistently, it is required to program aprotocol layer in the two CPUs, which performs the following tasks:

Separating the data blocks into modules of the permissible size,

transferring the individual modules,

assembling the modules at the receiver,

checking the complete transfer and validity of the data; if required,new request of the transfer.


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An application exists which solves this task for the connection of two

SIMATIC CPUs. (Compare /5/) However, please observe that thefunctionality still has to be programmed on the Allen-Bradley side in thiscase.

6.6 Transferring large data volumes

The PROFIBUS scanner is limited to input/output ranges of 246 data byteseach.

If larger data volumes are to be exchanged between the controllers, thepresented methods are no longer feasible.


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Structure, Configuration and Operation of the Application

Installation and Startup


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Structure, Configuration and Operation of theApplication

Content

This part takes you step by step through structure, important configurationsteps, startup and operation of the application.

7 Installation and Startup


... the hardware and software you have to install and the steps necessary tostart up the example.

7.1 Installation of hardware and software

This chapter describes which hardware and software components have tobe installed. The descriptions and manuals as well as delivery informationincluded in the delivery of the respective products should be observed inany case.

7.1.1 Hardware installation

For the required hardware components, please refer to chapter 2.3 andTable 2-3.

Note In general, the installation guidelines of the individual components haveto be observed.

Configuration of the SIMATIC rack

For the hardware configuration, please follow the instructions listed in thetable below and observe Figure 7-1:

Table 7-1: Hardware installation of the SIMATIC rack

No. Instruction

1. Use a backplane bus connector to connect the CPU 315 2DP and the SM 374 module.

2. Attach all three components side by side on a suitable rack.

3. Connect the 24V power supply of the CPU to the voltage source (PS 307). Ensure thatthe polarity is correct. Connect the PS307 source to the network. (230 V alternatingcurrent)

4. Connect the CPU to the PROFIBUS network.

The configuration of the CPU can be performed either via PROFIBUS orthe MPI.


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Figure 7-1: Component set of the SIMATIC rack

VOLTAGE

SELECTOR

DC 24 V

x 2

3 4

PS 307

5A SFATF

DC5V

FRCE

RUN

STOP

RUN

STOP

MRES

SIEMENS

x 2

3 4

CPU315-2 DP SM374IN/OUT 16

x 2

3 4

SM 374

Profibus network

24V DC

Backplane bus connector

Configuration of the Allen-Bradley rack

For the hardware configuration, please follow the instructions listed in thetable below and observe Figure 7-2:

Table 7-2: Hardware installation of the ControlLogix rack

No. Instruction

1. Insert the modules side by side into a suitable rack. Ensure the correct order andassignment of the slots (seeTable 7-3 )!

2. Connect the PA72B voltage source to the network. (230 V alternating current)

3. Connect the PROFIBUS scanner to PROFIBUS.

4. Connect the CPU to your Allen-Bradley network.

Note You are free to select your Allen-Bradley network; any network can beused which is supported by the used CPU. This application is completelyindependent of the existence of an Allen-Bradley network.

The configuration of the ControlLogix CPU is performed via the serial porton the front of the housing. The PROFIBUS scanner is also configured via

the serial port on the front of the scanner.The order of the modules in the rack must be as follows:


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Table 7-3: Order of installation of the modules in the Allen-Bradley rack

Slot Module

-- 1756-PA72/B power supply

0 1756-L1M2 ControlLogix 5500 CPU

1 1756-IB16D input module

2 1756-OB 16E output module

3 SST-PFB-CLX-RLL PROFIBUS scanner

Figure 7-2: Component set of the Allen-Bradley rack

A l l e n - B r a d l e y

Logix5500 DC INPUT DC OUTPUT SST Profibus SCANNER

DIAG NO STI C EL ECTR ONIC FU SINGCOMM SYS OK

COPN

RUN REM PROG

RUN I/O

RS232

BAT OK

POWER0 1 2 3 4 5 6 7

23809864 AB ProfibusScanner DOKU V10 e

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