NewsSummer 2006 Issue

News about the World’s Most Popular Industrial Protocol

Modbus in theWireless WorldWe’re not kidding when we say Modbus is everywhere. Asthe most ubiquitous industrial communicationsprotocol in the world, Modbus is found in everyconceivable industry and application. Modbusserial predominates in many legacy applicationsand the number of Modbus TCP/IP applications grows asEthernet becomes the preferred communication medium.

The most recent space to findModbus is in wireless applications.This is the focus of the ModbusOrganization’s exhibit planned forISAEXPO 2006.

We will be showcasing applications in four wirelesstechnology spheres. Member companies will be there to talkabout Modbus products in:

• GPRS (General Packet Radio Service)(Spectrum Controls)

• Radio(ProSoft Technology, Inc.)

• 802.11 (Wi/Fi)(Sealevel Systems)

• Bluetooth(Schneider Electric)

Visit the Modbus-IDA booth to learn about devices andapplications in all four technologies. Members will displaytheir products and be available to help out with questionsabout both wireless and traditional Modbus applications.

Modbus TCP/IPIEC UpdateModbus-IDA Technical Director, Rudy Belliardi, has beenworking closely with the IEC as the Modbus TCP/IPprotocol progresses through the process of review andvoting by member countries.In September 2004, the protocol along with a companionprotocol known as RTPS, was submitted to IEC SC65Cas a real-time industrial Ethernet suite.With the positive vote in 2004, the Modbus TCP/IPprofile was accepted by the IEC as a Publicly AvailableSpecification and eligible to become partof future editions of the InternationalStandards IEC 61158 and IEC 61784-2.In approving the document, severalnational committees asked that thespecification be reformatted for betterintegration into the revision of IEC-61158 (Ed 4.0 2007),the well-known fieldbus standard.Today, the reformatted specification has been submittedfor review, and the organization is awaiting commentsand requests for changes that will be addressed by adeadline later in the year. After that, more review and afinal vote is expected in late 2007.When this process is completed, Modbus-IDA plans tomake the revised protocol available on the Modbus-IDAwebsite as soon as possible.The current version of the protocol is available on theTechnical Resources page , www.modbus.org/tech.php.

Members, join Modbus-IDA’sMarketing Committee. Help

steer the organization’smarketing programs to bestserve your company’s needs!e-mail info@modbus-ida.org

Visit Modbus-IDAISA EXPO 2006October 17 - 19Houston, Texas

Booth 2005

Organization News • Organization NewsMeet Some of Our Members...

JoinModbus-IDAsee back cover for

details...

The Betec Engineering developmentteam has extensive experience inindustrial electronics. They workcooperatively on complex tasks inhardware and software, bringinginnovative ideas to manufacturingreliably and economically. Together withthe users, technical designers and buyers,they define a project’s requirements,then set their development engineers tocreating the new design, coordinatinghardware and software developmentinto prototyypes, optimizing the newproduct until the prototype passestesting and is ready for production. Inshort, Betec offers technical supportduring product and processdevelopment; hardware and softwaredesign, system development, andhousing prototyping.(www.betec-electronic.de)

The Central Power ResearchInstitute (CPRI) is the powerhouse of the Indian electricalindustry. Set up in 1960 by theGovernment of India, it functions asa center for applied research inelectrical power engineering assistingthe electrical industry in productdevelopment and quality assurance.CPRI also serves as an independentauthority for testing and certificationof power equipment. CPRI’sgoverning body includesprofessionals from industry, utilities,academic and research institutions,and the government.(powersearch.cpri.res.in)

California-based AutomatedSolutions develops OPC servers andActiveX controls for HMI and SCADAdevelopment. The company offersfully functioning30-day trialversions of all itssoftware products.These include anOPC Server forModbus/TCPcompatible devices,OPC Server for Modbus RTU andASCII compatible devices, Modbus/TCP Master ActiveX Control, ModbusRTU and ASCII Master ActiveXControl, Modbus Plus Master ActiveXControl, and Modbus RTU/ASCII/TCP Slave ActiveX Controls.(www.automatedsolutions.com)

Hilscher develops and manufacturessolutions for fieldbus and industrialEthernet, including PC cards, gateways,ASICs for major systems such asModbus, Profibus, Profinet,DeviceNet, CC-Link, InterBus,CANopen, ControlNet, AS-Interface,SERCOS, Industrial Ethernet, andEtherNet/IP.Hilscher’s PKV 30 Protocol Converterprovides protocol conversion betweendifferent standard protocols such as3964R, RK512, Modbus, Modnet, andmore.(www.hilscher.com)

Join! Design! Test! Promote! Apply!Organization News • Organization News

FSC, Inc., basedin Falls Church,Virginia, is an independent softwarevendor providing IT solutions forproperty managers in the FederalEnterprise. The company’s Federal RealProperty Management/EnergyConsumption application supports therequirements of the Energy Policy Actof 2005 and includes an EDI modulefor processing invoices received fromutilities that are in electronic format.FSC’s advance meter module usesModbus protocol to collect intervaldata on an enterprise basis.(www.govtproperty.com)

Matrikon Inc. will be sponsoring itsMatrikonOPC User GroupConferences this fall. The conferencesare focused on “Driving Connectivity.”They promise to provide practicalhands-on information for industrial

connectivity issues.

The MatrikonOPC User Groupconference has something to offer forprofessionals from the plant-floor tothe boardroom. Sessions are designedto equip attendees with intelligence forusers of all experience levels, withtracks focused on OPC fundamentals,advanced OPC integration andcorporate strategies.Scheduled in Houston, Texas onSeptember 13 and 14 and Koln,Germany on October 11 and 12, 2006,MatrikonOPC, industry experts, andend-users will present best practices,lessons learned, case studies andvendor-neutral solutions. Eventssurrounding the conference datesinclude OPC hands-on workshops,Executive Standardization sessions,SCADA Security Classes and interactivepanel discussions.

Modbus-IDA will be at the conferenceat both the table-top exhibition and as apresenter. Fred Cohn, Modbus-IDApresident, will lead a session titled,Modbus Protocol’s Openness and SimplicityComplement OPC’s Power in IndustrialEthernet.He will focus on OPC as the industrystandard method for SCADA andinformation systems to access plantfloor information. OPC’s Client/Server architecture fits perfectly in thePC environments hosting SCADAsystems. For OPC Servers to acquiredata from the plant floor, a simple,cost-effective, open protocol is needed

Modbus Represented at UpcomingMatrikonOPC User’s Group Meeting in Houston

that is consistent with the architecturesand cost targets of industrial devices.The Modbus protocol, originallydeveloped for serial devicecommunications, has successfullymigrated to industrial Ethernetarchitectures due to its simplicity,openness, and scalability. Modbus,therefore, perfectly complements theOPC architecture by allowing OPCServers to communicate easily andefficiently to a full range of end devicesfound in industrial applicationsOther speakers at the conferenceincludes Dick Morley, father of theprogrammable controller (PLC); JimPinto, industry commentator; TomBurke, OPC Foundation President; EricMurphy, OPC Foundation HDAChairperson, and others.Conference topics include:

• Understanding the advantagesof implementing OPC technologies

• Learning different OPCspecifications (OPC DA, A&E,HDA, XML, UA)

• Resolving common and advancedDCOM problems

• Securely passing Process Datathrough firewalls

• Increasing system interoperability• Automating Process Control

systems• Data exchange and amalgamation• SCADA Security

Register for theMatrikonOPC UserConferenceDates:Houston, TX – Sept 13-14Koln, Germany – Oct 11-12www.matrikonopc.com/opcug

Phoenix Contact Inc. develops andmanufactures specialized electroniccomponents and connection systems.The company offers a diverse range ofproducts designed for industrialapplications including terminal blocks,power supplies, signal conditioners,industrial connectors, and automationsystems. Phoenix Contact has U.S.headquarters located in Harrisburg,Pennsylvania and world headquarters inBlomberg, Germany.(www.phoenixcon.com)

Trojan Technologies is a leadingwater treatment technology companywith the largest installed base of UVsystems in operation around the world.It specializes in the design, manufactureand sale of pressurized and open-channel ultraviolet disinfection systemsfor: municipal wastewater; municipal,commercial and residential drinkingwater; environmental contaminanttreatment; and industrial applications.(www.trojanuv.com)

Modbus Products and Innovations

Anybus X Gateways Translate(almost) Anything

HMS Industrial Networks picked the right namewhen they developed the Anybus X series gateways. TheAnybus-X Gateways have been designed for use in harshindustrial environments featuring standard DIN railmounting, IP 20 rating and 24-Volt DC power supply.

The Gateways are intelligent standalone devices supporting fanless operation andindustrial operating temperatures. The design is based on two embedded Anybuscommunication modules and one additional gateway processor. Thanks to the widerange of Anybus-S Slave and Anybus- M Master modules, more than 150 Anybus-Xgateway combinations are available. There is no programming involved. Yousimply choose the gateway version that supports the two networks you want tobridge. For each of all possible network combinations, there is a separate gateway. The gateway concept primarily focuseson the transfer of cyclic I/O data between two networks. During the set-up of the gateway, you select the amount ofI/O to be transferred between Network 1 and Network 2. Since industrial networks support different amounts of I/Odata, the network with the smaller amount of I/O data determines how much data can be transferred in each case.

The Anybus-X Gateway product family supports 17 different Fieldbus networks. The Anybus-X Gateways help controlsystems integrators to interconnect any two networks enabling consistent information flow throughout the entire plant.

For more information, visit www.anybus.com.

Phoenix Digital’s Modbus Port Expander Plus (MPE+) product operates as a ModbusMulti-Master Multiplexer, network server, and communication controller all in one.Phoenix Digital’s Modbus Optical Communication Modules (OCMs) provide multidropfiber optic communications for high reliability Modbus communications. The MPE+ and OCMs are available in modularstandalone, panelmount enclosures and 19-inch rackmount/panelmount enclosures with integral 120/220 VAC, 24 VDC, or125 VDC power supplies. Modbus Port Expander+ features include:• Multi-Master Multiplexer

Muliplex up to 8 Modbus Masters with a Single MPE+Cascade multiple MPE+ units for additional Modbus Master Multiplexing capability.

• Self-teaching, real-time databaseInstantaneous Modbus ResponseNo-Wait Screen Updating.

• Hot standby, failsafe operation• Peer-to-peer Modbus Communications

Communicate directly between Modbus slave devices• Host-to-Host Modbus Comunications

Communicate directly between Modbus host devices• Interfaces dissimilar Modbus devices

On-the-fly conversion of all Modbus communication parameters, including ASCII/RTUFor more information, visit www.phoenixdigitalcorp.com.

Modbus Port Expander Plus

Modbus Port Expander

Anybus X Gateway

Modbus-IDA Discussion Forums

On June 10th Ed Francy asked,I am starting development of aModbus slave. Is there some standardfor mapping Modbus registers forconfiguration and measurements? Howis a Modbus master configured to usethese if I just assign them any way Iwish?I have implemented a HART slavepreviously, and HART controllers havea special language (DDL) for defininghow HART masters interact with slaves.Is there anything like this for Modbus?All the specs. I have found on theModbus protocol define just theprotocol, not specfics about how tomap your device’s I/O. Am I missingsomething?Another question - must I do the“multiply floating point values thendivide on the other end” method totransfer floating point values? Or can Itransfer a 4 byte floating point numberwith two register reads?Dweebyone replied,

There are 4 basic types of register inModicon Modbus:• 0x register represents a digital output• 1x register represents a digital input• 4x register represents an analogue

output (16 bit)• 3x register represents an analogue

input (16 bit)Only the Modbus master can initiatecommunications. The Modbus mastercan request data from any slave on thenetwork. It should receive a reply fromthe slave in question. You can alsobroadcast i.e., send a request to ALLthe slaves on the network. Whenbroadcasting, no reply is given tomaster.There are various Modbus “Functioncodes” that specify what the master is

asking of the slave. For example, youmay wish to read one off 1x register,or multiple 1x registers. There would bea different function code for these twoinstructions. There are various functioncodes for reading/writing or both, for0x , 1x, 3x, and 4x type registers.See www.modbus.org for more info.An anonymous poster commented,Modbus is the protocol (language) thatyou use to communicate to the device.The address assignments are a functionof the device you are working with andthey vary.Modicon addressing (which is astandard since it was associated withModbus initially) uses the first digit todetermine if it is a digital or analoginput/output and the other digits forthe addressing.With PLCs, which allow you to addressthe I/O as you like, my experience is itis preferable to start your hardwareaddressing (input/output modules)from the lowest address and keep theaddresses contiguous. Allow for futureexpansion if required.If your device isn’t flexible then youhave to use the addressing that theyhave configured.Another user suggested:

Masters come in different shapes,forms, and flavors.Some Modbus masters have the abilityto read contiguous slave registers as a“block.”So you want to consider which slaveregisters might be most useful to themaster client and designate them ascontiguous registers. Leave the rarelyused or esoteric value registers on theperiphery of the slave map.

Newbie Question on RegisterAssignments...

From the Modbus User Forum…Q&A

Ask your question or helpout a fellow engineer on theModbus Discussion Forums:

modbus.control.com

Modbus RTU to Ethernet...On June 15th, Carsten Roll wrote:

I want to talk to some meters usingModbus RTU across Ethernet. I havean RS 485 serial to Ethernet converter.Is that possible with the device? Or doI need a special Modbus Ethernetconverter? I have the ADAM 4570from www.advantech.com, but I amwondering why they sell a specialModbus Ethernet converter. MyModbus network is a 2-wire RS485.bscook replied,

The single biggest factor in determiningcompatibility with converters is timing.Since Ethernet is packet-based, it canimpose delays into the serial stream.Modbus RTU doesn’t tolerate delaysgreater than 13 ms. This should be finefor most adapters on the market,provided that network routing is keptto a minimum. This involves thephysical and virtual architecture (e.g., ifyou’re trying to maintain control acrossa companywide network or (worse)the Internet, you’ll have troubles,especially if you have a busy network.)Also, if your network administratorpermits it, converters in UTP/IP modeare faster, have less overhead, andprovide the kind of timing you likelyneed. Many network admins don’tpermit it, because it floods the networkwith traffic.If you have a managed network, youradmin can probably set it up to permitUTP/IP across whatever segmentsyou’ll be using, without letting it floodthe rest of the network.The downside of UTP/IP vs TCP/IPis that it is more likely to introduceerrors into the data stream over verylarge packet-switched networks, but isgenerally just fine in smaller networks.To follow this discussion further, go tomodbus.control.com/1026223137

Modbus Application Stories

The Modbus-IDA NewsletterThis is the newsletter of Modbus-IDA, the international nonprofit organiza-tion devoted to the evolution and support of the Modbus and IDA protocols.For more information about membership and other services of Modbus-IDA, please refer to our website: www.modbus-ida.orgNewsletter Editor: Lenore Tracey

+1-508-435-7170lenore@modbus-ida.org

Copyright 2005 by the Modbus Organization, Inc.PO Box 628, Hopkinton, MA 01748 USAph +1-508-435-7170 • fax +1-508-435-6929info@modbus-ida.org

The Modbus-IDA MissionModbus-IDA is a group of independent users and suppliers of automa-tion devices that seeks to drive the adoption of the Modbus communi-cation protocol suite and the evolution to address architectures fordistributed automation systems across multiple market segments.Modbus-IDA will also provide the infrastructure to obtain and shareinformation about the protocols, their application and certification tosimplify implementation by users resulting in reduced costs.

It all started with a customer thatneeded to monitor 220 sites in real timefrom a central location. Thesites had a mix of newer andolder equipment fromseveral vendors, some withEthernet connectivity, mostwithout. The question was: How tointerconnect such a variety of devicesand protocols both locally and over adistance?Available options did not meet theproject’s required reliability, flexibility, orscale. Prices were sky-rocketing, andsimplicity and ease of use were oftenmissing.Browsing the Internet looking for newideas, the system integrator found theeWON web site and started to think hehad found “THE” solution for hiscustomer.. eWON could deliver all thefeatures he needed:• a serial to Ethernet gateway• a protocol gateway to Modbus orSNMP• secure, permanent Internet connection

• remote access for support and remotemonitoring

eWON’s openarchitecture andcompliance tocommon

industry standards offered features andservices he assumed he had to give up,such as a customized webinterface, local alarm management,and scripts programming.What’s more, the solution fit thebudget with a neat,straightforward implementation,designed specifically for theautomation industry.Modbus Connectivity

Modbus was chosen early in the projectas the standard for monitoring criticalprocess data. The PLCs at the newerinstallations all had Modbus TCP, butthe majority of sites had a mix ofModbus RTU, DF1 (Allen Bradleyserial protocol), MPI (Siemens’ S7 serialprotocol), and older AS511 devices(Siemens’ S5 series PLCs).

One option was to keep the variousprotocols and operate remote devicesusing VCOM gateways. That would beless expensive than purchasing networkcards and gateways and could alsostreamline and unify the communicationmodel. But VCOM lacked overallreliability, and for the scale of the

project, seemed flimsy andunconvincing.Another option was to upgrade theolder PLCs and let them speak theEthernet protocol of their ownmanufacturer. But cost and lead timeswere unacceptable, not to mention thatmaking major changes to the sites wasout of the project’s original scope.A less intrusive solution had to befound. And whatever option waschosen for IP connectivity at the localsites, the project still required a networkinfrastructure to connect 220 sites at areasonable cost.The customer first considered apermanent connection using leased lines.But the cost of installation andoperation far exceeded the budget.Dial-up routers on the PSTN or ISDNwould also work, but this wasinconvenient and would require toomuch time and attention to set up.Finally, the idea of connecting the sitesthrough the Internet was considered.Office IT equipment had done thiswithVPN technology for several years.Dial-up routers could connect to theInternet and establish secure andencrypted connections.Nice start, but this required outsourcinghalf the project to an IT and telecomcompany with the skills to build such anetwork architecture over the Internet.

eWON Industrial VPN Solution

VCOM lacked overall reliability,and for the scale of theproject, seemed flimsy andunconvincing.

Central Site: OPC server, SCADA, data acquisition, remote maintenance;Remote sites: serial or Ethernet devices (Modbus RTU, Modbus TCP, ASCII...

The issue of connecting serial deviceson each site remained.eWON VPN Solution

The eWON product family is designedto address the connectivity concerns ofthe automation industry. Locally, it is aserial to Ethernet gateway that acquiresdata in a number of protocols andpublishes it in Modbus TCP. It storesthe data in its own memory tags,monitors the data, and issues alarmnotifications, e.g., by e-mail or trapSNMP. It offers a web browserinterface to interact with the processthrough animated synoptics similar to aSCADA HMI.

It is also a transparent gateway,allowing remote maintenance ofthe serial device using themanufacturer’s programmingenvironment. Connectivitybetween the sites is achievedusing an eWON 4005. VPNclients connect through conIX

ADSL routers across the Internet to theeSYNC VPN server at the central site.eSYNC is a software applicationrunning on a server at the central site.All eSYNC requires is a public IPaddress from an Internet serviceprovider. eSYNC takes care ofconfidentiality, security, andauthentication of its clients. eSYNCestablishes the private intranet anddistributes the routing tables to allconnecting parties.On each site, access to the Internet isensured by a conIX ADSL router. Nextto conIX, eWON 4005 holds the VPNclient that connects and reconnectsautomatically to eSYNC.

Modbus Application Stories

eCATCHER, a VPN client running ona PC allows support personnel to jointhe virtual intranet and performnecessary interventions directly on thelocal process through the HMI oneWON website.By seamlessly integrating localautomation connectivity into a privatewide area intranet, eWON sets newprecedents for the industry. More thancombining PLC process control withIT and telecommunications, eWONbrings Internet tools and technologies— with all their benefits — into theautomation world.This brings significant changes to ourvision on remote infrastructuremanagement. The old days of modempolling are over.

Jean-Paul Verheylewegen (jpv@actl.be) isSales and Marketing Manager for eWONproducts. He is responsible for ACTL’sinternational network of distributors.

Locally, the eWon solution is aserial to Ethernet gateway thatacquires data in a number ofprotocols and publishes it inModbus TCP.

Join! Design! Test! Promote! Apply!We’re with you. Modbus-IDA exists tohelp suppliers and users of Modbusprotocols succeed. Our membersrange from suppliers of Modbus-compliant products, to system integra-tors, end users, educational institutions,and even individuals.The common link? They all value theinformation and services provided byModbus-IDA, and they all play a rolein determining the future of theworld’s most broadly applied protocol.

Designing with ModbusEach day, Modbus developers turn toModbus-IDA for valued assistancewith their projects:• Start with downloading specificationsand other design documents from themodbus-ida.org website.• To really save time, purchase theModbus TCP Toolkit CD (hint: it’sFREE with membership), whichcontains source code and a myriad ofother resources.• Then, if you come across technicalissues that have you stumped, post yourquestion on our highly activedeveloper’s forum. One of the manyexperienced Modbus implementerswho frequent this forum will likely haveyour answer.Conformance TestingWhen your project’s done, what then?How do you know it really conformsto Modbus specifications? How doyour users know?The answer starts with running theconformance test suite included withyour Modbus TCP Toolkit. This self-

test helps you check your designassumptions and catch the subtle“gotchas” that might otherwise slipthrough your design review.But to make the definitive statement ofyour company’s commitment to openprotocols, submit your product fortesting to the independent Modbus-IDA Conformance Test Lab. We’llcertify your product as compliant, andpost that information on the Modbus-IDA website for the world to see.Visibility for You and YourProductsAnd, speaking of the world seeingyour products, your membership inModbus-IDA opens the door to apowerful range of visibility options tohighlight your company as a supplierof Modbus-based products.Exposure on our website, in ournewsletter, and through our varioustrade show appearances are all optionsthat allow you to make the most ofyour Modbus-IDA membership.If your company is truly on the cuttingedge of new technology, you’ll likelyalso value the opportunity to participatein our technical committees. There,your company’s knowledge, experienceand technology can help guide futureenhancements, extensions and adapta-tions of Modbus to keep it the world’sleader for decades to come.Time to ApplyWhen it comes time to get yourModbus network up and running, it’scomforting to know that hundreds ofthousands of applications have pre-ceded yours. But what if things don’tgo as planned?The modbus-ida.org users forum isready to answer your questions andprovide guidance. Thousands of usersfrom diverse backgrounds read theforum, giving you a powerful base ofexperience from which to draw.The Future is YoursSo, whatever your role in the use ofModbus, consider joining Modbus-IDA. You’ll get the support you needtoday, and have opportunities to helpguide Modbus to a dynamic future.

The Modbus TCP ToolkitCD

The Modbus TCP Toolkit provides allthe necessary pieces to develop aModbus-compliant device, includingdocumentation, diagnostic tools,sample source code, and pre-testsoftware to prepare for Modbus-IDAconformance certification. The toolkitis available as a benefit of membershipin Modbus-IDA or can be purchasedseparately for US$500 plus shippingand handling.

Toolkit Contents

Modbus Documentation

• Modbus Application ProtocolSpecification, V 1.01a• Modbus Messaging on TCP Imple-mentation Guide, Rev. 1.0aTools

• Modbus/TCP Client Diagnostic Tool• Modbus/TCP Server DiagnosticToolSample Source Code

• Modbus/TCP Sample Client Codefor Visual Basic Win32• Modbus/TCP Sample Client Codefor C/C++ Win32• Modbus/TCP Sample Server Codefor C/C++ Win32• Modbus/TCP Sample Server Codefor C VxWorks• Modbus/TCP Sample Server Codefor C++ VxWorksConformance Testing

• Modbus/TCP Conformance TestSoftware

To join Modbus-IDA, ordera Toolkit, or arrange

conformance testing, visitour website:

www.modbus-ida.org