Phil Fieldbus

8/12/2019 Phil Fieldbus

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Phil HarrisDecember 3, 2008

ME EN 486


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What is a fieldbusHistory and Current StateWho, What, WhenApplication ExampleChanging StandardsTechnical PaperClass Application -- Fun Quiz


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Fieldbus is a general term that describes a digital communicationsnetwork that is being used in industry to replace the existingstandard (4-20 mA analog signal)

REVIEW -- Characteristics of Fieldbus networks

Bi-directional means it is a duplex port; the data can betransmitted in two directions at the same time.

Multi-drop is also referred to as multi-access and it can beinterpreted as a single bus with many nodes connected to it.

Serial-bus means the data is transmitted serially according toRS232 or RS485 protocol. Profibus uses RS485 protocol.

Fieldbus works on network structures such as daisy-chain, star,branch, ring, and tree network


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A Fieldbus is an industrial computer network for real-timedistributed control.

The Fieldbus links the PLCs to the components which actually do thework

Human Machine Interface (HMI)

Programmable Logic Controllers (PLCs)

FIELDBUS

Components -- sensors, actuators, electric motorsconsole lights, switches, and valves


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Fieldbus technology has been around since 1988Completion of the ISA S50.02 standard which tookmany years.

Previously computers were connected using RS-232by which only two devices could communicate.Now we can connect many nodes to a device.

In 1999, the IEC SC65C/WG6 standards committee metto resolve difference in the draft IEC fieldbus standard.

Developed 8 protocol sets or requirements for IEC61158 including Profibus, SwiftNet, Foundation Fieldbus

**More than 4,000 pages to IEC 61158**


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Ideally One consistent standard would govern all fieldbusapplicationsReality Many standards that vary depending on the applications

IEC 61158 consists of 6 parts under general title Digital data

communications for measurement and controlPart 1: Overview and guidance for the IEC 61158 seriesPart 2: Physical Layer specification and service definitionPart 3: Data Link Service definitionPart 4: Data Link Protocol specificationPart 5: Application Layer Service definitionPart 6: Application Layer Protocol specification

Currently Making changes and developments to make theprocessing more reliable and faster.


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In complex automatedsystems where anorganized hierarchy of

controller systems isneeded.In industrial andmanufacturing plantswhere many instruments need to beconnected.Know the worst casescenario and can adjust.

Used in FactoriesTo reduce installationcost by moving the

I/O interface from theprogrammable logiccontroller (PLC) to aremote I/O unitmounted close to themachine.Eliminate wire lengthsand number of wires


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A major advantage of fieldbus is the capitalexpenditure ( CAPEX) savings associated with

cable eliminationmultiple devices share wire-pairs in order tocommunicate over the bus networkfaster testing and shorter time to operation

Ongoing maintenance and process controlsystem performance are significantly enhancedthrough fieldbus systems, which results inoperations expense savings ( OPEX).


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THE GOOD(CAP-EX) Savings(OP-EX) Savings

THE BADCost of Devices

Fieldbus components can be expensiveFieldbus Cards = $50 up to $1,000s EtherCAT = $100s

Risk of Evolution

Cost to InvestEngineering costs May need specific applications/components fromsupplying companyEquipment costsInstallation costsMaintenance costs Short Term INCREASED, Long Term DECREASEDOperating costs Additional Training needed

Retooling costs


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Profibus is a vendor-independent, open fieldbusstandard for a wide range of applications inmanufacturing, and process automation.

Devices made by multiple manufacturers can worktogether and communicate. Few adjustments areneeded.

Profibus uses C/C++ Application Program Interface(API ) is a set of functions, procedures, methods, classes orprotocols that an operating system, library or service providesto support requests made by computer programs

Profibus can be used for:Complex tasks

High-speed, time-critical data transmission


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Profibus family consists of three compatible versions: Profibus-FMS (Fieldbus Message Specification)

For communication tasks at the cell level and can be usedfor FMS services.

Profibus-DP (Decentralized Peripherals)Designed for communication between automation controlsystems and distributed I/O at the device level (only cardused in EAAL).

Profibus-PA (Process Automation)

Designed for process automation; permits sensors andactuators to be connected on one common bus.

PROFIBUS (Process Field Bus) is the most popular fieldbus today


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ABSOLUTELY Fieldbus Components:

Bus TerminalEtherCAT

Fieldbus BoxLightbusPC Fieldbus CardsSwitches

FactoryLevel

CellLevel

FieldLevel

Bus CycleTime

< 1000 ms

Bus CycleTime

< 100 ms

Bus CycleTime

< 10 ms

MMS, TCP/IP Backbone

Profibus-FMS

Profibus-DP Profibus-PA

I/ODrive ValvesField

DeviceTrans-mitter

FieldDevice

AreaController


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www.relcominc.com/fieldbus/fblinks.htmlwww.us.profibus.comwww.eg3.com/WebID/indust/fieldbushttp://www.profibus.com/pall/applications/casestudies/article/02539/http://www.beckhoff.com/english.asp?fieldbus_components/default.htmhttp://www.fint.no/en/Products/Starter_Kits/PROFIb

us/ST41+Starterkit+for+T410.9SVTFlI56n_d2Z-0ow_j1X9f3TP9D6CJ1MZI.ipshttp://www.industrialethernet.com/clskecat.htmlProfessor Ed Red


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Fieldbus continues to be an important elementof the automation industry.

Starter Kits AvailablePC ProgramCircuit Board

Surveys 70-80% of large manufacturingfacilities use fieldbus and most connected tointernetProfibus Limitations from Application example


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Cummins EngineAssembly in UK

There are more than 2,000possible engine variantsEngines were transportedthrough themanufacturing process bya combination ofoverhead chain conveyor,powered floor conveyorand an AGV system.All replaced by an EMS(Electric Monorail System)during a two week

shutdown in 2006.


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The EMS comprises 600 metersof overhead monorail, 50carriers, 14 switch points, 3 liftunits, 1 rotate unit, 34 assemblystations and 4 pressure test

stationsStatus and Command words arereceived and sent to each carrierfrom the S7-317DP PLC againvia PROFIBUS DPSince the system was installed,production rates increased from220 engines per day to 350engines per day.Limited to -40/0 to 85 Celsius***LIMITATIONS? ***


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Ethernet-based industrial communication systems recentlyestablished

Currently the issue stopping most Ethernet fieldbus implementations is theavailability of device power.Measurement & control devices need power from the bus and Power-Over-Ethernet does not deliver enough.

IEC 61158 is an evolving standard with a 5-year maintenance cycle.Hybrid wired/wireless PROFIBUS networks supported bybridges/routersFerreira, L. Alves, M. Tovar, E. Portugal; 2002

Recently there has been the desire to extend the capabilities of fieldbuses tocover functionalities not previously considered in such networks, withparticular emphasis on industrial wireless communications.Thinking about wireless means considering hybrid wired/wireless solutionscapable of interoperating with legacy (wired) systems. One possible solution isto use intermediate systems (IS) acting as repeaters to interconnect the wiredand wireless parts


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Real-time fieldbus communications using Profibus networks

Tovar, E. Vasques, F.Dept. of Comput. Eng., Polytech. Inst. of Porto ;This paper appears in: Industrial Electronics, IEEE Transactions Volume: 46, Issue 6

Goal: Find different solutions of how to make Profibus systems to operate inreal-time and respond appropriately

Profibus is based on a simplified timed token (TT) protocol, solution for real-time communication systems

Worst case is that only one real-time message is made per timed token visit Come up with two different ideas that have different applications

More responsive systems (tighter time requirements/deadlines) Increased non real-time traffic throughput


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http://www.directindustry.com/prod/pepperl-fuchs/fieldbus-diagnostic-module-7315-364678.html

Follow signal from fieldbus to component and backagainDiagnostic devices (green) that check the systemBuses and devices provide feedback about systems

SMAR Videohttp://www.smar.com/products/dt302.aspShows Profibus ImplementationNames some advantages


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THE FUN QUIZPROFIBUS is the most popular fieldbus today T / FPOE Stands for:

A Power On EthernetB - Power Over EthernetC - Power Onto Ethernet

Correct relation of Fieldbus to other componentsA - Human Interface Fieldbus Components PLC

B - PLC Human Interface Components FieldbusC - Human Interface PLC Fieldbus ComponentsD - PLC Fieldbus Human Interface Components


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Fieldbus used mostly by industrial applicationsCosts Saves money through Capital and OperationalexpensesRequires supporting technologyContinuously evolving and upgradingProfibus is the most widely used

Promoted in 19893 Different Types

Still making improvements and developmentsWireless IntegrationFaster, Even more reliableEthernet

Phil Fieldbus

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