Distributed Control System Basics

DCS EVOLUTION-CENTRALISED CONTROL

DCS EVOLUTION-DISTRIBUTED CONTROL

DCS EVOLUTION-FIELDBUS CONTROL

DCS EVOLUTION- WEB CONTROL

DCS EVOLUTION-WEB CONTROL APPLICATION

ABB DCS ARCITECTURE

ABB DCS HARDWARE

CONTROL SYSTEMS TREND1) PLC2) DCS3) PC - Based Control.• PLC : Introduced in the late 1960 to replace Relays and Hard-wired Programming.

DCS : Introduced in the Mid-1970 toreplace pneumatic controls by usingcomputers.• PC-Based Control : Introduced by the early 1980s to avoid the proprietary PLC & DCS systems.

DCS EVOLUTION• LOCAL CONTROL : Initially control was performed local to the equipment control. The ADVANTAGE was low wiring costs .DISADVANTAGES were - not much control, monitoring, alarming & history.• CENTRALISED CONTROL: With the advent of minicomputer, sensors and actuators were into the Central Control (Computer).• DISTRIBUTED CONTROL: With the advent of microcomputer, Distributed control systems were installed in the plants near to the control room via proprietary digital communications lines called as Data Hiway. First DCS was developed by Honeywell,U.S in 1975. The ADVANTAGES were greatly reduced wiring costs, much more limited failure and less cost to add more points. The DISADVANTAGES were that wiring costs were that wiring costs were still significant and there was lack of interoperability among controllers of various manufacturers due to the proprietary protocols. Hence the user was locked into a single vendor.

DCS System Installations in RCF1. Yokogawa - CS 3000 : Ammonia II2. Yokogawa - CS 3000 : ANP3. Yokogawa - CS 3000 : NNAP4. Moore - APACS : Methyl amine5. Fisher - Rosemant - Delta V field Bus : STP6. Honeywell - GUS : Ammonia I Synthesis7. Yokogawa - Centum Excel : Steam Generation Plant8. Moore - APACS : Suphala9. Yokogawa - Micro Excel : Methanol10. Yokogawa - Micro Excel : S A P/C N A11. ABB - Freelance 2000 : ABC12. Honeywell - TDC 3000 : Ammonia I13. Honeywell - GUS : Ammonia/Urea - Thal14. Fox boro - I/A series : D M A C - Thal15. Fisher - Rosemant RS3 : PGR16. Fisher - Rosemant RS3 : Steam Generation - Thal17. Moore - APACS : Water Treatment Plant - Thal

DCS• The importance of DCS systems to increase as global competitive dynamics in food and beverage, specialty metals, pulp and paper, pharmaceutical and fire chemical processing.• The DCS has networking capabilities which are useful for business management.• The DCS has capacity for processing large number of I/O points. TYPES OF DCS :1) Conventional DCS .2) PLC based DCS.3) Hybrid DCS.4) Open DCS System

CONVENTIONAL DCS This is a pure “Process only” control system. Usually purchased from one vendor. This DCS arranged into three categories:• Small - Less than $ 100,000.• Medium - Greater than $100,000 & Less than $500,000.• Large - Greater than $500,000.PLC Based DCS. This is a network of PLC’s used to perform the task of conventional DCS and programmable functionality when required.Hybrid DCS. Performs both process and sequential control.Open DCS System. This is Field-Bus Control. Advantages are lower wiring cost and less failure, smaller expansion costs and multi vendor interoperability DCS and PLC can be more closely and efficiently interconnected.

Honeywell TDC 3000 DCS Architecture US#1 US#2 HM LCN A B HG AMC Field EC Link AMC Field Data Hiway A B

Hiway Gateway (HG)• LCN Module. Provides a two way communication link between the Local Control Network and data hiway.• 68020 based high performance intelligence module.• Converts data and protocol between Local Control Network and data hiway.• Scans the hiway for alarm conditions.• Synchronize time keeping for hiway-based process connected boxes.• One HG is required for each data hiway that is connected to the LCN. Up to 20 data hiway pairs can be connected to an LCN.• Connects following hiway resident boxes to LCN 1. AMCs 2. CPC ( critical process controller ). 3. DHP. 4. Hiway traffic director etc… HG Functions : 1. Data access :- gets box data requested from LCN modules. 2. Event processing :- sends process and box alarm to LCN modules 3. Database configuration :- 3000 points per hg can be configured.

Data Hiway Data hiway provides communication link between hiway gateway, preferred access devices and process connecting box. Data hiway operates at250 kbps. It is redundant pair of 75 ohm coax cable connected to box. It may be 20,000 feet long. There are 3 kinds of devices on the data hiway,1. Respond only devices Ex:- A-MC (Advanced Multifunction controller)2. Polled devices Ex:- PIU’s (Process interface unit)3. Preferred access devices

History Module• LCN Module. Stores process and system information that can be displayed.• Based on microprocessors 68020.• Winchester disk for data storage.• Communicates with all Modules on the LCN.• Stores history and general information.

Universal Station Universal station (US) communicates with all modules on the LCN, process connected devices on the hiway via hiway gateway and UCN via network interface module (NIM). The following are the features of US,• Intelligent man/machine interface in the TDC 3000 system.• Stands on the LCN. Communicates with all Modules on LCN, process connected devices on the Hiway via Hiway Gateway.• Provides comprehensive facilities to the process operator, process engineer and maintenance technician on the Universal Window. US provides comprehensive facilities to the following people,• Process engineer• Process operator• Maintenance technician.

AMC• TDC 3000 controller 1. Based on Motorola 68000 Microprocessor. 2. Faster execution and control with 500 ms processing rate.• Multifunction – Modulating, sequence, logic, I/O monitoring communication and diagnostic.• Faster peer to peer communication over EC link ( 500 kbits/sec ).• Proven control techniques 1. Full function algorithms. 2. Process oriented programming.• Configured as a box on TDC 3000 Data Hiway. Supported by 1. LCN devices – US, AM, HM.

HONEYWELL - GUSPrinter Drive’s Printer - - US#1 US#2 US#3 US#4 Universal Station HM History Module A B Local Control Network Network Interface Module NIM Universal Control Network HPM High Performance Manager HPM HPM

Honeywell System Description• Global User Station• History Modules• Network Interface Modules• Communication Subsystem - Local Control Network & Universal Control Network• High Performance Process Manager

Global User Station Overview The TPS system provides an integrated interface between the process and the end user. This interface is named as the Global User Station (GUS). GUS is an important part in the Honeywell Total plant Solutions offerings. It provides access to plant wide process network, plant or organization wide intranet or even Internet. The following hardware is available to enhance the functionality of the GUS:• Integrated Keyboard for Operators as well as Engineer.• Matrix printer supported by Windows NT.• 8 * CD-ROM• 100MB ZIP Drive• 3.5” Floppy Drive GUS has following functionalitys :• The “Human ” interface allows effective interaction of the Operator through the use of operating displays• Engineering functions such as data point building, display building and report building are available.• Communication with other LCN modules is accomplished.• Communication on Ethernet.

Honey well GUS Hardware:• Processor : Pentium Pro / 200MHZ• Memory : 64MB RAM ECC• Cache : 256KB ECC• Storage : 2 GB hard disk drive, CD ROM, Cartridge Drive• Video : 21” high resolution screen 1280 * 1024 Pixels• Colours : 256 color palette• Keyboard : Integrated keyboard with mouse• PIN Connection : Built in Ethernet• Cursor Control : QWERTY & Mouse/Touch ScreenPeripherals supported• Printer• 8 * CD-ROM• 1/4” Steamer Tape• 3.5” Floppy Drive• 100 Mb ZIP Drive• Annunciator relay on the console-based keyboard

Honeywell GUS software• Operating System : Windows NT version 4.0• Base System : Provides real time data exchange between the network and all GUS functions.

History Modules The History Modules is the bulk module that can be utilized by all module connected to the Local Control Network. It is as the name implies the mass memory of the TPS System. The memory components of this module are one 1.8 gigabyte Winchester discs. It is controlled by an M68040 microprocessor. This provides the module with significant computing power that this used to structure much of the incoming data and format it into a form for easy retrieval. The history in the model is provided by the History Module. Process variables are available for hourly, shift, daily and monthly average calculation and recording. All system event history such as process alarms, system status changes, and error messages are stored into the History Modules. Other modules have access to data in the History Modules for their functions.The History Module provides two functions, storage only and data structuring

HM functions and Historization parameter HM functions : It can automatically backup the control databases in the HG, AM, CG. HM can store,• Continuous process history.• Event journal (history).• Active system files.• Static system files.• On process analysis program (maintenance aid)HM Historization parameters : There can be up to 10 HM’s on the LCN. There can be maximum of 150 groups per HM. Each group can have up to 20 points. All points in the group must be in the same unit.

Network Interface Module (NIM) The Network Interface Module (NIM) provides the link between the local ControlNetwork and the Universal Control Network. As such it make the transition from thetransmission technique and protocol or the Local Control Network to the transmissiontechnique and the protocol of the Universal Control Network. The NIM provides accessby LCN modules data from UCN resident devices. The NIM is available in the redundantconfiguration to provide continued operation in the event of the primary failure. It canalso do event processing. There can be up to 10 redundant NIM pairs per LCN. A NIM can host upto 8000 tagnames and supports a data transfer rate of 2400 parameters per second.

Communication Subsystem Local Control Network (LCN) The backbone of every TPS system is a communication network, known as Local Control Network. The LCN is a LAN through which TDC 3000 modulescommunicate with each other. The LCN is a broadcast type of LAN. It is high speed redundant communication bus that connect all the control room equipment. All information is transferred on the network at 5 million bits per sec.,serially. It is based on the IEEE 802.4 Token passing and Bus Standard. Each LCN device that is connected to the Local Control Network is called a module. Up to 64 modules may be connected to the Local Control Network in a TPS system. The Local Control Network is designated as the primary and the other as the back

Communication Subsystem Universal Control Network (UCN) The Universal Control Network is a high speed, high security processcontrol network based on open system interconnection standards. It features a 5megabit/second, carrier band, token bus network compatible with IEEE and ISOstandards. It is used as the real time redundant Communications backbone forprocess connected devices such as the High Performance Process Manager(HPM), Advanced Process Manager . The UCN supports peer-to-peercommunication for sharing data and allowing greater co-ordination of controlstrategies among network devices. The UCN uses redundant co-axial cables and cansupport up to 32 redundant devices UCN supports 2 types of devices

High Performance Process Manager (HPM)The High Performance Process Manager is the latest in the Progression of HighPerformance control products offered by Honeywell for the application toImprove controlling of existing and new industrial processes. High PerformanceProcess Manager is a fully integrated member of the TPS family. It is capable of :• performing data acquisition and control functions• fully communicating with operators and engineers at the GUSs and universal Work stations.• Supporting higher-level strategies available on the Local Control Network through the Application Module and Host Computers.

High Performance Process Manager OverviewThe High Performance Process Manager uses a powerful multi-processor architecture with separate microprocessors dedicated to perform specific tasks. The HPM consists of two modules Communication and Control Module (CCM) and the I/O subsystem the I/O subsystem consist of up to 40 Smart I/O Modules (SIOM). All controloperation are performed within the communication and control module. The processengineer has complete flexibility of choice within the maximum HPM design limits. These selections are implemented using the interactive tools provided by both the GUS and Universal Work Station. The I/O processors, for example, provide such functions as engineering unit conversion and alarm limit checking independent of the communication and control modules.

YOKOGAWA CENTUM EXCEL ARCHITECTURE EOPS EOPS ENGG. Micro-XL /1 /2 STATION A BHF BUS(1 Mbps) EFCD EFMS EFGW I/O #1 ncst Closed loop Monitoring signals Third party system with PLC, I/O #2 control signal Through I/O NEST Gas Analyser etc. thr RS 232C port ncst Through I/O NEST At the rate of 9600 bps I/O #3 I/O #5 HF BUS : High frequency Bus: no. of station on HF Bus are 32 ncst EOPS : Extended Operator station: Hard disk capacity of EOPS is 80 MB EFCD : Extended field control I/O #4 station : 80 laps per controller EFMS : Extended field mauture A B station Max 255 inputs NIO Bus EFGN : Extended field gateway unit ENGS : Engineering station NIO : Nest I/O bus.

Windows NT Based Centum CS Configuration INTERPLANT NETWORK PC (OPTIONAL) Ethernet Connectivity (optional)OPERATOR/ENGINEERING STATION OPERATOR STATION SUB-SYSTEM Inkjet HIS DM HIS HIS Printer PRT PRT Printer DUAL “V NET” 10 Mbps FCS RIO BUS HIS – Human Interface Station. NIU NIU FCS – Field Control Station. NIU – Node Interface Unit. RIO Bus – Remote I/O Bus.

Centum CS 3000 System Overview Centum CS 3000 is an integrated production control system for medium and large controlapplications. This system is a synthesis of the latest technology with Yokogawa’s experienceand specialist know-how.Centum CS 3000 system features :• Synthesis of DCS with Personal computers.• Online Documentation.• Powerful Operation and Monitoring Functions.• Two Types of Control Station.• Compact I/O Modules.• Powerful Control and Communication Functions.• Efficient Engineering.• Virtual Test functions don’t require Control Station hardware.• Full-Featured Batch Package.• CENTUM CS micro-XL Integration ( to be released ).

Centum CS 3000 System OverviewCentum CS 3000 is an integrated production control system for medium and large controlapplications. This system is a synthesis of the latest technology with Yokogawa’s experienceand specialist know-how.Centum CS 3000 system features :•Synthesis of DCS with Personal computers.•Truly open system for integrating multi-vendor solutions.•High Reliability of computed process data by the unique fault tolerant control processor.•Powerful built in “RISC PROCESSOR” with high speed and dynamic error correcting code.•Remote I/O concept enables geographically distribution of I/O Modules thereby reducing cabling cost.•1:1 Redundancy at almost all the system levels except for control processor which employs a special Redundancy with 4 identical CPU’s.•Powerful Control Tools and Communication Functions.•Virtual Test functions don’t require Control Station hardware.•Full-Featured Batch Package.•Built in security features to prevent mal-operations.•CENTUM CS micro-XL Integration ( to be released ).

CS3000 – System Configuration INTERPLANT NETWORK PC (OPTIONAL) Ethernet Connectivity (optional)OPERATOR/ENGINEERING STATION OPERATOR STATION SUB-SYSTEM Remote Domain System CGW Inkjet HIS DM HIS HIS Printer PRT PRT Printer V NET 10 Mbps FCS BCV RIO BUS CS, CS 1000 Centum – XL, -V, -MXL NIU NIU HIS – Human Interface Station. FCS – Field Control Station. NIU – Node Interface Unit. RIO Bus – Remote I/O Bus. CGW – Communication gateway unit BCV – Bus Converter

CENTUM CS 3000 NETWORK HIS HIS HIS V net FCS FCS FCS

CENTUM CS3000 SYSTEM SPECIFICATION• NO. OF TAGS MONITORED 1,00,000• TOTAL NO. OF STATION 256• NO. OF DOMAINS 16• NO. OF STATIONS IN A DOMAIN 64• NO. OF HIS / DOMAIN 16 NOS

CENTUM CS3000 SYSTEM SPECIFICATION• Max. no. of stations : 256 / system• Max. no. of Domains : 16 / system• Numbering of Domains : 1 to 64• Domain No. CS3000 Domain (V net Domain) : 1 to 16• Max. no. of stations/Domain : 64• Domain No.Virtual Domain (Non V net Domain) : 17 to 64• Station NO. HIS : 1 to 64 in descending order• Station NO. FCS : 1 to 64 in ascending order• Max. No. of ICS / Domain : 16• Max. No. of NIU / FCS : 8• Max. No. of IOU / FCS : 40 ( Max. 5/ IOU)• Max. length of Vnet : 20 Km• Max. length of RIO bus : 20 Km (750m ~ 20Km)

Centum CS-3000 CommunicationV net V net is 10 mbps real time control bus which links station such as FCS , HIS , BCV and CGW. It can be dual redundant. It can be up to 500m using coaxial cable alone, or up to 20Km when repeater are used or optical fiber is used.• 10BASE2 cable used by HIS, maximum segment length = 185 m• 10BASE5 cable used by stations other than HIS(FCS,CGW etc.) maximum segment length = 500 m

V net Communication HIS HIS V netProtocol : IEEE802.4Access Control : Token PassingTrans. Speed : 10 MbpsTrans. Distance: 500m to 20KmMedia : Coaxial/optical fiber FCS FCS

V net specification ITEM SPECIFICATION Transmission route Coaxial or fiber optical cable Type Bus type or Multi-drop type Communication rate 10 Mbps Transmission Distance 500M –20Km Max Redundancy Dual-redundant Proto type Token passing

V- net Features• Real time control bus. ( Dual redundant possible )• Cable : 50 ohm coax. cable with BNC connector ( 10Base2 comp. )• Communication speed : 10 Mbps.• High reliable token passing communication ( performance guaranteed )• Std. max. length : 185 m. BNC Connector• Max. length : 20 Km ( with optical fiber ) 1.6 Km ( with coax. Repeater ) VL net cable VL net I/F card ( PCI )

Ethernet HIS and ENG, HIS and supervisory systems can be connected by anEthernet LAN; supervisory computers and personal computers on the EthernetLAN can access messages and trend data in the CS 3000 system. The Ethernetcan also be used for sending trend data files from the HIS to supervisorycomputers, or for equalizing the data in the two HIS station ( rather than usingthe V net control bus to do this ). A system with only one HIS with engineeringfunctions installed, does not need Ethernet – but in general Ethernet ( andcorresponding network engineering ) is required.

Ethernet SpecificationITEM SPECIFICATIONTransmission Route Coaxial or Fiber optical cableType Bus type or Multi–drop typeCommunication Rate 10 MbpsTransmission Distance 500m – 2.5 Km max.Redundancy Not availableProto type CSMA/CD Type

TYPES OF HIS• Console type HIS• Desk top type HIS• PHIS Yokogawa brand OPS

HIS Hardware• CPU Pentium 166• Main memory 96MB or larger(for op & monitoring only)• Hard disk 1 GB or larger• Display 256Colors min. resolution 800*600 1024*768 recommend(1280*1024 best)• Serial port RS232C*1 or more (for operation keyboard)• Parallel port 1 port for printer or more• OS Windows NT 4.0 Workstation• Operator stations Max. 8 stations

Field Control Station Configuration Ethernet HIS HIS HIS V net I/O Unit RIO Bus Node Interface Sub system Unit Node I/O Unit Sub system Compact FCS Standard FCS

Connection to Centum CS 3000 System Exapilot client (engineering, operation) Ethernet HIS ENG ExaopcExapilot client(engineering, operation) Exapilot server (engineering, operation) V-net Exapilot communication data Process data read/write FCS FCS

Features of Exapilot• Standardize and Automate Manual Procedures• Improve Plant Operating Efficiency• Improve safety of Plant Operation Features of Event Analysis Package• Analysis DCS Event History to Help You Enhance Efficiency.• Enhance Process Stability: Balance Process Events and Operator Actions.• When, Where, What (3W) Filters Help You Narrow Focus of Analysis.

OPEN DCS SYSTEMEthernet Field Bus Power Supply Flow Trans. Terminator HMI Control Valve Safety Barrier Pressure TX.

Field bus It is a standardized digital communication protocol between a process Control field devicesand the Control room. It is a simple pair of wires to power and carry the communication signal between the field devices and the Control room.FEATURES :• Drastic reduction in cable, conduits cable trays, marshallive racks, and connectors etc.• Drastic reduction in installation cost.• Fewer non field devices.• More reliability due to the smaller number of devices.• More efficient operation due to better accuracy (no A/D and D/A conversion).• Easy integration into plant management system.• Flexibility for different suppliers are interoperable and interchangeable.• Major reduction in maintenance cost.

Field-bus Benefits Wire Screw I/O ISWiring (pair) Terms Cards BarriersTraditional 3500’ 168 2 2Field bus 640’ 64 1 1Savings 2860’ 104 1 1Savings % 82% 63% 50% 50%Savings $ $ 3000 Material $ 2000 Labor $ 5000 TotalTypically comments from a plant personal :•Easy to identify what’s out there.•Consistent calibration procedure.•Two days versus four days to commission system.•Familiar with twisted pair wiring – comfortable.

FOUNDATION™ fieldbus VocabularyBlocks Basic Components Valve Resource Resource Block Block FOUNDATION™ Transducer fieldbus (Servo) Function Function Block Block(s) Block(s)

FOUNDATION™ fieldbus VocabularyBlocks Basic Components Resource Resource Block Block FOUNDATION™ fieldbus Transducer Function Function Block Block(s) Block(s)TemperatureTransmitter

FOUNDATION™ fieldbus VocabularyH1 and H2• H1 Segment • H2 Segment – Moderate speed – High speed – Use existing wiring – Link multiple H1 – Bus powered Segments – Can be intrinsically – I/O subsystem bus safe – Replace – Low power 2 wire proprietary devices networks – 4 wire devices – New wiring – Replace analog & proprietary digital

FOUNDATION™ fieldbus VocabularyNew Approach for H2• 100 Meg Ethernet technology with extensions – Improve time to market – High speed – Mandatory redundancy – Widely available technology and silicon – Widely available tools – Limited incremental development – Many suppliers – High volume for low cost – Works with installed equipment – Evergreen technology• Better than ANY other solution!

FOUNDATION™ fieldbus VocabularyH1/H2 Bridges Server H2 Segment 100 Meg Ethernet Control PLC H1/H2 Module BridgeH1/H2 Bridge H1/H2 Bridge H1 Segment Replaces ReplacesTraditional I/O Traditional I/O H1 Segment H1 Segment

FOUNDATION™ fieldbus StandardsOrganizations• IEC – International Electro-technical Commission• ISA – International Society for Measurement and Control (formerly: Instrument Society of America) • SP50• CENELEC – European standards body • Parallel (competitive?) Working Groups to IEC

FOUNDATION™ fieldbus Topography H1 Fieldbus Installations Cost savings: Cost savings: •• wiring wiring •• I/O cards & I/O cards & Controller cables cables Similar I/O Cards Reduced Wiring Junction •• terminations terminations Similar I/O Cards H1 I/O Reduced Wiring Box •• IS barriers Interface IS barriers •• marshaling marshaling H1 I/O Terminations FewerTerminations FewerTerminations H1 Fieldbus all-digital Marshaling H1 Fieldbus all-digitalFewer Terminations Fewer Terminations IS (Ex i) Barriers Fewer IS barriers Fewer IS barriers

FOUNDATION™ fieldbus TopographyIntrinsic Safety Barriers

DeltaV System Architecture Engineering station Operator station Printer Printer 8 port Hub 8 port Hub primary Redundant 12 wide carrier for 8 wide carrier forPower/Controller P P A AA DDD I/O subsystem Contr. Contr. Serial S S I I O I I OPower supply H1 Controller I/O extension cable Connector RS232 Modbus PLC For Blank H Blank Blank Blank D Blank Blank 8 DI & 8 DO O I Fieldbus Transmitter Pressure Transmitter 3244MVF1NAB4 3051TG2A2B21AB4M5FF Smart valve positioner FSDVC0400-201 Fieldbus Power

DCS communication system Hierarchy Level 5 Management MIS Low data rates High Superior responsibility Level 4 Scheduling SCHED. Low Level 3 Supervisory control SUP. SUP. Level 2 Direct digital Control (DDC) DDC DDC DDC DDCLevel 1Sensors (S)& Actuators (A)High data rates S A A S A S S S A S S ALow responsibility PLANT

History of Process Control Signal Around 50 years ago, most plant used 3-15psi pneumatic signal to control their process. The last change change in signal standard was the open protocol HART digital communications format. The HART protocol provides simultaneous digital communications with the 4-20 mA output. The next protocol change will be fieldbus. Fieldbus is entirely digital-there is no analogSignal. Fieldbus also allows migration of control functions to field devices. Process control Timeline – The Evolution of Signal Standard Signal standards have evolved over the years, starting with the 3-15 psi standard. There are also other communication methods, but they have not gained widespread Digital: Fieldbus acceptance. Digital plus Analog: HART with 4-20mA With many standard there is typically a slow transition period as plant Analog: 4-20mA engineers and Pneumatic: 3-15 psi managers test period does gain widespread acceptance. However, once the benefits of the 1940 1950 1960 1970 1980 1990 2000 2010 Fieldbus become tested and proven, more plant will install Fieldbus because of its

I/O Bus Network Protocol I/O Bus Network Device bus network Process bus network Discrete AnalogByte-wide Bit-wide Several Hundred Data data Data Bytes

Protocol Standard Field Bus Foundation (Field Bus std.)Process bus network Profibus Trade Organization (Profibus std.) Device net Byte-Wide CAN Bus Data SDS Inter Bus-SDevice bus network Seriplex Bit-Wide Data ASI Inter Bus Loop

Fieldbus ArchitectureFieldbus is more than just a new signal communications protocol, but a whole new way to control the process. With the release of the low fieldbus (H1), the entire fieldbus will be defined. Most of the recent published literature has focused on the intricate details of the fieldbus architecture, especially those layers that have not been released. However, except Maintenance Workstation information physical layer and the user layer, these layer are transparent to the engineers and the system manager. User Layer System management Network Management Application Layer stack Data Layer Physical Layer Multivariable Valve Level Pump Transmitter Transmitter

Open System Interconnected Reference Model MBAP, SMB, FTP, SMTP, FMS, Physical – Provides the standard for transmitting rawApplication electrical signals over the communication channels. IEC 61158, ANSI/ISA S50.2,IEEE 1451Presentation Data link – Contains the rule for interpreting electrical signals as data, error checking and physical addressing Session Network – Describes the rule for routing messages Transport TCP, SPX, UDP through a complex network and deals with congestion. Transport – Establishes a dependable end-to-end Network IP, IPX, NetBeui connection between two host. HDLC, ETHERNET, ANSI/ISA S50.02 Session – provides Management and Synchronization Data link of complex data transaction. Physical EIA-485, ETHERNET,ANSI/ISA S50.02 Presentation – Establishes protocol for data format conversion, encryption and security. Application – Contains protocol that accomplish task such as e-mail, file transfer or reading a set of registers from a PLC. For the purpose of Process control, the top and bottom four layers are used. Layers 5 and 6 are important to large commercial networks.

Field BusField Bus is a bi-directional digital communication that interconnects smart field devices to control system or to instrument located in the control room.Field Bus is based on the OSI (Open System Interconnect), which was developed by the ISO(International Standard Organization) to represent the various functions required in any Layer FunctionCommunication network. 7 Application Provides formatted data 6 Presentation Converts data 5 Session Handles the dialogue 4 Transport Secures the transport connection 3 Network Establishes network connections 2 Link Establishes the data link connection 1 Physical Connects the equipment

Field Bus The OSI model consists of seven layers. However for real time application layers 3 to 6 are not considered since they deal with transference of data among networks. For such application following layers are used:• LAYER 1 - PHYSICAL LAYER Defines the type of signal, transmitting medium, data transmission speed, etc.• LAYER 2 – DATALINK LAYER Define the interface between the physical layer and the application layer. It establishes how the messages shall be structured and normalizes the use of multiple masters.• LAYER 3 – APPLICATION LAYER Defines howwas invented by an Indian engineer Mr. Ramrepresentation. The Fieldbus data is specified, its addresses and its Ramchandran ( M.S in Comp. Tech , Texas)

PHYSICAL LAYERThe Physical layer defines the medium that transport the messages frames, the signal shape and amplitude limits, data transfer rate, and power distribution.Technical Characteristics:Physical Medium Three types are defined: wires, optic fiber, and radio signals. The specification for wire has been already approved.Bit rate for wire media 31.25 Kbps (H1) 1 megabits and 2.5 megabits (H2). H1 and H2 are classification of the two hanks of Field Bus target applications. H1 has low speed and utilizes existing wires. H2 has high speed and may require independent wires to power up field devices.Number of devices per link (31.25Kbps) 2 to 32 devices, without power and no IS (intrinsic safety). 2 to 6 with power and IS.Maximum distance Up to 1900 meters for 31.25Kbps, without repeaters. Up to 750 meters for 1 megabits. Up to 500 meter for 2.5 megabits.

PHYSICAL LAYERSignal Modulation Manchester bi phase L synchronous.Physical layer preamble on transmissions, the physical layer will add to the data sent by the layer above a preamble and one start delimiter in the beginning of the frame and one end delimiter at the end delimiter at the end of the of the frame.

DATA LINK LAYERThe Data Link Layer will assure the integrity of the message by using the frame check sequence:Two bytes added to the frames and a polynomial calculation of all frame data.The Data Link Layer also checks to see that the data reaches the devices correctly.Technical characteristicsMedium Access: There are three forms to access the network:• Token passing: Token is the right to initiate a transaction on the bus. A device must have the token to initiate a conversation. As soon it finishes it will return the token to the LAS (Link Active Scheduler). The LAS send the token to the unit that requested in either in a pre-configured way or via scheduling.• Immediate response: A master station will give an opportunity to the station to reply with one frame.• Requested token: a device request a token by using a code in any of the response sent to the bus. The

APPLICATION LAYER AND MANAGEMENTThe Application Layer provides a simple interface to the end user’s application. Basically , it defines how to read, write , interpret and execute a message or command. A big part of this job is to define the message syntax. The contents include the requested message, action taken, and the response message.The management defines how to initialize the network : tag assignment, address assignment,clock assignment, clock synchronization, distributed application scheduling across the networkor association of the input and output parameters of the function blocks. It also controls theoperation of the network with statistic of faults and detection of the addition of the new elementor the absence of a station. The system always look for the new stations on the bus by pollingthe possible station addresses.

Digital Communication ProtocolISO - International Standard Organization. Responsible for developing the model that the communication specification are based upon as well as standards for each layer of communication specification.IEEE - Institute of Electrical and Electronics Engineers. Formed the IEEE 802 project for defining standards for network media and access methods.SP72 - Institute Society of America, Standards and Practice committee Number 72 Developing EIA1393 companion standard for process control messaging.SP50 - Institute Society of America, Standards and Practice committee Number 50 Developing standards for digital communication between field devices.F.I.P - Factory Information Protocol, approved French National Standard.Profibus - Process Fieldbus, approved German National Standard.

HART COMMUNICATION PROTOCOLWhy HART protocol ? 4-20 ma is tried, tested and widely used standard but only limited amount of information is sent by a 4-20 ma signal. HART (Hiway Addressable Remote Transducer) protocol enhances these operations by transmitting digital data along with the 4-20 ma signal – without interfering with it ! HART permits two-way communications. It also has all digital mode that allows instrument to be connected to a single cable, cutting installation costs dramatically.Features : 1. Field proven concept that is easy to understand and use. 2. Compatible with existing 4-20 ma systems. 3. Simultaneous point-to-point 4-20 ma and digital communication. 4. Alternative multi-drop mode. 5. Measured variables, tag no. , range and span settings, device information, diagnostics and simple messages transmitted. 6. Digital response time of 500 msec; burst mode response of 300 msec. 7. Open architecture; freely available to any vendor and every user.

HART COMMUNICATION PROTOCOLMethod of Operation : The Hart protocol operates using the FSK principal. The digital data is made up from two frequencies –1200 Hz and 2200 Hz representing bits 1 and 0 respectively. Sinusoidal waves of these frequencies are superimposed on the DC analog signal cables to give simultaneous analog and digital communicationsHART Protocol Structure : HART follows the basic Open Systems Interconnection (OSI) reference model, developed by the International Organization for Standard (ISO). The HART protocol uses a reduced OSI model, implementing only layers 1,2 and 7

HART COMMUNICATION PROTOCOL OSI reference modelOpen Systems Interconnections LAYER FUNCTIONS HART 7 Application Provides formatted HART instructions data 6 Presentation Converts data 5 Session Handles the dialogue 4 Transport Secures the transport connection 3 Network Establishes network connections 2 Link Establishes the HART protocol data link regulations connection 1 Physical Connects the Bell 202

HART PROTOCOL LAYERSLayer 1, the physical layer, operates on the FSK principle Data transfer rate: 1200 bit/s Logic “0” frequency: 2200 Hz Logic “1” frequency: 1200 Hz the vast majority of existing wiring is used for this type of digital communication.Layer 2, the link layer establishes the format for a hart message. HART is a master/slave protocol. the structure of these messages is given below: Preambl SD AD CD BC Statu Dat Parity e s a SD – start character. AD – display terminal and field addresses. CD – HART instruction. BC – Byte count. Status – Field device and communication status (only from field device to master) The individual characters are : 1 start bit, 8 data bits, 1 bit for odd parity and 1

HART PROTOCOL LAYERSLayer 7, the application layer, brings the HART instruction into play. The master sends messages with requests for specified values, actual values and any other data or parameters available from the device. The field device interprets these instruction as defined in theHART protocol. The response message provides the master with the status information and data from the slave.For slave devices, logical uniform communication is provided by the following command sets: Universal commands – understood by all field devices. Common practice commands – provide functions which can be carried out by many, though not all, field devices. Drive-specific commands – provide functions which are restricted to an individual

HART PROTOCOL – TECHNICAL DATADATA TRANSMISSION Types of data transmission : Frequency shift keying (FSK) Transfer rate : 1200 bit/s. ‘0’ bit information frequency : 2200 Hz ‘1’ bit information frequency : 1200 Hz Signal structure : 1 start bit, 8 data bits, 1 bit for odd parity, 1 stop bit. Transfer rate for simple variables : Approximately 2/s (poll/response)DATA INTEGRITY Physical layer : Error rate destination circuit : 1/(10^5) Link layer : Recognizes : all groups up to 3 corrupt bits and practically all longer and multiple groups. Application layer : Communication status terminated in a response message.

MODBUS The MODBUS protocol describes an industrial communication and distributedcontrol system developed by Gould-Modicon. MODBUS is a Master/Slavecommunications protocol, whereby one device (Master), controls all serial activities byselectively polling one or more slave devices. The protocol provides for one master deviceand up to 247 slave devices on a common line. Each device is assigned an address todistinguish it from all other connected device. Only a master initiates a transaction. Transactions are either a query/response type,or a broadcast/no-response type. A transaction comprises a single query and singleresponse frame or a single broadcast frame. Certain characteristic of a MODBUS protocol are fixed such as frame format, framesequences, handling of communication errors and exception conditions, and the functionsperformed.

RS-232 Communication RS-232 is an asynchronous communication network. Normally, a binary system isused to transmit data in ASCII (American Standard Code for Information Interchange)format. This code translates human readable code (letter/numbers) into “computer readable”code(1’s and 0’s). There are 2 types of RS-232 devices. The first is called a DTE (Data TerminalEquipment) device and a common example is a computer. The other type of device is calledDCE (Data Communication Equipment) device and a common example is a modem. In RS-232 the first thing a terminal send is start bit. This start bit is a synchronizingbit added just before each character being send. The last thing send is a stop bit. This stop bitinforms to the receiving terminal that the last character has just being send.

RS-232 CommunicationRS-232 communication is done through Serial port which usually has a 9-pin configuration. The pin and their purposes are shown below. 9-PIN PURPOSE 1 Frame ground 2 Receive data (RD) 3 Transmit data (TD) 4 Data terminal ready (DTR) 5 Signal ground (GND) 6 Data set ready (DSR) 7 Request to send (RTS) 8 Clear to Send (CTS) 9 Ring indicator (RI) *only for modems*

PC-to-PC Communication through Serial Port CD 10 01 CDRXD 20 02 RXDTXD 30 03 TXDDTR 40 04 DTRGND 50 05 GNDDSR 60 06 DSRRTS 70 07 RTSCTS 80 08 CTS RI 90 09 RI 9-Pin D Connector

PC-to-PC Communication through LPT1 Port 1 1 2 2 3 3 4 4 5 5 6 6 7 7 8 8 9 9 10 10 11 11 12 12 13 13 14 14 15 15 16 16 17 17 18 18 19 19 20 20 21 21 22 22 23 23 24 24 25 25

Flavours of Internet TelephonyPC-to-PC The Internet PC PC Dial-up or Local ISP Local ISP Leased LinePC-to-Phone The Internet PC Phone Local ISP Local ISP Voice GatewayPhone-to-Phone Access Code The Internet Phone Phone Local ISP Local ISP Voice Gateway Voice Gateway

APACS - Operation PlatformDatabase OwnershipOperator Console Engineer Console Operator Console Console Level Controller Level Controller Module I/O Level I/O Modules •TAGS •Range •Engineering Unit Transmitter Interlock I/P Valve •Diagnostics

TODAYS INDUSTRIAL SYSTEMS PlanningApplication HMI ----------------------- HMI Drivers 1 2 3 4 5 6 Devices I/O PLC DCS

PC Based Industrial SystemsOPC Client Planning Application HMI ---------------------------------- HMI OPC Server 1 2 3 Devices I/O PLC DCS

Enterprise Automation Schemes Windows NTCorporate IT Network Windows NT ServerControl network Embedded Real System

Windows NT (“New technology”)FEATURES:• A true 32 bit processing.• A very reliable operating system.• Real operating system.TECHNICAL ASPECT:• Multiprocessing, Multithreading and partitioned memory space.• Security - C2 compliance.• In-built networking.• Internationalization .• Human interface as Windows 95.• Object - based : DCOM/OLE - ActiveX.• for special need of the process industries. DCOM and OLE are not robust, deterministic and secure.• Client - Server architecture.

Windows NT InterconnectivityTransparent inter-connectivity to typical business systems in plants: 1) ODBC : It provides access to most SQL databases. 2) ActiveX/OLE : Supports data access between application and embedding of one applications function within another. 3) DDE : Dynamic Data Exchange supports simple data exchange between applications such as plant data populating an Excel spread sheets.

Windows NT features Windows NT is gaining ground in open control because of the following advantages :• User acceptance.• Corporate interoperability• Ease of use.• Connectivity.• Scalability for small and large application. However, Windows NT has the following disadvantages :• Needs a lot memory and processing power.• Optimized for office, not control, requirements.• Requires a disk drive which may fail.• Depends on single vendor.• Reboots at unexpected times• Unstable operating system.

Embedded control Operating System - QNXQNX real-time operating system, has evolved from the first-ever micro-kernel operatingsystem for PCs into one of the best selling and most trusted operating systems for missioncritical application. Today, QNX is the real time operating system in industrial automation, hand held devices, controllers and soft PLCsQNX is recognized as :• The fastest and most dependable real time operating system.• The most proven high speed, deterministic real time kernel.• Having a hard real time engine that gives PLC-style control.• Enabling data acquisition with milliseconds resolution.• Providing a fault-tolerant architecture on which you can run control, events, alarms in a virtually crash-proof environment.

Windows NT - for Process controlWindows NT features :• A true 32 bit processing.• A very reliable operating system.• Real operating system.• Multiprocessing, Multithreading and partitioned memory space.• Security - C2 compliance.• In-built networking.• Internationalization.• Human interface.• Object-based DCOM/OLE : The sending object is shown as client and receiving object is known as server. The MS technology allows any developer to produce small, self contain objects that have “packaged” visual component and specific action. These components are called “ActiveX” objects. NT’s OLE technology is part of Microsoft’s Distributed Component Object Model (DCOM) operating across networks. Anyone can develop ActiveX Object using VC++ or even VB on a PC. For special needs of the process control industries DCOM and OLE are not secure, deterministic and robust enough.

Ethernet Ethernet was originally designed by Digital, Intel and Xerox (DIX) in the early 1970’sand has been designed as a broadcast system. The original format for Ethernet was developedin Xerox Palo Alto Research center (PARC), California in 1972. The two inventors wereRobert Metcalf and David Boggs. Ethernet version 1.0 and 2.0 followed until the IEEE 802.3 committee re- jigged theEthernet II packet to form the Ethernet 802.3 packet. Nowadays you will see eitherEthernet II (DIX) format or Ethernet 802.3 format being used. The ‘Ether’ part of Ethernet denotes that the system is not meant to be restricted only toone medium type, copper cables, fiber cables and even radio waves can be used. Briefly, stated Ethernet what is referred to as the Physical layer and the Data- link layersprotocols. The physical layer defines the cable types, connectors and electrical characteristics.The Data link layer defines the format an Ethernet frames, the error checking method and the

Ethernet10Base5 Traditionally, Ethernet is used over ‘thick’ coaxial cable called 10Base5 ( the 10denotes 10 Mbps, base means that the signal is baseband i.e, takes the whole bandwidthof the cable, 5 denotes 500m maximum length ). The minimum length between stationsis 2.5m. The cable is run in one long length forming a ‘Bus Topology’. The segments areterminated by 50 ohm resistor and the shield should be grounded at one end only.10Base2 Thin Ethernet (Thinnet) uses RG-58 cable and is called 10Base2 (the 2 denotes200 mtr maximum length cable). Each station connects to the Thinnet by way of

Ethernet10BaseT Nowadays, it is becoming increasingly important to use Ethernet across UnshieldedTwisted Pair (UTP) or Shielded Twisted Pair (STP), this being called 10BaseT (the Tdenotes twisted pair). UTP is installed in star wire format and Ethernet Hubs with UTP ports(RJ45) centrally located. Also there should be no more than a 11.5db signal loss and theminimum distance between devices is 2.5 meters. The advantages of the UTP/STP technology are gained from the flexibility of thesystem, with respect to moves, changes, fault finding, reliability and security.10BaseF 10BaseF standard developed by IEEE 802.3 committee defines the use of Fiber for Ethernet. 10BaseFB allows up to 2 Km per segment and is defined for Backbone

EthernetThe following table shows the RJ45 pin outs for 10BaseT : RJ45 Pin Function Colour 1 Transmit White/Orange 2 Transmit Orange/White 3 Receive White/Green 4 Blue/White 5 White/Blue 6 Receive Green/White 7 White/Brown 8 Brown/White

PC-to-PC Communication throughEthernet RJ45 RJ45 1 1 2 2 3 3 4 4 5 5 6 6 7 7 8 8

Ethernet Topology Segmented (star) topology Bus topologyWorkstation Workstation Workstation Workstation Switched Hub Controller Controller Controller Controller

Wireless LANWireless LAN is based on standard IEEE 802.11b which throughput of up to 11Mbps in the2.4 Ghz band. Similar Wireless Personal Area Network (WPAN) are Bluetooth and Infrared. Ethernet works on the CSMA/CD technology but wireless LAN has difficulty of detectingcollision in Radio frequency. Therefore they are using CSMA/CA (Collision Sense MultipleAccess / Collision Avoidance) technology to transmit data. Physical Layer is either Photonic orRadio frequency.

Process control Software characteristics The most important feature of process control system is that it needs to be reliable. Theprocess control system used has to be completely crash-proof and any changes in thesystem need to be made on-line. The process control needs to be made real time, which means that it can update the I/Odata table and process the control program in the time required by the process. A process control system that is deterministic refers to whether the operating systemallows the highest priority task to work without interruption from task with lower priority. Software offerings in the automation and the process control fields must be versatile andopen enough to address the needs of different applications. Finally the chosen solution must deliver tangible, quantifiable values such as :1. Reducing project implementation time and cost.2. Improving time-to-market.3. Achieving higher production and quality.4. Cutting maintenance and training cost.

PC-based control system features Unlike the other systems, PCs provide a more open architecture making them ideal for improving, optimizing and integrating the overall automation process, as well as conducting control task. In addition PCs offer the following features :• Lower cost.• Ease of use.• Graphical user interface.• Easy integration of logic, motion and process control.• Simplified application development.• Software portability• Independence from proprietary control system. Using PCs enable the following functions,• Millisecond time stamping which is essential to utilities.• Real time control.• Sequence of events.• Alarming.• Data collection.

PLC conceptual overview SCADAProcess History & Alarm & Other Aspect configurationGraphics Trend Events system editor OP Client SCADA Control Aspect OPC server SCADA Real-time server database Protocol Protocol opc Modbus comli xx yy Siemens Allen GE ABB Bradley Fanuc ….

PLC Programming Standards The open, manufacturer-independent programming standard for automation isIEC 61131-3. You can thus choose what configuration interface you wish to use whenwriting your application :• Ladder Diagram• Instruction List• Function Block Diagram• Sequential Function Chart• Structured Text All users, be they plant electrician or computer scientists, thus have a configuration interface in which they can feel at home.

Industrial IT TrendsThe availability of information is becoming increasingly crucial in the view of growing global competition. In future, a decisive competitive edge can only be achieved by providing the right information at the right time, in the right place and in the right form for the right person. these leading- edge application are continuously optimized and repositioned. Industrial IT consists of five components: 1. Engineering IT 2. Operation IT 3. Production IT 4. Optimization IT 5. Evolution / Information

Industrial IT Trend Business Sales & Systems MarketingPlanning & e-PRODScheduling Real-time ION OPTIMIZAT UCTIVI Automation & ASSETPlant & Information TYProcess Eng. Operation & Maintenance Distribution Plant

Distributed Control System Basics

by Pratap Komaravolu on Jun 29, 2011

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Distributed Control System Basics — Presentation Transcript