Agenda

Alarm & Trip System

DCS

PLCAshwani KansalSr. Engineer Instrumentation23/1/2006

Human Intervention Alarm SystemMechanical Intervention - PRVsShut Down System Intervention - ESDSControl System Intervention (DCS)Normal Operation (LOCAL CONTROL)Layered Protection

Control System: System compensates for minor disturbances, adjusting the process as needed.

Alarm System: This alerts the operator to problems beyond the capabilities of the control system to enable human intervention.

Relief System: If changes are beyond human intervention or too fast for intervention, relief systems energy to prevent unsafe condition from occurring.

Shut Down System: If the plant continues in to an unsafe region, independent shut down system should stop operation.

Basic Concepts of Control System

Evaluation History and benefits of DCS

Basic Concepts of DCS

What is a Control?Measurement of a Process Variable

Processing of measured data with other information

Cause a control action

Process VariablePressureTemperatureFlowLevel Relative HumidityCurrentVoltage, ETC.

Types Of Control

Two Position ControlFloating ControlAnalog ControlProportional ControlPI ControlPID ControlDigital Control

ANDINPUT AINPUT BINPUT COUTPUT X

Evaluation of Control Systems1930s Machine type instrument, manual control1940s Large size pneumatic control instrument1950s Small size pneumatic control instrument1960s Small size analog instrument1970s Distributed control system, CRT operation1990s Microprocessor based DCS, PLC, etc. Now Compact systems, PC based systems, Open connectivity, MIS, etc.

Control TechniquesManual OperationPneumatic Controllers (Phase - I & Phase - II)Electronic Analog ControllersSupervisory Control ComputersDistributed Control System (DCS)Field Bus Technology

Advantage of Pneumatic Controller over Manual ControllerImproved ReliabilityCentralized System Improved Operator EfficiencyAuto OperationReduced Manpower

Problems of Pneumatic Control SystemFailures due to moving parts(Baffles & Nozzles assembly)Signal Loss due to long travelHigh Maintenance cost

Advantage/Disadvantage of Electronic ControlImproved Reliability (No moving Parts)No signal LossBetter representation of ProcessNo data storage and retrieval ability

Introduced in late 1970s.The concept behind the DCS was to use microprocessor technology for implementing control.Control loops were distributed among many smaller controllers each with its own Central Processor Unit.Controllers were linked together along with Operator Console and Engineering Station through a Communication Highway.Provides RedundancyDistributed Control System - DCS

Basic Layout of DCSBus ControllerProgrammable ControllerOutputInputInput / OutputAnalog / Digital SignalsField / MCCControl RoomBUSDCS

Example of Analog Signal Flow From Field To DCSINPUT1-5 VDCMMIA/DD/AISOLATORI/PPIDSET POINTSignal Conversion& IsolationPV4-20 mA1- 5 VDCPVDIGITAL SIGNALMVDIGITAL SIGNALI/O CardSignalProcessingINPUT SIGNAL CONDITIONERFieldSensorDCSBusControl Room

Example of Digital Signal Flow From Field To DCSTERMINALBOARDSEQUENCE CONTROLMMIRELAYBOARDDIGITALINPUTCARDBUSI/O NESTPROCESSORDIGITALOUTPUTCARDFieldMarshallingDCSC/RSensor

Outline Of Control SystemInput moduleOutput ModuleProcessing ModuleCommunication ModuleBus Controller ModuleBus System

Function Of Input ModuleSupplies power to Transmitters or transducersSignal VerificationDigitization, Parallel/Serial ConversionStorage of Measured valueAddress allocation

Module can be Analog or Digital

Function Of Output ModuleConversion of digital values in to Analog/Binary signalsStorage of signal for OutputAddress allocationPower supply for the driven end

Module can be Analog or Digital

Function Of Processing ModuleAccept Input data from the BusExecutes Control/Logical/Arithmetic functions as per written programData SimulationDiagnostic FunctionsChecks the Redundancy

Function of Bus Controller & Bus SystemProvides Hardware path for travel of informationClock GenerationAddress generationData TransmissionData Reliability Checking

Advantages of DCSSuperior reliability due to RedundancyImproved EffectivenessImproved Operation EfficiencyBetter Diagnosis of ProblemFacilitates the use of advanced controlAlarm generation capabilitiesModular SystemLess expensive per loopLess expensive to expand

Data storage and retrieval featuresEasier modificationMinimum Down timeEase of Maintenance (less Complexity)Reduction in costDCS can be placed away from Control Room (Reduces Cable Cost)

ABB Procontrol P13 DCS

DCS Systems in CFCL

Ammonia / Urea I: Yokogawa Centum XL

Ammonia / Urea II: Yokogawa Centum CS

Offsite & Utilities: ABB Procontrol P13/42

Ammonia / Urea I: Yokogawa Centum XL

System hardware Configuration

TerminologyEOPS : OPERATOR STATIONEOPC : OPERATOR CONSOLEENGS : ENGINEERING STATIONEFCD : DUPLEX FIELD CONTROL STATIONEFMS : FIELD MONITORING STATIONEFGW : FIELD GATEWAY UNITEPRT : PRINTERSHF BUS : BUS FOR INTER CONNECTING CONTROL STATIONS AND OPERATOR STATIONSECHU : COLOUR HARD COPY UNIT

Salient Features Of Control StationProcessor : Dual redundantCommunication : Dual redundantControl cards : Dual redundantBattery backup : 72 hoursBus Transmission : 1 Mbit / secTransmission distance : Upto 1 kmNo of stations : Upto 63Self diagnostics

PHASE I AMMONIA PLANT

MAN MACHINE INTERFACE

CENTUM CS3000

YOKOGAWA

SALIENT FEATURES OF OPERATOR STATIONCPU : MC68030 (25 MHz, 32 bit)Memory : 8 MBHard Disk : 80 MBTouch screen operationSelf DiagnosticsApplication CapacityNo. of tags : Upto 16000Trend points : Max 2300Graphics pages : 300Alarm Messages : Max 7680

Functions of MMI SystemDisplay of Process DataTrendingRecordingControl FunctionExternal System ConnectivitySequence of event recording

DCS Configuration Ammonia II

TerminologyFCS: Field control stationICS: Information & command stationEWS: Engineering work stationACG: Advance Gateway unitABC: Bus convertersV-NET: Bus for connecting FCS & ICS real time control networkE-NET: Communication network EWS to ICS and Gateway to secondary system.APS: Application StationACS: Advance Control StationRIO BUS: Remote I/O BusNIU: Node interface Unit

HARDWARE SPECIFICATIONS & MODEL CODES

Processor: RB3000 (25 MHz)

Memory size: 8 Mb (Enhanced type - 16 Mb)

Battery backup time: 72hrs max. Recharging time: 48hrs or longer Communication: V-NET Duplex or Single: RIO bus Duplex or Single Power Supply: 100 to 120 AC : 50 0R 60HZ +/- 3HZ

Connectivity to LAN - Overview

Salient Features Of Centum - CS DUAL REDUNDANT V-NET SUPPORTS

MAX. NO. OF STATIONS: 256/SYSTEMMAX. NO. OF DOMAINS: 16/SYSTEMSTATION NO. ICS:1 TO 64STATION NO. FCS: 1 TO 64MAX. NO. OF ICS/DOMAIN: 16MAX. NO OF NIU/FCS: 8MAX. NO. OF I/O UNIT/FCS: 40MAX. NO. OF NEST/IOU: 5MAX. LENGTH OF V - NET: 20KM (WITH OPTICAL FIBER)MAX. LENGTH OF RIO BUS: 20KM (WITH OPTICAL FIBER)

O&U Plant

Procontrol P13/42 DCS

ABB

Salient Features of DCS SystemModular SystemMulti Processor SystemExpandable System

Processor : Dual RedundantBus Traffic Director: Dual RedundantIntra Plant Bus : Dual redundantCycle Time: 5, 10, 20, 40 mSec (User Selectable).Programming Language: Procontrol P10Bus Transmission (Local Bus): 0.2 Mbits/Sec.Bus Transmission (IPB): 0.27 Mbits/Sec.Transmission distance : Upto 1 km (2 Km with amplifier card)No of stations : Upto 64Max. No. of addresses on Local Bus: 256 word address (FF)Total No. of addresses: 16384

O&U Plant

Man Machine Interface

Advant AS160OS DAS

ABB

Configuration DiagramControl RoomEngineering Station IPB 1A/1BInformation Network (TCP/IP) IPB 2A/2BAS 160OS Operator StationAS 160OSServerPrinter # 3 Hub

Features Of ABB ADVANT AS160OS MMI SystemDirect integration with Procontrol P13 DCSSystem structure modular, flexible, openEasy operation point and clickObject orientedSafe operationEfficient navigationUser authorization and security levelsEasy to engineer

Task Performed by ServerData acquisition and processingData management, archiving and retrievalInterface to P13 DCS busInterface to LANTime synchronisationSystem diagnostics

Overview of DAS FunctionsDatabase

Analog inputs 1200Binary inputs 3000Analog drives 50Binary drives 100ReportsDaily reports 24 nosMonthly reports 7 nos

Overview Of DAS Functions UsedMimic displays 85 pagesReal time trend displays 42 pagesHistorical trend displays 42 pagesGroup displays 62 pagesUFF criteria displays 19 pagesCharacteristic curves display 12 pagesProfile displays 12 pagesAlarms process, system, operator actionsSystem configuration display