plc ddcmis

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PLC

&

DDCMIS



What is PLC?

ProgrammableLogic

Controller

… a nice replacementfor electromechanical

relay controls



• A PLC is an industrially hardened computer-based unit that performs discrete orcontinuous control functions in a variety ofprocessing plant and factory environments.

•

Originally intended as relay replacementequipment for the automotive industry, thePLC can be found in some part of virtuallyevery type of industry imaginable.

• The primary reason for designing such a

device was eliminating the large costinvolved in replacing the complicated relaybased machine control systems.

What is PLC?



What is inside a PLC?

PROGRAMMINGDEVICE

POWER SUPPLY CPU MEMORY

I/O SYSTEM MODULES

OUTPUTDEVICES

INPUTDEVICES

SOLENOIDS

MOTOR STARTERS

ETC

SWITCHES

PUSH BUTTONS

ETC

I/O BUS




Power SupplyIt converts Power Line voltages to those required by electronic

components of PLC.

It may be Integral or separately mounted.

It provides the isolation necessary to protect electronic componentsfrom most high-voltage line spikes.

It is rated for heat dissipation requirements for plant floor operation.




Input SystemsInputs are defined as real-world signals giving the controller real-time

status of process variables.

These signals can be analog or digital, low or high frequency,

maintained or momentary.

They are presented as a varying voltage, current or resistance value.

Signals from thermocouples and RTDs are common examples of

analog signals.

Pushbuttons, limit switches & electromechanical relay contacts arefamiliar examples of digital, contact closure type signals.




Outputs There are three common categories of outputs:

• Discreet: Pilot lights, solenoid valves, annunciator windows (lamp

box)

• Register: Panel meters or displays

• Analog: Variable speed drives or I/P converters (control valves)

Most I/O systems are modular in nature; that is, a system can be arranged

by use of modules that contain multiples of I/O points.These modules can

be composed of 1, 4, 8, or 16 points and plug into the existing bus

structure.

The bus structure is really a high-speed multiplexer that carries

information back and forth between the I/O modules and the CPU.

One of the important functions of I/O is its ability to isolate real-world

signals from the low signal levels in the I/O bus




Central Processor UnitIt performs the tasks necessary to fulfill the PLC function. Among

these tasks are

• Scanning

• I/O bus traffic control

• Program execution

• Peripheral & external device communications

• Self Diagnostics

One important factor which rates a PLC is scan time. It is roughly

defined as the time it takes for the PLC to interrogate the input

devices, execute the application program and provide updated signals

to the output devices.




Memory UnitIt is the library where the application program is stored.

It is also where the PLC’s executive program is stored. An executive

program functions as the operating system of the PLC. It is the

program that interprets, manages and executes the user’s application

program.

It is the part of PLC where process data from the input modules and

control data for the output modules are temporarily stored as data

tables.

Memory can be volatile or nonvolatile. Volatile memory is erased ifpower is removed. Battery backup is provided for most units with

volatile memory to avoid loss of program in the event of power outage.




Programmer UnitIt provides an interface between the PLC and the user during

program development, start-up and troubleshooting.

The instructions to be performed during each scan are coded and

inserted into memory with the programmer.

Programmers vary from small hand-held units the size of a large

calculator to desktop stand-alone intelligent CRT-based units.

Programmers come complete with documentation, reproduction, I/O

status & on-line and off-line programming ability.

Many PLC use a PC as the programming tool using the serial

interface and a Programming Software.



How a PLC Operates?

Step 1-CHECK INPUT STATUS-First the PLCtakes a look at each input to determine if it is

on or off. It records this data into its memory to

be used during the next step.

Step 2-EXECUTE PROGRAM-Next the PLC

executes your program one instruction at atime using the input data obtained in previous

step and decides about the states of output. It

will store the execution results for use later

during the next step.

Step 3-UPDATE OUTPUT STATUS-Finally the PLC updates thestatus of the outputs using the results obtained in previous step.

After the third step the PLC goes back to step one and repeats the

steps continuously.



How a PLC is Programmed?Ladder Diagrams

• Ladder diagrams are one traditional method of describing control

circuits.

• There are a few basic symbols that are used to express the meaning

and purpose of a control circuits. They are

Normally OpenContact

Normally Closed

Contact

Normally OpenPush Button

Normally Closed

Push Button

(T.O.)

(Time to Open)

Time Delayed

Contact

Starter/Relay/Solenoid Coil



Example PLC Program

Let us consider a simple example. In the

given circuit, the coil will be energized

when there is a closed loop between the +

and - terminals of the battery(When both

the switches SW1 & SW2 are closed).

This simple circuit is represented in a

ladder Diagram as below. A ladder diagram consists of

individual rungs just like on a real

ladder. Each rung must contain one

or more inputs and one or more

outputs. The first instruction on a

rung must always be an inputinstruction and the last instruction on

a rung should always be an output

(or its equivalent).Some PLC require that every

ladder diagram include an END

instruction on the last rung.



Advantages of PLCCompared with electromechanical relay systems, PLCs offer the

following advantages:

Ease of programming and reprogramming in the plant.

A programming language that is based on relay wiring symbols

familiar to most plant personnel

High reliability and minimal maintenance

Small physical size

Ability to communicate with computer systems in the plant

Moderate to low initial investment cost Rugged construction

Modular design



PLC Applications at Our Project

Some of the areas using PLC are:

Coal Handling Plant Stage-II

Ash Handling Plant Stage-II

DM Water Plant Stage-II Condenser Tube Cleaning System Stage-II

Generator Stator Water Conductivity/Flow Protections Stage-I

Boiler Feed Pump Delta-T Protection in Unit-II



WHAT IS DDCMIS ?

DISTRIBUTED

DIGITAL

CONTROL,MONITORING &

I NFORMATION

SYSTEM

Distributed means there is no

centralized control and control

is spread across multiple units

Digital means processing of

process information is done in

digital form using micro-

processor based hardware

MIS interfaces the human with

process using computers



• LOCAL PNEUMATIC CONTROLLERS

• MINIATURIZED AND CENTRALIZED PNEUMATIC

CONTROLLERS AT CONTROL PANELS AND CONSOLES

• SOLID-STATE CONTROLLERS

• COMPUTERISED CONTROLS (SUPERVISORY)

• DIRECT DIGITAL CONTROL(DDC)

• DISTRIBUTED MICROPROCESSOR BASED CONTROL

PROGRESS OF INSTRUMENTATION USED TO IMPLEMENT

AUTOMATIC PROCESS CONTROL

DDCMIS – TECHNOLOGICAL

BACKGROUND



Why DDCMIS?

Disadvantages of earlier Systems

• Analog instrument panels required huge space, lot of

wiring and are less user friendly for monitoring of large

number of parameters.• Accuracy obtained with solid-state controls is not good and

they tend to drift with time.

• Supervisory controls are inflexible as changing of control

configuration requires change in routing of wires.• Use of centralized control leads to complete failure during

shutdowns.



Components of DDCMIS

CONTROL SYSTEM

MAN MACHINE INTERFACE & PROCESS

INFORMATION SYSTEM

DATA COMMUNICATION SYSTEM

( DATA HIGHWAY)



DATA COMMUNICATION SYSTEM

• LOCAL SYSTEM BUS – It is just lines on the backplane of

control panel to which all the modules are connected directly. It

serves as communication medium between the modules.

• INTRAPLANT BUS(IPB) – It is a coaxial cable which runs

through all the panels of control system and interconnects

them.

• LOCAL AREA NETWORK(LAN) – It is a network of

computers which are connected to a single point(HUB).

SOME FORM OF REDUNDANCY IS PRESENT





FUNCTIONAL DIVISION

• SG-C&I SYSTEM

• TG-C&I SYSTEM

• BOP-C&I SYSTEM

CONTROL SYSTEM

HARDWARE COMPONENTS

• POWER SUPPLY• CONTROL PANEL

• ELECTRONIC MODULES



SG-C&I SYSTEM

CONSISTS OF

• BURNER MANAGEMENT SYSTEM (BMS)

• SOOT BLOWER CONTROL SYSTEM (SBC)

• SECONDARY AIR DAMPER CONTROL SYSTEM (SADC)

• AUXILIARY PRDS CONTROLS (APRDS)

• HP BYPASS SYSTEM(HPBP)



TG-C&I SYSTEM

CONSISTS OF

• ELECTRONIC TURBINE PROTECTION (ETP)

• AUTOMATIC TURBINE RUN-UP SYSTEM (ATRS)

• AUTOMATIC TURBINE TESTING SYSTEM (ATT)

• ELECTRO- HYDRAULIC TURBINE CONTROL SYSTEM (EHTC)

• TURBINE STRESS CONTROL SYSTEM (TSC)

• LP BYPASS SYSTEM (LPBP)

• GLAND STEAM PRESSURE CONTROL

• GENERATOR AUXILIARY MONITORING PANEL (GAMP)



BOP-C&I SYSTEM

• CONSISTS OF OPEN LOOP CONTROL SYSTEM (OLCS) AND

CLOSED LOOP CONTROL SYSTEM (CLCS)

• OLCS - THE SEQUENCE CONTROL, INTERLOCK OF ALL THE

PLANT SYSTEMS WHICH ARE NOT COVERED IN THE SG-C&I AND

TG-C&I. THIS INCLUDES MAJOR AUXILIARIES LIKE FD/ID/PA

FANS, AIR-PREHEATER, BFP/CEP/CWP/ BCWP , DMCWP/CLCWP

AND ELECTRICAL BREAKERS.

• CLCS - THE MODULATING CONTROL FOR VARIOUS IMPORTANT

PLANT PARAMETERS, LIKE FW FLOW (DRUM LEVEL), FURNACE

DRAFT, COMBUSTION CONTROL (FUEL FLOW AND AIR FLOW), PA

HDR PRESSURE CONTROL, DEAERATOR/HOTWELL/HEATER

LEVEL CONTROLS ETC.



CONTROL SYSTEM - HARDWARE

PROCONTROL MODULES• INPUT

• OUTPUT

• PROCESSOR

•DRIVE

• BUS COMMUNICATION

THE CONTROL SYSTEM USED IN STAGE-II IS

PROCONTROL P13/42



INPUT MODULE

It receives the process signal, convert them to digital form andcommunicate the value on local bus

• ANALOG – Voltage(EA01) 4-channel

– Current(EA02) 4-channel

– RTD(EA03) 4-channel

– Thermocouple(EA04) 8-channel

• DIGITAL

– Voltage(EB01) 4-channel

– Single contact(EB02) 16-channel

– Change-over contact(EB03) 5-channel




OUTPUT MODULES

They receive the value from localbus and give output to theprocess/field.

• ANALOG

– Voltage(AA01) 4-channel

– Current(AA02) 4-channel

• DIGITAL – Voltage(AB01) 16-channel

– Contact(AB02) 16-channel




PROCESSOR MODULE ( PR05)

• IT IS RESPONSIBLE FOR THE EXECUTION OF ALL THELOGICS THAT IS PROGRAMMED INTO IT

• IT CAN BE USED IN REDUNDANT MODE• IT IS PROGRAMMED USING SK06 KIT, WHICH IS A

COMPUTER BASED UNIT FOR INTERFACING WITHPROCESSOR

• THE LOGICS ARE PROGRAMMED USING THE P10LANGUAGE




DRIVE MODULES

• THESE ARE USED FOR CONTROLLING THE DIFFERENTTYPES OF PROCESS ACTUATING ELEMENTS

• THEY HAVE PREDEFINED LOGICS BUILT INTO THEM• TYPES

– ANALOG (AS06)

• USED FOR DRIVING ANALOG CONTROL DRIVES SUCH ASVARIABLE SPEED DRIVES, CONTROL VALVES THROUGHI/P CONVERTER ETC

– DIGITAL (AS04)• USED FOR OPERATING MOTORS, ELECTRICAL VALVES,

SOLENOID VALVES ETC




BUS/COMMUNICATION MODULES

BUS TRAFFIC DIRECTOR

• IT CONTROLS THE COMMUNICATION PROCESS ON THEBUS

- THERE ARE TWO TYPES OF TRAFFIC DIRECTORS: – LOCAL BUS(BV05)

– INTRAPLANT BUS(FV05)

BUS COUPLER(BK02)

• IT CONNECTS THE LOCAL BUS TO THE IPB

BUS END MODULE(BA01)

• IT IS USED FOR TERMINATING THE LOCAL BUS




CONTROL SYSTEM OVERVIEW

IPB

TRAFFIC

DIRECTOR

BUS

COUPLER

BUS

COUPLER

BUS

COUPLER

IPB

TRAFFIC

DIRECTOR

WSPOSE

PANEL

SERVER

BK 02

IPB - 1

IPB - 2

Local Bus -1.0BLocal Bus-1.0C,2.0C

Local Bus -1.0C



• VPC OPERATION• OTHER OPERATOR INFORMATIONS THROUGH VARIOUS

DISPLAYS

• ALARMS, LOGS, HISTORICAL AND LONG TERM STORAGE.

• PERFORMANCE AND OTHER CALCULATIONS

MMIPIS –

MAN MACHINE INTERFACE & PLANT INFORMATION

SYSTEM

Functions


PMS AND WSPOSE ARE EXAMPLES OF MMIPIS SYSTEM

WSPOSE OVERALL VIEW



WS POSE PANEL ( DDC – MMI INTERFACE PANEL )

SERVER 1

LAN

OWS 1 OWS 5

LOCAL BUS STATIONS

PS

PR05

BK

I /P I /P O/P

PS

PR

BK

I /P I /P O/P

O/P

WSPOSE OVERALL VIEW

IPB 1 & 2

SERVER 2



SG PACKAGE TG PACKAGESTATION

C & I

IPB - 1

IPB - 2

IPB - 3

IPB - 4

IPB

ACCESSCOUPLER

LAN

OWS -1 OWS -2 OWS -3 OWS -4

SERVER2 SERVER1

WORKSTATIONS

PMS PANEL

PMS

SYSTEM



WHY DDCMIS ?1. VERY HIGH FLEXIBILITY FOR MODIFICATION

IN CONTROL STRATEGY

2. VERY HIGH SELF-DIAGNOSTIC

3. VERY LOW DRIFT (ONLY IN I/O CARDS) , HENCE

NO NEED OF FREQUENT RE-CALIBRATION

4. MUCH HIGHER RELIABILITY (BASED ON MTBF)

5. BETTER LONG TERM SUPPORT DUE TO

CHANGING TECHNOLOGY

6. MUCH BETTER OPERATOR INTERFACE



PLC & DDC - COMPARISION

• DCS systems are used for large applications and closed loop

controls, whereas, PLC are primarily used for small applications

and sequential controls.

• DCS systems are very costly for small applications, whereas,PLCs are much cost-effective for both small and large

applications.

• While DCS systems are superior in communication redundancy

and data security, PLCs are better for logic, are faster and have

more rugged I/O.

• DCS systems are more difficult to design than PLCs.



SALIENT FEATURES OF

DDCMIS



SALIENT FEATURES OF DDCMIS

• INTEGRATED PLANT CONTROL FOR SG,TG AND BALANCE OF PLANT CONTROLIT MAY BE REMEMBERED THAT HISTORICALLY

THE TERM DDCMIS USED BE REFERRED TO FOR

THE SO-CALLED “BOP - C&I” .

THE SG-C&I, i.e. FSSSetc. TG-C&I i.e. ATRS, TURBINE PROTECTION etc.

ORIGINALLY WERE NOT CONSIDERED UNDER

DDCMIS OR DCS AS PER MANY SUPPLIERS. ONLY

RECENTLY THE TYPE OF SYSTEMS FOR ALL THE

SYSTEMS HAVE BECOME SIMILAR (WITH SOMEDIFFERENCE WHICH WILL BE DISCUSSED LATER),

WE TEND TO CONSIDER THESE SYSTEMS UNDER

DDCMIS.




• INTEGRATED PLANT OPERATIONTHROUGH FULLY INTERCHANGEABLE

OPERTAOR WORK STATIONS (OWS) FOR

SG, TG AND BALANCE OF PLANT(SOMETIMES THIS MAY NOT BE POSSIBLE DUE TO

PACKAGING CONCEPT)




• PROVISION OF EXTENSIVE SELF-DIAGNOSTICS

• USE OF LARGE VIDEO SCREENS FOR

PROJECTIONS OF VARIOUS PLANT

MIMICS ETC.

• PROVISION OF FAULT ALARM

ANALYSIS TO GUIDE THE OPERATOR TO

THE MOST LIKELY EVENT • PROVISION OF TREND ALARMS




• PROVISION OF SAFETY HARDWARE FORBURNER MANAGEMENT SYSTEMS

• PROVISION OF FAIL-SAFE HARDWAREFOR TURBINE PROTECTION SYSTEM

• PROVISION OF ADEQUATE RELIABILITY

AND AVAILABILITY WITH PROPERREDUNDANCY IN SENSOR, I/O AND

CONTROLLER LEVELS.



DDCMIS CONFIGURATION

HMIREDUNDANT

SERVERS

Redundant

F.G.Controllers

ENGG.STN.

FOR CONTROL SYS.

HMIENGG. STN

FOR HMI

PROCONTROL

SYSTEM

Measurement system / I/O

subsystem

I.P. BUS Max. 4nos. rdundant

maxDNA

SYSTEM

MMI LAN



CONTROL SYSTEM



CONTROL SYSTEM

PROGRAMMING & MMIPIS M & S

CONFIGURATION SYSTEM CLOCK

SG- C&I BOP- C&I TG- C&ISYSTEM SYSTEM SYSTEM

DCS



2 X 100 %

CONTROLLERS (INCL. COMM. CONT.)

LOCAL BUS

I/O CARDS DCMS **

DCS



FUNCTIONAL GROUPS

• SIGNIFICANT REDUCTION IN NUMBERS EXPECTED IN

FORTHCOMING PROJECTS

• COMBINING OF OLCS AND CLCSCONTROLLERS - HISTORICAL

BACKGROUND

•EXCEPT FOR CERTAIN SUPPLIERS,ALL HAVE VERY POWERFUL

CONTROLLERS• TRANSPARENCY 6,7,8 FOR GROUP DRAWINGS



MMIPIS



MAN-MACHINE INTERFACE AND

PLANT INFORMATION SYSTEM • LATEST STATE-OF-THE-ART WORKSTATIONS

AND SERVERS BASED ON OPEN-ARCHITECTURE

AND INDUSTRY STANDARD HARDWARE AND

SOFTWARE TO ENSURE BETTER CONNECTIVITY.

• e.g. HARDWARE FROM COMPAQ/DIGITAL, HP,

SUN MICRO-SYSTEM OR OTHER MAJOR

SUPPLIERS (LESS DEPENDENCE ON THE C&ISYSTEM SUPPLIER IN THE LONG RUN)

• OPERATING SYSTEM WINDOWS-NT, OPEN-VMS

OR UNIX.



MAN-MACHINE INTERFACE AND

PLANT INFORMATION SYSTEM • 64-BIT SERVER/OWS WITH HIGH-SPEED

AND LARGE MEMORY (256/512 MB RAM, 8

GB HDD FOR SERVER AND 128/256 MB RAM

AND 4/6 GB HDD FOR OWS) TO ENSURE

FAST RESPONSE

• PROVISION OF LVS

• CONNECTION TO OTHER SYSTEMTHROUGH STATIONWIDE WAN

• TRANSPARENCY NO 9 & 10



MMIPIS FUNCTIONALITIES

• VPC OPERATION

• OTHER OPERATOR INFORMATIONS

THROUGH VARIOUS DISPLAYS

• ALARMS, LOGS, HISTORICAL AND

LONG TERM STORAGE.

• PERFORMANCE AND OTHERCALCULATIONS



DCS



REDUNDANT DATA

COMMUNICATION SYSTEM (DCS)

• 1. MAIN SYSTEM BUS

• 2. LOCAL SYSTEM BUS

• 3. LOCAL BUS OR I/O BUS

• 4. OWS LAN

• 5. STATION-WIDE WAN



DDCMIS CONFIGURATION

HMIREDUNDANT

SERVERS

Redundant

F.G.Controllers

ENGG.STN.

FOR CONTROL SYS.

HMIENGG. STN

FOR HMI

PROCONTROL

SYSTEM

Measurement system / I/O

subsystem

I.P. BUS Max. 4nos. rdundant

maxDNA

SYSTEM

MMI LAN



UNIT C&I

SYSTEM

(TYP)

OFF-SITE C&I

SYSTEM

(TYP)

OFF-LINE LAN

STATION-WIDE ON-LINE LAN

GATEWAY TO CORP.

CENTRE

OTHER

UNITS

POWER SUPPLY SYSTEM



POWER SUPPLY SYSTEM

• CONTROL SYSTEM POWER SUPPLY TWO SETS

OF DC POWER SUPPLIES - ONE SET FOR SG/TG-C&I AND OTHER FOR BOP-C&I EACH WITH 2 X

100 % CHARGER AND 2 X 100 % BATTERY.

•OTHER IMPORTANT AC LOADS LIKE MMIPIS,PANEL INSTRUMENTS, ANALYSERS ETC.

SHALL BE POWERED FROM UPS COMPRISING

OF 2 X 100 % CHARGER, 2 X 100 % INVERTER

AND 1 X 100 % BATTERY.• HEAVY DUTY Ni-Cd BATTERIES HAVE BEEN

ENVISAGED FOR LONGER LIFE & LESSER

MAINTENANCE

CABLING & TERMINATION



CABLING & TERMINATION

• EXTENSIVE GROUPING OF SIGNALS BY LARGE

SCALE USE OF JBs AT STRATEGIC LOCATIONS

• USE OF CABLES WITH HIGHER NO OF PAIRS

• USE OF MAXI-TERMI CONNECTION FOR

SYSTEM CABINETS, MARSHALLING PANELS &

OUTGOING SIDE OF JBs, CJS BOXES etc.

• USE OF PLUG-IN SOCKET AND CONNECTORS

FOR TRANSMITTERS, SWITCHES, LS/TS etc.



IMPORTANT SG/TG RELATED C&I SYSTEM

• FLAME MONITORING SYSTEM

• COAL FEEDER C&I

• ELECTROMATIC SAFETY VALVES

• FURNACE TEMP PROBES

• ACCOUSTIC PYROMETER FOR FURNACE TEMP PROFILE

• BOILER FLAME ANALYSIS SYSTEM• COAL BUNKER LEVEL MONITORING SYSTEM

• ELECTRONIC DRUM/SEPARATOR LEVEL MONITORINGSYSTEM

• TURBINE SUPERVISORY SYSTEM

• TDBFP TURBINE SUPERVISORY SYSTEM

• IN PACKAGED SYSTEM, THESE AREUNDER SG & TG PACKAGES.



SCOPE OF SUPPLY OF C&I SYSTEM

• DDCMIS (IN C&I PACKAGE, SG-TG C&I & ASSOCIATEDMMI etc. EXCLUDED)

• OTHER SG/TG C&I (ONLY FOR TURN-KEY PACKAGE)• MEASURING INSTRUMENTS• SWAS• CONTROL DESK/PANELS• ALARM ANNUNCIATION

• ELECTRIC POWER SUPPLY• CONTROL VALVE AND ACTUATORS (ONLY FOR 500 M

PROJECTS, BEING DELETED FROM C&I IN RECENTPROJECTS)

• MAINTENANCE & CALIBRATION EQUIPMENT

• INSTRUMENTATION CABLES• PROCESS CONNECTION & PIPING• PA SYSTEM• OFF-SITE PLANT CONTROL SYSTEM (ONLY FOR TURN-

KEY PACKAGE, ELSE IN RESPECTIVE MECH. PKG)

OPERATION PHILOSOPHY



OPERATION PHILOSOPHY

• CENTRALISED OPERATION OF MAIN PLANT THROUGH

OWS & LVS• OFF-SITE PLANTS TO BE CONTROLLED FROM THEIR

LOCAL STATIONS WITH STATION-WIDE LAN DATA LINK

• MINIMUM BACKUP INSTRUMENTATION ( ORIGINALLY

CONSERVATIVE, NOW REDUCED. CRITERIA - HANDLINGEMERGENCY & SAFE SHUT-DOWN)

• GEOGRAPHICAL DISTRIBUTION - ALTHOUGH NOT VERY

USEFUL FOR POWER PLANTS AS COMPARED TO

PROCESS/INDUSTRIES, BEING ADOPTED FOR FEW AREASWHERE SIGNALS ARE CONCENTRATED (REDUCTION OF

CABLING, MUCH LESS ERECTION & COMMISSIONING

TIME)

REDUNDANCY



REDUNDANCY • IN CONTROL SYSTEM

– ORIGINALLY THE CONTROLLERS

– ALT-I - SINGLE LOOP NON-RED

– ALT-II- MULTI-LOOP REDUNDANT

– NOW ALT-I ABOLISHED. NOW 2 X 100 % OR 2 OUT OF 3.

• I/O REDUNDANCY - CURRENT PROJECTS HAVE HIGH

LEVEL OF I/O & DRIVE CONTROL MODULES

REDUNDANCY DUE TO LOWERING OF BACK-UP ANDINCREASE IN NO. OF CHANNELS. IN FUTURE PROJECTS,

LIMITED TO SAFETY SYSTEMS AND CASES WHERE

SENSOR REDUNDANCY IS THERE.

• DATA COMMUNICATION SYSTEM - 100 % REDUNDANT• MMIPIS

– - REDUNDANT SERVERS

– MULTIPLE OWS (PRESENTLY 10 NOS, BEING REDUCED TO 6 NOS.)

DESIGN CRITERIA



S GN C

• PROVENNESS

– SUPPLIER’S EXPERIENCE

– SYSTEM EXPERIENCE

– PROVENNESS VS OBSOLESCENCE

• RELIABILITY AVAILABILITY

– HARDWARE QUALITY (PUBLISHED MTBF etc.)

– CONFIGURATION

– REDUNDANCY

– FAULT TOLERANCE

• STANDARDISATION AND UNIFORMITY OF H/W

– SAME SERIES & FAMILY OF H/W AS FAR AS POSSIBLE

– DIFFICULTIES BECAUSE OF PACKAGING CONCEPTS &

RESPOSIBILITY CENTRE & INTERFACES (EVEN IN TURNKEY

PACKAGE)

DESIGN CRITERIA



• OPERABILITY – DESIGN CONCEPT - FAIL SAFE ETC.

– FALSE TRIP VS SAFETY – OPERATOR CONVENIENCE DURING NORMAL RUNNING &

EMERGENCY

– MANAGEMENT REPORTING

• MAINTAINBILITY – STANDARDISATION (AS INDICATED ABOVE)

– MODULAR DESIGN AND EXPANDABILITY

– DIAGNOSTIC, FAULT IDENTIFICATION AND FAULT TOLERANCE

– GUARD AGAINST OBSOLESCENCE

– AVAILABILTY OF SPARES

• OTHER CRITERIA – UNIT OPERATION PHILOSOPHY

– MARKET TRENDS AND EVOLUTION OF INFORMATIONTECHNOLOGY

FEEDBACKS FROM EXISTING SYSTEMS

plc ddcmis

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