1.CHART RECORDERS

                                        1.Eurotherm,UK

                                         2.CHINO JAPAN

                                         3.ABB,UK

                                         4.YOKOGAWA,JAPAN

2.

1.00.00   DESIGN CRITERIA

   The Bidder shall provide Control  & Instrumentation

         System for control, monitoring and operation of entire

         Plant in all regimes of operation in safe and most

         Efficient manner.  The Bidder shall provide all systems,

         Equipment, accessories and associated equipment in a

         Fully operational condition acceptable to the Owner. 

         The  bidder shall also provide all  material,  equipment

         and  services which may not be  specifically  stated  in

         The specifications but are required for completeness of

         The equipments/systems furnished by the bidder and for

         Meeting   the   intent   and   requirements   of    this

         Specifications.   The work shall be   consistent with

         Modern power plant practices and shall be in compliance

         With all applicable codes, standards, guidelines and

         Safety requirements in force on the date of award of the

         contract.  The  requirements  of  statutory  authorities

         (e.g.  MOEF, Inspector of Factories, IBR,TAC,  CPCB/SPCB

         etc. with regard to various plant areas like main plant,

         fuel oil plant/system, chlorination plant, fire fighting

         system,  Emission  measurements etc.)shall  be  complied

         even if not actually spelt out.

         The   bidder  shall  provide  all  systems/   equipments

         described in this specification for one unit. There  are

         Two Units  are in the scope of bidder.

1.01.00  Reliability and Availability

         Each  component & system offered by the bidder shall  be

         of    established   reliability.  The   minimum   target

         reliability  of  each  piece  of  equipment  like   each

         electronic  module/card.  Power supply, peripheral  etc.

         shall  be  established by the  Bidder,  considering  its

         failure  rate/mean time between failure(MTBF),  meantime

         to  repair(MTTR),  such  that the  availability  of  the

         Complete C&I system is assured for 99.7% or better.

         Further the bidder shall ensure that all  equipment/part

         of  his  system, that is not listed  under  recommended

         spares  shall have normal life expectancy exceeding  the

         expected life of the plant i.e. thirty (30) years.

         In  order  to ensure the target reliability  the  Bidder

         shall  ensure  selection of  proper  materials,  control

         manufacturing process, use quality controlled components

         and  parts, take adequate design margins &  Derating  of

         Electronic components and parts and carry out necessary

         tests etc. 

         The bidder shall submit detailed reliability calculations

         for  each system/ equipment which (with the help  of  a

         schematic  of various sub-system connected in series  or

         in  parallel as the case may be and MTBF &  MTTR  values

         for the various equipments) shall show that availability

         calculation   is  as  per  IEEE  standard-  P  1046   or

         equivalent.  This shall be submitted by bidder along with

         bid.

1.01.01  When  more than one device uses the same measurement  or

         control  signal, the transmitter and  other  components/

         module  shall  be fully equipped to provide  all  signal

         requirements.  The system shall be arranged so that  the

         failure  of any monitoring device or control  components

         or  spurious intermediate grounding in the  signal  path

         shall  not  open the signal loop nor cause the  loss  or

         malfunction  of signal to other devices using  the  same

         signal.

1.01.02  To  ensure availability, adequate redundancy  in  system

         design shall be provided.  Redundancy of components  and 

         system  shall  be dictated by availability  criteria  in

         Cl.1.01.00,  to  ensure that  the   system  availability

         target  as  well as safety  considerations  in  critical

         applications are fully met.

         To  ensure the availability of control system,  suitable

         redundancy  shall  be provided at sensor  sensor  level,

         hardware  and  software.   For  the  protection   system

         independent  sensing device shall be provided to  ensure

         adequate safety of plant equipment.

1.02.00  Standardization

         To  ensure  smooth  and  optimal  maintenance  including

         efficient   spare  parts  management  of   various   C&I

         instruments/   equipments  like   vibration   monitoring

         systems,    all   4-20   mA   electronic    transmitters/

         transducers,   control  valves,  actuators   and   other

         instruments/  local devices etc. being furnished  by  the

         bidder  for  SG,  TG and  other  plant  auxiliaries  for

         similar applications, the bidder shall ensure that  they

         are of the same make series and family of hard wares.

1.03.00  Operability & Maintainability

     1.  The design of the control systems and related equipments

         shall adhere to the  principle of `Fail Safe’  operation

         wherever   safety  of  personnel/  plant  equipment   is

         involved. `Fail Safe’ operation signifies that the   loss

         of  signal,  loss  of  excitation  or  failure  of   any

         component shall not cause a hazardous condition however,

         at  shall also be ensured that occurrence of false  trips

         are avoided/ minimized.

         The  types of failure, which shall be taken into  account

         for ensuring operability of the plant shall include  but

         not limited to -

         -  Failure of sensor or transmitter

         -  Failure of controller other modules during  automatic

            operation

         -  Loss of motive power to final control element

         -  Loss of control power

         -  Loss of instrument air

     2.  The  choice  of hardware shall also  take  into  account

         sound  maintainability principles and  techniques.   The

         same  shall  include  but shall not be  limited  to  the

         following :-

         -  Standardization of parts

         -  Minimum use of special tools

         -  Grouping of functions

         -  Interchangeability

         -  Malfunction  identification  facility  facility/self

            surveillance facility

         -  Easy modular replacement

         -  Fool proof design providing proper identification and

            other  features  to preclude  improper  mounting  and

            installation.

         -  Appropriate  Derating of electronic  components  and

            parts

     3.  Equipment/  devices which require maintenance  shall  be

         suitably located to ensure easy accessibility.

     4.  The   bidder  shall  supply  all  necessary   furniture

         including ergonomically designed chairs & desks for  use

         at the room desks and various programming stations.  All

         the  equipment like programmers stations,  PC’s  various

         peripherals  & similar devices shall be   complete  with

         desks, stands and other mounting accessories.

         All  necessary furniture such as table,  desks,  chairs

         etc.  shall  also be furnished to set up  maintenance  &

         calibration equipment laboratories and the same shall be

         completely erected & commissioned by the bidder.

1.04.00  The  equipment  shall employ latest state  of  the   art

         technology  to guard against obsolescence. In any  case,

         bidder  shall  be  required to ensure  supply  of  spare

         parts  for lifetime of the plant.  In case, it is  felt

         by  the  bidder  that certain  equipment/  component  is

         likely to become obsolete the bidder shall clearly bring

         out  the same in his bid and indicate steps proposed  to

         deal with such obsolescence.

1.05.00  Colour  Shade

1.05.01  Colour shade of  panel/ desk and Local panel,  cabinets,

         LIE etc.

a)    External colour  – RAL  7032

      b) Interior         – Briliant White

1.05.02  Colour of instrument  Junction Boxes  – Sky Blue      

1.05.03  Colour of Electrical  Actuator        – Blue            

1.05.04  Colour of  instrument  cable          – Sky Blue        

1.06.00  Environmental Conditions

         Instruments,  devices  and  equipment  for  location  in

         outdoor/indoor conditions area shall be designed to suit

         the  environmental conditions indicated below and  shall

         suitable   for  continuous operation  in  the  operating

         condition of coal fired utility.

1.06.01  Outdoor Location

     a)  Temp.Range          – 0-55 Deg.C

     b)  Relative Humidity   – 0-100%

     c) Atmosphere          – Dirty air

1.06.02       Indoor Location

     a) Temp. Range          – 0-50 Deg.C

     b) Relative Humidity   – 5-95 %

1.06.03       DCS, PLC etc shall design for operation in ambient

         Temperature ranges 0- 50 Deg.C.

1.07.00 Grounding

         Grounding System for DDCMIS, PLC, P A System etc. shall be  prefer  as per  IEEE standard  and  separate  from  Electrical grounding.

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2.00.00 DISTRIBUTED DIGITAL CONTROL, MONITORING AND   

        INFORMATION SYSTEM (DDCMIS)

         The  microprocessor based distributed  digital  control,

         monitoring   &   information   system(DDCMIS)shall    be 

         provided for the safe and efficient operation of SG, TG,

         balance  of plant and all auxiliaries in all regimes  of

         Operation.

The following standards shall be followed for design, manufacturing, installation and commissioning of the Distributed Control System:

a) ANSI/ISA84.01 1996 – Application of Safety Instrumented 

   System.

b) IEC – 61151 - Functional Safety- Safety Instrumented 

   System for Process Sector.

c) IEEE – 1046 – IEEE Application guide for Distributed  

   Digital Control Monitoring for Power Plant.

d) ANSI/ ISA – 77.13.01 – Fossil Fuel Power Plant Steam

   Turbine By-pass System.

e) NUREG – 700 – Human- System Interface Design Review

   Guidelines.

      f) ANSI/ISA-18.1-Annunciation Sequence and Specification.

2.01.00  GENERAL REQUIREMENTS

2.01.01  The   requirements  for  distributed   digital   control

         monitoring and information system(DDCMIS) are  indicated

         on functional basis in this specification. Bidder  shall

         be responsible for engineering, selection and connection

         of  all  components and sub-systems to form  a  complete

         system   whose   performance  is  in   accordance   with

         functional, hardware, parametric and other  requirements

         of this specifications.  It is not the intent or purpose

         of this specifications to specify all individual  system

         components since the bidder has full responsibility  for

         engineering and  furnishing of a complete system.

2.01.02  SYSTEM CONFIGURATION

         DDCMIS  shall  basically consist of  control  system  of

         boiler, turbine & balance of plant (namely SG-C&I,TG-C&I

         &   BOP-C&I  including  their   respective   measurement

         system);  Man-machine  interface and  plant  information

         system(MMIPIS);   system  programming  &   documentation 

         facility;   data  communication   system(DCS);integrated

         sequence of events recording system(SERS);  Annunciation

         system,  and  master & slave  clock system. 

         The basic configuration of DDCMIS shall be as  indicated

         in the  DDCMIS configuration drawing No.CED/STP/I/821,822,

         823.

2.01.03  SYSTEM EXPANDABILITY

         Modular  system  design shall be adopted  to  facilitate

         easy  system  expansion.   The  system  shall  have  the

         capability  and  facility  for  expansion  through   the

         addition  of   controller modules,  process  I/O  cards,

         drive  control modules, hand/auto stations, and push button

         stations, peripherals like CRT/ Keyboards, printers etc.

         while  the  existing system is fully  operational.   The 

         system shall have the capability to add any new  control

         loops  groups/ sub-groups, in control system  while  the

         existing system is fully operational.

2.01.04  ON LINE MAINTENANCE

         It shall be possible to remove/ replace on line  various

         modules(like  I/O module)from its slot  for  maintenance

         purpose  without  switching  off  power  supply  to  the

         corresponding  rack.   System design shall  ensure  that

         while doing so, undefined signaling and releases do not

         occur  and  controller  operation  in  any  way  is  not

         affected(including  controller  trip  to  manual,   etc)

         except that information related to removed module is not

         available  to  controller.  Further, it  shall  also  be 

         possible  to  remove/  replace  any  of  the   redundant

         controller  module without switching off the   power  to

         the  corresponding  rack  and this will  not  result  in

         system  disturbance or loss of any controller  functions

         for main controller.  The on line removal/ insertion  of

         controller, I/O modules etc. shall in no way  jeopardize

         safety of plant and personnel.

2.01.05  FAULT DIAGNOSTICS

         The  DDCMIS  shall  include on  line  self  surveillance,

         monitoring  and diagnostic facility so that  a  failure/

         malfunction can be  diagnosed automatically down to  the

         level  of  individual  channels of  modules  giving  the

         details  of  the fault on the   programmer  station  CRT

         displays  supplies, sensor fault, any channel  fault  in

         2V3 channels etc. These faults on CRTs as well as  local

         indication   on   the  faulty  channel/module   and   on

         corresponding  rack/  cubicle shall be  available.   The

         diagnostic  system  shall  ensure that  the  faults  are

         detected before any significant change in any controller

         output  has taken place.  Failure  of any  I/O  modules,

         controller etc.shall be suitably grouped and annunciated

         to annunciation facia and to OWS(Operator work Station).

2.02.06  FAULT TOLERANCE

         The DDCMIS shall provide safe operation under all  plant

         disturbances  and on component failure so that under  no

         condition the safety of plant, personnel or equipment is

         jeopardized. Control system shall be designed to prevent

         abnormal  swings  due to loss of  control  system  power

         supply,  failure of any control system  component,  open

         circuits/ short circuits, instrument air supply  failure

         etc.   On   any  of  these   failures   the   controlled

         equipment/parameter shall either remain in last position

         before  failure  or shall come to fully  Open/ Close  or

         ON/OFF  state  as  required for  the  safety  of  plant/

         personnel/  equipment and as finalised  during  detailed

         engineering.

2.01.07  DDCMIS  shall  meet all  requirements  stipulated  under

         other   sub-sections/sections  of   the    specification

         including   general   technical   conditions.    General

         technical  requirements, quality  assurance,  parametric

         requirements etc.

2.01.08  SIGNAL EXCHANGE

         All  the  signal exchange   between  various  functional

         groups of each control group ( i.e. within SG, TG & BOP

         C&I) shall be implemented through redundant main  system

         bus  (The  main bus connecting  various  sub-systems)and

         local  system  bus  within  a  sub-system  as  per   the 

         standard  practice of the bidder.  It shall  be  ensured

         that any single failure in electronics involved for such

         communication,   e.g.  communication  controllers,   bus

         interface  modules, physical communication  media,  etc.

         does  not  result in loss of such signal  exchange   and

         there  in no deterioration in specified system  response

         and   system   parametric  requirements.   In   case   a

         controller utilizes some inputs generated/ processed  by

         any   other   controllers/functional   group   and   the 

         requirement of controller response time as specified  in

         Clause   2.04.02   is   not  met   due   to   inadequate

         communication  rate/ procedure, then the   bidder  shall

         provide  hardwired  signal  exchange  for  such  inputs. 

         Bidder  shall furnish documentary evidence  through  its

         standard  catalogues and drawings explaining as  to  how

         this  requirement  is being met by them.   Bidder  shall

         also  furnish  along with the above documents,  list   of

         coal  fired thermal power stations where  the   proposed

         scheme  for  such signal exchange  is  already  working. 

         Further,  bidder  to  note that if  his  offered  system

         cannot  meet  the  above  requirement  of  communication

         redundancy  and specified system response  &  parametric

         requirements  then  all the  signal exchange,  analog  as

         well as binary among various functional groups shall  be

         carried out through hardwiring only and not through  bus

         system.

         However,  if  in  the opinion of the   employer,  a  few

         signal  exchanges are found required  to  be  hardwired,

         the  same shall be  provided by the bidder.   Control  &

         protection signal exchange between control systems of SG,

         TG  and  BOP C&I shall be  hardwired  only.   Protection

         signals  like MFT/Turbine/Generator or tripping of unit             

         shall  necessarily   be  hardwired and  redundant  even

         for exchange within  the  same  sub-system, as stipulated

         in NFPA 85. Signal to or from BOP shall be galvanized or  

         optically isolated. 

2.01.09  No  single failure either of equipment or  power  source

         shall  be  capable of rendering  any  part/  system/sub-

         system of DDCMIS in operative to any degree.

2.01.10 SYSTEM SPARE CAPACITY

         Over and above the equipment and accessories required to

         meet  the fully implemented system as per  specification

         requirements.   DDCMIS  shall have  spare  capacity  and

         necessary   hardware/  equipment/accessories   to   meet

         following requirement for future expansion at site.

2.01.10.01   10%  spare  channels in each  of  the   input/output

         modules, fully wired up to marshalling cabinets.

2.01.10.02  Wired in space for 20% modules in each of the  system

         cabinets  for   mounting electronic modules  wired  up to

         corresponding   spare terminals in marshalling  cabinets

         such that implementation of any additional control loop/

         logic  can  be achieved only by insertion  of  necessary

         electronic modules(s) in system cabinets,  configuration

         of   corresponding   controller   and   connection    of

         inputs/outputs  at  field end of  marshalling  cabinets/

         logic cabinets as applicable.

2.01.10.03  MMIPIS shall be provided with capacity to handle  25%

         or   at least    1  No.of  each   type   of   peripherals

         additionally, like CRTs, keyboards, printers, PCs etc.,

         over and above already specified, without any additional

         hardware or software.

2.01.10.04   each  controller shall have  30%  spare  functional

         capacity  to implement additional function blocks,  over

         and   above  implemented  logics/loops,   further   each

         controller  shall have spare capacity to handle  minimum

         20%  additional  inputs/outputs of  each  type(including

         2.01.10.01  &  02  above), over  and  above  implemented

         capacity.   Each  of  the  corresponding   communication

         controller  shall also have same spare capacity as  that

         of controller.

2.01.10.05  The data communication system (including main  system

         bus  and  other bus system)shall have  the  capacity  to

         handle the additions mentioned in clause  Nos.2.01.10.01

         to  2.01.10.05.  This will be in addition to  50%  spare

         capacity specified under this clause.

2.01.10.06  20% spare relays of each type and rating, mounted and

         wired in relays cabinets.  All contacts of relays  shall

         be  terminated in terminal blocks of relay cabinets.  In

         each  of  the relay cabinets 20% spares terminal  blocks

         shall  be  provided  so that additional  relays  can  be

         mounted and wired.

2.01.11  the spare capacity as specified above shall be uniformly

         distributed throughout all cubicles.  The system  design

         shall  ensure that above mentioned additions  shall  not

         require any additional controller/ processor/ peripheral

         drivers  Power   supply  module, software  etc.  in  the

         system  delivered  at  site.  Further,  these  additions

         shall  not  deteriorate the  system  response  time/duty

         cycle etc.from those stipulated in the specification.

2.01.12  DDCMIS  shall  meet system  performance  and  parametric

         requirements as stipulated under specification.

2.02.00  SYSTEM  DESCRIPTION

         The  DDCMIS  shall include following  main  systems/sub-

         systems.  The  DDCMIS shall work in full  integration  &

         conjunction  with  field equipments/drives  like  pumps,

         motors,  valves, actuators, dampers,  hydraulic  control

         systems(eg.for  HP/LP bypass etc.)and field  instruments

         to   be   provided   by   the   Bidder.    The    DDCMIS

         hardware(controllers,   modules/  cards  etc.)shall   be

         housed   in  cabinets  located  in   control   equipment

         room(CER) except for operation interfaces located in UCD

         & UCP in unit control room.

2.02.01  CONTROL  SYSTEM

         The  control  system along with its  measurement  system,

         shall perform functions of closed loop control, sequence

         control, interlock & protection of SG TG and auxiliaries

         in all regimes of Unit operation.

         The  measurement system of control system shall  perform

         the  functions of signal acquisition,  conditioning  and

         signal  distribution of various types of  inputs/outputs

         like analog (4-20 mA DC, thermocouple, RTD)binary  pulse

         etc. The inputs, which are required for only  information

         & monitoring  purposes shall be distributed suitably  in

         various groups of the measurement system.

2.02.02  MAN-MACHINE   INTERFACE  &  PLANT  INFORMATION   SYSTEM

         (MMIPIS)

         The MMIPIS shall perform control, monitoring & operation

         of SG,TG & auxiliaries in all regimes of unit operation,

         interacting  with the control system.  For  this  MMIPIS 

         shall primarily perform following functions.

         i)  Operator interface for control system.

         ii)  Plant  Supervisory functions like  displays,  alarm

         monitoring  &  reporting(reports &  logs,  calculations,

         trend recording, historical and long term data storage &

         retrieval etc.).

2.02.03  SYSTEM PROGRAMMING & DOCUMENTATION FACILITY

         The  programmer  stations shall be provided for -

      i) On line configuration & tuning of control system.

     ii) On line program development/ modifications in MMIPIS.

         In addition, latest state of the art workstation  based

         system documentation for the complete plant.

2.02.04  DATA COMMUNICATION SYSTEM (DCS)

         The  data  communication system shall be   provided  for

         communication   between   control   system   &    MMIPIS

         communication   &   signal  exchange   between   various

         functional  groups  as  well  as  communication  between

         various units & off site/ off line systems.

2.02.05  SEQUENCE OF EVENTS RECORDING SYSTEM(SERS)

         The DDCMIS shall be  capable of carrying out sequence of

         event recording function to  scan & record events in the 

         sequence of occurrence within a resolution of 1 milli sec.

2.02.06  MASTER AND SLAVE CLOCK SYSTEM

         Master & slave clock system shall be  provided to ensure

         uniform  time  indication throughout the  various  plants

         facilities  and  time  synchronization  between  controls

         system,  MMIPIS, switchyard disturbance recorder,  PLC’s

         etc.

2.02.07  ANNUNCIATION SYSTEM

         A facia annunciation system shall be provided with  lamp

         boxes in the unit control room.  The annunciation  logic

         will  be  implemented as a part of DDCMIS through  which

         the  lamp  boxes shall be driven.   However,  additional

         facility  to drive stand-alone printer in case of  total

         MMIPIS & system bus failure shall be provided.

2.03.00  MEASUREMENT FUNCTIONS OF CONTROL SYSTEM

2.03.01  All  the signals coming into/going out of  the   control

         system  shall  be  connected either directly  or  routed

         through  marshalling cabinets. The input/output  modules

         employed  in the  control system shall be separate  from

         controller hardware.

2.03.02  ANALOG SIGNAL CONDITIONING & PROCESSING

2.03.02.1  the  conditioning  and  processing  functions  to  be 

         performed as a minimum for the  analog input coming  for 

         control & information purposes are :-

         i)  Galvanic isolation of input & output signals wherever

             required.

         ii) Transmitter  power  supply  with  per  point   fuse

             protection  or  current limiting  and  power  supply

             monitoring.

         iii)Transducer/transmitter signal output limit check.

         iv) Implementation of multiple measurement schemes.

         v)  Square root extraction

         vi) Pressure & temp.compensation.

         vii)On line ADC gain & drift monitoring & correction  at

             periodic intervals.

        viii)Linearisation of thermocouple signals.

         ix) Reasonability check for all analog inputs.

2.03.02.2 all  analog  signals  for  control  purpose  shall   be

         acquired, validated, processed and their respective data

         base  updated  at  a  maximum  interval  of  250   milli

         secs.except for some fast acting control loops for which

         the  above-referred  time  shall  be   as  per  process

         requirement.  For signals required for information only,

         the above functions shall be performed at an interval of

         1  sec. The validated analog inputs shall be   converted

         into engineering units on a per point basis.

2.03.02.3  The 4-20 mA input analog cards shall be  suitable  for

         interfacing  transmitters giving 4-20 mA  analog  signal

         along with super imposed HART interface signals. 4-20  mA

         DC signal will only be used for control purpose &  super

         imposed  HART  signal will be  used  for  configuration,

         maintenance  diagnostic  & record keeping  facility  for

         electronic  transmitters  & analyzers etc. 

2.03.03  BINARY SIGNAL CONDITIONING & PROCESSING

2.03.03.1  The  changeover type contacts (i.e.NC +  NO  together)

         shall be wired to the control system for all the  binary

         inputs  required for control purposes, except for  input

         from MCC/SWGR, actuators and inputs related to hardwired

         signal exchange among various functional groups for which

         non-changeover type contract(NC or NO)shall be wired  to

         the  control  system.  The  binary  input  required  for

         information  purposes  only shall be  wired  to  control

         system in the form of non-changeover type contacts.

2.03.03.2  The  conditioning  and  processing  functions  to   be

         performed  as a minimum for the binary input coming  for

         control & information purposes are :-

      i) 24  V DC power supply for contact interrogation  for    

         all  potential  free contacts with  per  point  fuse    

         protection   or  suitable  current  limit   feature/    

         isolation  through optocoupler.

     ii) Contact  bounce filtering delay time of 15 milli secs.

    iii) Facility  for  pegging the binary  signal  to  logic             

         one/zero or last correct value in case of failure of    

         binary input module.

     iv) Binary  signal distribution to different user  shall    

         be in such a way so as to ensure that a short/ground    

         fault  on  one user is not reflected  to  the  other     

         user.

      v) Implementation  of multiple measurement schemes  for    

         signals for control purpose.

     vi) All  binary  signals  shall  be  acquired  validated    

         processed, alarm checked and their database updated    

         within  1  sec.  In addition  to  this  requirement,    

         binary  signals  required  for  SOE  shall  have   a    

          resolution of 1 milli sec.

      vii)Checking for excessive No.of status changes for  all   

          binary/contact inputs.

     viii)Facility to delete any binary input from scan or  to     

          return to scan on operator demand.

      ix) The  non-coincidence monitoring shall  be   provided     

          for  binary  inputs  for  all  changeover   signals,     

          namely   process  actuated  switches  required   for     

          control purpose.

       x) All relay contacts shall be hermitically sealed.

2.03.04       Two out of Three Measurement

       a)Triple  measurement scheme for analog  inputs  employing

         three  independent  transmitters connected  to  separate

         tapping points shall be  employed for the most  critical

         measurements used in analog control functions  including

         the  following  but not limited to furnace  draft,  feed

         water  flow,  throttle  pressure,  turbine  first  stage

         pressure,  drum level, drum pressure,  deaerator  level,

         turbine  speed.  Turbine control valve  position,  power

         measuring  device  LP  &  HP  Heater  Level,  PA  Header

         pressure etc.

      b) The three signals shall be auctioneered to determine the

         median/average  value , which will be  used  for  control

         purpose.   In  case  one  transmitter  fails  or   shows

         excessive  deviation with respect to others, it will  be

         removed from computation of medium/ average value &  the

         average  of the other two transmitter outputs  shall  be 

         used  for  controls.   The control loop  shall  trip  to

         manual  when  any two of the three  transmitter  outputs

         shall be used for controls. The control loop shall  trip

         to manual when any two of the three  transmitter signals

         fail.   The operator shall be able to select any of  the 

         transmitters  or   the  median/average  value  from  the

         control desk.  The outputs of the transmitters shall  be 

         continuously  monitored  for excessive  deviation  which

         shall  be   displayed, logged &  alarmed.

c)    For MFT/ Turbine/Generator/Unit tripping;Triple Sensor shall

   be  provided.

d)    For auto starting of pumps, pump tripping due to  very Low

   level of water, Triple Sensor shall be provided.

2.03.05       One Out of Two Measurement

      a) Dual measurement scheme for analog inputs  employing two

         independent transmitters, connected to separate tapping

         points/  temp.  element  shall  be   employed  for   the 

         remaining measurements used for analog control functions.

         The  output  of  the  redundant  transmitters  shall  be

         continuously monitored for excessive deviation.  In case

         the deviation is within limits, the mean value shall  be

         used  for the control loop.  If the   deviation  becomes

         high  (with  both transmitters remaining  healthy),  the

         other  transmitter remains healthy, then the  output  of

         the  healthy transmitter shall be used for control.   If

         the  other  transmitter also fails, loop shall  trip  to

         manual.   The  outputs  of  the  transmitters  shall  be

         continuously  monitored  for extensive  operation  which

         shall be displayed and logged and alarmed.

         Individual transmitter signal, their status and selected

         value for control/measurement shall be available on OWS.

      b) All sensor other than MFT(Boiler)Tripping,Turbine Tripping,

         Generator Tripping etc. for  safety interlock.

c)    All pressure/ Temperature/Level Switches in Control loop.

d)    All Water/ oil Tank level alarm for Very low.

e)    All non critical Measurement for Control loops.

f)    Any other service recommended by equipment manufacture or

IEC/ISA/ASME/Standard/ code .

2.03.06  For  Binary  and  analog inputs required  in  furnace  &

         turbine  protection  triple  sensing  devices  shall  be 

         provided.  Binary and analog inputs which  are  required 

         for  protection of more than one equipment  (e.g.  flame

         failure,  deaerator  level very low, etc.)  as  well  as

         protection  signals  for  MDBFP,  triple   sensing

         devices  shall be provided.  For other  critical  binary

         and analog inputs required for protection and  interlock

         purpose  of  other  equipment,  dual  sensors  shall  be

         provided.

2.03.07  Wiring  scheme for inputs to control system shall be  as

         follows :-

2.03.07.1  Each  of  the dual triple redundant  binary  &  analog

         inputs  shall  be wired to separate input  modules.   In

         addition,  for functions employing 2V3 controllers  like

         BMS/Turbine  protection, each of the redundant binary  &

         analog signals shall be  wired to separate input modules

         associated   with   each   controller   in   line   with

         configuration drawing of BMS & TPS & meeting requirement 

         stipulated  under  clauses  2.04.01  of  this   section.

         Similarly  each  of the dual redundant binary  &  analog

         inputs shall be  wired to separate input modules.  These 

         redundant  modules shall be placed in  different  racks,

         which   will   have  separately  fused   power    supply

         distribution.   Implementation of  multiple  measurements

         scheme  of  these  inputs  will  be  performed  in   the

         redundant  hardware loss of one input modules shall  not

         affect the signal to other module and also other channels

         of these modules can be used by other inputs of the same

         functional group.

2.03.07.2  the single binary & analog signal required for control

         purposes shall be wired as follows :-

      i) The  limit  &  torque  switches  and  the   MCC / SWGR

         check backs  shall  be  wired to  drive  control  modules

         wherever  provided.  For the drives where  DCM  are  not

         provided,  these  signals shall be  connected  to  input

         module only.

     ii) Other  single analog & binary inputs shall be  wired  to

         single input modules.

2.03.08  The binary and analog outputs from one sub-system of the

         control  system  to other which are  required  in  these

         systems  for  control purposes shall be  made  available

         from  triple/dual  redundant binary  and  analog  output

         modules.  However, redundancy in binary & analog outputs

         to  indicators/ recorders, SERS and  Annunciation  facia

         lamps are not required.

2.03.09  The   signal   conditioning  functions   like   multiple

         measurement  schemes  square root  extraction  for  flow

         signals,  pressure  &  temperature  compensation,  limit

         value  computation  can  be   performed  either  in  the 

         controllers  or in signal conditioning   and  processing

         hardware outside  controllers.

2.03.10  The  maximum No.of inputs/outputs to be   connected  to

         each type of module shall be as follows:-

         1.  Analog input module            -    16

         2.  Analog output module           -    16

         3.  Binary input module            -    32

         4.  Binary output module           -    32

         5.  Analog input & output(combined)-    16           

         6.  Binary input & output(combined)-    32 

             (Note:- For Binary inputs, one changeover contact is

                     counted as 2 inputs)

         Further,  minimum 10% spare channels shall be kept in

         each of the input/output modules.

2.03.11  The following requirements shall be met :

2.03.11.1 Input filters to attenuate noise shall be provided.

2.03.11.2  All analog/ binary   input  shall   be   capable   of

         withstanding  500 V DC common mode and 500 V AC peak  to

         peak.  All analog outputs shall be short circuit  proof.