First Semester

[ 24 - 108 ]

M.Tech. Degree Examination

Industrial Process Instrumentation

COMPUTER CONTROL OF PROCESS

(Effective from the admitted batch of2007-2008)

Time: 3 Hours Maximum marks: 70Answer any FIVE questions.

All questions carry equal marks.

1. a) Explain the concept of state variable feedback with a neat blockdiagram and an example. (6)

b) The state equations of a linear time-invariant system are represented

dX(t) . . . '.by dt = AX(t) + Bu(t).Fmd the state transition matrix and'

characteristics equation when A = [~4 ~5J and B =[: l(8)2. a) Explain the importance of feed forward control with an example.

Why is this control generally not used alone. Outline the steps indesigning a feed forward control system. (8)

b) Discuss under what circumstances a cascade control isrecommended. Give the relative merits and demerits of cascadecontrol and conventional single-loop control. ' (6)

3. 'a) Draw the block schematic diagram, of a programmable logic'controller (PLC) and explain the functions of each block. (6)

b) Explain with neat schematic diagrams, the application PLCs forthe following: (i) Batch sequence control and (ii) Alarm monitoringand reporting. (8) ,

1 [p.T.O:]

[ 24 - 108 J4. a) Explain the development of direct digital control (DDC) and show

how hierarchical type computer control has been adopted in thepresent day process control s stem. (8)

b) Explain Kahnan's digital control algorithm by means of an example.(6)

5. a) Describe a method of tuning a digital P+I+D controller. .(6)b) Develop a dead-beat control algorithm for a second order control

system with dead time equal to 2T. (8)

6. a) Discuss the merits and demerits of distributed control system overcentralized control system. (4)

b) Explain the various methods of presentation and monitoring of datain a distributed control system. Discuss the options available ininterfacing with a personal computer for this task. (10)·

7. a) Give the requirements of a personal computer in a real time contro Isystem. (6)

b) Explain how personal computers are used for quality control in aprocess industry with examples. (8)

8. Write short notes on the following:a) Controllability and observability of control system. (5)b) Data acquisition systems. (5)c) Analog and digital sub systems in process, control computer

systems. (4)

[09] S/19]

2

[ 24 - 108 ]

M.Tech. Degree Examination

Industrial Process Instrumentation

First Semester

COMPUTER CONTROL OF PROCESS

(Effective from the Admitted Batch of 2007 - 2008)

Time: 3 Hours Maximum marks: 70Answer any FIVE questions.

All questions carry equal marks.

L a) Enumerate the advantages of automated process control systems.(4)

fi"'-How do you determine the type of process that would require afeed forward control? What are the basic differences between afeed forward and a feedback control system? Explain your answerwith examples. . (10)

2. a) What are the advantages of composite control modes over individual.control modes? Explain P+I+D control mode with an example.(6)

,-li}-.Explain with a block diagram a computer based Data Acquisitionsystem with alarm facility for a process industry where in 120 analogsignals have to belogged. Give the details of signal conditioningcircuits and interfacing circuits. (8)

3.~xplain about dead-beat controllers. Develop a Dead-beat#rithm and explain its operation with a flow chart. (6)

MWhat is meant by Duct Digital control and explain the generalstructure of Direct Digital control? Derive the position algorithmused in Duct Digital Control. (8)

4. a)

1

[ 24 - 108 ]

b}-EXplain the need for tuning of a controller. Explain the controllersettings by the method of process reaction curve. (6)

5. ~lain the basic approach of the Distributed Digital controlsystem. with a neat block schematic diagram. What are its advantages

and disadvantages over conventional digital control system? (8)b) Discuss the different types of data links used in Distributed Digital

control systems. Enumerate their merits and demerits. (6)

6. a) What is a process control computer? Describe the processingcapabilities and other features of a process control computer. (6)

b) Explain the concept of sub-systems in a Distributed Digital controlsystem and give the importance and functions of a local field station.

(8)

7~escribe the various analog and digital peripheral systems used ina process controlled system using personal computers. (8)

b) J)eSCribe with a neat block schematic diagram the self tuning of a/ process control system using adaptive control system. State its

advantages over other methods of tuning. (6)

.8. Write short notes on the following:

a) Dahlin's algorithm

b) Interactive control systems

c) Applications ofPLCs in Digital control systems

[081S/27]

2

Time: 3 Hours Maxim urn marks: i00

f :\1 I P I - 10J I

M,Tech, -Degree "Exarniua tio n

Industrial Process Instrumentation

_fin! sem.ester

-,AI;s~~r.any FIV~. ~u~sti~_ns,

Allquestions carry ~aJrnMks,': .•• ft,. • "." \.,..::

1. a) How are state equations ~blaintd=f~~'discrete - .data systems ?Ikscribe a method of getting so~uti~nSo(~e-discrete stat-eequations.

. ..- . .

b) Explain with an example bow the addition of feed forward controlwith feedback control gives superior performance.

2,/'/ Explainthe use of computer as (i) supervisor; controller, and\.. ~r~tdigitai controller when 200 loops in an industry are to be

tackled. Draw the functional block diagram in each case and also.'-memi-e.n1:'~e-di-ffereHG€:-bet-ween_the.lWQ_~ ofcontrol. . ._.. _

-. ·4:" .

3, a) It is required to count the numberof'solidobjccts moving on a beltconveyor, A green.light is swit~hed on when the count is I~ than50,ye~lo~light is switched on when the count is 50, and ~'~-ljghlis switched on when the count is.greater.than 50, Design-aPl.Crequired for.this purpose with ladder diagram.

b) What is meant by physical iy unreaiisable digitai controller? Explainwith ar~-ex:ampre. '--

~. a) Explain the 'reset windup ' problem that may occur in positionf()i!T> of digital ?-'-f.;-.D cor.troller

rp -r- {'J;•.•..i .\./:

MIPf - 103

5/a) W~at ~e the performance indices? Describe an adaptive control-_ sy~t~g:.)p'GHrealises a speci.ft~o performance.index. - _ -;_:,::-...-_ .•.. __ . - - . . ..

WE~?:~a~?with ~block diagrammodel reference adaptive controlt- - __system. How IS the reference model chosen? - - .':

- -- 60 a) ° Give the details of the informationprovided in thefollowingdisplays

in a I?CS: Overview display: group display, trend display,___schematic display, and alarm display.

~~piaip. ~ow the ~onfiguration of .{i) ~~rating ~y~t~~, and..C1i}controller functions are performed ill a distributed control system.

7. a) Des~ri~e the modifications.required to enable personal computersolve real- time process control problems.

b) Whatis maintenance management? Explain the use of computersfor maintenance management in industries.

[032S127]

Time: 3 hours Max. Marks: i00

M.Tcch. Degree Examination

.FIRST SEMESTER' .,~: "."\. .- .

+ ".. - - - ",

.·,,"':0. : "C ; •.Fnd us trial.Process-Instrurnenratiou-; -. -:.;:" .::-~':-.7·':"~-";".:'., .;.... __COMPUTER CONTROL OF PRocESsES

.:·:.·:~;;:}::·(;~..·.~~ft~~ti~~~~6~-iki~d~J~~a.b~t~h·~f~OOO-20(1)"- -: .. ~~ ; 1~:.; ~.. ~ - _.

. .- -:;-~:-2:':'_~~1_~·:".

A~;~:6[any FlVE'·-questiO·ils~--·" - .. -:- ):- . ~. . . .

.All questions carry equal manes:. ." ~. .

. 1. a) What is meant by interactive control system? Explain with 'example...., , how the interaction can adversely affect theperformance of control. .". : .... ". ~- '.. '. , . . ",.. - .. -.' '. .

system.

:~}..Definecoutroilabrlity and observabiiity. What are the necessaryand sufficient conditions for the system to be (1) completelycontrollable and (ii) completely observable?

.:~::!.:~'::~:~-:<.::."! -~: :~ ';.--: .: ;.~ ~- . .' '". - ..

. ---2_.-: a)~I:;iSi:-fue.bep.e~ts;o-£Using_comp-~r~LfQ(R-~scontrol.Also discuss. '." the problems-a control engineer has to face ~ile handling co~lputer.

. .. control loop.·

:-:b;. E~fain Wl~~i~IOc~di?gram supervisory control system. Mention.. - the'~6I'e'~fc~mp~'ter-mth,s'oontroj~~'ffi ... ' '.

3, a) Wha; is a ladder diagram? Consider a simple logic control systemand draw ladder diagram for the same.

,b).-'W ri't~-ex'presslons-for' position -fo'rm-arrci-'feioc if-I fOrtH- '0.[·8 i~ital, ~

PIn iaigorith.,rllS Discuss the advantages of velocity form everposi.ion form.

[\-l1P1 - 103

·::L Design a Dahlin digital.contioller: tOF~ process withrransfer function

IDe -25

--- (time in second). The-d~s~-;;a'c:f~:Sedloop response should0_5 s + 1

have a tiffie~-OnstaritoJ..4_.s~c: A:ss.~iiie5amp{iii.gtime asI see anduse .ze~o-=Ord~~hold t~'con~ert'd.is~~t~-time signal into conti nuoussignaL

5: a) Give the irnportance.ofnitiing ofcontrollers. Why does the needarise to change the controller sertings? -

- . - . () -, . ..- ..

b) Explain any Doe rnethodof'impiementiag self-tuning control. Arecontroller settiegs determined at every-sampling instant in self-tuning. ~.

control?

6_ a) Draw the functional block-diagram of'a distributedcontrol systemandgive the complete details of field controi unit.

. -~-.h) Consider any one commercial ncs. Explain its specifications and

fault tolerance capability.

7_ a) What~e the peripheral devices used wirhcomputer in a computer__~~Cotifrnl4~piDiwus-s:the--fole:O-fthese-devic-e'S:rn::-rhe perrormance --

.c-ofthe-loop_ - '.

b) A personal computer is to be used as a PID controller for four-.loops, Explain the additi?naI hardware and software requirements .

. - 8_ Write short notes on the following:

a) State variable feedbackb) Dircctdir;:italcoo..tm_L. · -: ·_ ---- ---

.- -.--.---~- Ringing i;' di;i:ai contro llers CVa..h1t-.'J ~~~'5J

2

;:-'":7.--

le:3 hours Max'. Marks: i00

M r P 1 :.: I OJ 1"'~.

"-·;VLTcch. Degre.c Examination

First Scm ester

In dust ria! Process Inxrru ment afio n :

COf\~PUT£R COi'HROL OF PROc:£S0ES

(Effect ivc from the Admitted Balch of 2000-.20(1)--:- .

----:--:--:-.!.:..:.-: '.

if~{

i~

a) Consider a typical multivariable control system. Identify the input, ~.output and state variables. Write state equations governing the t

:-~-:--system.~._ ..__ .... (10) f .--.- ..-.----- ---rO··-·-·----··-· -----J--

.~~~=~~~};~;.f.e~·~nc.ti~n:Ota.system is-given by G{s)·.=. s(s.; 1) !:;~:~ri~tri;ct:·.·thieediffe~ntstate moods for this sySte'm'~o~tha! ~~'~~i)~~n~.~sboth controIlabka-ridb·oser.vable· I

.....:,1:ii):;oneiscontrollable but not-observable and. '. :'.::iii)~o~his observable but not controllable. (10) J !

..... ! .

Answer any FIVE questions.AI i questions carry equal marks.

~A) Draw the block diagram of a cornp uter based multidiatne'l dJt"7- -.I

acquisition system and explain the Iunctibn of each block. H0W i~the sarnpling j irne chosen in a DA.S? (10)

b) Explain the details or a direct digitai control system ';l-'hcrci;; it

computer hasto serve SO loops. (10)

i•t,I~""'.

Jay Describe a microprccessor based PLC with a block diagram \Vj,?;

are its advantages ovc: relay based PLC? (:,;!. h\ j:;xnlain the bas ic concept or dead-beat algorithm.

'::" -,!)~·.:;ig;! :i I\>::i!(!';"!..Etigi;::;~·C;:l:;o;kT lor a proccs • ,Vii;) 1:';lCi;::(cr--"

'J,'). -Js..::.,.'\..

Ie.: iiC;:;\,i! (t 1;;; ~~ ::1 5cco::d). L'sc zero - ~)f"L~Cr ~lUid a Ildi-;- 55

{lS~U!TlE 5~:!l-:p!lhg :ifTlc'Yr:~'; ~cc:-Al<:;P" m-erltibri the' Jd-v2.n~a!,(esof.~ :~ •....

:(alll1a~laigoJ.i!iun 0\-"('; ~ib;crdigi{a! conrro] algori~hl11s (20)

Qa) txplain ihe (~itIcrcrl( cri rc:;-i{lt:scd ro cva 1uate the i1er~-(lrm(!nee 0 fafc:edbad c(lntro-1 svstelll (! 0)

Ck.<;cribc [i;:..- diff~r::l!i c,';;jj!!;ir?lil'n~ l.){adaptivc L:()iiLrol- "

b)( 10)

~ . "

__ 7~_J~ ()~~t ,: :~ l.i~e_.s.pe.c.i Gc i~~'-:)-i-j~<:' 1:i-f-c.--t'-t"J-,-H-pu-i:er- eho SOl \\'"11e n CfJe-- _

':":-J/:lpi.;icris to DCused {IX process C0!!u'oI application? Lxplair; inocra.r. (10)

bj :\ micr·~p;occssor. IS <0 be used as a on-off controlier in atCr.lper;;ii.l;-e conlroi S~,'s[crn" Draw tlie required block diagram?nd ilr.H\·C;1Cir( <l:/<i eXr!;!:i:. (10)

. ~- ...~- -- - .

a ) Feed for\'/ard conr rn!

b) 'Supervisory control

':i .. ' - ..! t: ....

-:

1 24 103 1f'v1.Tech. Degree Exam inat io n

Indusrria! ·erQcess - Instrumentation

.First"· s~lilest:e'r-:-". .

COMPUTER CONTROL 'OF PROCESSES

(Effectt ve from the Admitted BatchoiWG3 - 2004)-. ",<,4 .. : ";:'-~:j~~:r':':-.':':;:'~':';::~':. - .

..M~~l!r1:1. ~~~.§ .'. LQ9Answer: any FIvE' questions.

..... -... ,.. - "" - - '.;

. AILqueStionsca~q,uaLm.¥ks.Un:

UL a) Explain the concept of state variable feedback with a block diagram

arid an example. . -, ' ',~/' ,

b) The state equations of a linear time-invariant system are represented- . \. .

dxi.t)~'j, .h,' -- = .1 y ft\ + E ,,{t\vj L \". r<o. \"/' ~ •. \.t..J.'_dt , ' 'Find the state transition rJ?2trix and-characteristic-equation when

fn, I v'

A'= 1-4L .

..... . - .. - - _.,~\.-.~..;..-. -_.- - -- --.- -:-.~--:--'-. -:-:-=-:-:----, ----------.

Explain with a block diagram a computer ..based data acquisitionsystem with alarm facility required (or:aproccssindustrr,r."h,:::rct"I20 analog signals (each 4 ~"-20tilA) have to be togged. Give tiledetails of the signal conditioning circuits and interfacing circa itsalso,

3. a) ft is f~guircd,_ to .s_t~m~~~o_r ~J.~in~,~_~~,after '~T ~~T._:~Uli\':, ,',Dressed motor B 10 minutes after motor A is started a:lr.! rn: -: 'i, 'C S minutes an::;, motor B is started. After one hour o(cO(;-;;"",-,i

OPC:2tl0!l, ",ii ltlC motors should be switched ocr simull2,1(:,--~', :'(' :; •.,~ d -v,.,. ...; .•...t -,:"1.- n:·:!.,.~ Dr r F",-..,r- d·,;c ,...,.r-r..hl~ ;.,....,.....ictr1;1""'Irt i"'ll"-:r..::.~ ..i.,~.-.- ...'J I •.••.•• '.t~_ ·~ c c , l.l '\" \..1.' •.•• J ~ .;. •••••••1. '-1. •••••-..) t-'" \...I V 1.\""-1. 1..'" I..•J._~.....•.•.....•..•...•.'t:- ,1,. ••••..••.•.:'-, "'-LJI..':''=- ,,;"

, " ;.

24 l()J

b) Explain why it is n~s~.'E~ ~~ig~;ad~gital controller w ith all ofits poles being positive. "

-'~ :;--=.~. - . : !" = - ;'-:~,~:-••.:-~ :

~.4 Discuss -t~~ significanceofIi) -sampling time, and (ii) order ofhold ~4"~~i'ton th~t:iesi~9f~lgt~:(~ntroll~s. .

4 'E~p1ain'~lrir~' sdi~i-;1'~n'~I~alg6ri'tfun'by means of an example.

/a) ..·D~~ri~.aH1eth~d':itlmi.nKd~g!!aI.P.~~~D'.conttoU'ef.:~~.;~~::::!j.:-:.:... :..:..".\.~:-:..: "~'. - .

t b) Explain with ablockdiagrarn a self tuning control system in which. on-ii~e~ystemid~~tificii·dbnistlScif.·: ...

, .,. ,_' '. " ... ·-:,.:~·>-:~...~t -d ".i-="-.: .. - -)!.~-,:.- :t .;~,'.. ; '. _.~. .'6: a) ·'Discuss· themerits and 'dementS ofdistributed control system over

centralised control system.b) Explain the ~ousfuriction.s carried out at the following levels 0f

hierarchy-in a DeS: ~eid ievel,area control.level, plant control.level and plant management lc.rd.. .. . . - .. .~. - ':"

.../' 7.,4) What is 3....'1 industrial computer? List a few industrial computersavailable ill the market. Describe.the processing Capabilities andother f~tures- ~f ind~~'~nli}ti~~~~ .

AS) . Explainho.w~~n,a.L.co.mpu.tas:are:!used:.,JGl:.-qu.a1ity-eeIltroh1.T a'.- --.- _. --- . .., .'.

p~~d~:~~'}:-';~::-~~:~-:~;~~~~~~~:'; .... . ..- "--.-'

. ~ ,-.~.~.-:.~?::._:~:-r\'~~~?:~-:'":'~·-:':.·::·~~-~:::.:::;_~!-.::ft·.;!:-~~.::':'.::-.'Write short.notes.on the,{911oWJng:=. ~.;..

, , .:' ~'l.:\-=' -" ~--:';:;..: .. f:;,: ~....-.:.-.,!.:;-/-::._-,;} ..!" ;..:':'.'~.

\. a) Cascade control :. .

b) Features of commercial DeS

c) Analog and digital subsystems for process controlcomputers. .

___. -1---. ----. _..----

[04 !S/20 i 1