63863-Ch04
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Intro Automation-3e-S 11-15, 1 6/06, 06/04/07 Chapter 4 INTRODUCTION TO AUTOMA TION REVIEW QUESTIONS 4.1 What i s automation? Answer: Several e!initions o! automation are "iven throu"hout the #oo$. %he e!inition "iven in this &ha'ter is the !o ll o(in": Aut oma tion &an #e e!in e as the te&hnolo") #) (hi& h a 'ro&ess or 'ro &e ure is a&&om'lishe (ithout human assistan&e. 4.* An a utomate s) stem &onsists o! (hat three #asi& ele ment s. Answer: %he three #asi & elements o! an automa te s)ste m are +1 'o(er to a&&om'li sh the 'ro&ess an o'erate the s)stem, +* a 'ro"ram o! instru&tions to ire&t the 'ro&ess, an +3 a &ontrol s)stem to a&tuate the instru&tions. 4.3 What i s the i! !e ren &e # et( een a 'ro &es s 'ar amet er an a 'r o&ess v aria #le ? Answer: ro&ess 'arameters are in'uts to the 'ro&ess, su&h as tem'erature settin" o! a !urna&e, &oorinate ais value in a 'ositionin" s)stem, an motor on or o!!. ro&ess varia#les are out'uts !rom the 'ro&ess !or eam' le, the a&tua l tem' erature o! the !urna &e, the a&tua l 'osi tion o! the ais, an the rotational s'ee o! the motor. 4.4 What ar e t(o rea sons (h) e&i sio n-ma $in" is r eui re in a 'ro "ramme (or$ & )& le? Answer: easons "iven in the tet are +1 o'erator intera&tion is reuire, so the o'erator enters the e&ision, +* i!!erent 'art or 'rou&t st)les are 'ro&esse #) the s)stem, an the s)stem must e&ie ho( to 'ro&ess the &urrent (or$ unit, an +3 there are variations in the startin" (or$ units, an e&isions must #e mae a#out a2ustments in the (or$ &)&le to &om'ensate. 4.5 What is the i !! eren& e #e t(e en a &los e-lo o' & ontrol s)s tem an an o' en-loo ' &o ntrol s )s tem? Answer: A &lose loo' & ontrol s)stem is one in (hi&h the out'ut varia#le is &om'are (ith an in'ut 'arameter usin" a !ee#a&$ loo', an an) i!! eren&e #et (een the out'ut an in'ut is use to rive the out'ut into a"reement (ith the in'ut. ) &ontrast, an o'en loo' &ontrol s)stem o'e rates (ithout the !ee#a&$ loo', an so there is no veri!i&ation that the &ontrol a&tion has #een &orre&tl) &arrie out. 4. 6 Wh at is sa !et ) mo ni to ri n" in an automate s)stem? Answer: Sa!e t) monitor in" in an automate s)stem involves the use o! sensors to tra&$ the s)stem s o'erat ion an ie nti !) &oni tions an events tha t are unsa !e or 'ot ent iall ) uns a!e . %he s) st em is 'ro"ramme to res'on to unsa!e &onitions in some a''ro'riate (a) , su&h as sto''in" the s)ste m or sounin" an alarm. 4.7 What is erro r e te& tio n an re &ov er) in an auto mat e s )s tem ? Answer: rror ete&tion an re&over) re!ers to the &a'a#ilit) o! an automate s)stem to #oth ia"nose a mal!un&tion (hen it o&&urs an ta$e some !orm o! &orre&tive a&tion to restore the s)stem to normal o'eration. In the ieal re&over) moe, the s)stem re&overs !rom the mal!un&tion on its o(n, (ithout human assistan&e. 4. ame thr ee o ! t he ! our 'ossi#le stra te" ies in err or re&ov er) . Answer: %he !our 'ossi#le strate"ies ienti!ie in the tet are +1 ma$e a2ustments at the en o! the &urrent (or$ &) &le to re&ove r !rom the mal!un& tion, +* ma$e a2ustme nts urin" the &urrent &) &le, +3 sto' the 'ro&e ss to invo$e &orre &tive a&tion , an +4 sto ' the 'ro& ess a n &all !or hel'. 4.8 Ie nti! ) t he ! ive lev els o! aut oma tion in a ' ro u&t ion ' lant . Answer: %he !ive levels o! automation e!ine in the tet are +1 evi&e level, +* ma&hine level, +3 &ell or s)stem level, +4 'lant level, an +5 enter'rise level. 13
Transcript of 63863-Ch04
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Intro Automation-3e-S 11-15, 16/06, 06/04/07
Chapter 4
INTRODUCTION TO AUTOMATION
REVIEW QUESTIONS
4.1 What is automation?
Answer: Several e!initions o! automation are "iven throu"hout the #oo$. %he e!inition "iven in this &ha'ter
is the !ollo(in": Automation &an #e e!ine as the te&hnolo") #) (hi&h a 'ro&ess or 'ro&eure isa&&om'lishe (ithout human assistan&e.
4.* An automate s)stem &onsists o! (hat three #asi& elements.
Answer: %he three #asi& elements o! an automate s)stem are +1 'o(er to a&&om'lish the 'ro&ess ano'erate the s)stem, +* a 'ro"ram o! instru&tions to ire&t the 'ro&ess, an +3 a &ontrol s)stem to a&tuatethe instru&tions.
4.3 What is the i!!eren&e #et(een a 'ro&ess 'arameter an a 'ro&ess varia#le?
Answer: ro&ess 'arameters are in'uts to the 'ro&ess, su&h as tem'erature settin" o! a !urna&e, &oorinateais value in a 'ositionin" s)stem, an motor on or o!!. ro&ess varia#les are out'uts !rom the 'ro&ess !or eam'le, the a&tual tem'erature o! the !urna&e, the a&tual 'osition o! the ais, an the rotational s'ee o! the motor.
4.4 What are t(o reasons (h) e&ision-ma$in" is reuire in a 'ro"ramme (or$ &)&le?Answer: easons "iven in the tet are +1 o'erator intera&tion is reuire, so the o'erator enters the e&ision,+* i!!erent 'art or 'rou&t st)les are 'ro&esse #) the s)stem, an the s)stem must e&ie ho( to 'ro&ess the&urrent (or$ unit, an +3 there are variations in the startin" (or$ units, an e&isions must #e mae a#outa2ustments in the (or$ &)&le to &om'ensate.
4.5 What is the i!!eren&e #et(een a &lose-loo' &ontrol s)stem an an o'en-loo' &ontrol s)stem?
Answer: A &lose loo' &ontrol s)stem is one in (hi&h the out'ut varia#le is &om'are (ith an in'ut 'arameter usin" a !ee#a&$ loo', an an) i!!eren&e #et(een the out'ut an in'ut is use to rive the out'utinto a"reement (ith the in'ut. ) &ontrast, an o'en loo' &ontrol s)stem o'erates (ithout the !ee#a&$ loo',an so there is no veri!i&ation that the &ontrol a&tion has #een &orre&tl) &arrie out.
4.6 What is sa!et) monitorin" in an automate s)stem?
Answer: Sa!et) monitorin" in an automate s)stem involves the use o! sensors to tra&$ the s)stemso'eration an ienti!) &onitions an events that are unsa!e or 'otentiall) unsa!e. %he s)stem is
'ro"ramme to res'on to unsa!e &onitions in some a''ro'riate (a), su&h as sto''in" the s)stem or sounin" an alarm.
4.7 What is error ete&tion an re&over) in an automate s)stem?
Answer: rror ete&tion an re&over) re!ers to the &a'a#ilit) o! an automate s)stem to #oth ia"nose amal!un&tion (hen it o&&urs an ta$e some !orm o! &orre&tive a&tion to restore the s)stem to normal o'eration.In the ieal re&over) moe, the s)stem re&overs !rom the mal!un&tion on its o(n, (ithout human assistan&e.
4. ame three o! the !our 'ossi#le strate"ies in error re&over).
Answer: %he !our 'ossi#le strate"ies ienti!ie in the tet are +1 ma$e a2ustments at the en o! the &urrent(or$ &)&le to re&over !rom the mal!un&tion, +* ma$e a2ustments urin" the &urrent &)&le, +3 sto' the
'ro&ess to invo$e &orre&tive a&tion, an +4 sto' the 'ro&ess an &all !or hel'.
4.8 Ienti!) the !ive levels o! automation in a 'rou&tion 'lant.
Answer: %he !ive levels o! automation e!ine in the tet are +1 evi&e level, +* ma&hine level, +3 &ell or s)stem level, +4 'lant level, an +5 enter'rise level.
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