Chapter 08 Discrete State Process Control

Princess Sumaya Uni. !lectronic !n"ineerin" Dept.

3442 Industrial Instruments 2 Chapter 8 Discrete-State Process Control Dr. Bassam Kahhaleh

Princess Sumaya Uniersity

3442 - Industrial Instruments 2

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8$ Discrete-State Process Control Definitions %he discrete state o& o& the process at any moment is the set o& all input and output alues. 'n event in in the system is de&ined (y a particular state o& the system) i.e. particular alues o& inputs and outputs. ' discrete-state process control is is a particular sequence of events throu"h throu"h *hich the process accomplishes some some o(+ectie



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8$ Discrete-State Process Control Definitions %he discrete state o& o& the process at any moment is the set o& all input and output alues. 'n event in in the system is de&ined (y a particular state o& the system) i.e. particular alues o& inputs and outputs. ' discrete-state process control is is a particular sequence of events throu"h throu"h *hich the process accomplishes some some o(+ectie



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8$ Discrete-State Process Control Exam ple Example ,rost-&ree re&ri"erator#&reeer Discrete-state I#P  Door open#closed  Cooler temp. hi"h#lo*  ,reeer temp. hi"h#lo*  Po*er s*itch on#o&&  ,rost detector on#o&&  ,rost eliminator timer out#not out



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8$ Discrete-State Process Control Exam ple Example ,rost-&ree re&ri"erator#&reeer Discrete-state #P  /i"ht on#o&&  Compressor on#o&&  %imer on#o&&  0eater on#o&&  Ba&&le open#closed



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8$ Discrete-State Process Control Discrete-State Variables  Continuous Control



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8$ Discrete-State Process Control Discrete-State Variables  Continuous Control 

Discrete Control



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8$ Discrete-State Process Control Discrete-State Variables  Continuous Control 

Discrete Control  Composite Discrete#Continuous Control



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8$ Discrete-State Process Control Process Specifications  Process (+ecties 

Process 0ard*are 

Input Deices  /imit S*itches  Comparators  Push Buttons



utput Deices  /i"hts  5otors  Solenoids



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8$ Discrete-State Process Control Event Sequence Description  7arratie Statements  ,lo*charts 

Binary-State  :#9

:#

9:

9 # 9#9



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8$ Discrete-State Process Control Event Sequence Description Flowchart Example



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8$ Discrete-State Process Control Event Sequence Description Flowchart Example



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8$ Discrete-State Process Control Event Sequence Description Binary-State Example 9. 2. 3. 4.

,ill the tan; to leel ' &rom ale '. ,ill the tan; to leel B &rom ale B. Start the timer) heat) and stir &or 1 minutes. pen output ale C until the empty s*itch en"a"es.



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8$ Discrete-State Process Control Event Sequence Description Binary-State Example I/P Variables O/P Variables   /' <'   /B
/! %U

   



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8$ Discrete-State Process Control Event Sequence Description Binary-State Example State$

/' /B /! %U <'


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8$ Discrete-State Process Control Relay Controllers & Laer Dia!ra"s  Control =elays >=elay Se?uencer@



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8$ Discrete-State Process Control Relay Controllers & Laer Dia!ra"s  /adder Dia"ram



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8$ Discrete-State Process Control Relay Controllers & Laer Dia!ra"s Ladder Diagram Example



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8$ Discrete-State Process Control Relay Controllers & Laer Dia!ra"s Ladder Diagram Example 9. Ahen the S%'=% (utton is pushed) the plat&orm is drien to the do*n position. 2. Ahen the S%P (utton is pushed) the plat&orm is halted at *hateer position it occupies at that time. 3. Ahen the UP (utton is pushed) the plat&orm) i& it is not in do*n*ard motion) is drien to the up position. 4. Ahen the DA7 (utton is pushed) the plat&orm) i& it is not in up*ard motion) is drien to the do*n position.



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Start

Stop



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8$ Discrete-State Process Control Relay Controllers & Laer Dia!ra"s Ladder Diagram Example S%'=%

S%P

Po*er



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 5otor S%P

Po*er



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UP  5otor

Do*n

 5otor S%P

Po*er



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CR

CR



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8$ Discrete-State Process Control #ar$ire Pro!ra""in!  =elay Se?uencers Pro!ra""able Lo!ic Controllers %PLCs  Processor 

Input 5odules  utput 5odules



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8$ Discrete-State Process Control Pro!ra""able Lo!ic Controllers %PLCs  Input 5odule



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8$ Discrete-State Process Control Pro!ra""able Lo!ic Controllers %PLCs  utput 5odule



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8$ Discrete-State Process Control Pro!ra""able Lo!ic Controllers %PLCs  /o"ic Pro"rammin" Usin" a 7C s*itch to turn o&& a li"ht *ith relay lo"ic and *ith P/C pro"rammin"$ a@ %he (utton turns the li"ht ,,. (@ Aith relay lo"ic the (utton turns the li"ht 7. c@ Aith a P/C pro"ram the (utton turns the li"ht 7



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8$ Discrete-State Process Control Pro!ra""able Lo!ic Controllers %PLCs  /o"ic Pro"rammin" 7 s*itches are considered I!"#I$E *hen they are read as open circuit) and !"#I$E *hen they are read as closed circuit. In the ladder dia"ram) 9 must (e !"#I$E *hile 3 must (e I!"#I$E to turn 8 7.

Chapter 08 Discrete State Process Control

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