SEQUENCE CONTROL (LOGIC CHART)

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SEQUEN CE CON TROL

( LOGI C CH ART)

PT. Yo ko g a wa Indo ne sia

Wisma Aldiron Dirgantara 2

nd

floor, suite 202-209

Jl. Jend. Gatot Subroto Kav.72 Jakarta 12780

Phone : 021-799 0102, Fax : 021-799 0070

SEQUEN CE CON TROL

( LOGI C CH ART)

By I GS – Rev 0.0807

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PT YOKOGAWA INDONESIA Training Center –Technical Support Group

TYPES OF SEQUENCE CONTROL BLOCKS

The following funct ion blocks are cat agorized as sequence

cont rol blocks:

1.

Sequence Table Blocks

2.

Logic Chart Block

3.

Sequent ial Funct ion Chart Block

4.

Swit ch I nst rum ent Blocks

5.

Sequence Elem ent Blocks

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TYPES OF SEQUENCE CONTROL BLOCKS ( 2/ 2)

LOGIC CHART BLOCK

This funct ion blocks perform s int erlock sequence cont rol pr ogram m ed in t he expr ession

of a logic chart diagram .

The following is t he funct ion block cat agorized as logic chart :

•

Logic Chart LC64

Num ber of input elem ent s: 32

Num ber of out put elem ent s: 32

Num ber of logic elem ent s: 64

I n a logic chart block, t he condit ions and operat ions are list ed and t he com binat ion of

condit ions w it h t he logic operat iors corresponding t o t he logic requirem ent m ay

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LOGI C CHART BLOCK ( LC64)

Logic chart funct ion block can handle up t o 32 input elem ent s, 32 out put elem ent s

and 64 logic elem ent s/ operat ors ( how ever, logic elem ent such as W.O, SR/ Flip- Flop,

or CMP is count ed as 2 logic elem ent oper at ion.

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LOGI C CHART BLOCK ( LC64)

Ge n e r a l Ou t look Of A Logic Ch a r t

•

Pr oce ssin g Tim in g

There ara t wo processing t im ings:

St a r t / Ex e cu t ion Tim in g

I t refers t o t he t im ing at w hich cont rol algorit hm s

are execut ed when receiving input signals. Select

one of t he following t ype

-

Periodic Execut ion

( T)

-

One- Shot Processing

( O)

-

St art up at I nit ial Cold St art / Rest art of FCS

( I )

-

Rest rict ed I nit ial Execut ion

( B)

Out put Tim in g

I t indicat es t he condit ion or behaviour of act ion

signals in conj unct ion w it h t he condit ion signal

st at us change. For logic chart , t he out put t im ing is

fixed t o

-

Out put Each Tim e Condit ions Are Sat isfied

( E)

•

Sca n Pe r iod

Sequence t able wit h per iodic execut ion t ype ( T) is

act ivat ed at defined scan period.

There are t hree t ypes of scan periods:

--

Basic Scan ( 1 second

–

fixed)

--

Medium Speed Scan ( 200 & 500 m illiseconds)

50, 100, 250 m illiseconds are also applicable.

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LOGI C CHART BLOCK ( LC64)

St art / Execut ion Tim ing

Periodic Execut ion ( T)

The periodic execut ion m eans t hat t he sequence cont rol block is repeat edly execut ed in a

preset cycle.

One

-

Shot Execut ion ( O)

When execut ion t im ing of a funct ion block is defined as one- shot t ype, t he block is execut ed

only w hen it is invoked by ot her funct ion block. A one- shot funct ion block can invoke anot her

one- shot funct ion block. How ever, such succession is lim it ed t o seven blocks. I nvocat ion can

only be init iat ed from t he sam e FCS.

I nvoking funct ion

block

One- shot t ype

funct ion block

I nvocat ion signal

Sequence process execut ion

ACT.OFF

ACT.ON

I dle

Execut ing

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LOGI C CHART BLOCK ( LC64)

St art / Execut ion Tim ing

I nit ial Execut ion/ Rest art Execut ion ( I )

I n t his execut ion t ype, t he sequence block execut es it s process w hen t he FCS perform s a cold

st art or a rest art .

Rest rict ed I nit ial Execut ion ( B)

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LOGI C CHART BLOCK ( LC64)

Out put Tim ing

Out put Each Tim e Condit ions Are Sat isfied ( E)

The sequence t able blocks out put it s operat ion/ act ion signal every scan period as long as t he

j udged condit ions are sat isfied.

Condit ion/ input

change

Act ion/ out put

change

Act ion change/ int erupt ion is

n ot

possible as long as t he

condit ion rem ains sat isfied.

False

True

False

True

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LOGI C CHART BLOCK ( LC64)

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LOGI C CHART BLOCK ( LC64)

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LOGI C CHART BLOCK ( LC64)

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LOGI C CHART BLOCK ( LC64)

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LOGI C CHART BLOCK ( LC64)

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Sw it ch I nst rum ent Block

Valve Monit oring Block ( VLVM)

Tim er Block ( TM)

Regulat ory Cont rol Blocks

Soft w are Count er Block ( CTS)

Calculat ion Blocks

Pulse Train I nput Count er Block ( CTP)

Faceplat e Blocks

Code I nput Block ( CI )

SFC Blocks

Code Out put Block ( CO)

Unit I nst rum ent Blocks

Relat ional Expression Block ( RL)

Sequence Table Blocks

Resource Scheduler Block ( RS)

Logic Chart Block

Condit ion Signal Descript ion ( Funct ion Blocks and I / O Dat a)

Funct ion blocks t hat can be processed in a sequence t able are show n below .

I / O dat a t hat can be processed in a sequence t able are show n below .

Processing I / O ( Digit al I nput / Out put )

Soft w are I / O ( I nt ernal Sw it ch, Annunciat or, Global Sw it ch)

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LOGI C CHART BLOCK ( LC64)

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LOGI C CHART BLOCK ( LC64)

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LOGI C CHART BLOCK ( LC64)

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Condit ion Signal Descr ipt ion ( Code I nput Block [ CI ] )

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LOGI C CHART BLOCK ( LC64)

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LOGI C CHART BLOCK ( LC64)

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LOGI C CHART BLOCK ( LC64)

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LOGI C CHART BLOCK ( LC64)

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LOGI C CHART BLOCK ( LC64)

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LOGI C CHART BLOCK ( LC64)

Condit ion Signal Descr ipt ion ( Calculat ion Block) 4/ 4

The t able list s t he calculat ion

blocks t hat can be referenced

in t he condit ion signal as one-

shot oper at ion.

The form at is:

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LOGI C CHART BLOCK ( LC64)

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LOGI C CHART BLOCK ( LC64)

Condit ion Signal Descr ipt ion ( Sequent ial Funct ion Chart Block)

The follow ing list s t he dat a

it em s of SFC block t hat can

describe dat a values in

condit ion specificat ions and

t heir set t ing ranges:

STEPN O: 1 t o 9 9

SW CR[ 5 ] : 0 t o 1 5

SW ST[ 5 ] : 0 ,1

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LOGI C CHART BLOCK ( LC64)

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Condit ion Signal Descr ipt ion ( Processing I / O Block)

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LOGI C CHART BLOCK ( LC64)

Condit ion Signal Descr ipt ion ( Soft ware / Com m on Swit ch)

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LABORATORY WORKS

Creat e a logic sequence from t his cont rol narrat ive:

Ca se

1

I n a cascade loop, if t he process variable of t he m ast er cont roller is

High- High

alarm t hen t he slave cont roller m ode w ill have t o sw it ch t o

MANUAL

m ode and t he m ast er cont roller m ode w ill have t o sw it ch t o

AUTO

m ode.

The cont rol m ode of t he slave cont roller cannot be changed unt il t he

alarm vanishes ( process variable is in norm al st at e) .

TI C 1 0 1

PI C 1 0 1 TT- 1 0 1

PT- 1 0 1 _{PV - 1 0 1}

Mast er Cont roller

Slave Cont roller Condit ion :

Alarm High- High

Act ion :

Mode changes t o Aut o

Condit ion :

Mast er cont r oller alarm high- high

Act ion :

Mode changes t o Manual

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LABORATORY WORKS

Creat e a logic sequence from t his cont rol narrat ive:

Ca se

2

I n a cascade loop, if t he process variable of t he m ast er cont roller is

High- High

alarm t hen t he slave cont roller m ode w ill have t o sw it ch t o

MANUAL

m ode w it h it s out put drops t o MV 25% and t he m ast er

cont roller m ode w ill have t o sw it ch t o

AUTO

m ode.

How ever, t he operat or is allow ed t o change t he m ode of slave cont roller

t o

CASCADE

or

AUTO

m ode even t hough t he process variable is st ill in

High- High

alarm st at e.

TI C 1 0 1

PI C 1 0 1 TT- 1 0 1

PT- 1 0 1 PV - 1 0 1

Mast er Cont roller

Slave Cont roller Condit ion :

Alarm High- High

Act ion :

Mode changes t o Aut o

Condit ion :

Mast er cont r oller alarm high- high

Act ion :

Mode changes t o Manual

Out put ( MV) dr ops t o 25%

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I f PSW = 0, MV is norm al

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PT. Yo ko g a wa Indo ne sia

Wisma Aldiron Dirgantara 2

nd

floor, suite 202-209

Jl. Jend. Gatot Subroto Kav.72 Jakarta 12780