Delta DVP-ES2 - Manual (Page 29)

1 . P L C C o n c e p ts
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Example 16 - Traffic light control (Step Ladder Logic)
Traffic light control
Red light Yellow light Green light
Green light
blinking
Vertical light Y0 Y1 Y2 Y2
Horizontal light Y20 Y21 Y22 Y22
Light Time 35 Sec 5 Sec 25 Sec 5 Sec
Vertical
Light
Horizontal
Light
Timing Diagram:
5 Sec
Y0
Y1
Y2
Y20
Y21
Y22
Vertical
Light
Red
Yellow
Green
Horizontal
Light
Red
Yellow
Green
5 Sec
25 Sec
5 Sec 5 Sec
25 Sec
SFC Figure:
S0
S20
S21
S22
S0
M1002
T0
T1
T13
Y0
S23
T2
TMR T0 K350
Y2
TMR T1 K250
Y2
TMR T2 K50
M1013
Y1
S30
S31
S32
T10
T11
S33
T12
Y22
TMR T10 K250
Y21
TMR T12 K50
Y22
TMR T11 K50
M1013
Y20
TMR T13 K350