Module Title Programmable Logic Controllers

1
MODULE TITLE: PROGRAMMABLE LOGIC CONTROLLERS
TOPIC TITLES: PROGRAMMABLE FACILITIES AND
ADDITIONAL FACILITIES
TUTOR MARKED ASSIGNMENT 3

2
Question 1
Design of the ladder logic
For the momentary pushbutton (Normally open)
push button1 → I 0.0
For the first timer with an off delay of 30 seconds,
Timer 1→ T1.0
The first output is designated by,
Output 1 →O0.0
For the second timer,
Timer 2→ T 2.0
The second output,
Output 2 →O0.1
The second push button (Normally connected)
Push button→ I0.1
The designed ladder diagram is presented below,

3
Question 2
Redesign of the Pelican crossing ladder diagram,
The outputs are designated by L1 , L2 ,❑❑ ❑❑❑❑ L 3 , L 4 , L5 , L6 while the inputs are
represented by S1∧S2
State transition
LABEL No L1 L2 L3 L4 L5 L6 Transmission
line
Green E/W 1 1 0 0 0 0 1 S1
Yellow E/W 2 1 0 0 0 1 0 Delay
Green N/S 3 0 0 1 1 0 0 Delay
Yellow N/S 4 0 1 1 1 0 0 S2

4