This document summarizes a student project to control a two-directional traffic light using a PLC. It introduces the use of traffic lights to indicate when it is safe to drive or walk. It then discusses timers used in PLCs to provide time delays. Finally, it presents a ladder logic diagram to control the traffic lights in four stages, with one direction green at a time, repeating continuously while a push button is engaged.

1. 1
Controlling two dimension traffic light by
using PLC
Student Name: Muhammad Jawhar Anwar
Class: 4 Stage – Group:A1
Course Title: PLC Lab.
Department: Mechanical and Mechatronics Engineering
EXP NO: 5
College of Engineering
Salahaddin University-Erbil
Academic Year 2021-2022

2. 2
Introduction
AUTOMATIC TRAFFIC SIGNAL CONTROLPLC BASED:
A traffic light or traffic signal is a signaling device positioned at a
road intersection, pedestrian crossing, or other location in order to indicate
when it is safe to drive, ride, or walk using a n universal color code
A traffic light, traffic signal, or stop light is a signaling device positioned at a
road intersection, pedestrian crossing, or other location in order to indicate
when it is safe to drive, ride, or walk using a universal color code
However for the pedestrians, there have only two lights, a red light and a green
light that mean go and stop Respectively The traffic lights have given many
benefits to all road users. Besides reducing the number of accidents, it made the
traffic flow smoothly and possibly could save people time.
Traffic load is highly dependent on parameters such as time, day, season,
weather and unpredictable situations such as accidents, special events or
construction activities. If these parameters are not taken into account, the traffic
control system will create bottlenecks and delays. A traffic controlsystem that
solves these problems by continuously sensing and monitoring traffic conditions
and adjusting the timing of traffic lights according to the actual traffic load is
called an intelligent traffic control system. Traffic signals have strengths and
weaknesses that must be considered when deciding whether to install them.
Signal intersections can reduce delay for side road traffic and reduce the
occurrence of collisions by turning traffic and cross traffic. But they may also
cause delay for traffic on the main road, and often increase rear-end collisions by
up to 50%.

3. 3
TIMER:
Timers are an electronics devices used to to provide time delay at different
conditions and situations. Range of timer in logix pro varies from 0-255. In
accordancewith PLC there are three types of timers-
• ON delay timer
• OFF delay timer Pulse timer

4. 4
Ladder Diagram:
It is a graphical programming language, initially programmed with simple
contacts that simulate the opening and closing of relays. Ladder Logic
programming has been expanded to include functions such as Counters, Timers,
shift registers and math operations. Ladder logic is a method of drawing electrical
logic schematics. It is now a graphical language very popular for programming
Programmable Logic Controllers (PLCs). The name is based on the observation
that programs in this language resemble ladders, with two vertical "rails" and a
series of horizontal "rungs" between them. A program in ladder logic, also called
a ladder diagram.

5. 5
32767 sec/60 = 546.1167 min /60= = 9.1019 hr
While, for 11.6667 hr. for one day at least 3 timers required
Discussion
WORKING
The ‘PLC’ program is designed to associate traffic light system working in
parallel with the barrier cut, consists of four stages: Now press push button
switch and process goes on
At First stage, in programmed 3 POLEs in all RED’S are ON condition. All
GREEN’S are OFF condition in particular time, the timer is ON
The second stage, when the time is completed only POLE-1 GREEN is ON
condition at a time POLE-1 RED is OFF condition remaining POLE-2 and
POLE-3 RED’S are ON condition and GREEN’S are OFF condition in
particular time
The third stage, when the time is completed only POLE-2 GREEN is ON
condition at a time POLE-2 RED is OFF condition, remaining POLE-1 and
POLE-3 RED’S are ON condition and GREEN’S are OFF condition in
particular time.
The fourth stage, when the time is completed only POLE-3 GREEN is ON
condition at a time POLE-3 RED is OFF condition, remaining POLE-1 and
POLE-2 RED’S are ON condition and GREEN’S are OFF condition in
particular time.
This process (step-2and step-3 and step-4) conditions are continuously repeated.
When the push button is OFF the process will be STOP